NV Fire Sprinkler cheat sheet

Density/area method: design density (gpm/ft²) × remote area (ft²) = minimum flow; select density from NFPA 13 curves based on hazard classification.

Hazen-Williams: friction loss per foot = 4.52 Q^1.85 / (C^1.85 × d^4.87), where Q is gpm, d is internal pipe diameter in inches, C is roughness coefficient (120 for steel, 150 for cement-lined cast iron).

Remote area size may be reduced by 25% for dry systems, 30% for double-interlock preaction, and up to 40% for quick-response sprinklers in light hazard, per NFPA 13 allowances.

Minimum design pressure at the most remote sprinkler is 7 psi (0.5 bar) unless the listing requires higher; add 15 psi for safety margin in pump calculations.

Sprinkler K-factor: flow (gpm) = K × √P (psi); K=5.6 for 1/2-inch orifice, K=8.0 for 17/32-inch, K=11.2 for 3/4-inch, K=14.0 for 1-inch, K=25.2 for 1-1/4-inch.

Balance the system by adjusting pipe sizes so that branch line friction losses are within 10% of each other; use the most demanding branch to determine required pressure.

For tree systems, calculate the most remote sprinkler, then work back to the source; for grid systems, use the loop or node method with simultaneous equations.

Include elevation pressure (0.433 psi per foot of rise) and device losses (backflow preventer, alarm valve, check valve) in the hydraulic calculation.

Sprinkler spacing: light hazard max 15 ft between sprinklers and 225 ft² per sprinkler; ordinary hazard max 15 ft and 130 ft²; extra hazard max 12 ft and 100 ft².

Minimum clearance below deflector: 1 inch below ceiling for standard spray upright/pendent; 18 inches below noncombustible ceilings for extended coverage; 12 inches below combustible ceilings for ESFR.

Branch line and cross main pipe sizes must be supported: hangers within 6 ft of end of line, max 12 ft spacing for 1-inch and smaller, 15 ft for 1-1/4-inch and larger.

Sprinkler temperature ratings: ordinary 135–170°F (orange/red), intermediate 175–225°F (yellow/green), high 250–300°F (blue), extra high 325–375°F (purple), ultra high 400–650°F (black).

Quick-response sprinklers required in light hazard occupancies, and may be used in ordinary hazard with 30% remote area reduction; ESFR only in storage occupancies with specific ceiling height limits.

NFPA 13 requires a main drain at the riser capable of flowing at the system demand rate, and auxiliary drains at low points; test the main drain annually per NFPA 25.

Sprinkler escutcheons are required for recessed and flush sprinklers; for pendent sprinklers in concealed spaces, use listed ceiling plates.

In areas subject to freezing, use dry-pipe, preaction, or antifreeze systems; antifreeze solutions must be listed and maintained per manufacturer and NFPA 25.

Fire pump rated flow: 150% of rated capacity at not less than 65% of rated head; churn pressure shall not exceed 140% of rated head for centrifugal pumps.

Fire pump testing: annual flow test at 100%, 150%, and churn; weekly no-flow churn run for diesel pumps; monthly for electric pumps if not automatically exercised.

Standpipe classes: Class I for fire department use (2-1/2-inch outlets, 100 psi at top), Class II for occupant use (1-1/2-inch hose, 100 psi), Class III for both.

Standpipe hydraulic design: 100 psi residual at the topmost outlet for 2-1/2-inch outlets; for 1-1/2-inch outlets, 100 psi may be reduced to 65 psi if approved.

Water supply curve: plot available pressure vs. flow from hydrant flow test; system demand curve must fall below supply curve at all points; add safety margin.

Fire pump sizing: select pump so that rated flow is at least equal to system demand, and pump curve does not exceed 140% churn pressure.

Standpipe systems in buildings over 4 stories or with floor level >30 ft above fire department access require automatic wet standpipe with 2-1/2-inch outlets.

Backflow prevention: reduced pressure zone (RPZ) backflow preventer required for connections to public water; account for 5-10 psi loss in hydraulic calculations.

Weekly: inspect gauges (normal pressure), test alarm valves (if not monitored), check diesel fuel level and battery condition; monthly: inspect valve positions, test electric pump churn.

Quarterly: test waterflow alarm devices, inspect and test supervisory switches, check dry-pipe valve priming water level; annual: main drain flow test, pump flow test, trip test dry-pipe valve.

5-year: internal inspection of piping and sprinklers in dry systems; 10-year: internal inspection of wet system piping and replacement of dry-pipe sprinklers (or 10 years for quick-response).

Sprinkler spare stock: minimum 6 spare sprinklers for systems ≤300 sprinklers, 12 for 300-1000, 24 for >1000; include a sprinkler wrench.

Obstruction investigation: when a 2-inch main drain flowing at full rate shows a pressure drop of more than 10% from previous test, or when sprinkler discharge is reduced.

Valve status: all control valves must be open and supervised; if unsupervised, lock open and inspect weekly; post signage indicating open position.

Flow test: main drain test compares static and residual pressures; a drop of more than 10% from baseline indicates a possible obstruction or closed valve.

Record keeping: maintain records of inspections, tests, and maintenance for at least 1 year, or as required by AHJ; make available for review.

Nevada State Contractors Board (NSCB) licenses fire protection contractors under classification C-41 (fire protection systems) or A-13 (limited to fire sprinklers).

License requires: 4 years of experience (or equivalent education), passing trade and business exams, and a $10,000 surety bond; biennial renewal with 16 hours continuing education.

Bid limits: a licensed contractor may not bid on a project exceeding the monetary limit of their license classification; C-41 has no monetary limit.

Nevada requires written contracts for residential projects over $1,000; must include 3-day right to cancel, payment schedule, and lien warning notice.

Mechanic's lien: file preliminary notice within 31 days of first furnishing labor/materials; record lien within 90 days after completion; foreclosure action within 6 months.

Nevada OSHA (NVOSHA) enforces safety; contractor must provide workers' compensation insurance for employees; sole proprietors may exempt themselves.

Prompt payment: owner must pay contractor within 30 days of invoice; if not, contractor may stop work after 10-day written notice.

Advertising must include license number; using another's license or bidding beyond classification is grounds for disciplinary action and fines.

Nevada adopts the International Fire Code (IFC) with amendments; local jurisdictions (Clark County, Washoe County, City of Las Vegas) may add stricter requirements.

Clark County requires fire sprinkler systems in all new commercial buildings and in residential occupancies with more than 2 dwelling units, regardless of area.

Nevada requires automatic sprinkler systems in high-rise buildings (75 feet or more) and in all new construction of certain occupancies (e.g., hotels, motels) per state fire marshal amendments.

Fire flow requirements: Nevada adopts IFC Appendix B; minimum fire flow for light hazard is 1,500 gpm for 2 hours; for ordinary hazard 2,000 gpm for 2 hours.

Local amendments may require additional water supply for wildfire urban interface (WUI) areas; check with local fire authority for specific requirements.

Plan review: submit fire sprinkler plans to the local fire authority having jurisdiction (AHJ) and building department; approval required before installation.

Nevada fire code requires annual inspection and testing of sprinkler systems per NFPA 25, with records available to the AHJ upon request.

Nevada Revised Statutes (NRS) 477 governs fire safety; NRS 477.045 allows state fire marshal to adopt codes; local amendments must be filed with state.

Job hazard analysis (JHA) required before each task; identify fall hazards (use fall protection over 6 feet), electrical, and confined space entry.

Plans must include: hydraulic calculations, riser diagram, plan view with pipe sizes, sprinkler locations, hanger details, and water supply information.

Permits: obtain fire sprinkler permit from AHJ before installation; post permit and approved plans on site; schedule inspections at rough-in and final.

Lockout/tagout procedures required when working on electrical or water supply systems; use personal protective equipment (PPE) including hard hat, safety glasses, gloves.

Material handling: store pipe to prevent damage; keep sprinklers in original cartons; do not paint or alter sprinklers; replace damaged sprinklers with same make/model/temperature.

Coordination: verify ceiling heights, structural obstructions, and other trades before installation; use BIM or coordination drawings to avoid conflicts.

Testing: hydrostatic test at 200 psi for 2 hours (or 50 psi above maximum working pressure) for new systems; flush underground before connection.

Record keeping: maintain as-built drawings, test reports, and material certifications; provide to owner and AHJ upon completion.

Residential occupancies (NFPA 13R): 4-story max, use residential sprinklers with lower design density (e.g., 0.05 gpm/ft² over 4 sprinklers) and 10-minute duration.

ESFR sprinklers: for storage occupancies up to 45 ft ceiling height, design density 0.35-0.7 gpm/ft², 12 sprinklers flowing; require 12-inch clearance below deflector.

Clean agent systems (NFPA 2001): for computer rooms, use FM-200 or Novec 1230; design concentration per manufacturer, hold time 10 minutes, room integrity test required.

Kitchen hood suppression (NFPA 96): wet chemical system, manual pull station, automatic fuel shutoff; semi-annual inspection and cleaning required.

Foam-water systems (NFPA 11): for flammable liquid storage; use AFFF or fluorine-free foam; design density and application rate per foam manufacturer and NFPA 11.

Water mist systems (NFPA 750): use high-pressure or low-pressure mist; design per manufacturer listing; suitable for machinery spaces and special hazards.

Standpipe and hose systems in covered malls: Class I standpipes with 2-1/2-inch outlets at each floor; may be combined with sprinkler system; check local amendments.

Alternative suppression systems require approval by AHJ; submit design, calculations, and listing information; provide annual maintenance per manufacturer and NFPA standards.