DE Fire Sprinkler key terms

The minimum water flow rate, in gallons per minute, that must be delivered over each square foot of protected floor area. It is selected from the occupancy hazard classification and drives sprinkler spacing and pipe sizing.

The assumed operating area of sprinklers, in square feet, used in a hydraulic calculation. It is adjusted for ceiling height, dry systems, sloped ceilings, and quick-response sprinklers under the standards.

The hydraulically most demanding set of sprinklers in the system, meaning the heads that require the highest pressure to supply the design density. Pipe sizing and layout are checked against this area.

The point on a supply curve where the available water supply pressure equals the system demand pressure. It confirms the supply can meet both the required flow and the residual pressure at the base of the riser.

A graph or table showing the static pressure, residual pressure, and flow available from a water supply at a reference point. It is compared with the system demand curve to verify adequacy.

The water pressure measured when no water is flowing. It is used to check components, verify supply conditions, and establish the starting point for evaluating a water supply.

The pressure remaining at a reference point while water is flowing at a measured rate. It reflects friction losses in the supply and is the key value in determining available flow.

A field test that measures static pressure, residual pressure, and the flow rate from hydrants or test outlets to establish the available water supply for a sprinkler system design.

The empirical relationship used to adjust a flow test result to a different pressure, where flow varies with the 1.85 power of pressure. It allows designers to estimate available flow at the required residual pressure.

An extra allowance added to the calculated system demand so the supply exceeds the requirement by a set amount. It accounts for uncertainty in test data and future changes in the supply.

The categorization of an occupancy as light, ordinary, or extra hazard based on the amount and combustibility of its contents. The classification sets design density, design area, and sprinkler spacing limits.

An occupancy classification for areas with moderate to high combustibility and moderate quantities of combustibles, such as certain mercantile and storage areas. It requires higher design density than Group 1.

The most severe occupancy classification, covering areas with very high combustibility or flammable liquids and dusts. It requires the highest design densities and often protection of a larger design area.

The maximum and minimum distances permitted between sprinklers along a branch line and between branch lines. Spacing limits depend on hazard class, ceiling type, and the sprinkler's listed coverage.

The largest floor area a single sprinkler is permitted to cover, set by its listing and the hazard class. It is calculated from the spacing along and between branch lines.

The smaller pipe that carries water to individual sprinklers or to short groups of sprinklers. Branch lines connect to cross mains, which connect to the riser.

The main pipe feeding a series of branch lines. It is larger in diameter than branch lines and carries water from the riser or feed main to the branch lines it serves.

The vertical supply pipe that carries water from the supply main to the overhead piping. It usually includes the control valve, check valve, alarm connection, and main drain.

The short pipe section connecting the riser to the system piping above. It is often where the flow switch, pressure gauge, and alarm test valve are installed.

A sprinkler system in which the piping is filled with water under pressure at all times. It is the most common type and discharges water immediately when a sprinkler activates.

A system where the piping above the control valve holds compressed air or nitrogen and fills with water only after a sprinkler opens and the valve trips. It is used where piping is subject to freezing.

A valve that holds back water with a differential of air pressure above and water pressure below. It opens when air escapes through an open sprinkler and the air pressure drops enough to trip the valve.

A device on a dry pipe system that accelerates the release of air so the dry pipe valve trips sooner. It reduces the time between sprinkler activation and water delivery.

A system with open sprinklers or nozzles and a control valve that opens on a detection signal, discharging water from all nozzles at once. It is used for high-hazard or special protection areas.

A system where a detection system must operate before the control valve opens and water fills the piping. It protects areas where accidental discharge would cause serious damage.

A valve that allows water to flow in one direction only. It prevents backflow and keeps water from draining back out of the system or into the public supply.

An assembly that stops water from reversing into the potable supply. It is often required when a sprinkler system connects to a public water main and must be tested periodically.

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

A device that senses water movement in the riser or piping and sends an alarm signal. It must be tested to confirm it operates within the required time after flow begins.

A signal initiated by a flow switch or pressure switch when water moves through the system. It alerts occupants and the monitoring company that a sprinkler or valve has opened.

A valve at the end of the most remote branch line that simulates a single sprinkler opening. It is opened during testing to confirm the alarm and waterflow switch operate properly.

The step-by-step computation of pressure losses through pipes, fittings, and devices to prove the supply can deliver the design density over the design area with adequate residual pressure.

The standard equation used to calculate friction loss in water-filled sprinkler piping. It uses flow rate, pipe internal diameter, pipe length, and a roughness coefficient for the pipe material.

The pressure lost as water moves through pipe, fittings, and valves due to resistance. It is added to elevation and device losses to determine the total system demand.

A number describing a sprinkler's discharge characteristics, relating flow to the square root of pressure. It is used to compute flow from a sprinkler at a given pressure.

The series of tests performed when a system is completed, including hydrostatic, flow, alarm, and trip tests. Passing them is required before the system is placed in service.

A pressure test of the piping, conducted at a pressure above the working pressure for a set duration, to prove the system is leak-free before being placed in service.

A condition where a sprinkler system or part of it is out of service or unable to perform as designed. It requires notification, a tag, and a documented plan until restored.

A temporary patrol or monitoring measure used when a fire protection system is impaired or during certain hot work. It ensures early detection and notification until protection is restored.

Any work involving open flames, sparks, or heat that could ignite materials, such as welding or cutting. It requires a permit and often a fire watch and sprinkler protection measures.

The state body that adopts and enforces fire prevention regulations in Delaware, including requirements affecting sprinkler installation and inspection. Contractors should confirm current state-adopted codes.

The organization or official responsible for approving equipment, installations, and procedures under the applicable code. In Delaware this may be a state, county, or local fire official.

The official authorization required before installing, altering, or repairing a sprinkler system. It is issued by the local or state authority after plans are reviewed and fees are paid.

The process where the authority examines submitted drawings and hydraulic calculations for code compliance before issuing a permit. Approval is usually required before installation begins.

The state or local requirement that a business and its qualifying individual hold a license to perform sprinkler work. Unlicensed contracting can lead to penalties and invalid permits.

A document, often called a contractor's material and test certificate, that records the installed system, test results, and sign-offs. It is provided to the owner and authority at turnover.