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Failure of a ½” BSP cap under pressure on well service work

The following incident was recently reported to us. It occurred on an offshore installation where the half inch BSP cap appears to have blown off a pressure testing manifold under approximately 1200psi of water pressure. The cap and BSP/NPT connector were rated to 45000psi. The cap was not found, so the conclusions are based on the following assumptions:

  1. The cap was not fully engaged;
  2. It was over-tightened.

The key lessons learned from the incident were identified as:

  1. Be aware of the ratings, tightening procedures and limitations of all pressure fittings used in a temporary pressure system;
  2. Pressure fittings should be in good condition prior to use – in particular, threads should be free of paint and debris. If in doubt, use new fittings.

Safety Event

Published: 1 November 1999
Download: IMCA SF 06/99

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