Study on availability test procedure of two-unit same redundant system with exponentially distributed up and down times unit

Under the assumption that time to failure and time to repair of unit are exponentially distributed, this paper presents a general procedure for conducting an inherent availability test with fixed sample size of two-unit same redundant system. Above all, two design principles for general availability test procedure of redundant system are presented. One is that ensuring stated levels of producer´s and consumer´s risk of the one unit system test and stated levels of producer´s and consumer´s risk of the redundant system test are met. The other is that conducting general test only by conducting availability test of one unit. Then according to inherent availability of one unit system test procedure, the test procedure for inherent availability of two-unit same redundant system consisting of parallel system, cold standby system and warm standby system is designed to meet stated levels of producer´s and consumer´s risk based on system availability models. Next, this paper describes design course on the general test procedure which is presented through determining sample size and judgment rule. Finally, this paper analyzes a numerical example.