This alert is issued following the failure of a spring return pipeline emergency shut down valve (ESDV). The failure left the primary platform isolation device inoperable with the valve failed in the open position. Other ESDVs have been examined and have found to be at risk of failing in this manner. Spring return valves other than ESDVs are equally vulnerable.
Read the full report in https://www.hse.gov.uk/safetybulletins/pipelinevalve.htm
"This safety notice describes a specific degradation mechanism found inside stainless steel thermowells operating where the external atmosphere contains halides, as is typical in coastal locations or near to cooling towers. Thermowells can 'breathe' during normal operation as vessels heat up and cool down, drawing in the external atmosphere through non gas tight fittings. If the atmosphere contains halides this can leave any stainless steel susceptible to Chloride Stress Corrosion Cracking (CISCC). The HSL Research Report 902 (Reference 1) covers the susceptibility of stainless steel to CISCC in some detail and links to other research papers and published documents".
Read the full safety alert in this link https://www.hse.gov.uk/safetybulletins/thermowell-corrosion.htm
"A recent failure on a UK refinery involved an 8" diameter vertical relief line, approximately 5m in length, which catastrophically failed during normal operation part way along its length, releasing approximately 75 tonnes of extremely flammable material at elevated temperature and pressure. Connected to an insulated process header and vessels, the failure involved complete separation of the relief line (which was not insulated).
Subsequent examination of the line revealed excessive internal thinning which was very local to the failure point, but relatively normal wall thickness elsewhere along its length. The inspection regime included regular thickness testing at four locations, but not at the area local to the failure. Notably, an adjacent relief line was also found to have very similar localised and severe internal corrosion, which had also gone undetected".
Read the full incident in this link https://www.hse.gov.uk/safetybulletins/catastrophic-rupture-dead-leg-pipe-work.htm
"This safety alert is aimed at haulage contractors, users of tank containers and road tankers, companies servicing pressure/ vacuum relief valves and authorised inspection bodies contracted to verify the functioning of these valves.
Tank containers and road tankers used for flammable, corrosive and toxic liquids and gases will normally have a valve fitted to prevent damage to the tank from changes in the internal pressure. Haulage containers used for less hazardous liquids and gases may also have a valve.
Following a road incident in April 2020, investigations by Cleveland Police and HSE found evidence that a pressure/vacuum relief valve, originally manufactured by Fort Vale Engineering Ltd, had been modified by a third party. The valve cap had a nut welded to the top, most likely to allow it to be serviced without the use of a special tool to remove the valve cap. The unauthorised modification prevented the valve’s safe operation"
Read the full report here https://www.hse.gov.uk/safetybulletins/failure-road-tanker-pressure.htm
The 8-inch nominal bore, hydraulically operated MLA involved in the incident had been in service for 11 years and had been regularly maintained by various recognised industry contractors. It had a rigid link pantograph balancing system with independent primary and secondary counterweights linked to the inboard and outboard arms. The MLA failed as it was being manoeuvred towards a ship manifold for connection. A section of the MLA fell backwards onto a jetty handrail narrowly avoiding live plant and pipework on an upper-tier COMAH establishment.
Source: https://www.hse.gov.uk/safetybulletins/marine-loading-arm-failure.htm