Minimum fire rating for exposed supports for above-ground tanks?

Minimum fire rating for exposed supports for above-ground tanks?

• A. One hour
• B. Four hours
• C. Two hours or more
• D. Three hours

Answer: (C)

The essential idea is that the supports holding above-ground tanks must resist fire long enough to keep the tank in place during a fire, preventing collapse or rupture. The minimum fire-resistance rating assigned to those exposed supports is two hours or more, which provides a safety window for firefighting operations and cooling to protect the tank and its contents. One hour isn’t typically enough to ensure structural stability during a pool fire or exposure scenario, where heat can soften or damage supports and lead to movement or failure. A rating of three or four hours is more than the standard minimum for this particular application, though higher ratings may be required in certain situations. Therefore, two hours or more is the appropriate minimum.

The essential idea is that the supports holding above-ground tanks must resist fire long enough to keep the tank in place during a fire, preventing collapse or rupture. The minimum fire-resistance rating assigned to those exposed supports is two hours or more, which provides a safety window for firefighting operations and cooling to protect the tank and its contents.

One hour isn’t typically enough to ensure structural stability during a pool fire or exposure scenario, where heat can soften or damage supports and lead to movement or failure. A rating of three or four hours is more than the standard minimum for this particular application, though higher ratings may be required in certain situations. Therefore, two hours or more is the appropriate minimum.