CO Fire Sprinkler key terms

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

The hydraulically most distant portion of the sprinkler system that is assumed to be flowing at design density when calculating water demand, sometimes adjusted for slope and ceiling height.

The floor area, expressed in square feet, over which sprinkler discharge is assumed to occur for hydraulic calculation purposes, determined by occupancy hazard and construction features.

A step-by-step pressure and flow analysis of the piping network that proves the water supply can deliver the required density to the most demanding sprinklers while meeting minimum residual pressure.

A numerical discharge coefficient that relates water pressure at a sprinkler to the flow rate it produces, expressed as flow equals K times the square root of pressure.

A value describing how freely a sprinkler orifice passes water; higher coefficients allow more flow at the same pressure and are used for high-hazard or storage applications.

The pressure remaining in a water supply main while a specified flow is being drawn, measured during a flow test and used to build the supply curve for calculations.

The pressure reading in a water supply main when no water is flowing, used together with residual pressure to determine how much the supply drops under demand.

A plotted relationship between flow and residual pressure for a given water source, showing how much pressure remains as demand rises and whether the system demand point falls within it.

The extra pressure or flow added above calculated system demand to account for uncertainties such as supply fluctuations, pipe roughness, and future changes in the water network.

A heat-activated device with a sealed orifice that opens at a rated temperature to spray water in a designed pattern over a specific floor area below it.

The heat-sensitive component of a sprinkler, such as a fusible link or glass bulb, that fails at its rated temperature to release the seal and start water flow.

A soldered or brazed two-piece assembly in a sprinkler that melts apart at a specific temperature, allowing the orifice cap to be ejected and water to discharge.

A sealed liquid-filled vial in a sprinkler that shatters when heated, with the liquid color coding the activation temperature of the sprinkler.

The nominal activation temperature marked on a sprinkler, chosen to be above expected ambient heat but low enough to operate early in a fire.

The metal plate or frame part at the sprinkler outlet that breaks up the water stream into a controlled spray pattern matched to the sprinkler's listing and installation orientation.

The shape and distribution of water thrown by an operating sprinkler, which must cover the design area without excessive gaps or dry spots.

A sprinkler installed so its deflector hangs below the piping and discharges downward, commonly used under flat ceilings in occupied spaces.

A sprinkler mounted with its deflector above the piping and spraying upward toward the ceiling, used where piping is exposed and subject to overhead obstruction.

A sprinkler with a special deflector that throws water outward and downward from a wall mounting, used where ceiling piping is impractical and spacing is limited.

The maximum and minimum distances permitted between sprinklers and between sprinklers and walls, set by hazard classification and ceiling construction to ensure full coverage.

The maximum floor area that one sprinkler is permitted to protect, determined by hazard and ceiling conditions and used to lay out the sprinkler grid.

A sprinkler system in which the piping is always filled with pressurized water, so a sprinkler opens and discharges immediately upon activation.

A sprinkler system with air or nitrogen pressure in the piping and water held back by a valve, used where freezing temperatures make wet piping impractical.

A differential valve that holds water back with air pressure above it and opens when sprinkler operation releases enough air to let water pressure overcome the seat.

A system with dry piping that admits water only after a fire detection signal confirms a fire, protecting areas where accidental water discharge would be costly.

A system with open sprinklers or nozzles on all lines, where a single detection signal opens a control valve and floods the entire protected area at once.

A device that speeds opening of a dry pipe valve by quickly venting air from the intermediate chamber when the system begins losing pressure.

The time between sprinkler activation and water reaching the most remote sprinkler in a dry system, a critical performance measure that must be kept short.

An exterior pipe fitting where responding crews can pump additional water into the sprinkler system to supplement the on-site supply during a fire.

The vertical section of sprinkler piping that carries water up through a building and typically holds the main control valve, gauges, and alarm devices.

A valve and outlet at the low point of the system used to drain the piping and to conduct flow tests that verify the water supply and alarm operation.

A device that senses sustained water movement in the piping and triggers an alarm, distinguishing real flow from small pressure fluctuations.

A mechanical alarm driven by water passing through the system, sounding a local bell when a sprinkler or valve opens.

A support component that holds sprinkler piping at required intervals so the pipe weight and water flow forces do not cause sagging or failure.

Lateral and longitudinal restraints that keep sprinkler piping from swinging during earthquakes or water surge, protecting joints from damage.

A structural member or fitting installed to resist lateral or longitudinal movement of piping, often used together with hangers in seismic areas.

A small valve at the end of the most remote branch line that simulates a single sprinkler opening, used to test alarm and flow-switch response.

Any ceiling member, duct, or object that blocks the spray from reaching the floor, requiring additional sprinklers or adjusted placement to maintain coverage.