This video is exactly why the ASME B31 piping RAGAGEPs prefer hydrostatic pressure testing vs. pneumatic methods. When we take piping up to 400 psi and higher we are creating a serious hazard; thus the code(s) have built-in administrative controls to ensure personnel are NOT near the piping when the test pressure is achieved and LOWERED to the normal operating pressure when welds/flanges are being leak-tested.