FPAS Fire Systems Design (FSD) key terms

A detection system in which each detector or module has a unique address, letting the control panel identify the exact device in alarm or fault.

A detection system that groups devices into circuits or zones, so the panel reports only the zone containing an alarm rather than the individual device.

A detector that uses a light source and sensor to detect smoke particles scattering light inside a chamber, typically responding faster to visible smoke.

A device that responds to an abnormal rise in temperature or to a fixed high temperature, using a heat-sensitive element rather than smoke sensing.

A manually operated device, usually wall-mounted, that lets a person trigger a fire alarm by breaking glass or pushing a frangible element.

The central unit that receives signals from detection devices, monitors circuits, activates notification appliances, and displays alarm, fault, and supervisory conditions.

A feature that briefly delays alarm reporting from a detector to check for a continuing signal, reducing nuisance alarms from transient smoke or dust.

An audible or visual device such as a sounder, bell, horn, or strobe that warns occupants of a fire alarm condition.

A heat-activated device that opens at a rated temperature to discharge water in a designed spray pattern and, in most types, operate an alarm.

A sprinkler with a fast thermal element, identified by a low response time index, intended to operate sooner and limit fire growth.

A numerical coefficient relating sprinkler discharge flow to the square root of nozzle pressure, used to select orifice size and calculate flow.

The minimum water application rate, usually expressed in millimeters per minute over a stated area, that a sprinkler design must achieve.

The hydraulically most demanding area of sprinkler operation used in calculations, defined by shape and size for the hazard being protected.

A sprinkler system with pipes kept full of pressurized water, so a sprinkler opening discharges water immediately and activates the alarm.

A sprinkler system with pipes filled with compressed air or nitrogen; opening a sprinkler releases the gas, allowing water to enter and flow.

A sprinkler system that requires a fire detection signal to admit water into the piping before sprinkler operation, reducing accidental discharge risk.

A sprinkler system with open heads and a deluge valve that releases water to all nozzles at once when detection or manual release activates.

A device that senses water movement in a sprinkler pipe and sends an alarm or supervisory signal to the fire alarm panel.

A valved connection on a water main, typically outdoors, that supplies water to firefighting hose or pumpers through one or more outlets.

A fixed assembly of small-diameter fire hose wound on a reel, connected to a water supply and intended for first-aid firefighting by occupants.

A valve installed on a vertical fire main, usually in a stairwell or landing, providing a controlled outlet for firefighting hose.

A pipe network that distributes water from a supply source to hydrants, landing valves, hose reels, or sprinkler systems.

The water pressure measured at a point when no water is flowing, representing the stored or elevation-derived pressure available in the system.

The pressure remaining at a point while water is flowing, showing the pressure available after friction losses in the supply.

A test that measures static pressure, residual pressure, and flow rate at a hydrant or outlet to estimate available water supply for firefighting.

A volatile fire suppressant that leaves little or no residue after discharge and is safe for occupied spaces when used at its design concentration.

The suppressant concentration, usually a percentage by volume, that must be maintained in the protected space to extinguish or inert a specific hazard.

The period for which a gaseous agent concentration must remain above the design concentration in a room after discharge, allowing safe egress.

A door-fan test that measures air leakage in an enclosure to predict whether it can retain a gaseous agent for the required hold time.

An audible and visual warning activated automatically before a gaseous system discharges, alerting occupants to leave the protected space immediately.

A system using carbon dioxide as the extinguishing agent, suitable for unoccupied or normally unoccupied spaces because of its asphyxiation risk.

A pre-engineered system that automatically discharges wet chemical onto cooking appliances, filters, and hood plenums to extinguish cooking-oil and deep-fat fires.

A hand-carried or wheeled unit containing an extinguishing agent and manual discharge mechanism, intended for immediate use on small fires.

A classification showing which fire classes an extinguisher can safely tackle, such as Class A, B, C, D, or K.

A pressurized multipurpose extinguisher typically containing ammonium phosphate powder, effective on ordinary combustibles, flammable liquids, and energized electrical equipment fires.

A stored-pressure unit that discharges carbon dioxide gas, mainly for flammable liquid and electrical fires, leaving no residue but providing limited cooling.

An extinguisher containing an alkaline solution that reacts with cooking oils to form a soapy layer, intended for Class K kitchen fires.

A pressure test in which an extinguisher cylinder or hose is filled with water and subjected to a specified pressure to prove structural strength.

A user technique for extinguishers: pull the pin, aim at the base of the fire, squeeze the lever, and sweep the nozzle across the fire.

The maximum distance a person should have to travel from a point in a space to reach a suitable portable extinguisher, set by occupancy hazard.