scope:

Specifies a method based on ISO 8990 to measure the overall thermal transmittance (U-value) of a window or door in a hot box. This includes all effects of frames, sashes, door leaves and fittings in a test specimen. Edge effects occurring outside of the perimeter of the specimen are excluded. Furthermore energy transfer due to solar radiation through any glazing in the specimen is not taken into account, and air leakage is excluded. The method is designed to provide both standardised tests, which enable a fair comparison of different products to be made, and specific tests on products for practical application purposes. The former specifies standardised specimen sizes and applied test criteria. The dermination of the overall thermal transmittance is performed for conditions which will correspond to a similar situation of the window and door in practice.