This part of ISO 5630 specifies a procedure for moist heat treatment of paper or board and the general approach for testing properties of the heat-treated materials. This method is based on work on printing and writing papers, but may be used with discretion for other types of paper and board. The procedure is not recommended for papers such as resin-impregnated or varnish-treated papers, which increase in physical strength on heating. The procedure is not applicable to certain electrical insulating papers, for which different conditions apply (see ISO 5630-4). This part of ISO 5630 does not specify the tests to be made on the paper or board. It is left to the interested parties to determine which tests are appropriate for the type of paper or board being evaluated.