Under what condition should mufflers not be used on a safety relief valve according to ASME code?

The condition under which mufflers should not be used on a safety relief valve, according to ASME code, is specifically related to high temperature water boiler safety relief valves. In these scenarios, the use of a muffler can impede the proper operation of the valve and potentially interfere with its ability to discharge steam or water at the required flow rate. Safety relief valves need to operate efficiently and rapidly in the event of overpressure, ensuring that the safety of the boiler system is maintained.

The installation of a muffler can cause a buildup of pressure and heat, leading to a malfunction or delayed response of the safety relief valve. This is particularly critical in high temperature applications where the safety mechanisms are vital in preventing catastrophic failures. Thus, maintaining the integrity and functionality of the safety relief valve in high temperature systems is paramount, making this condition a fundamental aspect of safety in boiler operation.