Chapter 18 - Oxygen systems safety

Abstract

Oxygen is a powerful oxidizer in both gaseous and liquid states, and its use involves a degree of risk that should never be overlooked. Oxygen is reactive at ambient conditions, and its reactivity increases with increasing pressure, temperature, and concentration. The successful design, development, and operation of oxygen systems require special knowledge and understanding of ignition mechanisms, material properties, design practices, and test data. The design approach to managing the risks associated with oxygen systems should focus on limiting the amount of oxygen available, using ignition and burn resistant materials where practical, limiting the amount of heat generated within oxygen systems, and limiting the exposure of personnel and equipment. Oxygen pressure and concentration can have sizeable effects on material flammability and ignitability. In general, materials are easier to ignite and burn more readily as oxygen pressure or concentration increases; therefore, oxygen systems should be operated at the lowest possible pressure and oxygen concentration. Likewise, poor material choice greatly can increase the likelihood of a fire occurring in an oxygen system. Some materials are harder to ignite than others, and when ignited, they are resistant to sustained burning. Materials also vary for energy released when they burn. Therefore, careful selection of materials can enhance the ignition, burn resistance of a system, and limit the amount of damage resulting from a fire. Even though heat sources can be inherent to an oxygen system or its surroundings, design elements can limit the amount or dissipate altogether the heat generated within an oxygen system.