This part of ISO 22088 specifies a method for the determination of the environmental stress cracking (ESC) behaviour of thermoplastics when they are subjected to a constant tensile deformation in the presence of a chemical medium. It is applicable to test specimens prepared by moulding and/or machining and can be used for the assessment of the ESC behaviour of plastic materials exposed to different environments, as well as for the determination of the ESC behaviour 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 Alternative methods for the determination of environmental stress cracking by means of a constant-strain test are specified in ISO 22088-3 and ISO 22088-4. A method for the determination of environmental stress cracking by means of a constant tensile load is specified in ISO 22088-2.