Inspection for corrosion at trunnion pipe supports
H R Peramatzis1 and Chris Scales2
1ESR Technology, Milton Park, Oxfordshire OX14 4SA, UK
2HSE, UK
Trunnion pipe supports are a common means to support/restrain process pipework both on- and offshore; a length of pipe (trunnion) is welded to the process pipework and often has an end plate welded on to seal it, resulting in an enclosed volume. Consequently, trunnion supports do not permit general visual inspection of areas of the process pipe susceptible to corrosion.
The potential failure of process pipework results from the ingress of water/moisture through small-diameter ‘weephole’ drilled in the trunnion as part of the welding process. Failure of process pipework supported by trunnions is time dependent; the risk of hydrocarbon release (HCR) increases with the age of assets. HCRs resulting from pipework failure at trunnions have been investigated by the UK HSE and instances have been reported on- and offshore. The aim of this HOIS project is to develop trial-based guidance on the suitability of available non-destructive testing techniques to identify the presence of corrosion within trunnions and, where possible, characterise/quantify it. The completed guidance document will provide a practicable, good practice approach to the management and inspection of trunnions.
This paper will describe the progress achieved to date on this project and outline key aspects of the trial results.
The potential failure of process pipework results from the ingress of water/moisture through small-diameter ‘weephole’ drilled in the trunnion as part of the welding process. Failure of process pipework supported by trunnions is time dependent; the risk of hydrocarbon release (HCR) increases with the age of assets. HCRs resulting from pipework failure at trunnions have been investigated by the UK HSE and instances have been reported on- and offshore. The aim of this HOIS project is to develop trial-based guidance on the suitability of available non-destructive testing techniques to identify the presence of corrosion within trunnions and, where possible, characterise/quantify it. The completed guidance document will provide a practicable, good practice approach to the management and inspection of trunnions.
This paper will describe the progress achieved to date on this project and outline key aspects of the trial results.
