The minimum length of a cooling leg from a heating coil to a steam trap should be:

The minimum length of a cooling leg from a heating coil to a steam trap should be:

• A. 5 feet
• B. 2 feet
• C. 8 feet
• D. 10 feet

Answer: (A)

In this concept, the cooling leg between the heating coil and the steam trap must give enough space for condensate to drain, cool, and separate from any entrained steam before it reaches the trap. A minimum length of five feet ensures gravity flow and provides time for the condensate to drop out of the steam phase, reducing the chance that steam carries into the trap and disrupts proper condensate discharge. If the leg is too short, steam can reach the trap and hamper drainage, potentially causing trap instability or water hammer downstream. Longer legs are acceptable, but the five-foot minimum is the standard to ensure reliable operation.

In this concept, the cooling leg between the heating coil and the steam trap must give enough space for condensate to drain, cool, and separate from any entrained steam before it reaches the trap. A minimum length of five feet ensures gravity flow and provides time for the condensate to drop out of the steam phase, reducing the chance that steam carries into the trap and disrupts proper condensate discharge. If the leg is too short, steam can reach the trap and hamper drainage, potentially causing trap instability or water hammer downstream. Longer legs are acceptable, but the five-foot minimum is the standard to ensure reliable operation.