Stress corrosion cracking in refrigeration systems

It is generally understood that stress corrosion cracking can occasionally affect the high pressure vessels in ammonia refrigeration systems, but the nature of the problem is often mis-represented in design codes, safety standards and textbooks and ways in which the initiation of stress corrosion can be prevented are ignored. It is also not appreciated that stress corrosion can also affect low pressure vessels and pipework in ammonia systems, and copper pipework in fluorocarbon refrigeration systems.This paper provides an overview of published literature on stress corrosion cracking and then presents some recent case study material illustrating various ways in which stress corrosion has arisen in practice. The conclusions will provide guidance for design engineers and equipment owners on eliminating stress corrosion cracking and on dealing with it if it arises.