HI Fire Sprinkler flashcards

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

NFPA 13 scope

Sets minimum requirements for design and installation of automatic sprinkler systems in commercial, industrial, and storage occupancies, excluding one- and two-family dwellings covered by NFPA 13D.

NFPA 13R

Covers automatic sprinkler systems in residential occupancies up to and including four stories, with reduced design criteria compared with full NFPA 13 systems.

Listing versus approval

Listing means a product has been tested by a recognized laboratory to a published standard; approval means the authority having jurisdiction has accepted the product or installation.

Light hazard density

Typically 0.10 gpm per square foot over the hydraulically most remote 1,500 square feet, applied to occupancies such as offices, schools, and churches.

Ordinary Hazard Group 2

Design density of about 0.20 gpm per square foot over 1,500 square feet for occupancies such as machine shops, repair garages, and post offices.

Extra Hazard Group 1

Design density of about 0.30 gpm per square foot over 2,500 square feet for occupancies with moderate quantities of flammable liquids or high heat release.

Dry system area increase

Dry pipe and double-interlock pre-action systems require the remote area to be increased, commonly by 30 percent, because water delivery is delayed after a sprinkler opens.

Hose stream allowance

The flow added to the sprinkler demand at the base of the riser to account for fire department hose use, varying with hazard and standpipe presence.

Hazen-Williams formula

Friction loss in psi per foot equals 4.52 times flow in gpm raised to 1.85, divided by roughness coefficient raised to 1.85 times inside diameter raised to 4.87.

Elevation pressure conversion

Each foot of elevation change converts to 0.433 psi; pressure decreases with rise and increases with drop in the piping system.

Waterflow test data

Static pressure, residual pressure, and flow rate recorded at a hydrant; results are plotted and extrapolated to estimate pressure at the required fire flow.

Safety margin

The required cushion between available supply pressure and system demand pressure, ensuring the demand point falls below the water supply curve.

Backflow preventer loss

A fixed pressure loss added to hydraulic calculations for each backflow prevention device, along with losses from check valves and dry pipe valves.

Sprinkler temperature rating

Ordinary ratings of 135 to 170 degrees Fahrenheit; intermediate 175 to 225 degrees; high 250 to 300 degrees. Rating must exceed maximum ceiling temperature.

Standard spray deflector distance

Deflectors of standard spray sprinklers are positioned 1 to 12 inches below the ceiling, with specific rules for concealed and recessed types.

Light hazard spacing

Maximum spacing generally 15 feet between sprinklers and 15 feet between branch lines, with coverage not exceeding 225 square feet per sprinkler.

Sidewall sprinkler limits

Sidewall sprinklers have reduced coverage areas and specific distance-from-wall and deflector rules compared with pendant and upright sprinklers.

Quick-response reduction

Quick-response sprinklers may allow a limited reduction in design area for some light and ordinary hazard applications, subject to conditional requirements.

Riser check valve

A valve in the riser that prevents water from flowing back into the supply, protecting the public water system from contamination.

Dry pipe valve function

Holds air pressure above and water below; when a sprinkler opens and air escapes, the valve trips and admits water into the piping.

Pre-action valve

Requires a detection signal before water enters the piping; single-interlock admits water on detection, double-interlock also requires a sprinkler to open.

Inspector's test valve

Located at the hydraulically most remote point, it simulates a single sprinkler flow to test alarms, waterflow switches, and dry pipe valve trip time.

CPVC limitations

CPVC piping is listed for specific light hazard and residential applications, with limitations on temperature, pressure, and exposure to sunlight.

Hydrostatic test

Piping is tested at 200 psi for two hours, or at 50 psi above working pressure when working pressure exceeds 150 psi, with no leakage allowed.

Main drain test

Records static and residual pressure at the riser; a significant drop compared with prior tests indicates a supply or valve problem.

Dry pipe trip test

Confirms the dry pipe valve trips at the manufacturer's specified air pressure and records the time required for water to reach the test connection.

Underground flushing

Underground mains are flushed before connection to the sprinkler system at a velocity sufficient to clear debris, preventing clogging of sprinklers and valves.

Working plan contents

Shows occupancy, hazard classification, sprinkler types and spacing, pipe sizes and materials, hanger locations, control valves, and test connections.

Hydraulic calculation submittal

Must identify the hydraulically most remote area, node-by-node pipe lengths, fittings, elevations, and the resulting demand at the supply point.

As-built drawings

Reflect field changes from approved plans; deviations require re-review and approval before installation proceeds.

Impairment procedure

When a system is taken out of service, notify the owner, insurer, and fire department, and provide a fire watch or temporary protection as required.

Change order

A written document authorizing a change to the contract scope, such as revised sprinkler design, requiring coordination with the owner, architect, and authority having jurisdiction.