Fire Without Cause of an Oxygen Component With an Aluminum Seal

摘要

It is common, even for high pressure service, for most of the components in oxygen systems to contain nonmetallic materials. The risk of an oxygen fire is low if the design of the component and its metallic and non-metallic materials are properly selected. From a safety point of view, it is obvious that a component made completely of metal with metallic seals should have a lower risk of fire. However, during a test series performed at the outdoor test site of the German Federal Institute for Materials Research and Testing (BAM), "BAM Test Site Technical Safety," an oxygen component burned out that contained metallic seals only. In the test, a bursting metallic diaphragm produces a single pressure shock at a specified oxygen pressure. In the incident, an aluminum diaphragm with a thickness of 1.5 mm was used at a burst pressure of 171 bar. At first, investigations at BAM focused on the question of whether a bursting aluminum diaphragm is able to ignite a bulk metal. Stress rupture tests were performed on this particular aluminum. A high-speed infrared camera helped reveal information on the temperature rise in the rupture zone. Furthermore, other possible ignition sources such as contamination or flow friction were considered, also. This paper discusses the results of the investigation, and it tries to answer the question of whether aluminum sheet materials increase the fire risk in oxygen components.