【国外标准】 Standard Guide for Improved Laboratory Accelerated Tests to Predict the Weathering and for Use in Developing Protocols to Predict the Design Life of Building Sealant Systems

4.1 This guide is intended to serve as a reference of recommended methodology for users developing relevant, reliable and valid tests for predicting natural weathering effects and for use in developing methods to determine design life of building sealant systems through the use of accelerated test protocols. The proposed standard corrects for some of the deficiencies of existing laboratory accelerated tests of sealants.4.2 The development of accelerated weathering tests capable of being used in protocols to reliably and accurately predict the long-term in-service performance of building sealant systems have limitations due to:4.2.1 The external factors that affect functional properties, which are numerous and require effort to quantify, so that many existing accelerated procedures do not include all factors of importance, and4.2.2 The sealant specimens are often tested in configurations different from those used in-service.1.1 This guide describes the steps for developing improved laboratory accelerated weathering tests for predicting the natural weathering effects on building sealant systems and for using those tests in development of methods for design life prediction of the systems.1.2 This guide outlines a systematic approach to development of laboratory accelerated weathering tests of building sealant systems including the identification of needed information, the development of accelerated tests, the application of data, and the reporting of results.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.