Which K-factor value is acceptable for sprinkler nozzles in commercial cooking equipment ducts?

Which K-factor value is acceptable for sprinkler nozzles in commercial cooking equipment ducts?

• A. 1.4
• B. 1.0
• C. 0.8
• D. 2.0

Answer: (A)

K-factor determines how much water a sprinkler nozzle delivers at a given operating pressure. For sprinkler nozzles protecting commercial cooking equipment ducts, an approved K-factor of 1.4 is specified because it provides the right balance: enough discharge to blanket and cool a grease-fire inside the duct, while staying within the typical pressure and flow limits of the building’s suppression system. If the nozzle had a smaller K (like 0.8 or 1.0), it would require higher pressure to achieve the same flow, which might not be available due to duct friction losses and system constraints, risking insufficient fire control. If the nozzle had a larger K (like 2.0), it would demand more flow than the system is designed to deliver into a grease-filled duct, potentially causing over-wetting, water damage, or nuisance discharges. The 1.4 value is chosen because it reliably provides the proper discharge at standard systems used for these ducts.

K-factor determines how much water a sprinkler nozzle delivers at a given operating pressure. For sprinkler nozzles protecting commercial cooking equipment ducts, an approved K-factor of 1.4 is specified because it provides the right balance: enough discharge to blanket and cool a grease-fire inside the duct, while staying within the typical pressure and flow limits of the building’s suppression system. If the nozzle had a smaller K (like 0.8 or 1.0), it would require higher pressure to achieve the same flow, which might not be available due to duct friction losses and system constraints, risking insufficient fire control. If the nozzle had a larger K (like 2.0), it would demand more flow than the system is designed to deliver into a grease-filled duct, potentially causing over-wetting, water damage, or nuisance discharges. The 1.4 value is chosen because it reliably provides the proper discharge at standard systems used for these ducts.