Methods to study service lives of building materials and components

This report deals with service life as a concept and an object of service life studies. As a concept service life is seen as a period of time in use before failure in an environment. Failure is the state of being where the object fails to meet the given performance requirements. The essential factors to be considered in service life test design are viewed for laboratory and outdoors exposure tests. The methods to study service life are grouped into laboratory (indoor) tests and natural (outdoor) tests. The main difference of these two groups is that in laboratory the degradation factors are simulated and controlled, and tests are often repeatable. Outdoor exposure provides a natural source of degradation, which, because of the variation of environmental parameters, can seldom be repeated. Both laboratory and outdoor exposure test results are needed to draw conclusions of service life. The apparatus needed for testing is shortly viewed. Laboratory apparatus are mostly for simulation and analyzing purposes and exposure site equipment are for climatological measurements. Also exposure site selection and exposure methods are discussed.