Antifreeze systems are used for the portion of the fire sprinkler system that is in an area where the temperature cannot be reliably maintained at or above ________

• A. 40 degrees F
• B. 32 degrees F
• C. 50 degrees F
• D. 60 degrees F

Answer: (A)

Antifreeze systems are used in parts of the sprinkler system that may be in unheated or intermittently heated spaces where you can’t rely on keeping the temperature at or above 40°F. Water-filled pipes will eventually freeze as ambient temperatures fall toward freezing, which can crack pipes or block sprinkler heads. Introducing an approved antifreeze solution lowers the liquid’s freezing point, so the piping remains protected even when the space dips below freezing. This is why 40°F is the threshold: it provides a safe margin above the actual freezing point of water and aligns with code guidance on when antifreeze is needed. If you can keep the area at or above 40°F, antifreeze isn’t required.