Corrosion in pipework trunnion supports

HSE Hazardous Installations Directorate have issued a Safety Bulletin following an LPG leak at a UK refinery.

The pipework support had a closed end to prevent moisture ingress with a small ‘weep hole’ to allow venting. But this hole was directly over the support structure and, as the support heated and cooled in service, moist air was drawn in, water condensed and then couldn’t drain out.

Over time there was localised external corrosion on the pipe, eventually resulting in a failure under pressure, and the LPG leak. A survey of similar pipe supports across the refinery identified up to 1 in 20 with evidence of similar corrosion.

Operators of pipework systems with this type of support that carry hazardous fluids are advised to check for the possibility of internal corrosion mechanisms and adjust their inspection regimes accordingly.

You can read the safety notice in full on the HSE website.

Ian Waldram

CFIOSH