MI Fire Sprinkler key terms

The minimum rate of water application, in gallons per minute per square foot, that must be delivered over the most hydraulically remote area of a sprinkler system for a given hazard classification.

The portion of a sprinkler system, usually the hydraulically most demanding area, where water flow is assumed to be concentrated when calculating whether the supply can meet design density and pressure requirements.

A grouping of occupancies by fire severity, such as light, ordinary Group 1 or 2, and extra hazard Group 1 or 2, that determines required design density, spacing, and hose allowance.

An additional water flow, expressed in gallons per minute, added to sprinkler demand during hydraulic calculations to account for manual firefighting hose streams used during a fire.

A step-by-step pressure and flow analysis through each pipe, fitting, and device from the most remote sprinkler back to the water source, used to prove the system can deliver its design demand.

A graphical plot of available pressure versus flow at the point of connection, derived from flow test data, showing how much water the public main or private source can deliver.

A field test measuring static pressure, residual pressure, and the flow discharged from hydrants or test outlets to establish the available water supply for hydraulic calculations.

The pressure measured in a water supply system when no water is flowing, expressed in pounds per square inch, used as a baseline in flow test analysis.

The pressure remaining in a water supply while water is flowing at a measured rate during a flow test; it reflects the friction and elevation losses under demand conditions.

The amount of water supply pressure or flow reserved above the calculated system demand to cover uncertainties and fluctuations, typically ten percent or ten psi above demand.

A discharge coefficient specific to a sprinkler that relates flow in gallons per minute to pressure in psi through the formula Q equals K times the square root of P.

The numerical value describing how freely a sprinkler or nozzle passes water at a given pressure; for sprinklers it is the K-factor used in flow calculations.

Pressure lost as water travels through pipe, fittings, and valves due to turbulence and pipe roughness; calculated using formulas such as Hazen-Williams or Darcy-Weisbach.

An empirical equation used to calculate friction loss in water-filled piping based on flow rate, pipe internal diameter, length, and a roughness coefficient C.

A sprinkler system in which automatic sprinklers are connected to piping containing water under pressure at all times, so a fused sprinkler discharges immediately.

A sprinkler system where piping is filled with pressurized air or nitrogen until a sprinkler operates, opening a dry pipe valve and allowing water to enter the piping.

A clapper-style valve with a larger air-side seat area than water-side area, using differential pressure to hold back water until air pressure drops and the valve trips.

A system using closed sprinklers with piping that may be dry, where a detection system must operate before water is admitted, offering protection against accidental discharge.

A sprinkler system with open nozzles connected to dry piping, where operation of a detection or manual device opens a deluge valve to discharge water from all nozzles simultaneously.

A valve that opens on a signal from a detection system or manual release to admit water to open sprinklers or nozzles in a deluge or preaction system.

The time required for a dry pipe valve to open and water to reach the farthest sprinkler after a sprinkler operates, limited to sixty seconds in most installations.

A sprinkler with a thermal sensitivity listed for fast activation, often required in light hazard occupancies and residential occupancies to reduce fire growth time.

The nominal operating temperature at which a sprinkler's heat-responsive element fuses or bursts, selected based on ceiling temperature and stored commodity heat exposure.

The maximum allowable distance between sprinklers and between sprinklers and walls, determined by hazard classification, ceiling type, and sprinkler listing.

The maximum floor area protected by a single sprinkler, set by hazard classification and sprinkler listing, and used with spacing to lay out branch lines.

The required distance between a sprinkler deflector and the ceiling or roof deck, typically one to twelve inches, which ensures proper spray pattern development.

A valve on the supply pipe to a sprinkler system that controls water flow, must be supervised open or clearly marked, and is checked during inspections.

A test connection at the hydraulically most remote part of the system that simulates operation of one sprinkler, used to verify water flow and alarm activation.

A valve and drain connection used to flow water from the system, measure supply capacity, and flush the piping during acceptance testing and routine maintenance.

A device that detects sustained water movement in the system and sounds an alarm, required to activate within a specified time when flow equals or exceeds one sprinkler.

Electrical or mechanical monitoring that signals a supervisory alarm if a control valve is closed or partially closed, required for valves controlling sprinkler systems.

A device mounted on a control valve that sends a signal to the fire alarm panel when the valve is moved from its normal open position.

The set of tests performed after installation, including hydrostatic testing, flow tests, alarm tests, and dry pipe trip tests, to confirm the system meets design and code requirements.

A pressure test of system piping conducted with water at a specified pressure, commonly 200 psi or 50 psi above static pressure, held for two hours to verify integrity.

The formal examination of submitted sprinkler drawings, hydraulic calculations, and specifications by the authority having jurisdiction before a permit is issued.

Detailed installation drawings showing pipe routing, sprinkler locations, hanger details, and hydraulic node information, submitted for approval before construction begins.

The written authorization issued by the authority having jurisdiction allowing installation or alteration of a sprinkler system, subject to plan review and inspection.

The organization, office, or individual responsible for enforcing code requirements and approving equipment, materials, installations, and procedures for fire sprinkler systems.

The administrative rules adopted by the state fire marshal under the Michigan fire prevention code, governing installation, inspection, and maintenance of fire protection systems.

The state official responsible for fire prevention administration, code enforcement, and licensing oversight for fire protection system contractors and installers in Michigan.

The Michigan statute and adopted model codes establishing minimum fire safety requirements, including those for automatic sprinkler systems in specified occupancies.

The credential issued by the state that authorizes a business to contract for fire sprinkler installation, alteration, or maintenance work within the regulated scope.

An individual holding the required certification or license who is responsible for supervising and directing fire sprinkler work performed under a contractor's license.

A credential demonstrating that an individual has met examination and experience requirements to perform or supervise fire sprinkler system work.