Analysis of Gases Produced by Three Underwater Cutting Devices

The gas produced during underwater testing of 3 cutting systems was collected and analyzed to assess the explosion hazard related to the 3 processes. The underwater plasma cutting system produced up to 6% H2, while the UK cutting rod produced up to 95% H2. As the lower flammable/explosive limits of H2 in air are 4%, H2 safety issues are potentially related to using both these cutting processes. However, the explosive risk associated with the plasma cutting system appears much lower than that with the UK cutting rod, due to the substantially lower concentration of H2 generated. The Broco cutting rod produced more than 90% 02, an amount of 02 associated with this cutting process that has long been recognized as a high risk factor. Unfortunately, the detection of up to 3.6% H2 in the system check casts some concern on the reliability of the samples drawn during the actual cutting tests.