A workshop foreman and technician were inside a test bay testing for leaks from a 5K choke manifold, the Thermowell 3/4" NPT failed and struck the technician on the leg resulting in a serious injury to the right knee. The technician was struck from a distance of approx. 0.5 metres.
Severe corrosion had effected the mechanical integrity of the female thread, when this thread failed the stored energy was released propelling the 3/4" Thermowell at a velocity of 42 metres per second or 94 Mph/151 kph.
The main headings for the underlying causes were identified as:
- Procedural Failure
- Procedural Ineffectiveness
- Pressure Bay Facilities