What could occur when isolating a pipe or vessel filled with refrigerant?

When isolating a pipe or vessel filled with refrigerant, there is a risk that a subsequent explosion may occur due to the rapid fluctuations in pressure and temperature within the isolated section. Isolating the refrigerant can lead to the accumulation of pressure as the refrigerant vapor expands in the absence of a pressure-relief mechanism. If there is a sudden release of pressure or if the isolated vessel or pipe gets heated, it can cause a significant increase in pressure that may exceed the system's design limits, potentially leading to a vessel rupture or explosion.

This phenomenon highlights the critical importance of proper isolation procedures and the need to ensure that safety systems, such as pressure relief valves, are functional when working with ammonia refrigeration systems. Understanding the properties of refrigerants, including ammonia, and maintaining proper system operating conditions is essential for preventing hazardous incidents in industrial refrigeration settings.