5703.6.8 Piping supports have three (3) recognized methods to protect piping that may be exposed to a “pool fire”. First lets look at the code language:
5703.6.8 Piping supports. Piping systems shall be substantially supported and protected against physical damage and excessive stresses arising from settlement, vibration, expansion, contraction or exposure to fire. The supports shall be protected against exposure to fire by one of the following:
1) Draining liquid away from the piping system at a minimum slope of not less than 1 percent.
2) Providing protection with a fire-resistance rating of not less than 2 hours.
3) Other approved methods.
Now let’s discuss what options #1 and #2 actually look like in the field. I will not be discussing the “other approved methods” as I have always used either #1 or #2.
To prevent structural collapse during an active fire, the code requires you to protect the pipe supports using one of three specific paths:
The 1% Slope Rule
- Instead of insulating the steel, we use a passive engineering control to prevent the fuel source from impacting the pipe support(s). The floor or ground beneath the piping rack/supports MUST be sloped at a minimum of 1 % (a 1-foot drop for every 100 feet of horizontal run) away from the piping footprint and toward a safe containment area, impoundment basin, or remote drainage system.
- If a spill ignites, the burning liquid cannot pool directly beneath the pipe supports. By draining the burning liquid away, you eliminate the intense localized pool-fire thermal radiation that would otherwise warp and fail the structural steel supports.
2-Hour Fire-Resistance Rating
- A facility can physically shield the load-bearing structural elements supporting the pipe. This is typically achieved by wrapping the steel columns and beams in a listed structural fireproofing material.
- The insulation layer ensures that even if a pool fire rages directly beneath the rack, the internal structural steel temperature remains below its critical failure threshold for AT LEAST 120 minutes—giving emergency response teams or automated deluge systems time to suppress the fire before a catastrophic structural collapse occurs.