This part of ISO 11403 specifies test procedures for the acquisition and presentation of multipoint data which demonstrate the behaviour of plastics under the following environments: — prolonged exposure to heat; — liquid chemicals; — environmental stress cracking under a constant tensile stress; — artificial weathering. The tests are listed in order of increasing severity of the environment. By testing under the least severe environments first, it is possible to make informed judgements regarding whether tests under more severe conditions are worthwhile.