If foam concentrate lines to injection points are underground or aboveground for more than 50 ft, what is required?

• A. They must be maintained full and have a means to check tightness
• B. They must be insulated with temperature sensors
• C. They must be connected to a nitrogen supply
• D. They must be replaced every year

Answer: (B)

When foam lines to injection points run outdoors or underground for a long distance, they face exposure to ambient temperatures that can cause foam concentrate to freeze. The standard requires those long runs to be insulated and equipped with temperature-sensing devices. Insulation reduces heat loss and helps keep the line above freezing, while temperature sensors continuously monitor the line temperature so action can be taken if freezing is imminent. This combination helps ensure the foam concentrate remains flowable and the system can perform when needed.

Other options don’t address the freezing risk for long external runs: keeping the line full and checking tightness is about general pipe integrity, a nitrogen supply isn’t part of this protection, and replacing the line annually isn’t a stated requirement.