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Abort Switch

The Abort Switch is used to momentarily interrupt the release circuit signal when the control unit is in the alarm condition .Components mounted on stainless steel switch plate.

Above-ground storage tank

Storage tank that is not buried. Compare Underground storage tank. Unburied tanks are more prone to physical damage, and leaks are released to the air or ground, rather than the soil surrounding a buried tank.


portion of dry-pipe system that bleeds air or shunts air pressure below the clapper valve when sprinkler pipe pressure drop is sensed, thus speeding operation of the valve to fill the system with water.


flammable fuel (often liquid) used by some arsonists to increase size or intensity of fire. May also be accidentally introduced when HAZMAT becomes involved in fire.

Acceptable Entry Conditions

conditions that must exist in a space to allow entry and ensure that employees can safely enter into and work within the space.

Accommodation Stairway

Accommodation Stairway

Active fire protection -

manual and automatic detection and suppression of fires, such as fire sprinkler systems and (fire alarm) systems.

Active Multiplex System

multiplexing system in which signaling devices such as transponders are employed to transmit status signals of each initiating device or initiating device circuit within a prescribed time interval so that the lack of receipt of such a signal can be interpreted as a trouble signal

Actuation Hoses

Actuation Hoses


A liquid such as foam concentrates, emulsifiers, and hazardous vapor suppression liquids and foaming agents intended to be injected into the water stream at or above the water pressure.

Addressable Device

fire alarm system component with discrete identification that can have its status individually identified or is used to individually control other functions.

Addressable Control Device

signaling system output device which, when operating with a compatible control unit, is used to control individual, preselected fire alarm components such as audible or visual alarm signaling appliances, fan circuits or door release circuits.

Addressable Fire Alarm System

An addressable fire alarm system is made up of a series of fire detectors and devices that are connected back to a central control panel. With addressable systems, each device has an address or location, enabling the exact detector that was triggered to be quickly identified

Addressable Zone Module

An addressable device that acts as a transponder for one or more conventional alarm devices. Activation of any conventional device connected to the zone module results in the addressable device’s address being reported

Adverse Condition

Any condition occurring in a communications or transmission channel that interferes with the proper transmission or interpretation, or both, of status change signals at the supervising station.

Aerial fire apparatus

A fire truck equipped with an aerial ladder that brings firefighters, water or equipment to higher levels, and also provides a means of escape from upper stories

Aircraft rescue and firefighting (ARFF)

a special category of firefighting that involves the response, hazard mitigation, evacuation and possible rescue of passengers and crew of an aircraft involved in an airport ground emergency.

Air monitoring meter

electronic device for measuring the presence of one or more chemicals in air, such as oxygen, carbon monoxide, hydrogen sulfide or volatile organic compounds; may have preset danger threshold alarms.

Air Sampling-type Detector

A smoke detector that uses a suction fan and tubing to sample remote areas for products of combustion.

Aerial ladde

A power-operated ladder permanently mounted on a piece of apparatus.

Air Receiver

A chamber, compatible with an air compressor, that can store air under pressure that is higher in pressure than that in the dry pipe or preaction system piping.

Air Reservoir

A chamber that can store air at the same pressure that is in the wet pipe system piping.


The route by which the air enters the structure to the fire and the subsequent path the heated smoke takes to exit the structure. Also referred to as "Flow Path"

Air Vessel

air vessel is a closed chamber containing compressed air at the top portion and liquid at the bottom portion of the chamber. At the base there is a opening through which the liquid may flow into the vessel or flow out of the vessel.FUNCTIONS:1) Obtain continuous supply of liquid at uniform rate.2) To run the pump at high speed. An air vessel simply a containing device for compressed air. the function of air vessel is to accumulate excess quantity of water flowing in


The state of a system that generates a visible or audible warning signal when abnormal conditions exist in a machine, system, or environment . See Alarm Condition and Alarm Signal.

Alarm Circuit

An electrical path that produces or transmits alarm information.

Alarm receiving centre (ARC)

Continuously manned premises, remote from those in which a fire alarm system is fitted, where the information concerning the state of the fire alarm system is displayed and / or recorded, so that the fire and rescue service can be summoned

Alarm Service

The service required following the receipt of an alarm signal.

Alarm Verification Feature

A feature of automatic fire detection and alarm systems to reduce unwanted alarms wherein smoke detectors report alarm conditions for a minimum period of time, or confirm alarm conditions within a given time period after being reset, in order to be accepted as a valid alarm initiation signal.

Alert Tone

An attention-getting signal to alert occupants of the pending transmission of a voice message.

All hands.

A working fire at which all units of the first alarm assignment are engaged in firefighting.

Alternative escape route

Escape routes sufficiently separated by either direction and space, or by fire-resisting construction to ensure that one is still available irrespective of the location of a fire

Alternate Sensitivity

The ability of an intelligent addressable device to change alarm threshold levels. Typically used to automatically change detector sensitivity levels for day and night operation.


An advantageous location, usually a barrier to fire spread, from which to start constructing a fireline.

ANSI (American National Standards Institute)

organization that oversees the development of consensus standards for products, services, processes, systems and personnel in the United States.

Antifreeze Sprinkler System

wet pipe fire sprinkler system that holds a small amount of antifreeze in the pipes to keep the water from freezing. When the sprinkler system activates, some of the antifreeze is discharged along with the water.


A unit containing one or more indicator lamps, alphanumeric displays, or other equivalent means in

Apartment Building

A building or portion thereof containing three or more dwelling units with independent cooking and bathroom facilities.

Approved document B (ADB)

Guidance issued by Government in support of the fire safety aspects of building regulations which each indication provides status information about a circuit, condition, or location.

As Built Drawing

Revised set of drawing submitted by a contractor upon completion of a project or a particular job. They reflect all changes made in the specifications and working drawings during the construction process, and show the exact dimensions, geometry, and location of all elements of the work completed under the contract.


The American Standards of Testing Materials


American Society of Mechanical Engineers

Area of higher fire risk

Room or other area which, because of its function and / or contents, presents a greater risk of fire occurring and developing than elsewhere

Area of operation

The maximum area over which it is assumed that the sprinkler will operate and is some time called the "assumed maximum area of operation"


An amplifier is an electronic device that increases the voltage, current, or power of a signal. Amplifiers are used in wireless communications and broadcasting, and in audio equipment of all kinds. They can be categorized as either weak-signal amplifiers or power amplifiers.

Analog Initiating Device (Sensor

An initiating device (sensor) that transmits continuous level of the value being sensed to a control panel. The control panel makes the alarm decision when the value reaches the minimum alarm level.

Antifreeze Sprinkler System

Awet pipe system using automatic sprinklers that contains a liquid solution to prevent freezing of the system, intended to discharge the solution upon sprinkler operation, followed immediately by water from a water supply.


A horizontal pipe that extends from the branch line to a single sprinkler or a sprinkler above and below a ceiling.

Aspirate (Foam)

To draw in gases (or other substances); nozzle aspirating systems draw air into the nozzle to mix with the foam solution.

Attack hose

A use classification of a fire fighting hose connected to output of a pump or other pressure source (e.g., gravity). Firehose used to apply water or other fire fighting agent directly to a fire or burning substance. Typically of 2 1/2 inches (65 mm) diameter or less.

Attack Line

A line of hose, preconnected to the pump of a fire apparatus and ready for immediate use in attacking a fire. Contrasted to supply lines connecting a water supply with a pump or to feeder lines extended from a pump to various points around the perimeter of a fire.

Attack Time

The starting date, hour, and minute of the first suppression work on a fire.

Attack Unit Response

The response of one attack unit to a fire or other emergency with no regard for the number of return trips to that same fire or emergency

Attic ladder

narrow, collapsible ladder used to access an attic space via a scuttle hole, which are often found in closets and other narrow passages. Also known as a closet ladder.

Automatic Alarm

An alarm input activated by a device such as a smoke detector, heat detector, flame detector, or water-flow switch, without any manual operation.

Automatic Evacuation Timer

Automatic Evacuation Timer

Authority having jurisdiction

A term used in many standards and codes to refer to the organization, office, or individual responsible for approving equipment, procedures and construction in a town, county, city or state.

Auto extended fire

structure fire that has gone out a window or other opening on one floor and ignited materials above, on another floor or other space (attic, cockloft).

Automatic Fire Detector

A device designed to detect the presence of a fire signature and to initiate action. For the purpose of this Code, automatic fire detectors are classified as follows: Automatic Fire Extinguishing or Suppression System Operation Detector, Fire–Gas Detector, Heat Detector, Other Fire Detectors, Radiant Energy– Sensing Fire Detector, Smoke Detector.

Auto Ignition Temperature (AIT)

The temperature at which a gas/air mixture will self ignite. As the temperature increases the Lower Flammable Limit (LFL) will approach zero. AKA Spontaneous Ignition Temperature (SIT).

Automatic Transfer Switch

Self-acting equipment for transferring one or more load conductor connections from one power source to another.

Auxiliary Pump

A secondary pump on an engine in addition to the main pump. Usually of small capacity.

Available flow

total amount of water that can be put on a fire, depending upon water supply, pump size, hoses, and distance to the fire. Incident Commander must assess available flow to determine whether additional apparatus or streams are required. See Fire flow requirement.


An underground formation that contains sufficient saturated permeable material to yield significant quantities of water.

Aquifer Performance Analysis

A test designed to determine the amount of underground water available in a given field and proper well spacing to avoid interference in that field. Basically, test results provide information concerning transmissibility and storage coefficient (available volume of water) of the aquifer.

BA Set

Breathing Apparatus Set consisting of a face-mask and compressed air cylinder


The explosion of heated gases that occurs when oxygen is introduced into a space within a burning building where the oxygen has been depleted by the fire.


A fire set along the inner edge of a fireline to consume the fuel in the path of a wildfire or change the direction of force of the fire's convection column.

Backing Fire

Fire spreading, or ignited to spread, into (against) the wind or downslope. A fire spreading on level ground in the absence of wind is a backing fire

Backflow preventer

Automatic valve used in hose accessories to ensure water flows only in one direction. Used in permanent fire department connections (FDC) to sprinklers and dry standpipes, as well as portable devices used in firefighting

Backpack Pump

A portable sprayer with hand-pump, fed from a liquid filled container fitted with straps, used mainly in fire and pest control.

Backstretch in

Doing a fire to hydrant procedure.


An instrument used for the measurement of atmospheric pressure


British Approvals for Fire Equipment

Baffle Plate

An object placed in or near an appliance to change the direction of or to retard the flow of air, air-fuel mixtures, or flue gases.


British Fire Protection Systems Association


Any obstruction to the spread of fire. Typically an area or strip devoid of combustible fuel


A natural or artificial barrier that effectively screens a magazine, building, railway, or highway from the effects of an explosion in a magazine or building containing explosives.

Bank down

What the smoke does as it fills a room, banks down to the floor, creating several layers of heat and smoke at different temperatures—the coolest at the bottom.


The act of completing a quick egress away from a fire room, on a ladder. This is done if flashover conditions are imminent

Basic First Aid Kit

Equipment or devices for managing infection exposure, airways, spinal immobilization, fracture immobilization, shock, and bleeding control.

Basic life support

Noninvasive emergency life-saving care to treat airway obstruction, cardiac arrest or respiratory arrest.

Battalion chief

The lowest ranking chief officer, also called district chief. These chiefs are often in charge of running calls and supervising multiple stations or districts within a city. A battalion chief is usually the officer in charge of a single-alarm working fire.

Bin Box Storage

Storage in five-sided wood, metal, or cardboard boxes with open face on the aisles. Boxes are self-supporting or supported by a structure so designed that little or no horizontal or vertical space exists around boxes.


An access control device that identifies an individual using a unique characteristic of the body.

Blind flanges

This is a flange without a centre bore, used to shut off a piping system or vessel opening.


Sudden increase in fireline intensity or rate of spread of a fire sufficient to preclude direct control or to upset existing suppression plans. Often accompanied by violent convection and may have other characteristics of a fire storm.

Boiling liquid expanding vapor explosion (BLEVE

Explosion of a pressure tank containing an overheated material when the vapor expansion rate exceeds the pressure relief capacity (e.g., steam boiler or LPG tank). If the contents are flammable, the rapidly released vapor may react in a secondary fuel-air explosion, usually violent and spectacular.


an event in the burning of certain oils in an open-top tank when, after a long period of quiescent burning, there is a sudden increase in fire intensity associated with expulsion of burning oil from the tank.

Bonding Conductor

A conductor connecting the non-current-carrying parts of the equipment or enclosures to the service equipment or system-grounding conductor.


Australian term for fixed wing fire-fighting aircraft. Also called "water bomber" or "borate bomber".

Branch Circuit

The circuit conductors between the final overcurrent device protecting the circuit and the outlet

Breathing apparatus

Self-contained apparatus designed to allow a fire-fighter to breathe in an otherwise non-respirable atmosphere for a limited period / is a device worn by rescue workers, firefighters, and others to provide breathable air in an immediately dangerous to life or health atmosphere (IDLH)

Breathing Air System

a complete assembly of equipment to compress, store, and deliver breathing air for the filling of respirator breathing air cylinders.

Break-glass Station

A manual alarm pull station with a visible glass rod that is broken when the station is operated. The rod is designed to serve as a psychological barrier against false alarms.

Buffer Zone

The creation of a ~buffer-zone~ implies the use of 3D defensive actions to reduce potential for an ignition of fire gases in the immediate area of a structure occupied by firefighters. This may create a temporary and more local zone of safety for firefighters, although offering far less protection than a safe-zone

Building Control Body

A term used to include both Local Authority Building Control and Approved Inspectors


A bund, in simple terms, is a containment around an area where hazardous liquids are handled, processed or stored. The type of bund most often seen consists of four walls and a base surrounding tank. If the tank leaks, the leak will be contained by the bund.

Bunker coat, bunker pants

The protective coat and trousers worn by a firefighter for interior structural firefighting. Also called turnout coat and turnout pants.


a fire in scrub or a forest, especially one that spreads rapidly

Butterfly Valve

A butterfly valve is a valve which can be used for isolating or regulating flow. The closing mechanism takes the form of a disk. They are generally used for handling large flows of gases or liquids, including slurries, but should not be used for throttling for extended periods of time. Because of compact design butterfly valve are more popular in industry.


The second ranking officer, between the lieutenant and battalion chief. Captains are often in charge of a company or fire station.

Clamps & Supports

Clamps & Supports

Carbon monoxide.

A toxic gas, odorless and colorless, that produced when substances are incompletely burned

Carbon dioxide (CO2) flooding system

A fixed installation designed to displace the oxygen in the protected space and thus extinguish the fire, usually used to fight fires in engine rooms, boiler rooms, pump rooms and holds. The system normally consists of a series of large CO2 cylinders.

Ceiling Height

The distance between the floor and the underside of the ceiling above (or roof deck) within the area

Ceiling Pocket

An architectural ceiling feature that consists of a bounded area of ceiling located at a higher elevation than the attached lower ceiling

Central Alarm Control Facility (CACF)

The main command and control center for fire alarm and other monitoring functions (e.g. security, air handling), or the room from which an emergency situation is managed.


Contractors Health & Safety Assessment Scheme


A path for voice or signal transmission that uses modulation of light or alternating current within a frequency band.

Circulation relief valve

A small relief valve that opens up and provides enough water flow into and out of the pump to prevent the pump from overheating when it is operating at churn against a closed system.


Either a means of providing power or a connection path between locations

Cellar fire

Cellar fires are difficult to attack directly because firefighters have to pass through the hot gasses and smoke accumulated on the cellar~s ceiling to gain access to the cellar space. Cellars typically do not have good emergency egress points, adding to the danger.

Cellar pipe

Cellar Nozzle. A distributing type nozzle that is inserted through an opening in the floor and into the space below, typically a basement or cellar. The nozzle directs a broken stream horizontally, either extinguishing or controlling the fire enough to allow a direct attack to be safely made. Can also be used on top of other containers.

Central Monitoring Station (CMS)

A location that maintains a vigilant watch over a number of remote systems and takes appropriate action in response to system activity

City Tie Module (CTM):

A system component that provides a connection to either the local fire department or a central monitoring station. Also known as Fire Department Relay (FDR).

Class A

fires consist of ordinary combustibles such as wood, paper, fabric, plastic, and most kinds of trash. These are fires whose fuel is flammable or combustible liquid or gas

Class A Foam

Foam intended for use on Class A or woody fuels; made from hydrocarbon-based surfactant, therefore lacking the strong filming properties of Class B foam, but possessing excellent wetting properties.

Class B

Fire extinguishers with a Class B rating are effective against flammable liquid fires. These can be fires where cooking liquids, oil, gasoline, kerosene, or paint have become ignited. Two commonly used chemicals are effective in fighting these types of fires.

Class B Foam

Foam designed for use on Class B or flammable liquid fires; made from fluorocarbon-based surfactants, therefore capable of strong filming action, but incapable of efficient wetting of Class A fuels.

Class C

These are fires whose fuel is flammable or combustible liquid or gas

Class D

A Class D fire is characterized by the presence of burning metals. Only certain metals are flammable and examples of combustible metals include sodium, potassium, uranium, lithium, plutonium and calcium, with the most common Class D fires involve magnesium and titanium.

Class F

These are fires involving cooking fats and oils. The high temperature of these types of fats and oil when on fire far exceeds that of other flammable liquids which means that normal fire extinguishers should not be used.

Class I Areas (Air Quality)

Geographic areas designed by the Clean Air Act subject to the most stringent restrictions on allowable increment of air quality deterioration. Class I areas include Forest Service wildernesses and nation memorial parks over 5,000 acres, National Parks exceeding 6,000 acres, international parks, as well as other designated lands


Capable of reacting with oxygen and burning if ignited.

Combination Detector

A device that either responds to more than one of the fire phenomena or employsmore than one operating principle to sense one of these phenomena. Typical examples are a combination of a heat detector with a smoke detector or a combination rate of- rise and fixed-temperature heat detector. This device has listings for each sensing method employed.

Combustion Efficiency

The relative amount of time a fire burns in the flaming phase of combustion, as compared to smoldering combustion. A ratio of the amount of fuel that is consumed in flaming combustion compared to the amount of fuel consumed during the smoldering phase, in which more of the fuel material is emitted as smoke particles because it is not turned into carbon dioxide and water.

Commission on Fire Accreditation International

A nonprofit organization that accredits fire and emergency service agencies.

Common balcony

A walkway, open to the air on one or more sides, forming part of the escape route from more than one flat or maisonette

Communications Circuit.

Any signaling path of an emergency communications system that carries voice, audio, data or other signals.

Compartment Fire:

An ""Isolated"" fire, or a fire which is ""boxed in"" or ""closed off"" from the rest of the structure. An example of this is a fire in a room where all the windows and doors are closed preventing the fire from spreading to other rooms./ A building or part of a building, comprising one or more rooms, spaces or storeys, constructed to prevent the spread of fire to or from another part of the same building, or an adjoining building

Company officer

The captain or lieutenant, or occasionally sergeant, who is in command of a team of firefighters, both on scene and at the station.

Competent person

A person with enough training and experience or knowledge and other qualities to enable them properly to assist in undertaking the preventive and protective measures.

Complex loop

A piping system that is sometimes called a "grid" and is characterized by one or more of the following:  more than one inflow point, more than one outflow point, and/ or more than two paths between inflow and outflow points.

Compressed Air Foam Systems (CAFS)

A generic term used to describe foam systems consisting of an air compressor (or air source), a water pump, and foam solution.

Computed Gross Weight

Term used in calculating from performance charts the permissible helicopter payload at which a helicopter is capable of hovering in ground effect or hovering out of ground effect, based on pressure altitude and air temperature.


Heat transfer within an item or from one to another by direct contact.




A fire is contained when it is surrounded on all sides by some kind of boundary but is still burning and has the potential to jump a boundary line.

Contact Device

A sensor or component that opens/closes a switch or relay as its system interface.

Construction drawings

Construction drawings are sometimes referred to as working drawings. They are used by all involved in a project to work on the actual building of the design. These drawings provide all the information, both graphic and written, about the project. ... Standard drawing symbols are used to cross reference information.

Control Area

A designated area, either indoors or outdoors, within which hazardous materials are allowed to be stored, used, handled, or dispensed in quantities not exceeding the maximum allowable quantity (MAQ).

Control Module

Control Module

Control Panel

The central unit of an alarm system which monitors the detection and input devices; then responds by activating signaling and other control devices in a prescribed manor.

Control Unit

A system component that provides the operational relationship between system inputs and system outputs and acts as the interface between the system and operator.


The electric control panel used to switch pump on and off and to control its operation.


Heat transfer by circulation within a gas or liquid.

Conventional Sprinkler

A sprinkler that has components similar to a standard-spray sprinkler and has a spherical water distribution directed towards the ground over a definite protection area. These sprinklers shall discharge from 40 or more percent of the total water flow initially in an upward direction.

Cooperative Fire Protection (CFP)

A staff unit within the branch of State and Private Forestry or Aviation and Fire Management in the National Forest System, USDA Forest Service, that coordinates cooperative fire activities.

Combined System

A standpipe system having piping that supplies both hose connections and automatic sprinklers.


The relationship between input functions (alarm, supervisory, monitor, etc.) and output functions (signals, relays, etc.).

Corrosion-Resistant Material

Materials such as brass, copper, monel, stainless steel, or other equivalent corrosion-resistant materials.

Cross lay

Arrangement of hose on a pumper such that it can be quickly unloaded from either side of the apparatus; often pre-connected to a pump outlet and equipped with a suitable nozzle. Also known as Mattydale Lay.


A fire that advances from top to top of trees or shrubs, more or less independently of the surface fire.

Crown Scorch

Browning of needles or leaves in the crown of a tree or shrub caused by heating to lethal temperature during a fire. Crown scorch may not be apparent for several weeks after the fire.

Crown Out

A fire that rises from ground into the tree crowns and advances from tree top to tree top. To intermittently ignite tree crowns as a surface fire advances.

Cross Zone

An alarm detection and processing method using two initiating device circuit such that both circuits must be activated before an output is generated. Typically used in automatic suppression system applications

Counting Zone

An alarm circuit detection and processing method that tallies the number of detection devices activated on a circuit, and upon reaching a specified number, activates its output, generating an alarm. Typically used in automatic suppression system applications


Technique used to establish the pressure lost to friction in a piping system.

Data Gathering Panel (DGP)

An addressable system interface that converts input signals to the format required by the addressable system and can convert commands from the addressable system controller into output contacts and signals.

DC-Blocking Capacitor

An electronic component wired in series with a device that allows the passage of an AC signal while blocking the DC supervisory current.

Dangerous Substances

A substance which because of its physico-chemical or chemical properties and the way it is used or is present at the workplace created a risk A substance subject to the Dangerous Substances and Explosive Atmosphere Regulations 2002 (DSEAR)

Deluge Sprinkler System

A sprinkler system employing open sprinklers or nozzles that are attached to a piping system that is connected to a water supply through a valve that is opened by the operation of a detection system installed in the same areas as the sprinklers or the nozzles. When this valve opens, water flows into the piping system and discharges from all sprinklers or nozzles attached thereto.

Deluge Valve

Deluge Valve


Fire detectors are designed to respond at an early stage to one more of the four major characteristics of combustion, heat, smoke, flame or gas. No single type of detector is suitable for all types of premises or fires. Detectors should be chosen for the best response to the effects of fires, as well the need to minimize unwanted false alarm activations.Detectors should be located where the early stages of fire will be detected, and ensure they are placed at regular intervals on the ceiling. The issue of unwanted fire alarm activations from environmental conditions must also be considered

Deep - Seated Fire

A fire burning far below the surface in duff, mulch, peat, or other combustibles as contrasted with a surface fire.

Design escape time

Calculated time from ignition until the time at which all the occupants of a specified part of a building should have been able to enter a place of safety

Design Discharge

The rate of water discharged by an automatic sprinkler expressed in gpm (mm/min).

Detection Pattern

he area of coverage a space detection device will detect its stimulus.

Diesel Engine

An internal combustion engine in which the fuel is ignited entirely by the heat resulting from the compression of the air supplied for combustion. The oil-diesel engine, which operates on fuel oil injected after compression is practically completed, is the type usually used as a fire pump driver.

Digital Alarm Communicator Receiver (DACR

A system component that accepts and displays signals from digital alarm communicator transmitters (DACTs) sent over the public switched telephone network.

Digital Alarm Communicator System (DACS)

A system that transmits signals from a digital alarm communicator transmitter (DACT) located on protected premises through the public switched telephone network to a digital alarm communicator receiver (DACR) at a monitoring location.

Digital Alarm Communicator Transmitter (DACT)

system component at the protected premises to which initiating devices or groups of devices are connected. The DACT seizes the connected telephone line, dials a preselected number to connect to a DACR, and transmits signals indicating a status change of the initiating device.

Disaster Drill

A hypothetical disaster drill is used to perfect your organization~s response to a particular emergency situation, such as extreme weather, bomb threat or lockdown. An effective disaster drill should be realistic, interactive and moderately stressful for the participants.

Discharge Hoses

Discharge Hoses

Desing Point: 

A point in the distribution pipe of a precalculated installation from where the pipework is sized by hydraulic calculation

Direct distance

The shortest distance from any point within the floor area to the nearest storey exit, or fire-resisting route, ignoring walls, partitions and fixings

Domestic premises

Premises occupied as a private dwelling, excluding those areas used in common by the occupants of more than one such dwelling

Down Comer Riser

An arrangement of firefighting within the building by means of down comer pipe connected to terrace tank through terrace pump, gate valve and non return valve and having mains not less than 100 mm internal diameter with landing valves on each floor / landing. It is also fitted with inlet connections at ground level for charging with water pumping from fire service appliances and air release valve at roof level to release trapped air inside.


Assembly consisting of a fixed part and one or more moveable parts, intended to allow or prevent access through permanent openings in separated elements

Door Holder

An electromagnetic device that retains a fire door in the open position and releases the door when directed by the fire alarm panel to control the spread of smoke.

Door Trip Switch

n electro-mechanical contact that is operated by any movement of a door.


The vertical difference between the pumping water level and the static water level.


Training during which an emergency is simulated and the trainees go through the steps of responding as if it were a real emergency

Dripproof Guarded Motor

A drip proof machine whose ventilating openings are guarded in accordance with the definition for drip proof motor.

Dripproof Motor

An open motor in which the ventilating openings are so constructed that successful operation is not interfered with when drops of liquid or solid particles strike or enter the enclosure at any angle from 0 to 15 degrees downward from the vertical

Drop-Out Ceiling.

A suspended ceiling system, which is installed below the sprinklers, with listed translucent or opaque panels that are heat sensitive and fall from their setting when exposed to heat.

Dry fire main

Water supply pipe installed in a building for fire-fighting purposes, fitted with inlet connection at the fire and rescue service access level, and with landing values at specified points, which is normally dry but is capable of being charged with water, usually by pumping from fire and rescue service appliances

Dry Riser

Dry Riser

Dry Pipe Sprinkler System

A sprinkler system employing automatic sprinklers that are attached to a piping system containing air or nitrogen under pressure, the release of which (as from the opening of a sprinkler) permits the water pressure to open a valve known as a dry pipe valve, and the water then flows into the piping system and out the opened sprinkler.

Duct Detector

fire alarms located in your HVAC ducts designed to detect smoke moving through your building.

Duel action manual release station

Duel action manual release station

Dust-Ignition-Proof Motor

A totally enclosed motor whose enclosure is designed and constructed in a manner that will exclude ignitable amounts of dust or amounts that might affect performance or rating and that will not permit arcs, sparks, or heat otherwise generated or liberated inside of the enclosure to cause ignition of exterior accumulations or atmospheric suspensions of a specific dust on or in the vicinity of the enclosure.

Duty holder

Person on whom legislation imposes a requirement to carry out a fire risk assessment


Any building that contains not more than one or two dwelling units intended to be used, rented, leased, let, or hired out to be occupied or that are occupied for habitation purposes.

Dwelling Unit

One or more rooms, arranged for the use of one or more individuals living together, as in a single housekeeping unit, that normally have cooking, living,sanitary, and sleeping facilities.


Electrical Contractors Association

Elastic Firestop Sealant

Elastic Firestop Sealant

Electrical Actuator

Electrical Actuator

Electrical Conductivity Heat Detector

A line-type or spot-type sensing element in which resistance varies as a function of temperature.

Electrical Fire

A fire in which the primary source of heat is electricity, resulting in combustion of adjacent insulation and other materials; may be hazardous to attempt to extinguish using water.

Electric Motor

A motor that is classified according to mechanical protection and methods of cooling.

Emergency Lighting System

A complete but discrete emergency lighting installation from standby power source to the emergency lighting lamp(s), for example, self contained emergency luminaire or a circuit from central battery generator connected through wiring to several escape luminaries.

Emergency medical technician (EMT)

A professional who provides prehospital care for people who are sick or injured, including transport, medication and the use of defibrillators. EMTs have differing levels of training:

EMT -Basic

. An emergency medical technician trained in basic emergency care skills, including oxygen therapy, bleeding control, cardiopulmonary resuscitation, automated external defibrillation, use of basic airway devices, and assisting patients with certain medication. Most EMTs fall into this category.

EMT – Intermediate

An emergency medical technician trained to do EMT-Basic care, plus IV therapy, interpretation of cardiac rhythms, defibrillation, and airway intubation.

EMT – Paramedic

An emergency medical technician with the most advanced training, capable of cardiac monitoring, administering drugs, inserting advanced airways, manual defibrillation, and other advanced assessment and treatment skills.

End Suction Pump

A single suction pump having its suction nozzle on the opposite side of the casing from the stuffing box and having the face of the suction nozzle perpendicular to the longitudinal axis of the shaft.

Enforcing authority

The fire and rescue authority or any other authority specified in Article 25 of the Regulatory Reform (Fire Safety) Order 2005

Engine company

A group of firefighters responsible for securing a water source, deploying hose lines, conducting search-and-rescue operations, and putting water on the fire

Escape bed lift

Escape lift able to carry persons in bed, together with any necessary attendants

Escape Lighting

The part of emergency lighting which is provided to ensure that the escape route is illuminated at all materials times, for example, at all times when persons are on the premises , or at times the main lighting is not available either for the whole building or the escape routes.

Escape Route

Route forming that part of the means of escape from any point in a building to a final exit.

Escape time

Time from ignition until the time at which all the occupants of a building, or a specified part of a building, are able to reach a place of safety


Removal of personnel from a dangerous area, in particular, a incident, burning building, or other emergency. Also refers to act of removing firefighters from a structure in danger of collapsing.

Evacuation level

Storey at which final exits suitable for the evacuation of persons are available

Evacuation Lift

Lift that can be used , during emergency , for self evacuation / A lift that may be used for the evacuation of disabled people in a fire.

Evacuation plan

Procedure for ensuring the safety of occupants and for limiting loss and damage to building structure, contents, the environment and business interruption

Evacuation signal

Audible and / or visible signal to indicate to occupants that they have to escape

External escape stair

Stair providing an escape route, external to the building

Expanding Firestop Foam

Expanding Firestop Foam

Expansion Below

Expansion Below

Explosion proof Motor

A totally enclosed motor whose enclosure is designed and constructed to withstand an explosion of a specified gas or vapor that could occur within it and to prevent the ignition of the specified gas or vapor surrounding the motor by sparks, flashes, or explosions of the specified gas or vapor that could occur within the motor casing.

Exposure Hazard

The risk of fire spreading from a building, structure or other property to an adjoining building or structure, or to another part of the same building or structure by radiated heat across the intervening space.

False alarm

A fire signal, usually from a fire warning system, resulting from a cause other than fire

Fault Tolerant External Control Circuit

Those control circuits entering and/or leaving the fire pump controller enclosure, which if broken, disconnected, or shorted will not prevent the controller from starting the fire pump and may cause the controller to start the pump under these conditions.

Female Coupling

Coupling made to receive a male coupling of the same thread, pitch and/or diameter.

Feed Main

That portion of a standpipe system that supplies water to one or more standpipes.


All circuit conductors between the service equipment, the source of a separately derived system, or other power supply and the final branch-circuit overcurrent device


Fire Industry Association

Field Observer (FOBS)

This ICS position is responsible for collecting and reporting situation information for an incident through personal observations and interviews and reports to the Situation Unit Leader.

Field Test

A job-related test of work capacity designed for those with moderately strenuous duties. This test consists a two-mile hike with a 25-pound pack. A time of 30 minutes, the passing score for this test, approximates an aerobic fitnes score of 40.

Final exit

An exit from a building where people can continue to disperse in safety and where they are no longer at danger from fire and / or smoke

Fingers of a Fire

The long narrow extensions of a fire projecting from the main body.

fire alarm system

A Fire Alarm System has a number of devices working together to detect and warn people through visual and audio appliances when smoke, fire, carbon monoxide or other emergencies are present. ... Alarms can be either motorized bells or wall mountable sounders or horns.

Fire Alarm Control Panel (FACP)

A Fire Alarm Control Panel (FACP), or Fire Alarm Control Unit (FACU), is the controlling component of a Fire Alarm System.

Fire Area

An area of a building separated from the remainder of the building by construction having a fire resistance of at least 1 hour and having all communicating openings properly protected by an assembly having a fire resistance rating of at least 1 hour.

Fire audit

Systematic and whenever possible, independent examination to determine whether standards of fire safety conform to those required in order to achieve the organization~s fire safety policy and objectives

Fire Axe

Fire Axe

Fire Barn

Another term for Fire station. Originally it referred to a stable which housed horses and the fire apparatus which they hauled. Although it may be colloquially employed to describe any such structure, the term is now most commonly used in rural areas

Fire Blanket

A fire blanket is a highly flame-resistant blanket that can be used to extinguish a small fire or to wrap around a person in case of a fire. Fire blankets are made from 2 layers of woven glass fiber fabric and an inner layer of fire retardant film. They work by cutting off the oxygen supply to the fire. Fire blankets deprive a small fire of oxygen by smothering it. In order to do this, fire blankets are made from fire resistant materials, such as wool or fiberglass. They may also be chemically treated to increase the fire resistance

Fire code

A set of legally adopted rules and regulations designed to prevent fires and protect lives and property.

Fire Damper

A closure which consists of a normally held open damper installed in an air distribution system or in a wall or floor assembly and designed to close automatically in the event of a fire in order to maintain the integrity of fire separation.

FIRDAT (Fire Data Manipulation Program)

A routine of FIREFAMILY that combines historical weather records with the equations of the NFDRS to produce frequency distributions of the NFDRS indexes and components.

Fire Agency

Official group or organization compelled and authorized under statutes or law to control fires within a designated area or upon designated lands.

Fire Analysis

Review of fire management actions taken on a specific fire, group of fires, or fire season in order to identify reasons for both effective and ineffective actions, and to recommend or prescribe ways and means of doing a more efficient job. Also called hot line review.

FDC (Fire Department Connection)

Location in which pumping apparatus hooks to a buildings standpipe and or sprinkler system. Usually a 3" female connection.

FIRDAT (Fire Data Manipulation Program)

A routine of FIREFAMILY that combines historical weather records with the equations of the NFDRS to produce frequency distributions of the NFDRS indexes and components.

Fire Agency

Official group or organization compelled and authorized under statutes or law to control fires within a designated area or upon designated lands.

Fire Analysis

Review of fire management actions taken on a specific fire, group of fires, or fire season in order to identify reasons for both effective and ineffective actions, and to recommend or prescribe ways and means of doing a more efficient job. Also called hot line review

Fire Behavior

The manner in which a fire reacts to the influences of fuel, weather, and topography.

Fire Behavior Analyst

Person responsible to the planning section chief for establishing a weather data collection system and for developing fire behavior predictions based on fire history, fuel, weather, and topography.

Fire Behavior Forecast

Prediction of probable fire behavior, usually prepared by a fire behavior analyst, in support of fire suppression or prescribed burning operations.

Fire Behavior Prediction Model

A set of mathematical equations that can be used to predict certain aspects of fire behavior when provided with an assessment of fuel and environmental conditions.

Fire Behavior Prediction System

A system that uses a set of mathematical equations to predict certain aspects of fire behavior in wildland fuels when provided with data on fuel and environmental conditions.

Fire Benefits

Fire effects with positive monetary, social, or emotional value or that contribute, through changes in the resource base, to the attainment of organizational goals.

Fire Cache

A supply of fire tools and equipment assembled in planned quantities or standard units at a strategic point for exclusive use in fire suppression.

Fire Crew

General term for two or more firefighters organized to work as a unit.

Fire Crew Work Formation

Standard crew arrangement used for fireline construction in direct or indirect attack; consists of line locator, line cutters, rakers, torch operators, and mop-up crew.

Fire Damage

Detrimental fire effects expressed in monetary or other units, including the unfavorable effects of fire-induced changes in the resource base on the attainment of organizational goals.

Fire Damage Appraisal

Fire Damage Appraisal

Fire Detector

A device which gives a signal in response to a change in the ambient conditions in the vicinity or within the range of the detector, due to a fire.

Fire devil

A small, burning cyclone that results when heated gases from a fire rise and cooler air rushes into the resulting areas of low pressure; usually occurs during forest and brush fires but also in free-burning structural fires.

Fire Door

A fire door is a door with a fire-resistance rating (sometimes referred to as a fire protection rating for closures) used as part of a passive fire protection system to reduce the spread of fire and smoke between separate compartments of a structure and to enable safe egress from a building or structure or ship. Fire doors are part of a building~s PASSIVE fire protection system, an essential requirement for ALL public buildings, offices and factories. They are also a requirement in certain domestic situations, such as: ... where a door leads into an integral garage, or.

Fire Escape

a means of evacuating people from a building in the event of fire, especially a metal staircase outside the building

Fire Exit

A way out leading to an escape route. This can either be a doorway or even a horizontal exit.

Fire Extinguisher

Fire Extinguisher

fire emergency evacuation plan (FEEP)

A fire emergency evacuation plan (FEEP) is a written document which includes the action to be taken by all staff in the event of fire and the arrangements for calling the fire brigade. It can include any relevant information in relation to the FEEP


A firefighter (also fireman and firewoman) is a rescuer extensively trained in firefighting, primarily to extinguish hazardous fires that threaten life, property, or the environment, as well as rescue humans and animals from fire

Fire Fighting Access

Approach facilities provided to or within a building to enable fire service personnel and equipment to gain access thereto for fire and rescue operations.

Fire fighting Shaft

A protected enclosure containing a fire fighting stair, fire fighting lobbies and, if provided, a fire fighting lift, together with its machine room.

Fire flow

Fire flow

Fire–Gas Detector

A device that detects gases produced by a fire

Fire Hazard

Materials, structures or processes that may result in creating a fire, permitting a fire to grow undetected, or preventing people from escaping a fire. or

Fire hook

A tool to pull down burning structures; used in Colonial times as the only way to stop a fire.

Fire inspector

A fire inspector is someone who visits and inspects buildings and other structures, such as sports arenas and shopping malls, to search for fire hazards and to ensure that federal, state, and local fire codes are met. They also test and inspect fire protection and fire extinguishing equipment to ensure that it works.

Fire Lift

The lift installed to enable fire services to reach different floors with minimum delay, having such features as required in accordance part.

Fire Load

Calorific energy of the whole contents contained in a space, including the facings of the walls, partitions, floor and ceilings.

Fire marshal:

Administrative and investigative office for fire prevention and arson investigation.

Fire Mortar

Fire Mortar

Fire Panel

Fire Panel

Fire Prevention

The whole set of precautions to prevent the outbreak of fire and to limit its effects.

Fire Pump Controller

A group of devices that serve to govern, in some predetermined manner, the starting and stopping of the fire pump driver and to monitor and signal the status and condition of the fire pump unit.

Fire Pump Unit

An assembled unit consisting of a fire pump, driver, controller, and accessories.

Fire Resistance

A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail a host of other criteria, involving other evidence of functionality or fitness for purpose

First responder

The first trained person to arrive at the scene of an emergency to provide initial medical assistance.

Fire risk assessor

Person who carries out, and documents the significant findings of, a fire risk assessment

Fire safety engineer

Person suitably qualified and experienced in fire safety engineering

Fire safety engineering

Application of scientific and engineering principles to the protection of people, property and the environment from fire

Fire safety induction training

Formal training, normally given verbally to new employees, as soon as practicable after their employment, with the objective of imparting sufficient information on the relevant fire risks, fire prevention measures, fire protection measures and fire procedures in the building to ensure the safety of employees from fire

Fire safety management

Task(s) carried out by a defined individual or individuals with appropriate powers and resources to ensure that the fire safety systems, passive, active and procedural, within the building are working properly at all times

Fire safety manager

A nominated person with responsibility for carrying out day-to-day management of fire

Fire safety manual

Record al of all design, procedural and management issues and events that relate to the fire safety of a building

Fire scenario

Detailed description of condition, including environmental conditions, of one or more stages from being ignition to after completion in an actual fire at a specific location

Fire Sprinklers

A fire sprinkler or sprinkler head is the component of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been exceeded. Fire sprinklers are extensively used worldwide, with over 40 million sprinkler heads fitted each year.

Fire Station

A structure which, in addition to housing apparatus and equipment, often includes living quarters and training facilities for the use of firefighting personnel when on-duty

Fire stopping

A seal provided to close an imperfection of fire or design tolerance between elements or components, to restrict the passage of fire and smoke

Fire Separation

The distance in meters measured from the external wall of the building concerned to the external wall of any other building on the site, or from other site or from the opposite side of street or other public space for the purpose of preventing the spread of fire

Fire Separating Wall

The wall provides complete separation of one building from another, or part of a building from another part of the same building, to prevent any communication of fire or heat transmission to wall itself which may cause or assist in the combustion of materials on the side opposite to that portion which may be on fire.

Fire Stop

A firestop is a fire protection system that seals the cracks and crevices of a space with fire proof material to keep a fire from spreading between rooms. This is a crucial step in ensuring fire and smoke from spreading through multiple spaces quickly. Depending on the space and space requirements in your building, there are different materials you can use for firestops.

Fire Stop Collar

Fire Stop Collar

Fire Stop Joint Spray

Fire Stop Joint Spray

Fire Stop Putty Pad

Fire Stop Putty Pad

Fire Stop Wrap Strips

Fire Stop Wrap Strips

Firestop Coated Acoustic Board

Firestop Coated Acoustic Board

Fire Wall

Building structure designed to delay horizontal spread of a fire from one area of a building to another; often regulated by fire code and required to have self-closing doors, and fireproof construction.

Fire warden

Individual charged with specific responsibilities in the event of fire, normally involving a check to ensue that a particular area of the building has been evacuated

Fire-warning system

A means of alerting people to the existence of a fire

Fire Weather Station

A meteorological station specially equipped to measure weather elements that have an important effect on fire behavior.

Fire Weather Watch

A Fire Weather Watch is issued to advise of conditions which could result in extensive wildland fire occurrence or extreme fire behavior, which are expected to develop in the next 12 to 48 hours, but not more than 72 hours. In cases of dry lightning, a Fire Weather Watch may be issued for the next 12 hours

Fire Whirl

Spinning vortex column of ascending hot air and gases rising from a fire and carrying aloft smoke, debris, and flame. Fire whirls range in size from less than one foot to over 500 feet in diameter. Large fire whirls have the intensity of a small tornado.


Building structure designed to delay horizontal spread of a fire from one area of a building to another; often regulated by fire code and required to have self-closing doors, and fireproof construction.

Fixed-Temperature Detector

A device that responds when its operating element becomes heated to a predetermined level.

Flame over (rollover)

The rapid spread of flame over surfaces.


Capable of being readily ignited.

Flame Detector

A radiant energy–sensing fire detector that detects the radiant energy emitted by a flame.


A flange can also be a plate or ring to form a rim at the end of a pipe when fastened to the pipe / A flange is an external or internal ridge, or rim (lip), for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc.


The stage of fire when all surfaces and objects are heated to their ignition temperature (flash point) and flame breaks out almost at once over the entire surface.

Flash Point

Is the lowest temperature at which the vapor produced by a substance will flash momentarily when a flame is applied.

Flow Switch

A flow switch is a device that monitors the flow of air, steam or liquid. It sends a "trip signal" to a different device in the system, such as a pump. The flow switch can indicate to the pump to shut off or to turn on. Some of the general uses are for pump protection, for cooling-circuit protection and alarms for too high or too low flow rates.

Flow Smart

Talco residential fire pumps designed specifically for systems using water storage tanks (not for booster applications). These pumps systems are based on a centrifugal end-suction pump coupled to a thermally protected single-phase AC motor.

Flow Meter/Flow Meter Loop

A fire pump system piping configuration which allows for system testing without flowing waste water out of the system. A connection on the discharge side of the fire pump system routes water through a venturi (a flow meter) which measures the water flow, the water is then routed back to the suction side of the fire pump and circulated back through the system or back to a storage tank


Stage in the development of a contained fire at which fire spreads rapidly to give large merged flames throughout the space

Flexible Connecting Shaft

A device that incorporates two flexible joints and a telescoping element.

Flexible Coupling

A device used to connect the shafts or other torque-transmitting components from a driver to the pump, and that permits minor angular and parallel misalignment as restricted by both the pump and coupling manufacturers.

Flow test: 

Tests conducted to establish the capabilities of water supply systems and referred to as flow tests because they involve flowing fire hydrants.  The objective of a flow test is to establish quantity ( gallons per minute) and pressures available at a specific location on a particular water supply system.

Flush Sprinkler

A sprinkler in which all or part of the body, including the shank thread, is mounted above the lower plane of the ceiling.

Flooded Suction

The condition where water flows from an atmospheric vented source to the pump without the average pressure at the pump inlet flange dropping below atmospheric pressure with the pump operating at 150 percent of its rated capacity.

FM 200

The FM-200 Fire Suppression System is an engineered system utilizing a fixed nozzle agent distribution network. The system is designed and installed in accordance with the National Fire Protection Association (NFPA) Standard 2001, “Clean Agent Fire Extinguishing Systems.”

Foam extinguishing system

Extinguishing system containing foam as the extinguishing medium

Foot Valve

Foot Valves are a form of check valve, installed at the bottom of Pump suction line, inside the wet well. Foot valves are an inexpensive way to prime a single centrifugal pump. Since Foot Valves are continually submerged in the wet well and not readily accessible for inspection or repair, it is important to select a Foot Valve of high quality long wearing construction

Friction loss:

Reduction of flow in a firehose caused by friction between the water and the lining of the hose. Depends primarily upon diameter, type and length of hose, and amount of water (GPM) flowing through.

Fully developed fire

State of total involvement of combustible materials in a fire

Fuel-Fired Heating Unit

An appliance that produces heat by burning fuel.

Gas cartridge

Pressure vessel that fits into, or is attached to, an extinguisher and that contains either compressed or liquefied gas that, on operation, is used to expel the extinguishing medium

Gas Detector

A device that detects the presence of a specified gas concentration. Gas detectors can be either spot-type or line-type detectors

Gas release panel

Gas release panel

Gear Pump.

A positive displacement pump characterized by the use of gear teat and casing to displace liquid.

Grades of release

Classification of the release of flammable gas or vapor into a hazardous area in terms of the probability of release

Gridded Sprinkler System

A sprinkler system in which parallel cross mains are connected by multiple branch lines. An operating sprinkler will receive water from both ends of its branch line while other branch lines help transfer water between cross mains.


That water that is available from a well, driven into water-bearing subsurface strata (aquifer).

Hardy cross method:

An interactive technique used for solving the complicated problems involving gridded water supply systems.


Hazardous materials, including solids, liquids, or gases that may cause injury, death, or damage if released or triggered.


a source of danger of personal injury or property damage; fire hazard refers to conditions that may result in fire or explosion, or may increase spread of an accidental fire, or prevent escape from fire. Under worker safety and health regulations, employers have a general duty to provide a workplace free of hazards.

Hazardous substance

A substance subject to the Control of Substances Hazardous to Health Regulations 2003 (COSHH)

Hazard zone

Classification within a hazardous area, representing the probability of a flammable gas or vapor and air mixture being present

Hazen-Williams formula

An empirical formula for calculating friction loss in water systems that is the fire protection industry standard.  To comply with the most nationally recognized standards, the Hazen-Williams formula must be used.


A quantity used to express a form (or combination of forms) of the energy content of water per unit weight of the water referred to any arbitrary datum.

Head of the fire

The main or running edge of a fire, the part of the fire that spreads fastest.

Hold time

Period of time during which a concentration of extinguishing medium greater than the fire extinguishing concentration surrounds the hazard

Horizontal Pump

A pump with the shaft normally in a horizontal position.

Horizontal split -case pump:

A centrifugal pump with the impeller shaft installed horizontally and often referred to as a split-case pump.  This is because the case in which the shaft and impeller rotates is split in the middle and can be separated exposing the shaft, bearings and impeller..

Hose adaptor

Fitting used for connecting lengths of hose which have dissimilar couplings

Hose coupling

Means used to join two lengths of hose together or to connect other equipment to a hose

Hydraulic platform

Fire appliance equipped with a hydraulically operated articulating boom with a cage or platform at the upper level and capable of rotating through 360º


A branch of hydraulics dealing with the properties of liquids (water) at rest, particularly in relation to pressures resulting from or applied to the static liquid.

Hydraulically most favorable area

Area of operation for which the water flow is at its maximum for a specified pressure, measured at the main control valve or pump set

hydraulically most unfavorable area

Area of operation for which the system pressure, when measured at the main control valve or pump set, is required to be at its maximum to achieve the specified design density

IDLH: Immediate Danger to Life and Health

An atmospheric concentration of any toxic, corrosive or asphyxiant substance that poses an immediate threat to life or could cause irreversible or delayed harm to health. There are three IDLH atmospheres: toxic, flammable and oxygen-deficient.

Inner room

A room which escape is possible only be passing through another room (the access room)

Indoor Area.

Indoor Area.

Internal Combustion Engine

Any engine in which the working medium consists of the products of combustion of the air and fuel supplied. This combustion usually is effected within the working cylinder but can take place in an external chamber.


Possessing the property of swelling under the influence of heat to form a protective, usually carbonaceous mass with insulating and / or sealing properties

IFC Drawings - Issued for Construction drawings

Issued for Construction drawings are sets of detailed design drawings prepared by the Design Consultant and are integral part of the Contract Documents. Contractual issues arise between Tender Drawings and IFC Drawings, as the case maybe.


– Institute of Fire Prevention Officers

Ignition point

The minimum temperature at which a substance will burn.

Ignition temperature

The minimum temperature at which a fuel, when heated, will ignite in air and continue to burn; the minimum temperature required to for a self-sustained combustion.

Incendiary fire

. An intentionally set fire.

Incident Management System

A management structure that can be quickly adapted to any situation, a standard approach with predefined roles, responsibilities, procedures and terminology.

Initial attack vehicle

A small fire truck, like a pumper but with less capacity to pump water.

Initiating devices

A change of state might be closing a sprinkler control valve, operating a manual fire alarm box, actuation of a fire detector, or operation of a fire suppression system. Initiating devices usually operate automatically. The only manual initiating devices are manual fire alarm boxes

Ironmongery, essential

Items specified as essential to achieve fire resistance performance of a fire door

Ironmongery, non essential

Items which are not required to achieve the fire resistance performance of a fire door but which if fitted might affect the performance

ISO or Insurance Services Office

An organization that gathers information about risk for the insurance industry, including ratings of fire departments’ abilities to suppress a fire.

Isolating Switch

A switch intended for isolating an electric circuit from its source of power. It has no interrupting rating, and it is intended to be operated only after the circuit has been opened by some other means.

Jockey Pump

A jockey pump is a small capacity, high pressure pump used to maintain constant pressures on the fire protection system. A jockey pump is often used to prevent the main pump from starting unnecessarily.

Lap joint flanges

This is again similar to a slip-on flange, but has a radius at the intersection of the centre bore and the flange face to accommodate a lap stub end.

Licensed premises

Any premises that require a license under any statute to undertake trade or conduct business activities

Life & health hazard

Potential injury or loss of life to be expected from the effects of exposure to toxic effluent and heat in a fire


A company officer who is usually responsible for a single fire company on a single shift; the first in line of company officers, in command when the captain is absent.

Life Safety Code

. NFPA 101, the code that describes the structures, equipment and behaviors that can protect life if there is a fire, such as size and location of exits and the need for regular fire drills.

Life safety rope

Rope used solely for the purpose of supporting people during firefighting, rescue, other emergency operations and training.


One or more lengths of connected hose.

Line-Type Detector

Adevice in which detection is continuous along a path. Typical examples are rate-of-rise pneumatic tubing detectors, projected beam smoke detectors, and heat-sensitive cable.

Load-bearing capacity

Ability of a specimen of a load-bearing element to support a defined load without exceeding specified criteria with respect to either the extent of, or rate of, deformation or both

Looped Sprinkler System

A sprinkler system in which multiple cross mains are tied together so as to provide more than one path for water to flow to an operating sprinkler and branch lines are not tied together.

Loss prevention

Approach to safety distinguished by emphasis upon incorporating safety into the initial design

Loss of Phase

The loss of one or more, but not all, phases of the polyphase power source.


Loss Prevention Certification Board

Manual Call Point

Manual alarm call points are designed for the purpose of raising an alarm manually once verification of a fire or emergency condition exists, by operating the push button or break glass the alarm signal can be raised.

Manual Standpipe System

A standpipe system that relies exclusively on the fire department connection to supply the system demand.

Manual Transfer Switch.

A switch operated by direct manpower for transferring one or more load conductor connections from one power source to another.

Mass loss

A switch operated by direct manpower for transferring one or more load conductor connections from one power source to another.

Mass loss concentration

Concentration of fire effluent from a material estimated by dividing the mass loss by the volume into which the effluents are dispersed

Material change

An alteration to the premises, process or service which significantly affects the level of risk to people from fire in those premises


Code that indicates a firefighter is lost, missing or requires immediate assistance.

Maximum flow demand:

The flow discharge from the sprinkler heads located at the hydranliclly most favourable area when balanced to a fire pumps flow / pressuer curve (QMAX point)

Maximum Pump Brake Horsepower

The maximum brake horsepower required to drive the pump at rated speed. The pump manufacturer determines this by shop test under expected suction and discharge conditions. Actual field conditions can vary from shop conditions.

Minimum ignition time

Duration of exposure of a material to a defined ignition source required for the initiation of combustion under specified conditions

Molten debris

Molten material separating from the specimen during the rest procedure and falling from a burning item without flaming

Mezzanine Floor

An intermediate floor, between two floors, above ground level, accessible only from the lower floor

Modular system

Fire-fighting system consisting of distributed containers of extinguishing medium, in which each unit is designed to protect a given volume and which in total provides cover for the whole hazard

Molten debris

Molten material separating from the specimen during the rest procedure and falling from a burning item without flaming


Extinguishing or removing burning material near control lines, felling snags, and trenching logs to prevent rolling after an area has burned, to make a fire safe, or to reduce residual smoke.

Multi-Criteria Detector

A device that contains multiple sensors that separately respond to physical stimulus such as heat, smoke, or fire gases, or employs more than one sensor to sense the same stimulus

Multi-Cycle System

A type of sprinkler system capable of repeated on–off flow cycles in response to heat.

Multi-Sensor Detector

The Discovery Multisensor Detector comprises optical smoke and thermistor temperature sensors which give both a combined signal as well as a separate heat signal for improved false alarm management.

Multipurpose Piping System

A piping system within a residential occupancy intended to serve both domestic and fire protection needs.

National Fire Incident Reporting System, or NFIRS System

A system by which fire departments provide computerized records of fires and other fire department incidents in a uniform manner.

Natural ventilation

Ventilation that is caused by buoyancy forces due to difference in density of the air because of the effects ..of temperature differences


National Examination Board in Occupational Safety & Health

Network System

A type of multipurpose system utilizing a common piping system supplying domestic fixtures and fire sprinklers where each sprinkler is supplied by a minimum of three separate paths


The National Fire Protection Association, a research group which sets a number of standards and best practices for *firefighting, equipment, and fire protection in the United States, and also adopted in many other countries. Also, slang for "No Free Publications Available"; used to reference any "must-have" documents that are prohibitively expensive


National Institute for Occupational Safety and Health. A U.S. agency responsible for investigation of workplace deaths, including firefighters.


The National Incident Management System. A federally mandated program for the standardizing of command terminology and procedures. This standardizes communications between fire departments and other agencies. It is based upon simple terms that will be used nationwide. Currently, U.S. federally required training programs, from DHS and FEMA, are in the process of standardizing many terms and procedures under NIMS.

Nominal Bore

Nominal bore (NB) is the internal dimension of any pipe. TuberÃas image by Raulmahón from . The bore is the hollow centre of any pipe. Nominal is used in the sense of "in name only" or "putative"-- approximate. Nominal bore is the approximate internal measurement across the diameter of the mouth of a pipe.

Nominal Pressure

Pressure Nominal (PN) is a term used to describe the pressure that a PE Pipe is designed to safely withstand. A pipe~s PN number describes the nominal pressure in bars that a pipe can support with water at 20oC.


Not capable of undergoing combustion under specific conditions

Non-detachable detector

Detector not designed t be easily removed from its normal operating position for maintenance and servicing purposes

Non-hazardous area (explosion)

Area in which explosive atmospheres are not expected to be present in hazardous quantities and in which special precautions for the construction and use of apparatus are not required

Non-hazardous area (dust)

Area in which combustible dust-air mixtures are not expected to be present in hazardous quantities and in which special precautions for the construction and use of apparatus are not required

Non-maintained emergency lighting

Lighting system in which all emergency lighting lamps are illuminated only when the supply to the normal lighting fails

Normal condition

Condition of a component of a fire alarm system in which it is giving neither fault nor fire signals, but in which it has the ability to give a fault or fire signal should such an event occur

Nozzle Pressure

Pressure required at the inlet of a nozzle to produce the desired water discharge characteristics.


National Security Inspectorate

Occupant capacity

Maximum number of persons assumed to be present within an enclosure for the purposes of design

Occupant(s) especially at risk

Building occupant(s) who, as a result of their physical or mental state, age or location in the building, are at greater risk from fire than an able-bodied, fully alert adult afforded adequate means of escape and other fire precautions, whether on a short-term or long-term basis

Occupant Load

The number of persons for which the means of egress of a building or a portion thereof is designed.

Optical smoke detector

Fire detector sensitive to products of combustion capable of affecting the absorption or scattering of radiation in the infra-red, visible and / or ultraviolet regions of the electromagnetic spectrum


Pipe is hollow and circular cross section used for transportation of fluid and gases in various process plants, fire water system, drinking water systems.

Orifice plate meter: 

An orifice plate meter is a device used for measuring water flow and is similar in principle to a Venturi meter.  The change of water velocity is accomplished by using a plate with an orifice that is smaller than the diameter of the pipe in which it is placed. 


A chemical reaction in which an element combines with oxygen. All fires are a form of oxidation.

PASS. Personal alert safety system

Device worn by a firefighter that sounds an alarm if the firefighter is motionless for a period of time.

Passive fire protection -

the installation of firewalls and fire rated floor assemblies to form fire compartments intended to limit the spread of fire, high temperatures, and smoke.


An emergency medical technician (EMT) with the highest level of level of training. Most EMTs are not paramedics, so the terms should not be used interchangeably. Paramedics are trained to do cardiac monitoring, administer drugs, insert advanced airways, perform manual defibrillation, and conduct other advanced assessments and treatments.

Personnel accountability system

A method of tracking the identity, assignment, and location of firefighters operating at an incident scene.

Phased evacuation

A system of evacuation in which different parts of the premises are evacuated in a controlled sequence of phases, those parts of the premises expected to be at greatest risk being evacuated first

Place of reasonable / safety

A place within a building or structure where, for a limited period of time, people will have some protection from the effects of fire and smoke. This place, usually a corridor or stairway, will normally have a minimum of 30 minutes fire resistance and allow people to continue their escape to a place of total safety

Place of total safety

A place, away from the premises, in which people are at no immediate danger from the effects of fire

Piezometer tube:

This device uses the heights of liquid columns to illustrate the pressures existing in hydraulic systems.

Pipe Class

A pipe class is a document (normally prepared by an operating or engineering company) for use within its confines and which contains the definition of pipe and all related components that are to be used under a specific pressure, temperature condition – including sometimes the service they are in

Pipe Flanges

A flange is a ring of steel (forged, cut from plate, or rolled) designed to connect sections of pipe, or to join pipe to a pressure vessel, valve, pump or other integral flanged assembly. Flanges are joined to each other by bolting, and are joined to the piping system by welding or threading (or loose when stub ends are used).

Pipe Schedule System

A sprinkler system in which the pipe sizing is selected from a schedule that is determined by the occupancy classification and in which a given number of sprinklers are allowed to be supplied from specific sizes of pipe.

Plinth Area

Plinth area is the built up covered area of a building measured at floor level of any storey. Plinth area is calculated by taking external dimensions of the building at floor level


An air compartment or chamber to which one or more ducts are connected and which forms part of an air distribution system.

Pnumatic Actuator

A pneumatic control valve actuator converts energy (typically in the form of compressed air) into mechanical motion. The motion can be rotary or linear, depending on the type of actuator.

Positive pressure ventilation

The practice of forcing contaminated air out of burning building by placing a blower in the doorway and blowing the air through a ventilation hole cut in the roof

PPE. Personal protective equipment

The helmet, hood, coat, gloves, self-contained breathing apparatus and boots worn by firefighters to protect against heat and water.

Pre-movement time

Interval between the time at which a warning of fire is given and the time at which the first move is made towards an exit

Premixed Antifreeze Solution

A mixture of an antifreeze material with water that is prepared by the manufacturer with a quality control procedure in place that ensures that the antifreeze solution remains homogeneous.


Any place, such as a building and the immediate land bounded by any enclosure of it, any tent, moveable or temporary structure or any installation or workplace

Preaction Sprinkler System

A sprinkler system employing automatic sprinklers that are attached to a piping system that contains air that might or might not be under pressure, with a supplemental detection system installed in the same areas as the sprinklers.

Pressure Control Valve

A pilot-operated pressure-reducing valve designed for the purpose of reducing the downstream water pressure to a specific value under both flowing (residual) and no flowing (static) conditions.

Pre-engineered System

A packaged sprinkler system including all components connected to the water supply and designed to be installed according to pretested limitations.

Pressure Drop

Pressure drop is defined as the difference in pressure between two points of a fluid carrying network. Pressure drop occurs when frictional forces, caused by the resistance to flow, act on a fluid as it flows through the tube.

Pressure Gauge

Pressure Gauge


Method of smoke control using pressure differentials, here the air pressure in the spaces being protected is raised above that in the fire zone

Pressure head:

Is a term used in fluid mechanics to represent the internal energy of a fluid due to the pressure exerted on its container. It may also be called static pressure head or simply static head.

Pressure Rating of Flanges

The concept of flange ratings likes clearly. ... The Pressure Class or Rating for flanges will be given in pounds. Different names are used to indicate a Pressure Class. For example: 150 Lb or 150 Lbs or 150# or Class 150, all are means the same.

Pressure Rating

Maximum allowable operating pressure or MAOP refers to the wall strength of a pressurized cylinder such as a pipeline or storage tank and how much pressure the walls may safely hold in normal operation. The MAOP is less than the MAWP (maximum allowable working pressure).

Pressure-Reducing Valve

A valve designed for the purpose of reducing the downstream water pressure under both flowing (residual) and nonflowing (static) conditions.

Pressure-Regulating Device.

A device designed for the purpose of reducing, regulating, controlling, or restricting water pressure. Examples include pressure-reducing valves, pressure control valves, and pressure-restricting devices.

Pressure-Restricting Device.

A valve or device designed for the purpose of reducing the downstream water pressure under flowing (residual) conditions only.

Pressure Switch

A pressure switch is a form of switch that closes an electrical contact when a certain set fluid pressure has been reached on its input. The switch may be designed to make contact either on pressure rise or on pressure fall. Pressure switches are widely used in industry to automatically supervise and control systems that use pressurized fluids.

Pressure Vessel

A pressure vessel is a container designed to hold gases or liquids at a pressure substantially different from the ambient pressure

Priming Tank

Centrifugal pumps are designed to pump liquids. For using a centrifugal pump to pump water, the pump casing must be filled with water before the pump is started, or the pump will not be able to function. This is known as "priming"

Products of combustion

Heat, smoke and toxic gases.

Protected lobby

A fire-resisting enclosure providing access to an escape stairway via two sets of fire doors and into which no room opens other than toilets and lifts

Protected Shaft

A shaft which enables persons, air or objects to pass from one compartment to another, and which is enclosed with fire resisting construction.

Protected stairway

A stairway which is adequately protected from the rest of the building by fire-resisting construction


In fire protection, pressure is most often dealt within units of pounds per square inch (psi).

Public Address System (PA System)

The complete chain of sound equipment (comprising essentially of microphones, amplifiers, and loud speakers) required to reinforce the sound emanating from a source in order to provide adequate loudness for comfortable hearing by the audience.


a mechanical device using suction or pressure to raise or move liquids, compress gases, or force air into inflatable objects such as tyres

Pump Head

Head is the height at which a pump can raise water up


A fire truck capable of forcing out at least 750 gallons of water per minute, with a hose at least 1,000 feet long, and a water tank holding at least 300 gallons. Some also have foam-making systems to smother flammable-liquid fires, or to make a different type of foam that reduces the surface tension of water so it penetrates more quickly.


The chemical decomposition of a compound into one or more other substances by heat alone; pyrolysis often precedes combustion.


A fire truck that has an aerial ladder as well as pump, hose, tank and ladders.


Heat transfer through electromagnetic waves, without objects or gases carrying it along. Radiated heat goes out in all directions, unnoticed until it strikes an object.

Rapid Cycle

A problem common with fire pumps that are controlled only by a pressure switch. Rapid build up and release of system pressure causes the pump to switch on and off several times a second until the pump burns up. See our 13D page.

Rated Capacity

The flow available from a device, at the designated residual pressure either measured or calculated.

Rate Compensation Detector

A device that responds when the temperature of the air surrounding the device reaches a predetermined level, regardless of the rate of temperature rise.

Rate-of-Rise Detector

A device that responds when the temperature rises at a rate exceeding a predetermined value.

Raw Water Source

A water supply taken from the environment that has not been treated and may contain foreign material that could accumulate freely and enter the sprinkler system.


erm used by fire weather forecasters to alert users to an ongoing or imminent critical fire weather pattern.

Reaction to fire

Response of a material in contributing by its own decomposition to a fire to which it is exposed, under specified conditions

Reflash, re-kindle

A situation in which a fire, thought to be extinguished, resumes burning.


A place of reasonable safety in which a disabled person and others who may need assistance may rest or wait for assistance before reaching a place of total safety. It should lead directly to a fire-resisting escape route

Refuge Area

? An area within the building for a temporary use during egress. It generally serves as a staging area which is protected from the effect of fire and smoke. / An area where persons unable to use stairways can remain temporarily to await instructions or assistance during emergency evacuation.

Relief valve:

The relief valve is provided to open up and discharge water to a drain should the pressure become excessive.  This valve is located between the pump and the discharge check valve and is required with pumps driven by variable speed drivers.

Repeater Panel

repeater panels are designed to provide secondary indication of the fire alarm or system fault condition at a location remote from the main control panel.


Physical removal of a live person or animal from danger to a place of comfort.

Rescue Company

Squad of firefighters trained and equipped to enter adverse conditions and rescue victims of an incident. Often delegated to a truck company.

Residual pressure

The amount of pressure in a hydrant system when a hydrant is fully open, such as during a fire; should be engineered to provide domestic supply of water to homes and businesses during a large fire in the district.

Residential Sprinkler

Residential Sprinkler


A maskworn over the mouth and nose to filter smoke and fumes from the air.

Response time

The time a fire company takes to get to a fire and begin fire operations.

RIC. Rapid intervention company/crew

A minimum of two firefighters who stand by at a fire, fully equipped and ready, to rescue injured or trapped firefighters.

Risk of fire spread

Probability of a fire, once started, growing to a size and character that could product life risk or property risk or both

Risk profile

Means of categorizing the risks for a range of building types of occupancies based on the building parameters, internal processes, occupancy profile and the potential rate of fire growth


The rapid spread of flame over surfaces (also called flame over).

Roof Exits

A means of escape on to the roof of a building where the roof has access to it from the ground. The exit shall have adequate cut-off within the building from staircase below.

Routine inspection

Check at regular intervals of the fire prevention and fire protection arrangements

Safe condition sign

Safety sign that provides information about safe conditions Self-closing device A device that is capable of closing the door from any angle and against

Scene safety

Steps taken at or near an emergency scene to reduce hazards and prevent further injuries to workers, victims or bystanders.


Specific pipe is identified by pipe diameter and another non-dimensional number for wall thickness referred to as the Schedule

Self-contained breathing apparatus (SCBA)

Respirator with independent air supply used by firefighters to enter toxic and otherwise dangerous atmospheres.

Semiautomatic Standpipe System

A standpipe system that is attached to a water supply capable of supplying the system demand at all times and that requires activation of a control device to provide water at hose connections.

Shop Drawings

A shop drawing is a drawing or set of drawings produced by the contractor, supplier, manufacturer, subcontractor, or fabricator. Shop drawings are typically required for prefabricated components. ... The shop drawing normally shows more detail than the construction documents

Simple loop: 

A loop in which there is exactly one inflow point and one outflow point, and exactly two paths between the inflow and outflow points.

Slip-on flanges

The flange is slipped over the pipe and then welded both inside and outside to provide sufficient strength and prevent leakage. Slip-on flanges are also used as loose back-up flanges when stub ends are used.


A fire edge that crosses a control line or natural barrier intended to confine the fire. Also called break over.

Smoke alarm

Device containing within one housing all the components, except possibly the energy source, for detecting smoke and giving an audible alarm

Smoke control

Measures to control the spread or movement of smoke and fire gases within a building in order to protect the structure, the contents, the means of escape, or to assist fire-fighting operations

Smoke damper

Mechanical device which, when closed, prevents smoke passing through an aperture within a duct or structure

Smoke ejector

Powerful fan for moving large amounts of air and smoke as part of ventilation task while fighting fire in a burning structure. May be operated by electricity or gas motor for positive or negative pressure ventilation.

Soda-acid extinguisher

Weak water/acid solution inside a pressure vessel which activates bicarbonate of soda when triggered, expelling "water" (mixture) under pressure from the resulting carbon dioxide. Obsolete and often replaced with an APW or multipurpose extinguisher.

Spark/Ember Detector Sensitivity

The number of watts (or the fraction of a watt) of radiant power from a point source radiator, applied as a unit step signal at the wavelength of maximum detector sensitivity, necessary to produce an alarm signal from the detector within the specified response time.

Specific Heat

The heat energy required to raise the temperature of unit mass of a substance through 1oC is the specific heat of the substance. (J/kg per oC)


A small fire that is ahead of the main fire that is caused from hot embers being carried to a receptive fuel bed. Spotting indicates extreme fire conditions.

Spot-Type Detector

A device in which the detecting element is concentrated at a particular location. Typical examples are bimetallic detectors, fusible alloy detectors,certain pneumatic rate-of-rise detectors, certain smoke detectors, and thermoelectric detectors.

Spray Sprinkler

A type of sprinkler listed for its capability to provide fire control for a wide range of fire hazards.

Sprinkler yoke

That part of the sprinkler which retains the heat responsive element in load bearing contact with the sprinkler head.

Stack Effect

Is the vertical natural air movement from the building caused by the differences in temperature and densities between the inside and outside air. This stack effect plays a vital role in smoke movement.

Stack Pressure

Pressure difference caused by a temperature difference creating an air movement within a duct, chimney or enclosure.

Staged fire alarms

A fire warning which can be given in two or more stages for different purposes within a given area (i.e. notifying staff, stand by to evacuate, full evacuation)


sector of incident command where responding resources arrive for assignment to another sector. Often an essential element in personnel accountability program.


system of pipes inside a building for conducting water for firehose attachments; may be pressurized with water ("wet") or remain "dry" until activated in an emergency; supplied either from a fire hydrant attachment or from a fire engine~s pump. Permits firefighters to reach higher levels of tall buildings without having to run hoses up the stairs.


The California Board of Forestry and Fire Protection classifies areas in which the primary financial responsibility for preventing and suppressing fires is that of the state. CDF has SRA responsibility for the protection of over 31 million acres of California’s privately-owned wildlands.

Static pressure:  

The normal pressure existing on a system before the flow hydrant is opened.

Storey exit

A final exit or a doorway giving direct access into a protected stairway, fire-fighting lobby, or external escape route

Straight stream

Round, hollow stream formed as water passes a round baffle through a round orifice (e.g., on an adjustable nozzle.) Compare solid stream.


a device having holes punched in it or made of crossed wires for separating solid matter from a liquid.


The phenomenon where the upward movement of smoke and gases ceases due to the loss of buoyancy


An engine strike team consists of five fire engines of the same type and a lead vehicle. The strike team leader is usually a captain or a battalion chief. Strike Teams can also be made up of bulldozers and hand crews.

Storz coupling

A type of coupling used on fire hose. The coupling is sexless, and secures with a 1/4 turn of the coupling. The coupling may or may not have some sort of locking device.

Structural fire

A fire in a residential or commercial building. Urban fire departments are primarily geared toward structural firefighting. The term is often used to distinguish them from wildland fire or other outside fire, and may also refer to the type of training and equipment such as "structure PPE" (personal protective equipment).

Structural fire protection

Features in layout and / or construction that are intended to reduce the effects of a fire

Subsidiary Station

A subsidiary station is a normally unattended location that is remote from the supervising station and is linked by a communications channel(s) to the supervising station. Interconnection of signals on one or more transmission channels from protected premises with a communications channel(s) to the supervising station is performed at this location.

Supervising Station

A facility that receives signals from protected premises fire alarm systems and at which personnel are in attendance at all times to respond to these signals.

System Demand

The flow rate and residual pressure required from a water supply, measured at the point of connection of a water supply to a standpipe system, to deliver the total water flow rate and the minimum residual pressures required for a standpipe system at the hydraulically most remote hose, and the minimum water flow rate for sprinkler connections, on combined systems.

System Operator

An individual trained to operate and or initiate a mass notification system.

System Unit

The active subassemblies at the supervising station used for signal receiving, processing, display, or recording of status change signals; a failure of one of these subassemblies causes the loss of a number of alarm signals by that unit.

System Working Pressure

The maximum anticipated static (nonflowing) or flowing pressure applied to sprinkler system components exclusive of surge pressures.

Sworn Personnel

Firefighters take a sworn oath to protect and serve the community in which they work

Talk Mode

A means of communications within a building normally dedicated to emergency functions. Commonly referred to as fire fighters’ phones, but can also be used for communications with fire fighters and/or fire wardens, including occupants, during an emergency, such as between a fire command center and a designated location, such as a stair, stairwell, or location of emergency equipment.

Tamper Switch

Tamper switches detect when a sprinkler valve has been partially to fully closed and usually activates a trouble signal at the control, although some cities require them activate alarms.


Portion at rear of fire engine where firefighters could stand and ride (now considered overly dangerous and against Department Policy in Carmel), or step up to access hoses in the hose bed.


An aircraft equipped to carry water or fire retardant for use in wildland fire suppression. Archaic: see "Tender", below

Taskforce Tip: (TFT)

Task Force Tips a popular brand of adjustable fog stream Combination Nozzle, now a ubiquitous term for that type of nozzle.

Thermal column

A cylindrical area above a fire in which heated air and gases rise and travel upward. The magnitude and intensity of a fire can often be judged from the thermal column.

Thermal imaging device

An electronic device that detects differences in temperature based on infrared energy and then generates images based on that data. Commonly used in obscured environments to locate victims.

Third-party fire risk assessor

Independent fire risk assessor, who is not an employee of the duty holder, but who is contracted to carry out a fire risk assessment on behalf of a duty holder on whom legislation imposes a requirement for a fire risk assessment

Total discharge value

Maximum number of persons that can evacuate a building through all available exits within a given time

Traditional System

A non-addressable alarm system that utilizes contact devices and circuit continuity to initiate an alarm condition and direct wired DC circuits to operate notification appliances. Also called a hardwired or conventional system.


A system component that provides an interface between signaling line circuits, initiating device circuits, or control units and the transmission channel.


A multiplex alarm transmission system functional assembly located at the protected premises.

Travel Distance

The distance to be travelled from any point in building to a protected escape route, external escape route of final exit.

Travel time

Time needed once movement has begun, for all of the occupants of a specified part of a building to reach a place of relative safety or a place of ultimate safety

Triple combination engine company

apparatus carries water, pumps water, carries hose and other equipment; firefighters who may carry out direct attack or support other engine companies.

Triple Lay

A method of loading preconnected attack line into a hose bed or crosslay, often facilitating rapid hose deployment in a pre-flaked configuration.

Trouble Signal

A system indication of a fault, such as circuit break or battery failure, occurring in the devices, wiring, or associated system component

Turnout coat and pants

The protective coat and trousers worn by a firefighter for interior structural firefighting. Also called bunker coat and bunker pants.


rotating base of an aerial ladder that permits the ladder to be elevated and extended in any direction from a fixed location.

Type I, II, III, IV, V Building

U.S. classification system for fire resistance of building construction types, including definitions for "resistive" Type I, "non-combustible" Type II, "ordinary" Type III, heavy timber Type IV, and "frame construction" Type V (i.e., made entirely of wood).

Two-stage alarm system

Fire alarm system in which initially the alarm is given only in a restricted part of the premises, with an alert signal being given in the remainder of the premises

Two-stage detector

Fire detector which gives one of two output states relating to either “normal” or “fire alarm” conditions

Unacceptable hazard

Degree of hazard that is regarded by society in general as too great to be allowed to occur repeatedly

Unexposed side

Face of the element, which is remote from the fire in a fire test of a separating element

UL Listed

The "Recognized Component Mark" is a type of quality mark issued by Underwriters Laboratories. It is placed on components which are intended to be part of a UL listed product, but which cannot bear the full UL logo themselves.

Under control

The stage of a fire at which it has been partially extinguished and authorities are confident can be completely extinguished.


In ICS, unified command is a unified team effort which allows all agencies with jurisdictional responsibility for the incident, either geographical or functional, to manage an incident by establishing a common set of incident objectives and strategies.

United States Fire Administration (USFA)

Division of the Federal Emergency Management Agency (FEMA), which in turn is managed by the Department of Homeland Security (DHS).

Universal precautions

The use of safety barriers (gloves, mask, goggles) to limit an emergency responder~s contact with contaminants, especially fluids of injured patients.

Unit Load

A pallet load or module held together in some manner and normally transported by material handling equipment.

Unprotected area

Part of a side or external wall of a building having a lower fire resistance than that required for elements of structure of the building, or clad with combustible material such that if ignited it would product significant thermal radiation

Uninterruptible Power Supply

A battery powered device that provides standby AC power to its load in the event of a failure of the AC power mains.

Utility rope

Rope used for securing objects, hoisting equipment, or blocking access to a scene. It is never to be used to support people.

Utility Truck

Usually manned by an engine company and responds to utility calls like water main breaks. Some small departments use them to respond to medical calls to save gas money.


A valve is a device that regulates, stops ,directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. … or Valves are the manual or automatic fluid-controlling elements in a piping system. They are constructed to withstand a specific range of temperature, pressure, corrosion and mechanical stress. Valves have some of flowing primary functions :- 1. Starting, stopping and directing flow 2. Regulating, controlling or throttling flow , preventing back flow 3. relieving or regulating pressure

Vapor suppression

Process of reducing the amount of flammable or other hazardous vapors, from a flammable liquid, mixing with air, typically by careful application of a foam blanket on top of a pool of material


Vent, enter, search - a fireground search method involving entering the building one room at a time through the windows with the goal of locating and rescuing viable victims. VES team searches the given room only and does not venture into the rest of the building


Vent, enter, isolate, search - a further development of the VES concept, emphasizing the importance of isolating the room being searched from the rest of the building containing the seat of fire, by closing the door as soon as such door is found, in order to improve the tenability and visibility in the room.

Vehicle fire

Type of fire involving motor vehicles themselves, their fuel or cargo; has peculiar issues of rescue, explosion sources, toxic smoke and runoff, and scene safety.


Supply of outside air into, or the removal of inside air from an enclosed space.

Venting Fire

The process of inducing heat and smoke to leave a building as quickly as possible by such paths so that lateral spread of fireand heat is checked, fire fighting operations are facilitated and minimum fire damage is caused.

Venturi effect

Creating a partial vacuum using a constricted fluid flow, used in fire equipment for mixing chemicals into water streams, or for measuring flow velocity.

Venturi meter: 

When coupled with a differential manometer, a venture meter may be used to measure water velocity.  The device consists essentially of a piece of pipe in which the cross-sectional area has been constricted.

Ventilation saw

A high-powered saw with metal-cutting teeth or disc for quickly making large openings in roofing materials.

Vertical ventilation

Ventilation technique making use of the principle of convection in which heated gases naturally rise.

Video Image Smoke Detection

The principle of using automatic analysis of real-time video images to detect the presence of smoke.

Video Switcher

An electronic device that routes video signals from one or more camera locations to one or more monitors. A switcher may be manually or computer operated and control sequencing, and camera presets.

Vision panel

A transparent panel in a wall or door of an inner room enabling the occupant to become aware of a fire in the access area during the early stages

Voice alarm system

Sound distribution system that provides means for automatically broadcasting speech messages and warning signals

Volume factor

Numerical factor that, when applied to the volume of an enclosure, indicates the basic quantity of carbon dioxide required for protection against surface fires

Volume to Plot Area Ratio (VPR)

The ratio of volume of building measured in cubic metres to the area of the plot measured in square metres and expressed in metres.

Voids (building)

Enclosed portions of a building where fire can spread undetected.

Wall box

The cabinet in which control panel equipment or devices are installed. Wall boxes may be surface, semi-flush, or flush mounted.

Wall-indicator valve

Type of control valve for sprinkler systems which is mounted to an outside wall and indicates "open" or "shut" in an indicator window on the valve body.


Person appointed to undertake prescribed duties leading to the effective and orderly evacuation of all or part of the premises in the event of fire

Warning sign

Safety sign that gives warning of a hazard


hardware circuit that monitors the integrity of microprocessor-based electronics/software and generates a trouble condition in the event of a failure.

Water curtain nozzle

Water curtain nozzle

Water drop:

A forest fire fighting technique when an airplane (also called an "air tanker") or helicopter drops a supply of water or other fire suppressant onto an exposed fire from above.

Water flow indicator

Device, electrical or mechanical which indicates a water flow

Water fog

Water discharged from a nozzle in finely dispersed form (mist) at high pressure, used to rapidly absorb heat, eject smoke and minimize water damage

Water tender

a vehicle that contains a substantial tank of water as well as a pump.

Water-flow Alarm

A sensor that initiates an alarm condition whenever water movement is detected in sprinkler system piping.

Water flow Detector

An electric signaling indicator or alarm check valve actuated by water flow in one direction only.

Water hammer

Large, damaging shock wave in a water supply system caused by shutting a valve quickly, or by permitting a vehicle to drive across an unprotected fire hose.

Water mist fire suppression

A sprinkler-like system that uses a very fine mist featuring much lower water flow than conventional sprinklers to suppress, rather than extinguish, a fire.

Water thief (valve)

Type of gated wye having one or more outlets smaller than the largest outlet.


The distance between the peaks of a sinusoidal wave. All radiant energy can be described as a wave having a wavelength. Wavelength serves as the unit of measure for distinguishing between different parts of the spectrum. Wavelengths are measured in microns (µm), nanometers (nm), or angstroms


Low mounted luminous tracks positioned on escape routes in combination with exit indicators, exit marking and intermediate direction indicators along the route, provided for use when the supply to the normal lighting fails,which do not rely on an electrical supply for the luminous output


Wooden blocks for temporary shut-off of activated sprinkler heads or holding doors open during firefighting or rescue operations.

Wiegand Card

An electronic access control card that uses ferromagnetic wires to create a unique identification code

Weld neck flanges

Designed to be joined to a piping system by butt welding. They are relatively expensive due to the weld neck, but are preferred for high-stress applications.

Wet Pipe Sprinkler System

A sprinkler system employing automatic sprinklers attached to a piping system containing water and connected to a water supply so that water discharges immediately from sprinklers opened by heat from a fire.

Wet Riser

An arrangement for fire fighting within the building by means of vertical rising mains of not less than 100 mm diameter with landing valves on each floor/landing for fire fighting purposes and permanently charged with water from a pressurized supply.


Wildland Fire Situation Analysis

Wheeled escape

Wheeled extending ladder, usually mounted on a fire appliance from which is can be removed and maneuvered into position for rescue or fire-fighting purposes


An electronic tone characterized by a repetitive signal starting at a low frequency, then rising steadily in frequency, and then terminating.

Wildfire or Wildland fire

Fire in forests, grasslands, prairies, or other natural areas, not involving structure fires


Land in an uncultivated natural state that is covered by trees, brush, weeds or grass.

Window Foil:

Conductive metal tape (usually lead) applied to detect intrusion by breaking circuit continuity.

Wireless Protection System

system or a part of a system that can transmit and receive signals without the aid of interconnection wiring. It can consist of either a wireless control unit or a wireless repeater.

Wireless Repeater.

A component used to relay signals among wireless devices, appliances, and control units. (SIGPRO

Working (Plan) Drawing

Those approved plans and drawings that are used for construction of the project.

Working Pressure

The maximum allowable pressure, including momentary surge pressure, to which a system, hose, or other component can be safely subjected while in service.


A defined space or an independent, principal piece of equipment using hazardous chemicals within a cleanroom or clean zone, where a specific function, a laboratory procedure, or a research activity occurs.


hose coupling for splitting one line into two or more outlets, often a larger line split into two smaller ones; often a gated wye having separate valves for each outlet. Not to be confused with Siamese, which is used to bring two smaller lines together into one.


An open, unoccupied space other than a court, unobstructed from the finished ground level to the sky on the lot on which a building is situated.

Yard Hydrant

A hydrant that is not designed to supply a fire department pumper.


An electronic tone characterized by a repetitive signal starting at a high frequency, then falling steadily, then ending.


Section of structure indicated on fire alarm control panel where sensor was activated.

Zone Boundary

A structural component designed to contain flooding or fire to a specified space within a vessel.

Zone Disconnect

A control panel feature that disables the devices that make up a zone such that activation of any device that is part of the zone is ignored and programmed zone instructions are not executed. Primarily used for system maintenance.

Zone indicator

Part of indicating equipment, which visually indicates the zone of origin of a alarm of fire or fault warning

Zone smoke control

System that combines depressurization of the smoke control zone containing the fire and pressurization for all contiguous spaces requiring protection

Ball Valve

Ball Valves are also designed to be operated fully open or fully closed with any liquid containing particles that could scratch the ball. Ball Valve have low pressure drops, open and close quickly, are simple and are trouble free. With the development of teflon seals, ball valve have grown in popularity. Opening or closing a ball valve too quickly can cause fluid hammer. Normally used above 3" NPS because ion small valves pressure drop is more.

Check Valve

Check valve, Non return valve is basically a directional control valve which allows the flow in on direction only. An important concept in check valves is the cracking pressure which is the minimum upstream pressure at which the valve will operate. Typically the check valve is designed for and can therefore be specified for a specific cracking pressure.

Gate Valve

A gate valve, also known as a sluice valve are designed to operate fully open or fully closed. Because they operate slowly they prevent fluid hammer, which is determined to piping systems. There is very little pressure loss through a gate valve. In the fully closed position, gate valve provide a positive seal under pressure.

Globe Valve

Globe valves , as is the case with all valves designs, have both advantages and disadvantages. Like a gate, they close slowly to prevent fluid hammer. You can thittle the flow and they will not leak under low pressure when they are shut off. Flow and pressure control valves as well as hose bibs generally use the globe pattern.

Solenoid Valve

A solenoid valve is an electromechanically operated valve. The valve is controlled by an electric current through a solenoid: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports.

Installation Control Valve

The alarm check valve is a water flow alarm device designed for vertical installation in the main supply to a wet pipe sprinkler system. When a flow of water from the system equals or exceeds that of a single sprinkler, the valve is to actuate a fire alarm.

Smoke Detector

A device that detects visible or invisible particles of combustion.

Aspirated smoke detectors

Aspiring-type systems eg (Vesda Systems) are more effective in etecting smoke than point type detectors in many applications. The sensitivity of the actual ‘sampling points’ is dependent on the sensing chamber sensitivity and the design of the aspiring pipe network.

Heat Detector

A fire detector that detects either abnormally high temperature or rate of temperature rise, or both

Carbon Monoxide (CO) fire detectors

Carbon Monoxide (CO) fire detectors

MultiSensor Detector

CO fire detectors respond to the presence of carbon monoxide (CO) in fires involving carbon based materials. CO is produced due to incomplete combustion during smouldering or slow burning fires. Not suitable for the detection of slow burning fires.

Flame Detector

Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line (such as a propane or a natural gas line), and activating a fire suppression system.

Battery Smoke Alarms

Are available in ionization and photo-electrical. Refer to comments above including suitable location

Beam Detector

An optical beam smoke detector is a device that uses a projected beam of light to detect smoke across large areas, typically as an indicator of fire. They are used to detect fires in buildings where standard point smoke detectors would either be uneconomical or restricted for use by the height of the building.

Fire - Gas Detector

Fire - Gas Detector

Ionization Smoke detectors

Ionization smoke detectors respond to very small smoke particles a wide range of responses. They are most sensitive to hot fast burning fires, and less sensitive to slow smouldering fires. Don’t locate them near cooking area’s, or in locations subject to high air velocity.

Hard wired smoke alarms

Are available in ionization and photo-electrical and are connected to a 240w power source, such as a lighting circuit. A battery back up ensures when power is shut off a working smoke alarm exists as long as the battery is in working order. Suitable to be linked to other smoke alarms

Flame Detector

A radiant energy–sensing fire detector that detects the radiant energy emitted by a flame

Linear beam smoke detectors

Linear beam smoke detectors measure the reduction of intensity of a beam of light due to the presence of smoke particles. They have road response to a wide range of smoke types, and are particularly useful for detection applications in large spaces. Require careful installation.

Combination Detector

A device that either responds to more than one of the fire phenomenon or employs more than one operating principle to sense one of these phenomenon. Typical examples are a combination of a heat detector with a smoke detector or a combination rate-of-rise and fixed-temperature heat detector.

Photoelectric smoke detectors

Photoelectric smoke detectors typically respond faster to a fire in its early, smoldering stage – before the source of the fire bursts into flames. These detectors are more sensitive to the large combustion particles that emanate during slow, smoldering fires, which usually occur at night when people are asleep.

Access Door

A door assembly, for installation in fire-rated walls or having a specific listing for installation in fire-rated floors or ceilings of floor-ceiling or roof-ceiling assemblies, that is used to provide access to shafts, chases, attics, spaces above ceilings, or other concealed spaces.

‘A’ gauge

Pressure gauge connected to a town main connection, between the supply pipe stop valve and the non-return valve.

Actuating Mechanism

A mechanism whose automatic or manual operation leads to the discharge of extinguishing agent.


Any device that allows fire hose couplings to be safely interconnected with couplings of different sizes, threads, or mating surfaces, or that allows fire hose couplings to be safely connected to other appliances.

Adjusting Device.

An auxiliary equipment system component; a connector device that allows adjustment to be made to a piece of equipment.


A characteristic of coal that causes coking on the fuel bed during volatilization.


A product that is dispensed from an aerosol container by a propellant

Agent Quantity

Mass of solid aerosol-forming compound required to achieve the design application density within the protected volume within the specified discharge time.

Aircraft Rescue and Fire Fighting.

The fire-fighting actions, performed both inside and outside of aircraft, that are taken to rescue persons and to control or extinguish fire involving or adjacent to aircraft on the ground.

Airport (Aerodrome)

An area on land or water that is used or intended to be used for the landing and takeoff of aircraft and includes buildings and facilities.

Airport Ramp

Any outdoor area, including aprons and hardstands, where aircraft can be positioned, stored, serviced, or maintained, irrespective of the nature of the surface of the area

Alarm check Valve

A check valve, of the wet, dry or composite type, which is specifically designed to allow a means of alarm notification when water flows through it. Each type of sprinkler systems mentioned in clause 3.2 have alarm check valves connected thereto.

Alarm Test Valve

A valve through which water may be drawn to test the operation of the water motor firm alarm and/or of any associated electric fire alarm.


A change or modification that results in a deviation from the original design specifications or criteria.

Alternate Power Source

One or more generator sets, or battery systems where permitted, intended to provide power during the interruption of the normal electrical service; or the public utility electrical service intended to provide power during interruption of service normally provided by the generating facilities on the premises


A device indicating an off-standard or abnormal condition by both visual and audible signals.

Anti-freeze system

Wet pipe sprinkler systems employing automatic sprinklers attached to a piping network containing anti-freeze solution and that are connected to a water supply. The anti-freeze solution is discharged, followed by water, immediately upon operation of sprinklers opened by heat from a fire


An accessory or attachment that enables the private fire service main to perform its intended function.

Arm Pipe

A pipe less than 300mm long, other than the last section of a range pipe, feeding a single sprinkler.

Ascent Device

An auxiliary equipment system component; a friction or mechanical device utilized to allow ascending a fixed line.

Assembly Occupancy.

An occupancy (1) used for a gathering of 50 or more persons for deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar uses; or (2) used as a special amusement building, regardless of occupant load.

Assumed Maximum Area of Operation

Hydraulically Most Favorable Location : The location in a sprinkler array of an AMAO of specified shape at which the water flow is the maximum for a specific pressure.


The device in a burner that breaks down liquid fuel into a finely divided state.

Attack Hose

Hose designed for use by trained fire fighters and fire brigade members to combat fires beyond the incipient stage.

Augmented Air Firing.

Supplementary firing with the addition of air at the duct burners to support and stabilize combustion or to reduce emissions.

Automatic-Closing Door

Doors that normally are open but that close when the automatic-closing device is activated.

Auto ignition Temperature

The minimum temperature required to initiate or cause self-sustained combustion of a solid, liquid, or gas independently of the heating or heated element.

Automatic Aid

A plan developed between two or more fire departments for immediate joint response on first alarms.

Automatic Changeover Regulator

An integral two-stage regulator that combines two high-pressure regulators and a second-stage regulator into a single unit designed for use with multiple cylinder installations.

Automatic Detection Equipment

Equipment that automatically detects heat, flame, products of combustion, flammable gases, or other conditions likely to produce fire or explosion and cause other automatic actuation of alarm and protection equipment.

Automatic Fire Check

A flame arrester equipped with a check valve to shut off the fuel gas supply automatically if a backfire occurs.

Automatic Transfer Switch

Self-acting equipment for transferring the connected load from one power source to another power source.

Auxiliary Air

Air that is supplied from an auxiliary source to maintain a minimum fuel mixture velocity in burner piping.

Auxiliary Fuel

In a fluidized bed boiler, generally a gaseous or liquid fuel used to warm the bed material sufficiently to allow ignition of the main fuel upon injection into the heated bed material.

Average Upper Gas Layer Temperature

Temperature based on the average of the four ceiling quadrant thermocouples and the center of the room ceiling thermocouple.

‘B’ gauge

Pressure gauge connected to and on the same level as an alarm valve, indicating the pressure on the upstream side of the valve.

Back Stock Area

The area of a mercantile occupancy that is physically separated from the sales area and not intended to be accessible to the public.

Barrier Layer

The layer of garment material, glove material, footwear material, or face protection device material designated as providing blood and body fluid-borne pathogen resistance.

Bed Compartment

Segments of a fluidized bed, which might be individually controlled with respect to combustion airflow and fuel feed.

Biological Terrorism Agents

Biological materials that are capable of causing an acute disease or long-term damage to the human body.


A vertically sliding door in which half of the door moves up and half of the door moves down in order to open, or a horizontal sliding door in which one door moves to the right and one moves to the left in order to open.

Body Fluids

Fluids that are produced by the body, including, but not limited to, blood, semen, mucus, feces, urine, vaginal secretions, breast milk, amniotic fluid, cerebrospinal fluid, synovial fluid, and pericardial fluid.


Pillows or similarly shaped units containing upholstery material covered by upholstery cover material, which might or might not be attached to the upholstered furniture item but are sold and delivered with it.

Booster Hose

non-collapsible hose used under positive pressure having a elastomeric or thermoplastic tube, a braided or spiraled reinforcement, and an outer protective cover.

Borrowed Lite.

A stationary window unit that is installed in an interior partition that allows the passage of natural or artificial light from one area into an adjoining space.

Box Track.

Box Track.

Boiler Control System

The group of control systems that regulates the boiler process, including the combustion control system but not the burner management system.

Branch Lines

The pipes supplying sprinklers, either directly or through sprigs, drops, return bends, or arm-overs.

Break Tank

A tank providing suction to a fire pump whose capacity is less than the fire protection demand (flow rate times flow duration).


A load-bearing connector that is an integral part of an auxiliary equipment system component and used to connect two pieces of webbing.

Building Automation System

An automated system used to control building functions such as HVAC control, lighting, and smoke management.


A device or group of devices for the introduction of fuel and air into a combustion chamber at the velocity, turbulence, and concentration required to maintain ignition and combustion of fuel.

Burner Shutoff Valve

In a pulverized fuel system, a valve that is installed in the fuel line between the pulverizer and the burner.

Bypass Stack

A stack applied in addition to and separate from the normal HRSG exhaust stack that allows combustion turbine exhaust gas to flow independently to the atmosphere.

‘C’ gauge

Pressure gauge connected to and on the same level as an alarm valve, indicating the pressure on the downstream side of the valve


The endothermic chemical reaction that takes place when converting calcium carbonate or calcium hydroxide to calcium oxide.


An auxiliary equipment system component; an oval or D-shaped metal, load-bearing connector with a self-closing gate used to join other components of a rope system.


A method of storage consisting of corrugated cardboard or paperboard containers fully enclosing the commodity

Center Latch.

A latch used to hold the two halves of a center-parting or biparting fire door together, which is usually two pieces surface-applied to doors and interlocked in the closed position.

Channel Frame

frame that consists of head and jamb members of structural steel channels, either shop assembled or field assembled, to be used with masonry walls.


Carbonaceous material formed by pyrolysis or incomplete combustion.

Charging Valve

In a gaseous or liquid fuel system, a small valve bypassing the main safety shutoff valve used for purging and charging the fuel headers and piping and for testing for leaks.

Chemical Plant

A large integrated plant or that portion of such a plant, other than a refinery or distillery, where liquids are produced by chemical reactions or used in chemical reactions.

Cinder Return

In a stoker-fired boiler, an apparatus for the return of collected cinders to the furnace, either directly or with the fuel.

Claims Analyst

An internal or external person (depending on risk financing processes being used) expected to investigate the claim, evaluate it, prepare a position, ensure the appropriate “network” is involved, and, if necessary, begin negotiation of a settlement.

Claims Occurrence

The loss occurs during the policy period, the claim can be made at any time.

Cleaning Glove

Multipurpose glove, not intended for emergency patient care, that provides a barrier against body fluids, cleaning fluids, and disinfectants and limited physical protection to the wearer during cleaning or care of emergency medical clothing and equipment.

Coking Plate

A plate adjacent to a grate through which no air passes and on which coal is placed for distilling the coal volatiles before the coal is moved onto the grate.

Compliant Product

Product that is covered by this standard and has been certified as meeting all applicable requirements of this standard that pertain to the product.

Concealed Sprinkler

A recessed sprinkler with cover plate.

Concentration-Time Curve

A plot of the concentration of a gaseous toxicant (ppm) as a function of time

Concrete Lintel

A precast concrete horizontal member spanning and carrying the load above an opening.

Condensed Aerosol

An extinguishing medium consisting of finely divided solid particles, generally less than 10 microns in diameter, and gaseous matter, generated by a combustion process of a solid aerosol-forming compound.

Combustion Chamber

The portion of the boiler or HRSG enclosure into which the fuel is fed, ignited, and burned.

Combustion Control System

The control system that regulates the furnace fuel and air inputs to maintain the air-fuel ratio within the limits that are required for continuous combustion and stable flame throughout the operating range of the boiler in accordance with demand.

Corrosion-Resistant Sprinkler

A sprinkler fabricated with corrosion-resistant material, or with special coatings or platings, to be used in an atmosphere that would normally corrode sprinklers.

Coupling Assembly

A complete coupling including its gaskets and the expansion rings or collar pieces used in attaching the coupling to the hose.

Cross Mains

The pipes supplying the branch lines, either directly or through riser nipples.

Cut-Off or open Sprinkler

A sprinkler protecting a door or window between two areas only one of which is protected by the sprinkler.

Day-Care Occupancy

An occupancy in which four or more clients receive care, maintenance, and supervision, by other than their relatives or legal guardians, for less than 24 hours per day.

Descent Control Device

An auxiliary equipment system component; a friction or mechanical device utilized with rope to control descent.

Design or demand Area

The design or demand area is a theoretical area of the sprinkler operation within a protected building in M2 representing the worst case area where a fire could burn.

Design Factor (DF).

A fraction of the agent minimum design quantity (MDQ) added thereto deemed appropriate due to a specific feature of the protection application or design of the suppression system.

Design Pressure Difference

The desired pressure difference between the protected space and an adjacent space measured at the boundary of the protected space under a specified set of conditions with the smoke-control system operating.

Detrimental Event

An incident or circumstance that produces or threatens to produce undesirable consequences to persons, property, or the environment that might ultimately be measured in terms of economic or financial loss.

Direct Gas-Fired Tank Heater

A gas-fired device that applies hot gas from the heater combustion chamber directly to a portion of the container surface in contact with LP-Gas liquid.

Discharge Device

A device designed to discharge water or foam­water solution in a predetermined, fixed, or adjustable pattern. Examples include, but are not limited to, sprinklers, spray nozzles, and hose nozzles.

Discharge Port

A passage such as nozzles or openings on an aerosol generator where aerosol is released when the generator is actuated.

Disconnect Switch

A manually operated switch, electrically supervised and secured from unauthorized use, that prevents the automatic or manual electrical actuation of the aerosol generators during maintenance by electrically opening the releasing circuit.

Dispersed Aerosol

An extinguishing medium consisting of fine particles of chemicals, generally less than 10 microns in diameter, already resident inside a pressurized agent storage container, suspended in a halocarbon or an inert gas.

Distribution Pipe

The piping network of a tree-type sprinkler system that provides water to the branch lines. A pipe feeding either arrange pipe directly or a single sprinkler on a non-terminal range pipe more than 300 mm long.

Direct Fired System

A system in which the fuel is pulverized and delivered in suspension directly to the burner

Door Closer

A labeled device that, where applied to a door and frame, causes an open door to close by mechanical force. The closing speed can be regulated by this device.

Door Holder

A labeled, fail-safe device, controlled by a detection device, used on an automatic-closing door to release the door at the time of fire.

Double Egress Doors

A pair of swinging doors, each leaf of which swings in the opposite direction of the other.

Drain Time

The time that it takes for a specified percent (customarily 25 percent) of the total solution that is contained in the foam to revert to liquid and drain out of the bubble structure.

Dry Sprinkler

A sprinkler secured in an extension nipple that has a seal at the inlet end to prevent water from entering the nipple until the sprinkler operates.

Duct Burner

A burner, mounted in a duct or discharging into a duct, used to heat the air, flue gas, or combustion turbine exhaust gas in the duct.

Dump Valve

An automatic valve installed on the discharge side of a positive displacement pump to relieve pressure prior to the pump driver reaching operating speed.

Dust Collector

An auxiliary separator that is used to separate the fuel dust from the air or inert gas prior to discharge of the latter from the system

Dutch Door

A door divided horizontally so that the lower part can be shut while the upper part remains open.

Early Suppression Fast-Response (ESFR) Sprinkler

Early Suppression, Fast Response) ceiling mounted sprinklers can be used in warehouses in place of in-rack fire sprinkler systems. ... ESFR high output, high volume systems are located in ceiling spaces as with conventional fire sprinkler systems.

Educational Occupancy

An occupancy used for educational purposes through the twelfth grade by six or more persons for four or more hours per day or more than 12 hours per week.

Electrical Clearance

The unobstructed air distance between extinguishing system equipment, including piping and nozzles, and unenclosed or uninsulated live electrical components not at ground potential.


The selective removal of fine solids from a fluidized bed by entrainment in the upward flowing products of combustion.

Emergency Medical Garment

An item of emergency medical protective clothing designed and configured as a single garment or an assembly of multiple garments to provide barrier protection to the wearer~s upper and lower torso, excluding the hands, face, and feet.

End Suction Pum

A single suction pump having its suction nozzle on the opposite side of the casing from the stuffing box and having the face of the suction nozzle perpendicular to the longitudinal axis of the shaft.

Ensemble Elements

The parts or items that comprise the chemical/biological terrorism incident protective ensemble.

Escape Belt

A belt that is certified as compliant with the applicable requirements of this standard for an escape belt, and that is intended for use only by the wearer as an emergency self-rescue device.

Escape Descent Control Device

An auxiliary equipment system component; a friction or mechanical device utilized with escape rope to control descent.

Explosion Vent

A vent to relieve explosion pressures resulting from ignition of a mixture of decomposition gases and air.

Extended Coverage Sprinkler

Extended coverage sprinklers are available in both standard response (EC) and quick response (QR-EC). ... These sprinklers are typically used in hotels, restaurants, office buildings, warehouses, and other areas where it is desirable to reduce the overall number of required sprinklers.

Extinguishing Application Density (g/m3)

Minimum mass of a specific aerosol-forming compound per cubic meter of enclosure volume required to extinguish fire involving particular fuel under defined experimental conditions excluding any safety factor.

Extra-large orifice (ELO) sprinkler

A type of spray sprinkler which discharges at a hemispherical pattern, provide greater flows at lower pressures in comparison to standard or large orifice sprinklers. (Also called CMDA – Control Mode density Application) sprinklers)

Exhauster Fan

A fan located at the pulverizer outlet used to draw the primary air through the pulverizer and to deliver the primary air-fuel mixture to the burner(s) or other apparatus.

Expansion Ratio

The ratio of the volume of the foam in its aerated state to the original volume of the non-aerated foam solution.

Exposure Fire

A fire that starts at a location that is remote from the area being protected and grows to expose that which is being protected.

Exposed plastic commodities

Those plastics not in packaging or coverings that absorb water or otherwise appreciably retard the burning hazard of the commodity.

Feed Mains

The pipes supplying cross mains, either directly or through risers

Fire and Emergency Services Personnel

Members of fire departments, other governmental agencies, or other organizations that have the public safety responsibilities and who would respond to terrorism incidents where a chemical terrorism agent(s),biological terrorism agent(s), or dual-use industrial chemical(s) has been or could be released.

Fire Door Assembly

Any combination of a fire door, a frame, hardware, and other accessories that together provide a specific degree of fire protection to the opening.

Fire Door Frame

A component, forming the perimeter of an opening in a fire door assembly, that is supplied welded or knocked down and anchored to the surrounding structure.

Fire Exit Hardware

Labeled devices for swinging fire doors installed to facilitate safe egress of persons and generally consisting of a cross bar and various types of latch mechanisms that cannot hold the latch in a retracted locked position.

Fire Pump Alarm

A supervisory signal indicating an abnormal condition requiring immediate attention.

Fire Pump Controller

A group of devices that serve to govern, in some predetermined manner, the starting and stopping of the fire pump driver and to monitor and signal the status and condition of the fire pump unit.

Fire Shutter

A labeled door assembly used for the protection of a window opening in an exterior wall.

Firestop System

An approved method that utilizes a combination of materials and/or devices, which could include the penetrating items, required to form a complete firestop.

Flame Baffle

A hinged piece of sheet metal within the hood that, when released, closes the space between the top of the curtain and the hood of a rolling door.

Flame Spread Index

A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame vs. time.

Flame Travel Distance

Distance that the flame travels beyond the extent of the gas burner flame.

Flexible Connecting Shaft

A device that incorporates two flexible joints and a telescoping element.

Flexible Coupling

A device used to connect the shafts or other torque-transmitting components from a driver to the pump, and that permits minor angular and parallel misalignment as restricted by both the pump and coupling manufacturers.

Flooded Suction

The condition where water flows from an atmospheric vented source to the pump without the average pressure at the pump inlet flange dropping below atmospheric pressure with the pump operating at 150 percent of its rated capacity.

Flue space

The spaces between rows of storage. Flue spaces that are less than a net 75 mm wide are not considered flue spaces for fire protection purposes. In addition, any space between rows of storage that exceeds 600 mm horizontally is considered an aisle for fire protection design purposes.

Flush Bolts, Automatic

A mortised bolt installed near the top or bottom of the inactive leaf of a pair of doors that holds the inactive leaf in a closed position until the active leaf is opened.

Flush Bolts, Manual

A mortised bolt installed near the top or bottom of the inactive leaf of a pair of doors in which the bolts are manually extended or retracted into or out of the header or sill by means of a lever.

Flush Sprinkler.

A sprinkler in which all or part of the body, including the shank thread, is mounted above the lower plane of the ceiling.

Foam Concentrate

The foaming agent as received from the supplier that, when mixed with water, becomes foam solution.

Foam Solution

A homogeneous mixture of foam concentrate and water in the mix ratio required to meet the needs of the user.

Foam­Water Density

The unit rate of foam­water solution application to an area, expressed in [L/min m 2 (gpm/ft2)].

Foam­Water Deluge System

A foam­water sprinkler system employing open discharge devices, which are attached to a piping system that is connected to a water supply through a valve that is opened by the operation of a detection system, which is installed in the same areas as the discharge devices. When this valve opens, water flows into the piping system and discharges from all discharge devices attached thereto.

Foam­Water Dry Pipe System.

A sprinkler system employing automatic sprinklers or nozzles that are attached to a piping system that contains air or nitrogen under pressure, the release of which (as from the opening of a sprinkler) permits the water pressure to open a valve known as a dry pipe valve. The water then flows into the piping system and out the opened sprinklers

Foam­Water Preaction System

A sprinkler system employing automatic sprinklers or nozzles attached to a piping system containing air that might or might not be under pressure, with a supplemental detection system installed in the same area as the sprinklers. Actuation of the detection system opens a valve that permits water to flow into the sprinkler piping system and to be discharged from any sprinklers that have activated

Foam­Water Spray System

A special system that is pipe­connected to a source of foam concentrate and to a water supply. The system is equipped with foam­water spray nozzles for extinguishing agent discharge (foam followed by water or in reverse order) and for distribution over the area to be protected. System operation arrangements parallel those for foam­water sprinkler systems as described in the definition of Foam­Water Sprinkler System.

Forestry Fire Hose

A hose designed to meet specialized requirements for fighting wildland fires.


Indicates a ratio of air to fuel supplied to a furnace that provides less than the minimum excess air needed for optimum combustion of the fuel.

Full Pneumatic

A closed system consisting of loading stations with inner doors and a fire-rated, normally locked, outer (intake) door; normally closed air damper above the topmost loading station; transport piping, both vertical and horizontal; waste or linen collector; fan with a fan damper; and a central process controller.

Fugitive Emission

Releases of flammable vapor that continuously or intermittently occur from process equipment during normal operations.

Furniture Mock-Up.

A representation of production furniture that uses the same upholstery cover material and upholstery material, assembled in the same manner as in production furniture but with straight, vertical sides.

General-Purpose Warehouse

A separate, detached building or portion of a building used only for warehousing-type operations.


In condensed aerosol systems, a device for creating a fire-extinguishing medium by pyrotechnical means.

Generator Casing

The surface of the generator, excluding the surface containing the discharge ports.

Glazing Angle Clips

Steel clips used to hold glass in place in windows glazed only with glazing compound. Glazing angles are attached to window members with screws and are covered completely by the glazing compound.

Gravity Pneumatic Transport System

A combination of a gravity chute and a horizontal pneumatic transport system. The gravity pneumatic system includes gravity chutes with a material discharge valve at the bottom, an air source at or near the bottom of the chute, air control dampers, horizontal piping with a pipe tee to connect to the chute, a collector, and a fan and fan damper.

Gridded layout

Sprinkler systems in which parallel cross mains are connected by multiple branch lines. An operating sprinkler will receive water from both ends of its branch line, while the other branch lines help transfer water between cross mains.


That water that is available from a well, driven into water-bearing subsurface strata (aquifer).

Halocarbon Agent

An agent that contains as primary components one or more organic compounds containing one or more of the elements fluorine, chlorine, bromine, or iodine.

Hand Hose Line System

A hose and nozzle assembly connected by fixed piping or connected directly to a supply of extinguishing agent.

Hard Suction Hose

A hose used for drafting water from static supplies (lakes, rivers, wells, and so forth). It can also be used for supplying pumps on fire apparatus from hydrants if designed for that purpose. The hose contains a semi rigid or rigid reinforcement designed to prevent collapse of the hose under vacuum.

Hazard Current

For a given set of connections in an isolated power system, the total current that would flow through a low impedance if it were connected between either isolated conductor and ground.

Hazardous Material

Material presenting dangers beyond the fire problems relating to flash point and boiling point.

Hazardous Reaction

Reactions that result in dangers beyond the fire problems relating to flash point and boiling point of either the reactants or of the products

Health Care Occupancy

An occupancy used for purposes of medical or other treatment or care of four or more persons where such occupants are mostly incapable of self-preservation due to age, physical or mental disability, or because of security measures not under the occupants’ control.

Heat-Actuated Device

Devices that include fixed temperature releases, rate-of-temperature-rise releases, and door closers with hold-open arms embodying a fusible link.

Heat Flux

Rate of heat transferred per unit area to surface, typically expressed in kilowatts/m2, kilojoules/sec-m2 or Btu/sec-ft2.

Heat Flux Meter

An instrument used to measure the level of heat flux energy incident on a surface.

Heat Transfer Fluid (HTF).

A liquid that is used as a medium to transfer heat energy from a heater or vaporizer to a remote heat consumer (e.g., injection molding machine, oven, or dryer, or jacketed chemical reactor).

High piled storage

Solid piled, freestanding, palletized, rack storage and shelved storage where the height exceeds 4M.

Hold Time

Period of time during which an extinguishant is required to maintain an even distribution throughout the protected volume in an amount at least at the extinguishing application density.

Hotel - Occupancy

A building or groups of buildings under the same management in which there are sleeping accommodations for more than 16 persons and primarily used by transients for lodging with or without meals.

Hot Work

Work involving burning, welding, or a similar operation that is capable of initiating fires or explosions

Hydraulically Calculated

A term applied to pipe work sized as specified in clause 10.5 or an installation in which all the pipe work downstream of the main installation control valve set is sized.

Hydraulically designed system

A calculated sprinkler system in which pipe sizes are selected on a pressure loss basis to provide a prescribed water density, in LPM/M2, or a prescribed minimum discharge pressure or flow per sprinkler, distributed with a reasonable degree of uniformity over a prescribed area.


The propensity for ignition, as measured by the time to sustained flaming, in seconds, at a specified heating flux.

Impact Switch

A device that can be attached to a power-operated fire door to stop or reverse the closing motion of a power-operated door upon meeting an obstruction.

Inactive Leaf

One door of a pair of doors that ordinarily is latched closed; the second operating door of a pair.

Indirect Attack

Fire-fighting operations involving the application of extinguishing agents to reduce the buildup of heat released from a fire without applying the agent directly onto the burning fuel.

Industrial Occupancy

An occupancy in which products are manufactured or in which processing, assembling, mixing, packaging, finishing, decorating, or repair operations are conducted.

Inert Gas Agent

An agent that contains as primary components one or more of the gases helium, neon, argon, or nitrogen. Inert gas agents that are blends of gases can also contain carbon dioxide as a secondary component.


The inner part of the protective footwear upon which the foot rests and that conforms to the bottom of the foot.

Inspected Vessel

A vessel operated on the navigable waterways of the United States that is subject to the regulations in 46 CFR, which require it to be certificated and inspected as a passenger ship, cargo ship, oceanographic ship, or tank vessel.

Intermediate level or Rack storage sprinkler

A sprinkler that is installed within a storage rack. A sprinkler equipped with integral shields to protect its operating elements from the discharge of the sprinklers installed at higher elevations. These sprinklers are typically K-5.6 (K-80), K-8.0 (K-115) or K-11.2 (K-160) non-storage ones equipped with an attached water shield over the top of the thermal sensing element. The water shield prevents wetting of the thermal sensing element by water from sprinklers at a higher elevation in the rack or at ceiling level

Institutional Occupancy

A building or structure or any portion thereof used by persons who are harbored or detained to receive medical, charitable, or other care or treatment or by persons involuntarily detained.

Institutional Sprinkler

A sprinkler specially designed for resistance to load-bearing purposes and with components not readily converted for use as weapons.

Ladder Belt

A belt that is certified as compliant with the applicable requirements of this standard and is intended for use as a positioning device for a person on a ladder.

Laser Safety Personnel

One who has authority to monitor and enforce the control of laser hazards and to effect the knowledgeable evaluation and control of laser hazards.

Large drop sprinklers

A type of spray sprinkler that is capable of producing characteristic large water droplets and is listed for its capability to provide fire control of specific high-challenge fire hazard. (Also called CMSA – Control Mode Special Application) sprinklers

Large-Stream Device

Any device that discharges water at a flow rate greater than 400 gpm (1600 L/min).

Life Safety Rope

Rope dedicated solely for the purpose of supporting people during rescue, fire-fighting, other emergency operations, or during training evolutions.

Life safety system

Sprinkler systems forming an integral part of measures required for the protection of life, especially where evacuating the building depends on the performance of the sprinkler system and sprinklers are required expressly for life safety purposes

Liquid Warehouse

A separate, detached building or attached building used for warehousing-type operations for liquids.

Local Application System

A system consisting of a supply of extinguishing agent arranged to discharge directly on the burning material.

Looped layout

Sprinkler system in which multiple cross mains are tied together so as to provide more than one path for water to flow to an operating sprinkler and branch lines are not tied together

Loss of Phase

The loss of one or more, but not all, phases of the polyphase power source.

Low Suction Throttling Valve

A pilot-operated valve installed in discharge piping that maintains positive pressure in the suction piping, while monitoring pressure in the suction piping through a sensing line.

Main Fuel

In a fluidized bed boiler, gaseous, liquid, or solid fuel introduced into the bed after the bed temperature has reached a value sufficient to support its combustion and that is used during the normal operation of the boiler. Main fuels necessitate the use of the fluidized hot bed as their ignition source.

Manual Transfer Switch

A switch operated by direct manpower for transferring one or more load conductor connections from one power source to another

Mass Loss Concentration

The mass loss of a test specimen per unit exposure chamber volume (g·m-3).

Mass Median Aerodynamic Diameter (MMAD)

The measurement, with the geometric standard deviation, used to describe the particle size distribution of any aerosol statistically, based on the weight and size of the particles.

Marine Systems

Systems installed on ships, barges, offshore platforms, motorboats, and pleasure craft.

Maximum Allowable Working Pressure

The maximum gauge pressure permissible at the top of completed equipment, a container, or a vessel in its operating position for a design temperature.

Mercantile Occupancy

An occupancy used for the display and sale of merchandise


A fixed or removable vertical member set in a double door opening that allows both leaves to be active or set between a door and a side light or a separate, framed, glazed area.

Net Positive Suction Head (NPSH

The total suction head in feet (meters) of liquid absolute, determined at the suction nozzle, and referred to datum, less the vapor pressure of the liquid in feet (meters) absolute.


A type of ensemble that provides protection to the upper and lower torso, head, hands, and feet but does not cover the wearer~s respirator.

No threaded Coupling

A coupling or adapter in which the mating is achieved with locks or cams but without the use of screw threads.

Obstructed Construction

Panel construction and other construction where beams, trusses, or other members impede heat flow or water distribution in a manner that materially effects the ability of sprinklers to control or suppress a fire.

Occupancy Classification

The system of defining the predominant operating characteristic of a portion of a building or plant for purposes of applying relevant sections of this code.

Office Occupancy

A building or structure or any portion thereof used for the transaction of business or the rendering or receiving of professional services.

Optical Density of Smoke (OD).

Smoke obscuration described in terms of logarithmic ratio of initial light intensity to instantaneous light intensity.

Overfire Air

Air supplied for combustion that is admitted into the furnace at a point above the burners or fuel bed.


The final stages of fire extinguishment, following knockdown of the main body of fire, during which pockets of fire are sought out to complete extinguishment.

Palletized storage

A Storage arrangement whereof commodities are stored on pallets. Pallet loads are placed one on top of another with the bottom load located directly on the floor.

Particulate Density

The density of solid particulate in grams per cubic meter after discharge of the aerosol system at the design application density. This information is used to assess the degrees of visibility obscuration and the potential health effects of accidental exposure to the agent.

Passive Fire Protection (PFP) Materials

Two distinct types are coating materials and panel materials.

Passive Fire Protection — Coating Materials

A material that is applied to a substrate and is designed to protect it from thermal effects.

Passive Fire Protection — Panel Materials

A material in the form of a panel or sheet, including pre-formed components, which are designed to stand alone prior to application to a steel substrate


An active cause of loss, such as a hurricane, fire, or accident.

Pendent sprinkler

Sprinkler designed to be installed in such a way that the water stream is directed downward towards the deflector which in turn directs the water downwards toward the protected area. The sprinkler is designed to have the deflector oriented vertically below the pipe to which the sprinkler is connected.

Pilot Ignition

The ignition of a material by radiation where a local high-temperature igniting source is located in the stream of gases and volatiles issuing from the exposed material.

Pilot Line Detector

standard spray sprinkler or thermostatic fixed-temperature release device used as a detector to pneumatically or hydraulically release the main valve, controlling the flow of water into a fire protection system.

Pilot Plant

An experimental assembly of manufacturing equipment for exploring process variables or for producing semi commercial quantities of materials.

Positive Displacement Pump

A pump that is characterized by a method of producing flow by capturing a specific volume of fluid per pump revolution and reducing the fluid void by a mechanical means to displace the pumping fluid.

Post flashover

The stage of a room fire during which average air temperature in the upper half of the room exceeds 600°C.

Potential Heat of a Material

The difference between the gross heat of combustion per unit mass of a representative specimen of the material and the heat of combustion per unit mass of any residue remaining after exposure of a representative specimen of the material to a defined heat source using combustion calorimetric techniques.

Power-Operated Fire Doors

Doors that normally are opened and closed electrically, pneumatically, or mechanically.


A structure, usually of greater length than width and projecting from the shore into a body of water with direct access from land, that can be either open deck or provided with a superstructure.


A term applied to pipework sized as specified in clause 10.4- or an installation in which pipe downstream of the design point is sized by calculations.

Pre-Engineered System

A system that has predetermined flow rates, nozzle placement, and quantities of carbon dioxide and that incorporates specific nozzles and methods of application that can differ from those detailed elsewhere in this standard and those that are listed by a testing laboratory.

Prep rimed System

A wet pipe system containing foam solution.

Pressurized Stairwells

A type of smoke-control system in which stair shafts are mechanically pressurized, with respect to the fire area, with outdoor air to keep smoke from contaminating them during a fire incident.

Primary Agent Supply

The amount of agent in the system primary agent supply shall be at least sufficient for the largest single hazard protected or group of hazards to be protected simultaneously.

Protected Volume

Volume enclosed by the building elements around the protected enclosure, minus the volume of any permanent impermeable building elements within the enclosure.

Pumping Liquid Level

The level, with respect to the pump, of the body of liquid from which it takes suction when the pump is in operation. Measurements are made the same as with the static liquid level.

Quick-Response (QR) Sprinkler

Quick response fire sprinkler heads are primarily used in light hazard applications and have a higher discharge pattern than standard response fire sprinkler heads.


Fused or stitched with thread through the upholstery cover material and through one or more layers of upholstery material


Any combination of vertical, horizontal and diagonal structural members that support stored materials or commodities.

Radiological Agents

Radiation associated with x-rays, alpha, beta, and gamma emissions from radioactive isotopes, or other materials in excess of normal background radiation levels.

Recessed Sprinkler

A sprinkler in which all or part of the body, other than the shank thread, is mounted within a recessed housing.


A plant in which flammable or combustible liquids are produced on a commercial scale from crude petroleum, natural gasoline, or other hydrocarbon sources.

Relay-Supply Hose

A single-jacket fire hose of 3 ½-in. (90-mm) diameter or larger used to move large volumes of water at low pressure aC224:C226nd manufactured prior to January 1987 to meet the requirements of the 1979 and previous editions of NFPA 1961, Standard on Fire Hose.


The physical discharge or emission of aerosol as a consequence of the condensed aerosol generator~s actuation or operation of the dispersed aerosol agent container.

Rolling Steel Door

A closure consisting of an interlocking steel slat curtain, bottom bar, wall guides, and an automatic-releasing device that, on release, causes the curtain to close.

Rope Grab Device

An auxiliary equipment system component; a device used to grasp a life safety rope for the purpose of supporting loads; can be used in ascending a fixed line.

Safety Alert

The action by which a manufacturer identifies a specific compliant product or a compliant product component, provides notice to users of the compliant product, and informs the marketplace and distributors of potential safety concerns regarding the product or component.

Safety Factor (SF).

A multiplier of the agent flame extinguishing or inserting concentration to determine the agent minimum design concentration.

Safety Margin

The difference between a predicted value and the actual value where a fault condition is expected.

Sea Level Equivalent of Agent

The agent concentration (volume percent) at sea level for which the partial pressure of agent matches the ambient partial pressure of agent at a given altitude.

Sea Level Equivalent of Oxygen

The oxygen concentration (volume percent) at sea level for which the partial pressure of oxygen matches the ambient partial pressure of oxygen at a given altitude.


Any permanent attachment of two or more materials in a line formed by joining the separate material pieces.

Service Counter Door

A labeled fire door assembly used for the protection of openings in walls where the primary purpose of the opening is for nonpedestrian use, such as counter service for food, a pharmaceutical dispensary, package and baggage transfer, or observation ports.

Service Test

Hydrostatic test conducted by users on all in-service hose to determine suitability for continued service.

Shelf storage

Storage on structures up to and including 750mm in depth and separated by aisles at least 750mm wide.

Side Light

An opening in a fire door frame alongside the fire door opening that is filled with glazing material

Side Light Frame

A fire door frame prepared for the application of a glazing material alongside the door opening.

Side Panel Frame

A door frame prepared for the installation of a fixed solid metal or wood panel alongside the door opening

Sidewall sprinkler

Sprinkler having special deflector that are designed to discharge most of the water away from the nearby wall in a pattern resembling one quarter of a sphere, with a small portion of the discharge directed at the wall behind the sprinkler.

Slatted shelf rack

A rack where shelves are fixed in place with a series of narrow individual solid supports used as the shelf material and spaced apart with regular openings.

Slow Operating Valve

A valve that has a mechanism to prevent movement of the flow regulating element from the fully closed position to the fully opened position or vice versa in less than 3 seconds.

Slug Flow

The discharge of distinct pockets of air and water or weak foam solution due to the insufficient or uneven mixing of foam concentrate, water, and air in a compressed air foam system (CAFS).

Smoke Developed Index

A comparative measure, expressed as a dimensionless number, derived from measurements of smoke obscuration vs. time.

Smoke Exhaust System

A mechanical or gravity system intended to move smoke from the smoke zone to the exterior of the building, including smoke removal, purging, and venting systems, as well as the function of exhaust fans utilized to reduce the pressure in a smoke zone.

Smoke Obscuration

The reduction of light transmission by smoke, as measured by light attenuation.

Smoke Refuge Area

An area of the building separated from other spaces by fire resistance rated smoke barriers in which a tenable environment is maintained for the period of time that such areas might need to be occupied at the time of fire.

Solid Aerosol-Forming Compound

A solid mixture of oxidant, combustible component and technical admixtures that produces a condensed aerosol upon actuation.

Solid piled storage

On-floor storage, without pallets or other material handling devices. Storage of commodities stacked one over the other leaving no horizontal spaces between unit loads..

Solvent Distillation Unit

An appliance that distills a flammable or combustible liquid to remove contaminants and recover the liquid.


The conditioned element, item, component, or composite that is tested. Specimens are taken from samples

Spiral Reinforcement

A hose reinforcement consisting of pairs of layers of yarn spiraled with no interlacing between the individual layers. The layers of yarn in each pair are spirally wound in opposite directions. A layer of rubber separates each pair of spiraled layers.

Splash-Resistant Eyewear

Safety glasses, prescription eyewear with protective side shields, goggles, or chin-length face shields that, when worn properly, provide limited protection against splashes, spray, spatters, or droplets of body fluids.

Spray sprinkler

Has a paraboloid water distribution directed towards the ground over a definite protection area. These sprinklers shall discharge from 80 or more percent of the total water flow in a downward direction.

Spring Release Device

A device that, when activated, releases part of the spring counterbalancing force and causes the door to close.

Sprinkler rosette

Plate covering the gap between the shank or body of a sprinkler projecting through a suspended ceiling, and the ceiling

Stack Effect

The vertical airflow within buildings caused by the temperature-created density differences between the building interior and exterior or between two interior spaces

Standpipe System and Mobile Supply

A system consisting of a mobile supply of carbon dioxide, designed to be quickly moved into position and connected to a system of fixed piping, supplying fixed nozzles or hose lines or both that are designed for either total flooding or local application.

Static Liquid Leve

The level, with respect to the pump, of the body of liquid from which it takes suction when the pump is not in operation. For vertical shaft turbine–type pumps, the distance to the liquid level is measured vertically from the horizontal centerline of the discharge head or tee.

Stay Rollers

A device used on horizontally sliding doors at their back lower corners to guide the door and prevent the door from moving away from the wall under fire conditions.

Storage Life

The life expectancy of the protective ensemble from the date of manufacture when it is only stored and inspected and has undergone proper care and maintenance in accordance with manufacturer~s instructions, but not used, donned, doffed, or repaired.

Storage Tank.

Any vessel having a liquid capacity that exceeds 230 L (60 gal), is intended for fixed installation,and is not used for processing.

Submersible Pump

A pump that is located inside a storage tank and positioned near the bottom of the tank, below the liquid level.

Suction Hose

A hose that is designed to prevent collapse under vacuum conditions so that it can be used for drafting water from below the pump (lakes, rivers, wells, etc.).

Super pressurization

The addition of gas to a fire extinguishing agent container to achieve a specified pressure therein.

Supervisory Device

Adevice arranged to supervise the operative condition of automatic sprinkler systems.

Supervisory Shutoff Valve

In a gaseous or liquid fuel system, a manually operated shutoff valve with a means to provide a “valve closed” position signal.

Supervisory Signal

A signal indicating the need for action in connection with the supervision of guard tours, the fire suppression systems or equipment, or the maintenance features of related systems.

Supply Hose

Hose designed for the purpose of moving water between a pressurized water source and a pump that is supplying attack lines.

Sustained Flaming

The uninterrupted existence of a flame on or over the surface of a test specimen for a specified time period.

System Riser

The aboveground horizontal or vertical pipe between the water supply and the mains (cross or feed)that contains a control valve (either directly or within its supply pipe), pressure gauge, drain, and a water flow alarm device.

Tenable Environment

An environment in which smoke and heat are limited or otherwise restricted to maintain the impact on occupants to a level that is not life threatening.

Thermal Clearance

The air distance between a condensed aerosol generator and any structure or components sensitive to the temperature developed by the generator.

Terminal Main Configuration

A pipe array with only one water supply route to each range pipe.

Terminal Range Configuration

A pipe array with only one water supply route from a distribution pipe.

Third Party Administrator (TPA).

An organization contracted by a self-insured employer to handle the administrative aspects of the employer~s plan.

Torch Fire

An ignited discharge of propane vapors under pressure.

Total Flooding System

A system consisting of a supply of carbon dioxide arranged to discharge into, and fill to the proper concentration, an enclosed space or enclosure around the hazard.

Total Discharge Head

The reading of a pressure gauge at the discharge of the pump, converted to feet (meters) of liquid, and referred to datum, plus the velocity head at the point of gauge attachment.

Trace Number

code that can be used to retrieve the production history of a product

Trunk Mains

A pipe connection to two or more water supply pipes to the installation main control valve set(s).


Buttoned or laced through the upholstery cover material and through the upholstery material.

Unlined Hose.

A hose consisting of only a woven jacket that is usually of linen yarns and is of such quality that the yarn swells when wet, tending to seal the hose.

Unloader Valve

A valve that is designed to relieve excess flow below pump capacity at set pump pressure.

Uninspected Vessel

A vessel operated on the navigable waterways of the United States that is subject to the regulations in 46 CFR Subchapter C, Parts 24–28, including pleasure craft, tugboats, towing vessels, and certain fishing vessels.

Unobstructed construction

Construction where beams, trusses and other building members do not impede the heat flow or water distribution in a manner that materially affects the ability of sprinklers to control or suppress a fire.

Upholstery Cover Material

The outermost layer of fabric or related material used to enclose the main support system, upholstery materials, or both, used in a furniture item.

Upholstered Furniture

For the purpose of this test method, a unit of interior furnishing that has any surface covered, in whole or in part, with a fabric or related upholstery cover material, contains upholstery material, and is intended or promoted for sitting or reclining

Upholstery Material

The padding, stuffing, or filling material used in a furniture item, which can be either loose or attached, enclosed by an upholstery cover material, or located between the upholstery cover material and support system, if present.

Upright sprinkler

Sprinkler designed to be installed in such a way that the water stream is directed upward against the deflector which in turn redirects the water downwards toward the protected area. The sprinkler is designed to have the deflector oriented vertically above the pipe to which the sprinkler is connected.

Utility Connection Assembly

A single hookup assembly located on the site and containing connections for any of the following: potable water, sewer inlets, electrical power, phone, or television.

Valve-Proving System

In a gaseous or liquid fuel system, a system that proves the leak tightness of all safety shutoff valves and prevents main burner or igniter light-off if the test is not satisfied.

Visible Smoke.

The obscuration of transmitted light caused by combustion products released during the test.

Visor Material

The transparent chemical-protective clothing material that allows the wearer to see outside the chemical/biological terrorism incident protective ensemble.

Volatile Matter

The portion of mass, except water vapor, that is driven off in a gaseous form when solid fuels are heated.

Warp Direction

In woven textiles, that direction on the roll of fabric that is parallel to the selvedges.

Waste Processing Systems and Equipment

Devices and processes used to change the physical form or characteristics of waste.

Water flow Alarm Device

An attachment to the sprinkler system that detects a predetermined water flow and is connected to a fire alarm system to initiate an alarm condition or is used to mechanically or electrically initiate a fire pump or local audible or visual alarm.

Water-Miscible Liquid

A liquid that mixes in all proportions with water without the use of chemical additives, such as emulsifying agents.


The cord or piping sewn into the seam or border edge of a cushion, pillow, arm, or back of a furniture item.

Wetting Ability

The ability of foam solution to penetrate and soak into a solid.


Astructure at the shoreline, having a platform built along and parallel to a body of water with either open deck or provided with a superstructure.

Window sprinklers

Sprinklers specifically listed to provide appropriate fire rating for heat strengthened or tempered glass windows using closed sprinklers.

Oxygen Consumption Principle.

The expression of the relationship between the mass of oxygen consumed during combustion and the heat released

Heating Flux.

The incident radiant heat flux imposed externally from the heater on the specimen at the initiation of the test

Effective Heat of Combustion

The measured heat release divided by the mass loss for a specified time period


A room in which the concentration of airborne particles is controlled to specified limits. Cleanrooms include areas below the raised floor and above the ceiling grid if these areas are part of the air path and within the rated construction.

Fire Propagation Index (FPI).

The propensity of a material to support fire propagation beyond the ignition zone in terms of the chemical heat release rate during upward fire propagation and TRP.

Smoke Yield (ys).

The mass of smoke particulates generated per unit mass of fuel vaporized.

Thermal Response Parameter (TRP).

A material characteristic that gives resistance to ignition upon exposure to a prescribed heat flux.

Critical Heat Flux (CHF)

The minimum heat flux at or below which there is no ignition.

Effective Heat of Combustion (EHC).

The energy generated by chemical reactions per unit mass of fuel vaporized.

Smoke Turbidimeters

The smoke turbidimeter measuring system shall measure smoke extinction coefficient and both characteristic smoke particle size and particle number density

Averaging Pitot Probe and Pressure Transducer

The averaging Pitot probe shall be inserted through a test section port 220 mm to 230 mm downstream of the thermocouple port and shall measure the mass flow rate of the gas stream by using at least four sets of flow-sensing openings.

Fire Propagation Test.

The fire propagation test shall be performed to determine the FPI of a material, through measurement of the chemical heat release rate of a vertical specimen during and after upward fire propagation.


The water space to be occupied by a boat or other vessel alongside or between bulkheads, piers, piles, fixed and floating docks, or any similar access structure.


A facility used for constructing, repairing, servicing, hauling from the water, storing (on land and in water), and launching of boats.


A vertical structural wall, usually of stone, timber, metal, concrete, or synthetic material, constructed along, and generally parallel to, the shoreline to retain earth as an extension of the upland, and often to provide suitable water depth at the waterside face.

Combustible Liquid

Any liquid that has a closed-cup flash point at or above 100°F (37.8°C).

Docking Facility

A covered or open, fixed or floating structure that provides access to the water and to which boats are secured.

Flammable Liquid

A liquid that has a closed-cup flash point that is below 100°F (37.8°C) and a maximum vapor pressure of 40 psia (2068 mm Hg) at 100°F (37.8°C).

Fuel Product Lines

Piping that connects the fuel storage tanks to the fuel dispensing pumps.

Fuel Storage

An area or structure (i.e., tank) that contains fuel products in storage for subsequent dispensing.

Fueling Station or Pier

An area on a pier, dock, bulkhead, or similar structure that is specifically used for the dispensing of fuel products.


A facility, generally on the waterfront, that stores and services boats in berths, on moorings, and in dry storage or dry stack storage.

Marine Power Outlet

An enclosed assembly that can include receptacles, circuit breakers, fused switches, fuses and watt-hour meter, and monitoring means approved for marine use.

Hold Space

The space enclosed by the ship’s structure in which a cargo containment system is situated.

Primary Barrier

The inner element designed to contain the cargo when the cargo containment system includes two boundaries

Secondary Barrier

The liquid-resisting outer element of a cargo containment system designed to afford temporary containment of any envisaged leakage of liquid cargo through the primary barrier and to prevent the lowering of the temperature of the ship’s structure to an unsafe level.

Interbarrier Space.

That space between a primary and secondary barrier, whether or not completely or partially occupied by insulation or other material.

Cryogenic Liquid

A refrigerated liquefied gas having a boiling point lower than -90°C (-130°F ).

Cargo Area

That part of the ship that contains the cargo containment system, cargo pump room, and compressor room and that includes the deck areas over both the full beam and the length of the ship located above the aforementioned.

Flammable Compressed Gas.

Any flammable gas that has been compressed, liquefied, or compressed and liquefied for the purpose of transportation and has a Reid vapor pressure exceeding 2.76 × 105 Pa (40 psia).

Coiled Vessels

Tank vessels using a closed system of heating coils that use thermal oil as the heating medium.

Tank Barge

Any tank vessel not equipped with a means of self-propulsion.

Tank Ship

Any tank vessel propelled by power or sail.

Visual Inspection

The physical survey of the space or compartment and surroundings in order to identify potential atmospheric and fire hazards.

Cold Work

Any construction, alteration, repair, or shipbreaking that does not involve heat-, fire-, or spark-producing operations.

Hot Work

Any activity involving riveting, welding, burning, the use of powder actuated tools or similar fire producing operations as well as grinding, drilling, abrasive blasting, or similar operations not isolated physically from any atmosphere containing more than 10 percent of the lower explosive limit of a flammable or combustible substance.

Pascal~s law

Principle 1, known as Pascal~s law, points out that pressure acts in all directions and not simply downward.



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