CT Fire Sprinkler cheat sheet

Design approach: pipe sizing by hydraulic calculation is permitted for any system; the pipe-schedule method is limited to small, light-hazard occupancies within stated area and story limits.

Sprinkler spacing rule: maximum coverage area per sprinkler and maximum spacing between sprinklers on a branch line both apply; the more restrictive limit governs. Light hazard commonly caps coverage near 225 sq ft per sprinkler with branch-line spacing near 15 ft.

Ordinary-temperature rated sprinklers are typically 135-170°F; intermediate 175-225°F; high 250-300°F. Rating must exceed the maximum expected ceiling temperature with margin.

Design density (gpm/sq ft) is applied over the hydraulically most demanding remote area; the remote area size may be reduced for dry systems only when permitted by the standard's specific allowance, not freely.

Quick-response sprinklers in wet systems may allow a reduced design area in qualifying light-hazard occupancies; the reduction depends on ceiling height and number of sprinklers calculated.

Hazard classification drives everything: light, ordinary Group 1 and 2, and extra Group 1 and 2 each carry distinct density/area curves and hose-stream allowance.

Hose stream allowance is added to sprinkler demand at the base of the riser; it varies with hazard and whether the supply is adequate for the combined demand.

A dry-pipe system requires the remote area to be increased (commonly 30%) because water travel time delays application; the exact allowance comes from the applicable standard.

Riser components: check valve, main control valve, pressure gauge, flow switch, and test-and-drain connection. A wet alarm valve or dry-pipe valve sits between supply and system.

Occupancy hazard classification: light hazard covers low-combustibility occupancies such as offices, schools, and churches; ordinary Group 1 includes parking garages and restaurants; ordinary Group 2 includes mercantile and manufacturing.

Sprinkler temperature rating selection: choose a rating at least 25°F above the maximum anticipated ceiling temperature, and higher where ceilings are near heat sources or skylights.

Maximum area per sprinkler depends on hazard and sprinkler type; for light hazard a common cap is 225 sq ft, while ordinary hazard Group 2 is smaller. Always verify the specific standard edition.

Branch-line spacing maximum is typically 15 ft for light hazard and 12 ft for ordinary hazard; the distance from the last sprinkler to the end of the branch line is limited (often half the maximum spacing).

Obstruction rules: sprinklers must be positioned to avoid obstruction to spray patterns; a common rule requires sprinklers within a specified distance of obstructions such as beams, ducts, and soffits.

Hydraulic calculation output must show the required supply pressure and flow at the base of the riser, including the hose-stream allowance and any safety margin.

Water supply testing: a flow test provides static and residual pressure at a known flow; plot the results and compare to the system demand curve to confirm adequacy.

Acceptance testing includes hydrostatic test at the specified pressure for the specified duration, plus main drain flow test and alarm/flow-switch verification.

Inspection, testing, and maintenance: gauges, valves, alarm devices, and waterflow switches require periodic checks; the schedule is defined by the applicable standard, not by preference.