The document is one of a series of approximately 25 planned standards which specify test methods for determining dimensions and properties of thermal insulating materials and products. It supports a series of product standards for thermal insulating materials and products which are under preparation within CEN/TC 88 deriving from the Construction Products Directive (89/106/EEC) through the consideration of the essential requirements. The document is applicable to thermal insulating products for applications in buildings but it may also be used in other areas where it is relevant. It specifies the equipment and procedures for determining the deviation from squareness for lenght, width and/or thickness of full-size products.