This document presents general principles and gives requirements and recommendations for the assessment of the stability of non-metallic materials for service in equipment used in oil and gas exploration and production environments. This information aids in material selection. It can be applied to help avoid costly degradation failures of the equipment itself, which could pose a risk to the health and safety of the public and personnel or the environment. This document also provides guidance for quality assurance. It supplements but does not replace, the material requirements given in the appropriate design codes, standards or regulations. This document addresses the resistance of thermoplastics to the deterioration in properties that can be caused by physical or chemical interaction with produced and injected oil and gas-field media, and with chemical treatment. Interaction with sunlight and ionizing radiation are excluded from the scope of this document. This document is not necessarily suitable for application to equipment used in refining or downstream processes and equipment. The equipment considered includes, but is not limited to, non-metallic pipelines, piping, liners, seals, gaskets and washers. Blistering by rapid gas decompression is not included in the scope of this document.