AZ Fire Sprinkler flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hazen-Williams Formula

p = 4.52 Q^1.85 / (C^1.85 d^4.87). It calculates friction loss in psi per foot of pipe, where Q is flow in gpm, d is internal diameter in inches, and C is the roughness coefficient.

Sprinkler Discharge Formula

Q = K times the square root of P, where Q is flow in gpm, K is the discharge coefficient, and P is flowing pressure in psi. A K-5.6 head flowing 15 psi discharges about 21.7 gpm.

Design Density

The minimum flow in gpm per square foot applied over the remote area. It is selected from the density-area curve based on the occupancy hazard classification and the assumed fire duration.

Remote Area

The hydraulically most demanding area of sprinkler operation used in calculations. Its size increases for dry systems, sloped ceilings, and high-temperature sprinklers under NFPA 13.

Elevation Pressure Loss

A column of water 1 foot high exerts 0.433 psi. Add this loss for each foot of rise and subtract it for each foot of drop in the hydraulic calculation.

Balancing Junction Flows

When two branch lines meet at a junction, flows divide in proportion to the square root of the available pressure drops. Iterate the calculation until the junction pressure converges.

Sprinkler Spacing Limits

Standard spray heads are spaced at most 15 ft on branch lines and 15 ft between lines for light and ordinary hazard. Extra hazard limits spacing to 12 ft.

Maximum Sprinkler Coverage

The largest floor area one sprinkler may protect: 225 square feet for light hazard, 130 for ordinary hazard, and 100 for extra hazard. Extended-coverage heads use listed values up to 400 square feet.

Sprinkler Distance to Wall

The maximum distance from a sprinkler to a wall or partition is one-half the allowable spacing between sprinklers. For light hazard, that maximum is 7 feet 6 inches.

Sprinkler Deflector Position

Standard spray sprinklers must be positioned 1 to 12 inches below the ceiling. Residential and extended-coverage heads are typically 1 to 6 inches below the ceiling unless listed otherwise.

Obstruction Rule

A sprinkler is required where an obstruction is more than 4 feet wide, within 12 inches of the ceiling, and the sprinkler is more than three times the obstruction depth away.

Pipe Schedule Sizing

For light hazard steel pipe, 1 inch serves 2 heads, 1.5 inch serves 5, 2 inch serves 10, 2.5 inch serves 20, 3 inch serves 40, 4 inch serves 100, and 6 inch serves 275.

Hanger Spacing

Steel pipe hanger spacing depends on diameter: 1 inch at 12 feet, 1.5 inch at 15 feet, 2 inch at 10 feet, 3 inch at 12 feet, 4 inch at 15 feet, and 6 inch at 15 feet.

Water Supply Flow Test

A test records static pressure, residual pressure, and flow in gpm. The results are plotted on log-log paper to extrapolate the available supply at the system demand.

Available Supply Calculation

Available pressure equals static pressure minus friction losses through the meter, service main, backflow preventer, and riser, minus elevation loss, minus the safety margin.

RPZ Backflow Assembly

A reduced pressure zone assembly protects against both backpressure and backsiphonage in high-hazard connections. It must be tested annually by a certified tester and reported to the water authority.

Double Check Valve Assembly

A low-hazard backflow preventer with two check valves. It protects against backpressure and backsiphonage but is not approved for high-hazard or toxic connections.

Fire Department Connection

An FDC allows the responding engine to supplement the system supply. It must be located within 100 feet of a hydrant and be accessible to fire apparatus.

Arizona ROC License

The Arizona Registrar of Contractors issues specialty licenses such as C-16 for fire sprinkler work. A qualifying party must pass the trade exam and be actively engaged in the business.

Arizona Contractor Bond

Arizona requires a $5,000 surety bond for residential contractors and a $10,000 bond for commercial contractors, plus general liability insurance of at least $100,000 per occurrence.

Arizona Mechanics Lien

A lien must be recorded within 120 days after completion of the work. A preliminary 20-day notice must be served before the lien is recorded.

Arizona Prompt Payment

Arizona statutes require progress payments within 7 days of billing and final payment within 7 days of completion, unless the contract specifies a different period.

Plan Submittal Package

Working plans, hydraulic calculations, an isometric riser diagram, the water supply flow test, manufacturer data sheets, and the contractor license are submitted to the AHJ for review.

Hydrostatic Test

The system is tested at 200 psi for 2 hours, or at 50 psi above working pressure for 2 hours when working pressure exceeds 150 psi, before ceiling closure.

Underground Flushing

Underground mains are flushed at a flow rate equal to or greater than the system demand before connection to the riser, to remove debris that could clog sprinkler heads.

Inspection Sequence

Underground piping is inspected before backfill, rough-in before ceiling closure, the hydrostatic test after installation, and the final inspection with the system in service.

Impairment Procedure

When a system is taken out of service, a red tag is placed on the riser, the fire department and insurer are notified, and a fire watch is posted for impairments over 4 hours.

Confined Space Entry

Entry requires atmospheric testing with oxygen between 19.5 and 23.5 percent, flammables below 10 percent of the LEL, a rescue plan, and a trained attendant.

Hot Work Permit

A written permit is required for cutting, welding, or grinding. A fire watch is maintained during the work and for 30 minutes after it ends.

Excavation Protection

Trenches 5 feet or deeper require a protective system such as sloping, shoring, or shielding. A competent person inspects the excavation daily before entry.

Bid Components

A bid includes material, labor, equipment, subcontractors, permits, bonds, insurance, overhead of about 10 to 15 percent, and profit of about 5 to 10 percent.

Change Order

A written document signed by the owner or general contractor before extra work proceeds. It states the price and time impact of the change to the contract.