Plastics tanks are normally designed for a finite life, usually between 15 and 25 years. However, due to economic pressure many of these tanks are still in operation beyond their design life, often with little or no engineering justification. It is also not uncommon for plastics tanks to be used for storing chemicals that they were not designed to contain. For these reasons it is important that operators of plastics tanks and vessels inspect them throughout their life. An issue at hand is that there are currently no standards for the in-service inspection of plastics tanks. There is also very limited expertise available on the visual examination of these tanks and virtually no use of non-destructive examination (NDE). Internal inspections are carried out less frequently, if at all, because they are expensive, potentially dangerous to the inspector, and result in a shut-down because the tank has to be emptied.The project will determine the potential failure mechanisms in plastics tanks and storage vessels, and develop ultrasonic NDE procedures, techniques and systems to identify these. An important aim of the project will be to develop an inspection system that is site-rugged and simple to operate. Welded joints representative of those used to fabricate plastics tanks and vessels will be manufactured containing known flaws. These will be inspected and the NDE data analysed to determine the limits of flaw detection. In parallel, the significance of flaw size and quantity will be established in relation to service requirements. This will be achieved by long-term mechanical testing of joints containing known flaws, and comparison with results for welds containing no flaws.The prototype equipment, designed and built for this project, will be assessed under both laboratory and field conditions, and the inspection procedures developed will be submitted to the European Committee for Standardization as the basis for producing a European standard for plastic tank inspection.