MD Fire Sprinkler flashcards
MD Fire Sprinkler · Build recall with a focused review session.
31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Light hazard design density
- Minimum 0.10 gpm/ft² over a 1,500 ft² design area for light hazard occupancies such as offices, churches, and schools under NFPA 13.
- Ordinary Group 2 density
- 0.20 gpm/ft² over 1,500 ft² for occupancies such as parking garages, restaurants, and mercantile areas classified as Ordinary Hazard Group 2.
- Dry-pipe design area increase
- Dry-pipe and double-interlock preaction systems require a 30% increase in the design area to account for the larger volume of gas that must be expelled before water flows.
- Quick-response area reduction
- Wet systems with quick-response sprinklers and ceilings 10 ft or less may reduce the design area to 75% of the standard area; above 10 ft up to 20 ft, 50%.
- K-factor flow formula
- Q = K times the square root of P. A K-5.6 sprinkler at 7 psi discharges about 14.8 gpm; a K-8.0 at the same pressure discharges about 21.2 gpm.
- Hazen-Williams friction loss
- Friction loss per foot equals 4.52 times Q to the 1.85 power, divided by C to the 1.85 power times d to the 4.87 power, with Q in gpm and d in inches.
- Draft curtain area reduction
- A 25% design area reduction is allowed when a full-height noncombustible draft curtain encloses the area, sprinklers are 12 ft or less apart, and one sprinkler is on each side.
- Maximum sprinkler spacing
- Light and Ordinary hazard branch lines permit 15 ft maximum spacing; Extra Hazard permits 12 ft. Maximum coverage per sprinkler is 225, 130, and 100 ft² respectively.
- Deflector distance to ceiling
- Standard spray upright and pendent sprinklers require the deflector 1 in minimum to 12 in maximum below the ceiling, measured perpendicular to the ceiling surface.
- Sidewall sprinkler limits
- Sidewall sprinklers require the deflector 4 in to 6 in below the ceiling, with maximum spacing of 15 ft and maximum coverage of 196 ft² per sprinkler.
- Hanger spacing by pipe size
- 1 in pipe every 12 ft, 1¼ in and 1½ in every 15 ft, and 2 in and larger every 12 ft; the first hanger is within 12 in of a branch line sprinkler.
- Sway bracing requirement
- All pipe 2½ in and larger must be sway braced at intervals not exceeding 40 ft, at the top of risers, and at changes in direction to resist seismic movement.
- Hydrostatic test pressure
- Systems rated 150 psi or less are tested at 200 psi for two hours; systems with higher working pressure are tested at 50 psi above working pressure for two hours.
- Riser assembly components
- A riser includes a main drain, supply and system gauges, alarm check or wet alarm valve, flow switch, and a test valve at the remote end of the system.
- Underground lead-in size
- The underground lead-in must be at least 4 in in diameter for a riser serving more than one sprinkler, with a gate valve and check valve in the riser assembly.
- Weekly gauge inspection
- Wet system gauges must be inspected weekly to confirm normal supply and system pressures; abnormal readings require investigation before the next scheduled test.
- Quarterly waterflow test
- Waterflow alarm devices must be tested quarterly by opening the inspector's test connection and confirming the alarm activates within 90 seconds.
- Annual main drain test
- The main drain flow test is performed annually, recording static and residual pressure; a residual drop exceeding 10% from the prior test signals a supply problem.
- Dry-pipe valve trip test
- Dry-pipe valves must be trip tested annually and internally inspected every five years, with internal parts replaced every three years per NFPA 25.
- Sprinkler replacement intervals
- Fast-response sprinklers are replaced at 20 years and standard-response at 50 years; any sprinkler showing corrosion, paint, or damage is replaced immediately.
- Gauge calibration interval
- Gauges are verified every five years against a calibrated reference; a gauge reading more than 5% off or showing damage must be replaced.
- Impairment fire watch
- When a system is out of service more than 4 hours, a fire watch is required; the fire department and occupants must be notified and restoration documented.
- Antifreeze concentration check
- Antifreeze solution concentration is checked annually and after any addition; the freezing point must protect the piping at the lowest expected ambient temperature.
- Maryland sprinkler code adoption
- Maryland adopts NFPA 13, 13R, 13D, and 25 through the Maryland Building Performance Standards and the State Fire Prevention Code enforced by the State Fire Marshal.
- State Fire Marshal permit
- A permit from the Maryland State Fire Marshal is required before installing, altering, or maintaining a sprinkler system; work may not begin without it.
- Maryland residential sprinkler mandate
- The State Fire Prevention Code requires sprinkler protection in new one- and two-family dwellings and townhouses, and local jurisdictions may adopt stricter rules.
- High-rise sprinkler threshold
- Maryland buildings over 75 ft in height require automatic sprinkler protection throughout, plus a fire command center and standby power for fire pumps.
- Plan submittal contents
- Submittals include hydraulic calculations, sprinkler layout, pipe sizing, hanger and bracing details, water supply test data, and manufacturer product data sheets.
- Water supply test age
- Water supply test data must be no more than 12 months old and must identify static pressure, residual pressure, flow, and the hydrant test location.
- Plan approval expiration
- Plan review approval expires if work does not begin within 12 months; one 12-month extension may be granted upon written request to the authority.
- Final acceptance documentation
- Final acceptance requires the contractor's material and test certificate, hydrostatic test records, and a completed NFPA 25 baseline inspection report.