This part of ISO 22088 specifies methods for the determination of environmental stress cracking (ESC) of thermoplastics when they are subjected to a constant tensile load in the presence of chemical agents. It is applicable to test specimens prepared by moulding and/or machining and can be used both for the assessment of ESC of plastic materials exposed to different environments, and for the determination of ESC of different plastic materials exposed to a specific environment. This is essentially a ranking test and is not intended to provide data to be used for design or performance prediction. NOTE Methods for the determination of environmental stress cracking by means of a constant-strain test are specified in ISO 22088-3, ISO 22088-4 and ISO 22088-5.