What pressure should a 400 psi boiler be hydrostatically tested at?

The hydrostatic testing of a boiler is a crucial procedure designed to ensure its integrity and safety. For a 400 psi boiler, the accepted practice is to test at a pressure greater than its maximum allowable working pressure to verify that it can withstand such conditions without leaking or failing.

Typically, the recommended testing pressure is 1.5 times the maximum allowable working pressure of the boiler. In this case, for a boiler rated at 400 psi, multiplying by 1.5 gives a testing pressure of 600 psi. This elevated pressure helps to identify any weak points or potential failures in the structure of the boiler that may not be apparent under normal operating conditions.

Conducting the hydrostatic test at this higher pressure is a standard industry practice and is key to maintaining safety and reliability in high-pressure boiler operation.