Fire Protection Glossary
Aboveground Storage Tank – a horizontal or vertical tank, listed and intended for fixed installation without backfill above or below grade and used within the scope of its approval or listing.
Absolute Pressure – pressure based on a zero reference point, the perfect vacuum.
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.
Acceptable Level of Risk – the minimum risk occurrence magnitude that is accepted by the stakeholders in the community.
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.
AHJ (Authority Having Jurisdiction) – organization, office or individual responsible for approving equipment, materials, installations an procedures.
Alarm System – combination of initiating devices, control panels and indicating appliances, designed to produce an alarm signal in the event of fire.
ANSI (American National Standards Institute) – organization charged with overseeing the development of 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.
Automatic Sprinkler System – fire suppression system that operates automatically in response to the heat from flames. When activated, the fire sprinkler system douses the area in its effect radius with water.
Baffle – an object placed in an appliance to change the direction of or retard the flow of air, air-gas mixtures, or flue gases.
BLEVE – boiling liquid expanding vapor explosion.
Boil-Over – 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.
Breathing Air System – a complete assembly of equipment to compress, store, and deliver breathing air for the filling of respirator breathing air cylinders.
Combustion – chemical process that involves oxidation sufficient to produce light or heat (fire). Combustible objects are objects capable of being set on fire.
Compliance – adherence or conformance to laws and standards.
Discharge Pressure – water pressure on the fire pump discharge manifold at the point of gauge attachment.
Dry Pipe Fire Sprinkler System – automatic fire sprinkler system that stores water in a central tank as opposed to in the pipes. Slightly increases sprinkler response time and is useful in areas where water stored in pipes can freeze.
Detector – device with a sensor that responds to heat or smoke created by a fire.
Duct Detector – fire alarms located in your HVAC ducts designed to detect smoke moving through your building.
Fire Alarm System – system that monitors and annunciates the status of fire alarm or supervisory signal–initiating devices and initiates the appropriate response to those signals.
Fire Control – the process of controlling the size of a fire by dumping water on it to decrease the combustion of items caught in the fire.
Fire Pump – pump that supplies the fire sprinkler system with water.
Fire Pump Controller – group of devices that govern the starting and stopping of the fire pump driver as well as monitoring and signaling the status and condition of the pump.
Fire Sprinkler System – system of pipes and sprinkler heads installed in a building to control and extinguish fires. There are four basic types of sprinkler systems: wet, dry, deluge and pre–action.
FM 200 Fire Suppression System – clean agent fire suppression system with no effect on the ozone layer. Used as a replacement for Halon 1301.
Foam – an aerated fire-extinguishing solution created by mixing air into foam solution to form bubbles.
Hydraulically Designed System – calculated sprinkler system where pipe sizes are selected based on pressure loss to prescribe water density in gallons/minute/sq.ft.
Ionization Smoke Detection – the principle of using a small amount of radioactive material to ionize the air between two differentially charged electrodes to sense the presence of smoke particles. Smoke particles entering the ionization volume decrease the conductance of the air by reducing ion mobility. The reduced conductance signal is processed and used to convey an alarm condition when it meets preset criteria.
Kink Test Pressure – a pressure equal to at least 1.5 times the service test pressure.
Line Gas Regulator – pressure regulator placed in a gas line between the service regulator and the appliance regulator.
Line Supervision – automatic monitoring of circuits and other system components for the existence of defects or faults that interfere with receiving or transmitting an alarm.
Non-Fire-Resistive Building – building of a certain type of construction in which the structural members, including walls, partitions, columns, floors, and roofs, do not qualify as fire-resistive.
Occupancy – the purpose for which a building or portion thereof is used or intended to be used.
Photoelectric Light-Scattering Smoke Detection – principle of using a light source and a photosensitive sensor arranged so that the rays from the light source do not normally fall onto the photosensitive sensor. When smoke particles enter the light path, some of the light is scattered by reflection and refraction onto the sensor. The light signal is processed and used to convey an alarm condition when it meets preset criteria.
Pipe Schedule System – sprinkler system in which pipe sizing is selected from a schedule determined by the occupancy of a building in which a given number of sprinklers are allowed to be supplied from specific pipe sizes.
Sprinkler Head – a sprayer made up of a threaded nipple connecting the head to a water pipe, an activation device such as a fusible link or heat sensitive bulb held in place by a yolk and a deflector that breaks up the water spray into fine droplets.
Sprinkler System – grid of water pipes and sprinkler heads installed in a building to control and extinguish fires.
UL – Underwriters Laboratories, a certification authority for many appliances and systems associated with fire protection.
Wall Hydrant – a hydrant mounted on the outside wall of a building that is fed from interior piping and equipped with control valves located inside the building. Wall hydrants are normally key operated and accessed via the building's exterior.
Water Hammer – a sudden surge of pressure caused when fast moving water is abruptly blocked. This pressure can be as much as seven or more times more powerful than static pressure!
Wet Pipe Fire Sprinkler System – a standard fire sprinkler system, with water stored directly in the pipes held back by the fire sprinkler heads until a fire starts.
Wet Barrel Hydrant – type of fire hydrant sometimes used where there is little to no danger of freezing weather. Each outlet of a wet barrel hydrant is outfitted with a valved outlet threaded for a fire hose.
Working Pressure – the maximum allowable pressure to which a sprinkler system, pipe or hose can be subjected to safely.
Waterflow Detector – a device that detects the flow of water in a deluge system.
Fire Sprinkler Components
Stop Valve – stops water from flowing from the city water supply into the fire sprinkler system if the fire sprinkler system is not going off.
Alarm Valve – disables the stop valve when the fire sprinkler system is activated, allowing for the flow of water into the sprinkler system.
Alarm Test Valve – allows you to test your fire sprinkler system at shut off conditions.
Escutcheon Plate – the small, round shield, often made of metal, around your fire sprinkler head.
Pressure Switch –enables the fire sprinkler system to alert the fire department your fire sprinkler system is going off by watching for a fall in water pressure after the alarm valve.
Flow Switch – monitors the flow of water through different sections of pipe within the automatic fire sprinkler system. If the flow switches sense enough water flowing, they trigger the alarm.
Pressure Gauge – measures the pressure within the fire sprinkler system.