Sprinkler Systems Flashcards

What is the minimum water supply duration required for a light hazard sprinkler system per NFPA 13?

Answer: 30 minutes

NFPA 13 requires a minimum 30-minute water supply duration for light hazard occupancies.

Which type of sprinkler head is designed to discharge water in a pattern that does not wet the ceiling?

Answer: In-rack sprinkler

In-rack sprinklers are positioned within storage racks and direct water downward without wetting the ceiling.

A wet pipe sprinkler system is found to have a constant drip from a sprinkler head that has not activated. What is the most likely cause?

Answer: A leaking sprinkler seat or cracked bulb

Constant dripping from an unactivated sprinkler typically indicates a failed heat-sensitive element or a leaking seat.

Under NFPA 13, what is the maximum distance allowed between sprinklers in a light hazard occupancy with standard spray sprinklers?

Answer: 20 feet

NFPA 13 allows a maximum 15-foot spacing between sprinklers in light hazard occupancies, but the maximum coverage area per head governs; 15 ft is the standard answer for spacing.

What component in a dry pipe sprinkler system prevents water from entering the piping until a sprinkler activates?

Answer: Dry pipe valve

The dry pipe valve holds pressurized air or nitrogen in the piping and only opens to admit water when pressure drops after sprinkler activation.

Which sprinkler temperature rating classification has a maximum ceiling temperature of 100°F per NFPA 13?

Answer: Ordinary (135–170°F)

Ordinary rated sprinklers (135–170°F activation) are used where maximum ceiling temperatures do not exceed 100°F.

A fire sprinkler system inspector notices the main drain test produces a residual pressure significantly lower than the system design pressure. What does this indicate?

Answer: A possible obstruction or inadequate water supply

A low residual pressure during a main drain test suggests a potential obstruction in the supply piping or an inadequate municipal water supply.