AZ Fire Sprinkler cheat sheet

Density/area method: design density (gpm/ft²) × remote area (ft²) = minimum required flow; check that the selected density-area point lies on or above the appropriate curve for the hazard classification.

Hazen-Williams friction loss: p = 4.52 Q^1.85 / (C^1.85 d^4.87), where p is psi per foot, Q is gpm, d is internal diameter in inches, and C is 120 for cement-lined cast iron or dry steel, 100 for unlined cast iron or wet steel.

Minimum operating pressure for a spray sprinkler is 7 psi; for a residential sprinkler the listing minimum is typically 7 psi at the listed flow, and extended-coverage heads use the pressure from their listing.

Balance the junction: flow splits in proportion to the available pressure drop, so Q₁/Q₂ = √(P₁/P₂) for branch lines of identical pipe and fittings; iterate until the pressure at the junction converges.

Remote area size increases 30% for dry systems, double-interlock preaction, and dry-pipe portions of a system; a sloped ceiling adds 30% to the remote area when the ceiling slope exceeds 2 in 12.

High-temperature sprinklers (above 155 °F nominal) permit a 25% reduction in design area, applied after other area adjustments; reductions below the listed minimum area are not permitted.

Sprinkler discharge: Q = K√P, where K is the discharge coefficient (e.g., 5.6, 8.0, 11.2, 14.0, 16.8, 22.4, 25.2) and P is flowing pressure in psi.

Hydraulic junction loss and elevation: 0.433 psi per foot of rise (1 psi ≈ 2.31 ft of head); add elevation loss on the supply side and subtract it on the discharge side of the calculation.

Velocity check: keep supply and cross-main velocities generally under 20 ft/s and branch-line velocities under 15 ft/s to limit surge, noise, and water-hammer damage.

Maximum spacing for standard spray upright/pendent heads: 15 ft on branch lines and 15 ft between branch lines for light hazard, 15 ft × 15 ft for ordinary hazard, and 12 ft × 12 ft for extra hazard; minimum spacing is 6 ft unless baffled.

Maximum coverage area per sprinkler: 225 ft² light hazard, 130 ft² ordinary hazard, 100 ft² extra hazard; extended-coverage heads use their listed coverage up to 400 ft².

Maximum distance from a sprinkler to a wall or partition is one-half the allowable spacing between sprinklers; the maximum to a wall for light hazard is 7 ft 6 in.

Sprinklers must be within 12 in of the ceiling for standard spray heads (1-12 in below the ceiling), and within 6 in for residential and extended-coverage heads unless the listing permits otherwise.

Obstruction rule: a sprinkler is required where an obstruction is more than 4 ft wide, within 12 in of the ceiling, and the sprinkler is more than 3 times the obstruction depth away from it.

Pipe schedule sizing (light hazard, steel): 1 in serves 2 heads, 1¼ in 3, 1½ in 5, 2 in 10, 2½ in 20, 3 in 40, 3½ in 65, 4 in 100, 5 in 160, 6 in 275, 8 in 400.

Riser and control valve: a listed check valve, main drain, flow switch, and pressure gauge are required on the riser; the main drain must be at least 2 in and capable of flowing at the system demand.

Hanger spacing for steel pipe: 1 in = 12 ft, 1¼ in = 12 ft, 1½ in = 15 ft, 2 in = 10 ft, 2½ in = 12 ft, 3 in = 12 ft, 4 in = 15 ft, 6 in = 15 ft, 8 in = 15 ft; place a hanger within 12 in of a sprinkler.

Available supply = static pressure minus friction loss through the service main, meter, backflow preventer, and riser, minus elevation loss (0.433 psi/ft), minus the safety margin (typically 10 psi or 5%).

Flow test data: static pressure, residual pressure, and flow in gpm; the test hydrant flow is extrapolated to the system demand using Q₂ = Q₁ × √((P_static − P_residual)/(P_static − P_residual_test)).

N₁.₈₅ method: plot the supply curve and the demand curve on log-log paper; the intersection is the available residual pressure at the required flow.

Backflow prevention: an RPZ (reduced pressure zone) assembly is required for high-hazard connections; a double-check valve assembly is used for low-hazard; a pressure vacuum breaker protects against backsiphonage only.

RPZ devices must be tested annually by a certified tester and the results reported to the local water authority; test ports are on the upstream and downstream check valves.

Arizona requires backflow assembly testers to hold a state or municipal certification; installation permits are issued by the local water provider, not the building department alone.

Fire department connection: a 4-in Storz or 2½-in connection is typical; the FDC must be within 100 ft of a hydrant and accessible to the responding engine.

Water supply capacity check: compare the available flow at the required residual pressure to the system demand; a 10-20% safety margin is common practice for design.

The Arizona Registrar of Contractors (ROC) licenses contractors; a fire sprinkler contractor must hold a specialty license (C-16 or equivalent) and a qualifying party must pass the trade exam.

The qualifying party must be an owner, officer, or full-time employee and must be actively engaged in the business; the license is not transferable to another entity without ROC approval.

Arizona requires a contractor to maintain a $5,000 surety bond (residential) or a $10,000 bond (commercial) and to carry general liability insurance of at least $100,000 per occurrence.

License renewal is every two years; continuing education of 8 hours per renewal cycle is required for the qualifying party.

Bidding law: a contractor may not perform work outside the scope of its license classification; unlicensed contracting is a class 1 misdemeanor and voids the contract.

Lien rights: an Arizona mechanics' lien must be recorded within 120 days after completion of the work, and a preliminary 20-day notice is required before recording.

Payments: prompt payment statutes require payment within 7 days of billing for progress payments and within 7 days of final completion, unless the contract states otherwise.

Arizona transaction privilege tax (TPT) applies to gross receipts from construction contracting; the contractor must be licensed with ADOR and file monthly or quarterly.

Plan submittal package: hydraulic calculations, working plans, isometric riser diagram, water supply flow test, manufacturer's data sheets, and a copy of the contractor's license.

Working plans must show pipe sizes, sprinkler locations, hanger locations, and the location of control valves, drains, and the FDC; plans are sealed by a licensed engineer or architect where required.

Arizona permits: a building permit is required for new sprinkler systems and for modifications that change the hydraulic demand; minor tenant improvements may use an over-the-counter review.

Inspection sequence: underground piping (before backfill), rough-in (before ceiling closure), hydrostatic test at 200 psi for 2 hours or 50 psi above working pressure, and final inspection with the system in service.

Hydrostatic test: 200 psi for 2 hours for systems with working pressure up to 150 psi; 50 psi above working pressure for higher-pressure systems, for 2 hours.

Flushing: underground mains must be flushed at a flow rate equal to or greater than the system demand before connection to the riser.

Final acceptance: the contractor provides a material and test certificate (NFPA 13 Figure), as-built drawings, and the owner's certificate of occupancy documentation.

Deficiency notices: the inspector issues a correction notice; reinspection fees apply after the second failed inspection in most Arizona jurisdictions.

Lockout/tagout: isolate and tag the fire protection system before any work that could release water; never leave a system out of service without notifying the owner and the fire department.

Impairment procedures: a red tag is placed on the riser, the fire department and insurance carrier are notified, and a fire watch is posted if the impairment exceeds 4 hours.

Confined space: a permit-required confined space entry requires atmospheric testing (O₂ 19.5-23.5%, LEL < 10%, H₂S < 10 ppm), a rescue plan, and a trained attendant.

Fall protection: guardrails, safety nets, or personal fall arrest systems are required at heights of 6 ft or more in construction; ladders must extend 3 ft above the landing.

Hot work: a written hot work permit is required for cutting, welding, or grinding; a fire watch is maintained for 30 minutes after the work ends.

Excavation: trenches 5 ft or deeper require a protective system (sloping, shoring, or shielding); a competent person must inspect daily before entry.

PPE: safety glasses, hard hat, steel-toe boots, and gloves are minimum on a sprinkler jobsite; hearing protection is required above 85 dBA.

Code compliance: the local authority having jurisdiction (AHJ) adopts the current NFPA 13 edition; Arizona jurisdictions typically adopt the IFC and NFPA 13 by reference with local amendments.

Takeoff: count sprinklers by type and K-factor, measure pipe by diameter and length, and list fittings, hangers, valves, and specialties; add 5-10% for waste and small material.

Labor units: use published labor units (e.g., NECA or MCAA) per fitting or per foot of pipe; adjust for height, access, and prevailing wage on public work.

Bid components: material, labor, equipment, subcontractors, permits, bonds, insurance, overhead (typically 10-15%), and profit (typically 5-10%).

Arizona prevailing wage: public works projects above the threshold require the state or federal prevailing wage; certified payroll is submitted weekly.

Change orders: a written change order signed by the owner or GC is required before performing extra work; the change order states the price and time impact.

Schedule of values: a progress billing document that allocates the contract sum to work items; retainage in Arizona is typically 10% until substantial completion.

Submittals: shop drawings, product data, and samples are submitted for approval; the review period is typically 14 days, and the contractor must track the submittal log.

Project closeout: as-built drawings, O&M manuals, warranties, and the final test certificate are delivered before final payment is released.