553.961  Test methods.--The manufacturer shall cause the testing of samples of each model of each product covered by this part. Test procedures identified in the code shall be the accepted test procedures for those products addressed by the code. Test procedures for products not addressed in the code shall be determined by the department. The department shall use United States Department of Energy approved test methods or, in the absence of such test methods, other appropriate nationally recognized test methods applicable to the respective products. The department may elect to develop and prescribe other test methods based upon the department's determination that use of such other test methods is justified due to decreased cost, increased accuracy, or the general use and acceptance of a specific test method by the industry involved.