NV Fire Sprinkler key terms

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

A step-by-step pressure-loss analysis that sums friction, elevation, and fitting losses from the most remote sprinkler back to the water supply to prove the system delivers the required density at the required pressure.

The hydraulically most demanding cluster of sprinklers, defined by a minimum square footage, that must be calculated to flow at design density. Its size increases for dry systems, sloped ceilings, and certain combustibles.

An added margin of pressure or flow applied to a hydraulic calculation to cover unknowns such as pipe roughness, future changes, and water supply fluctuation. Local practice often requires a set percentage above demand.

A discharge coefficient that describes how freely a sprinkler orifice passes water. Flow equals the K-factor multiplied by the square root of the pressure in psi, so a larger K-factor delivers more water at the same pressure.

The category assigned to an occupancy based on fuel load and expected heat release, such as light, ordinary group 1 or 2, or extra hazard. The classification sets design density, remote area size, and sprinkler spacing limits.

The maximum allowable distance between sprinklers and between the last sprinkler and a wall, governed by hazard classification, ceiling height, and sprinkler listing. It directly limits how much floor area each head protects.

The vertical clearance required between a sprinkler deflector and the ceiling or roof deck so the spray pattern develops properly. It varies with sprinkler type, temperature rating, and whether construction is combustible.

The smaller pipe that carries water to individual sprinklers on a single line. Branch lines feed into cross mains, and their size and the number of heads they serve affect friction loss and balancing.

The larger distribution pipe that supplies water to multiple branch lines and is fed by a feed main or riser. Cross main sizing is a key hydraulic variable and often determines whether the system balances.

The vertical supply pipe that connects the water source or underground main to the overhead sprinkler piping. It typically carries the main control valve, check valve, alarm devices, and drain connections.

A one-way valve at the riser that prevents water from flowing backward out of the sprinkler system into the public supply. It also holds system pressure and is often combined with alarm and pressure switches.

A device that stops contaminated water from reversing into a potable supply. Reduced-pressure zone and double-check assemblies are common on sprinkler connections, and they add friction loss that must be included in calculations.

A graph of available pressure versus flow at a given point in the supply. The system demand point must fall below this curve, and the gap between them shows the margin available for the sprinkler system.

A field test using hydrants and pitot readings that measures static and residual pressure at known flows. The results are extrapolated to estimate the available water supply for design and to verify adequacy.

The pressure in a water system when no water is flowing. It indicates elevation and supply head but says nothing about friction losses once water moves through the system.

The pressure remaining at a test point while a measured flow is being drawn. Comparing it to static pressure reveals the friction loss characteristics of the supply main and the available flow.

The maximum pressure a fire pump produces at zero flow. It is typically a percentage above rated pressure and must be considered when sizing piping, valves, and pressure-reducing devices downstream.

The flow in gallons per minute at which a fire pump is listed to deliver its rated pressure. Pump curves are plotted from churn through overload flow to confirm the system demand falls within an acceptable range.

A fixed piping arrangement with hose valves at various levels that lets firefighters connect hoses and reach upper floors or large areas. Classes are defined by hose size and intended user.

A valved outlet on a standpipe where firefighters attach hose. Its size, thread type, and whether it includes a pressure-reducing feature must match local fire department requirements.

A device that lowers downstream pressure to a safe level for hoses or sprinklers. In standpipe systems it protects firefighters from excessive nozzle pressure at lower floors of tall buildings.

A flow test through the riser drain that compares static and residual pressure to detect obstructions or closed valves in the supply. Results are recorded and compared with baseline readings over time.

A routine check of the system and supply pressure gauges on wet pipe systems to confirm normal conditions and detect leaks or valve problems. Abnormal readings trigger investigation and repair.

A test connection at the end of the most remote branch line that simulates a single sprinkler operating. Opening it verifies that water flows, alarms activate, and the delay time is within limits.

A device or switch that signals when water moves through the system piping. Testing confirms it activates within the required time after flow begins and transmits to the monitoring company.

Electrical monitoring of control valves so that any unauthorized closure sends a trouble signal. Supervised valves must be sealed or locked, and tamper switches must be tested periodically.

A documented field test at churn, rated flow, and overload flow that confirms the installed pump meets its curve. Results are compared with factory data and recorded for the authority having jurisdiction.

The state official responsible for adopting and enforcing the statewide fire code and licensing certain fire protection activities. Local jurisdictions may adopt amendments that are stricter than the state code.

The organization or individual empowered to interpret and enforce code requirements, approve plans, and accept completed work. It may be a state, county, or city fire agency depending on the project location.

The process of submitting drawings, calculations, and product data to the enforcing agency and receiving approval before installation. Work performed without required permits can be ordered removed and may affect licensing.

State or local authorization required to bid and perform fire sprinkler work. Licensing rules typically cover qualification, insurance, bonding, and the scope of work a licensee may legally perform.

A legal claim against property for unpaid work or materials. Contractors must follow statutory notice and deadline requirements to preserve lien rights, and missing them can bar recovery.

A written modification to the contract scope, price, or schedule signed by the parties. Without a signed change order, added work is often difficult to collect and may cause disputes.

Final drawings updated to show actual installed conditions, including rerouted piping and added devices. They support future inspections, maintenance, and modifications and are often required at project closeout.

A pre-task planning method that identifies each step of a job, the hazards involved, and the controls to be used. It documents worker training and supports safe execution of high-risk tasks.

A procedure for isolating energy sources before servicing equipment so that machinery cannot be re-energized unexpectedly. It requires locks, tags, verification, and clear communication among affected workers.

Systems and practices that prevent workers from falling from heights, including guardrails, personal fall arrest, and safe ladder use. Training and inspection of equipment are required before use.

Requirements for erecting, inspecting, and using elevated work platforms, including stable footing, guardrails, and trained operators. Unsafe use is a leading cause of serious injury in sprinkler installation.

A suppression system using electrically nonconductive gaseous agents that extinguish fire without leaving residue. It is common in rooms with sensitive electronics where water damage would be costly.

A dry pipe arrangement in which water is held back by a valve released by detection devices before sprinkler operation. It reduces accidental water discharge in areas where leaks are unacceptable.

An area with unusual fuel, height, or process conditions that standard sprinkler design may not adequately protect. It often requires engineered alternatives such as foam, water mist, or special listing.

The decorative plate that covers the gap between a sprinkler and the ceiling or wall surface. Recessed and concealed types affect deflector position and must match the sprinkler listing.