DC Fire Sprinkler flashcards
DC Fire Sprinkler · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Design density
- The minimum water flow rate in gallons per minute per square foot applied over the design area; selected from the occupancy hazard curve and multiplied by the remote area to determine required flow.
- Remote area
- The hydraulically most demanding area of sprinkler operation used in calculations; typically 1,500 square feet for light hazard, increased for dry systems, sloped ceilings, and pitched roofs.
- K-factor
- A sprinkler discharge coefficient relating flow to pressure by Q equals K times the square root of P; a K-5.6 sprinkler flows 5.6 gpm at 1 psi.
- Deflector distance
- The vertical distance from the sprinkler deflector to the ceiling; typically 1 inch below noncombustible or combustible ceilings and at least 18 inches below the ceiling for storage applications.
- Maximum sprinkler spacing
- The greatest allowable distance between sprinklers on a branch line and between branch lines; 15 feet for light hazard and 12 feet for ordinary hazard in hydraulically calculated systems.
- Hose stream allowance
- The water flow reserved for fire department hose use in a hydraulic calculation; typically 100 gpm for light hazard and 250 gpm for ordinary hazard, added to sprinkler demand.
- Sprinkler temperature rating
- The activation temperature of a sprinkler head, typically 155°F or 165°F for ordinary ratings; must be at least 100°F above the maximum expected ceiling temperature.
- Dry-pipe system
- A sprinkler system with air or nitrogen under pressure in the piping; the dry-pipe valve opens when a sprinkler operates and air escapes, allowing water to flow.
- Preaction system
- A system where a detection device must operate before water enters the piping; single-interlock requires detection only, double-interlock requires both detection and sprinkler operation.
- Alarm check valve
- A wet-pipe riser valve that opens on water flow and transmits an alarm through a retard chamber and water motor gong; it also serves as a check valve.
- Waterflow switch
- A device on the riser that detects water flow and sends an alarm signal to the fire alarm panel; typically set to operate at 10 to 30 gpm.
- Tamper switch
- A supervisory device that monitors the open or closed position of a control valve and reports an off-normal condition to the fire alarm panel.
- Escutcheon
- A decorative and functional plate that covers the annular space between the sprinkler and the ceiling or wall; required for recessed and concealed pendants.
- Backflow preventer
- A device such as a reduced-pressure-zone or double-check assembly that prevents contamination of the potable water supply by reverse flow from the sprinkler system.
- Hanger rod sizing
- The diameter of the rod supporting sprinkler pipe; 3/8 inch for pipe up to 2 inches, 1/2 inch for 2.5 to 4 inches, and 5/8 inch for 5 to 6 inches.
- Hydrostatic test
- A pressure test of the piping system, typically 200 psi for 2 hours for systems operating at 150 psi or less, to verify joints and fittings are leak-free.
- Inspector's test valve
- A valve at the most remote end of the sprinkler system, piped to drain, that simulates the flow of a single sprinkler to verify water reaches the end of the line.
- Main drain test
- A flow test at the riser that records static and residual pressure; a residual drop exceeding 10 percent indicates an obstruction or supply problem.
- Pipe pitch
- The slope of sprinkler piping to allow drainage; typically 1/2 inch per 10 feet toward the drain, with auxiliary drains at low points.
- Firestopping
- Listed materials used to seal penetrations through fire-rated assemblies so the fire-resistance rating is maintained; required for sprinkler pipe passing through walls and floors.
- Sway bracing
- Lateral and longitudinal bracing installed to resist seismic forces on sprinkler piping; required in seismic design categories where NFPA 13 mandates it.
- Underground cover
- The minimum depth of cover over the underground supply main, typically 42 inches in the DC area to protect against frost and physical damage.
- Weekly gauge check
- A weekly inspection of the system gauges to confirm normal water and air pressure and that control valves are open and supervised or locked.
- Annual trip test
- A test of a dry-pipe or preaction valve performed annually to verify it opens at the correct air pressure and that water reaches the inspector's test connection.
- Gauge replacement
- Sprinkler system gauges must be replaced every 5 years and whenever the reading is off by more than 5 percent of full scale.
- Sprinkler head replacement
- Heads must be replaced if corroded, painted, damaged, or if they reach 50 years for quick-response or 75 years for standard-response unless sample testing proves them functional.
- NFPA 25
- The standard for inspection, testing, and maintenance of water-based fire protection systems; it defines frequencies and acceptance criteria for sprinkler systems.
- Valve supervision
- All control valves must be open and either locked or electrically supervised; closed valves must be documented and reported to the fire department.
- NFPA 13
- The standard for the design and installation of automatic sprinkler systems in commercial and industrial occupancies; it covers density, spacing, hydraulics, and materials.
- NFPA 13R
- The standard for sprinkler systems in residential occupancies up to and including four stories; it permits reduced design criteria compared with NFPA 13.
- DC fire protection permit
- A permit issued by the DC Department of Buildings and approved by DC Fire and EMS before sprinkler installation; final inspection and acceptance testing are witnessed by the Fire Marshal.
- Master fire protection contractor
- A license issued through the DC Board of Industrial Trades authorizing a contractor to install and maintain fire protection systems; individual installers must work under such a licensee.