ME Fire Sprinkler key terms

The minimum amount of water, expressed in gallons per minute, that must flow onto each square foot of protected floor area during a fire. It sets the hydraulic starting point for sprinkler calculations.

The remotest area of sprinkler coverage, measured in square feet, that must be assumed to be flowing simultaneously when sizing pipe and water supply. Its size can be reduced for certain ceiling and sprinkler configurations.

The mathematical procedure that sums friction losses, elevation changes, and fitting losses through pipe to confirm the water supply can deliver the required pressure and flow at the most demanding sprinklers.

A graph or table showing the static pressure, residual pressure, and available flow from a public main, tank, or other source, used to judge whether the supply exceeds system demand.

The extra pressure or flow kept in reserve between the sprinkler system demand and the available water supply, so that normal supply fluctuations do not leave the system inadequate.

The pressure remaining at a test hydrant or gauge while water is flowing, as opposed to static pressure with no flow. It is the value used to plot the water supply curve.

The portion of the sprinkler system hydraulically farthest from the water supply, where pressure is lowest and which therefore governs the calculation. It often corresponds to the design area.

The maximum permitted distance between adjacent sprinklers and between sprinklers and walls, governed by ceiling height, sprinkler type, and hazard classification.

The floor area assigned to one sprinkler, found by multiplying its spacing along branch lines by the distance between branch lines. It limits how much area a single head may protect.

The required vertical clearance between the sprinkler deflector and the ceiling or roof above it, which allows the water spray pattern to develop properly and reach the fire.

The smaller-diameter pipe carrying water to individual sprinklers, fed by a cross main or feed main. Branch line size and the number of heads it serves affect friction loss.

The pipe that supplies water to branch lines and runs perpendicular to them. It is fed by the feed main or riser and is sized to carry the combined flow of all attached branch lines.

The vertical pipe that carries water from the supply main or riser assembly up to the sprinkler piping on each floor, including the riser nipple and associated valves and gauges.

The arrangement of pipe, fittings, valves, gauges, and drains at the point where the water supply enters the sprinkler system, including the main control valve and check valve.

A valve and pipe connection at the low point of the system used to flush the system and to conduct the main drain flow test, which confirms that the water supply can meet demand.

A valve at the remote end of the system that, when opened, simulates the flow of a single sprinkler so the alarm-initiating device and waterflow switch can be tested.

A device or switch that detects sustained water movement in the sprinkler piping and sends a signal to the fire alarm panel or monitoring company, indicating that a sprinkler has operated.

The categorization of an occupancy as light, ordinary, or extra hazard based on the quantity and combustibility of its contents, which determines design density and other requirements.

An occupancy classification for areas with moderate amounts of combustible contents or moderate dust and lint, requiring a higher design density than light hazard occupancies.

Any building element, such as a beam, duct, or light fixture, that can block the spray pattern of a sprinkler and may require an additional sprinkler or a change in layout.

The national standard for the design and installation of automatic fire sprinkler systems, covering occupancy classifications, hydraulic calculations, pipe sizing, and acceptance testing.

The standard for sprinkler systems in low-rise residential occupancies up to and including four stories, offering reduced requirements compared with full commercial systems.

The standard for one- and two-family dwellings and manufactured homes, designed to improve life safety rather than protect property, with limited water supply and duration requirements.

The standard for the inspection, testing, and maintenance of water-based fire protection systems, setting frequencies for gauges, valves, alarms, and flow tests after installation.

The national fire alarm and signaling code, which governs the monitoring, transmission, and testing of sprinkler waterflow and supervisory signals connected to a fire alarm system.

The standard for stationary fire pumps, covering installation, driver types, controllers, and acceptance testing where the water supply pressure is insufficient for the sprinkler system.

The standard for standpipe and hose systems, which are frequently installed alongside sprinkler systems in buildings where hose lines must reach upper floors or large areas.

The official who administers fire safety laws and rules for the state, including adoption of national standards, licensing, plan review, and enforcement of fire codes.

A national consensus code or standard, such as NFPA 13, formally incorporated by reference into state rule so that it carries the force of law in that jurisdiction.

The required pre-construction examination of sprinkler drawings, calculations, and specifications by a qualified reviewer to confirm compliance before installation begins.

Drawings and calculations that have been reviewed and stamped or otherwise accepted by the authority having jurisdiction, authorizing installation to proceed according to those documents.

Revised drawings showing the system as actually installed, including field changes from the approved plans, submitted for record and used during future inspections and modifications.

The organization, office, or individual responsible for approving equipment, installations, and procedures, often the state fire marshal's office or a local fire official.

The on-site testing performed when a new sprinkler system is complete, including hydrostatic pressure testing and main drain flow tests, before the system is placed in service.

A pressure test in which the piping is filled with water and pressurized above normal working pressure for a specified period to reveal leaks before the system is accepted.

The last inspection before a certificate of occupancy or system acceptance, confirming that the installed system matches approved plans and passes required tests.

Any condition in which a sprinkler system or portion of it is out of service or unable to perform as designed, triggering notification, a fire watch, and restoration procedures.

Written authorization from the authority having jurisdiction allowing a sprinkler system to be taken out of service for a defined period, with conditions for notification and restoration.

A temporary patrol by trained personnel, required when a sprinkler system is impaired, to detect fire and notify the fire department until protection is restored.

An electronic signal indicating an abnormal condition in the sprinkler system, such as a closed control valve or low air pressure, rather than an actual fire.