Gaseous oxygen impacts may occur in high-pressure oxygen systems whenever oxygen equipment is pressurized too fast. This is one of the main causes of fires in such systems. Therefore, equipment for high-pressure oxygen that contains nonmetallic sealing materials should be tested for burn-out safety. This is required by numerous international standards such as ISO, CEN or national standards as DIN in Germany. Because of new technical developments in industrial uses of oxygen, higher operating pressures up to 500 bar are becoming more and more frequent. With regard to this need, a new 500 bar gaseous oxygen impact tester has been designed and built at the Federal Institute for Materials Research and Testing (BAM) in Berlin (Germany). This paper describes all elements of this test system. The most important element of this BAM test apparatus is a new hydraulically operated quick opening valve that meets all international standards. First experiences on performance and maintenance of the new test apparatus are given.