Decommissioned Pipes and Valves

Question: Why is it important to remove decommissioned pipes and valves from an ammonia refrigeration system?

Answer: To prevent an accidental release due to a pipe or flange leak. Consider a scenario where a ceiling-suspended evaporator is removed from a system. The ammonia pipes are cut and capped, and the evaporator unit is removed from the premises. However, it is common to find the valve groups for the evaporator remain installed in the system even after the evaporator has been removed. Even if the valve groups are valved off, there is still a possibility that the isolation valve does not seal properly, or corrosion eventually leads to a pinhole leak. Valve maintenance is typically not performed on decommissioned valves which increases the chance of a failure.

A second reason to remove decommissioned pipes and valves from an ammonia refrigeration system is to avoid confusion. Whether a contractor is performing work on the system, or an emergency responder is isolating a leak, it is important to be able to easily locate the pipes or valves in question.