MA Fire Sprinkler key terms

The minimum water flow rate, in gallons per minute, that must be applied over each square foot of the most hydraulically demanding area of a sprinkler system.

The hydraulically farthest portion of a sprinkler system, used as the basis for sizing calculations because it typically experiences the lowest pressure and flow.

A mathematical analysis of pipe friction losses, elevation changes, and fitting losses used to prove a sprinkler system will deliver the required density and pressure.

A widely used equation for calculating friction loss in water-filled piping based on flow rate, pipe internal diameter, length, and a roughness coefficient.

The roughness coefficient used in the Hazen-Williams formula; lower values indicate rougher pipe and produce greater friction loss.

The extra pressure or flow deliberately left unused in a hydraulic calculation so the system still meets demand as pipes age or the water supply fluctuates.

A graph showing the pressure available from a water source at various flow rates, used to compare supply capability against system demand.

The pressure measured in a water system when no water is flowing, reflecting elevation and the pressure maintained on the supply main.

The pressure remaining in a water system while water is flowing at a measured rate; the drop from static pressure indicates available supply strength.

A field test that measures static pressure, residual pressure, and the flow rate discharged from a hydrant to establish the available water supply.

A number describing a sprinkler's discharge characteristics, relating flow in gallons per minute to the square root of the pressure in psi.

A heat-actuated device that opens at a set temperature to spray water in a defined pattern over a protected area at a specified flow rate.

The nominal temperature at which a sprinkler's heat-responsive element operates, selected to be above expected ambient temperatures in the space.

A heat-sensitive solder or metal element that melts or separates at a designated temperature to release water through a sprinkler.

The metal plate or frame component of a sprinkler that shapes the discharged water into the required spray pattern.

The maximum and minimum permitted distances between sprinklers and between sprinklers and walls, based on hazard and ceiling configuration.

The floor area protected by a single sprinkler, calculated from the spacing layout and limited by the hazard classification.

A valve that opens or shuts off water flow to a sprinkler system and must be supervised or locked in the open position.

The vertical section of pipe connecting the water supply main to the sprinkler system piping, typically containing the main control valve and alarm connections.

A one-way valve on the riser that allows water to flow into the system while preventing backflow out of the sprinkler piping.

A device that monitors and signals a change from the normal condition of a control valve, water level, or pressure, alerting occupants or the fire department.

A valve that both controls water to a sprinkler system and, when opened by water flow, activates an alarm signaling device.

A support device that suspends sprinkler piping from the building structure at required intervals to carry the pipe and water load.

A bracing element that resists lateral or longitudinal movement of sprinkler piping during earthquakes or water surge.

A table-based method of sizing sprinkler pipe by matching pipe diameter to the number of sprinklers downstream, without full hydraulic calculation.

A pump that boosts water pressure from the supply to meet the demand of a sprinkler or standpipe system, typically driven by electric or diesel power.

The discharge pressure a fire pump produces when running at rated speed with zero flow, often the highest pressure the system must withstand.

The device that starts and stops a fire pump automatically or manually and monitors its operating condition, including alarms and shutdowns.

A fixed vertical pipe system with hose connections at various levels, allowing firefighting personnel to attach hoses and obtain water inside a building.

An exterior connection where the fire department can pump supplemental water into a sprinkler or standpipe system.

A water supply pipe, located on private property, that delivers water from a source or public main to a building's fire protection systems.

The standard governing the design and installation of automatic sprinkler systems for commercial, industrial, and storage occupancies.

The standard for sprinkler systems in low-rise residential occupancies up to four stories, permitting reduced design criteria compared with NFPA 13.

The standard for sprinkler systems in one- and two-family dwellings and manufactured homes, focused on life safety rather than property protection.

The standard for inspection, testing, and maintenance of water-based fire protection systems, setting frequencies for valves, alarms, and components.

A test that opens the main drain to measure static and residual pressure at the riser, confirming the water supply and control valves are in working order.

The formal examination of submitted design drawings and calculations by an authority having jurisdiction before construction or installation approval.

Detailed installation drawings showing piping layout, sprinkler locations, sizes, and related details, submitted for review and permitting.

The official or agency responsible for enforcing code requirements and approving installations, plans, and permits for fire protection systems.