Cause & Consequence
- Uncontrolled release of a flammable gas or liquid
The cause of the wrap failure was initially thought to be insufficient curing time of the resin, however following further analysis it was established that the surface temperature of the pipework during application of the wrap was too low leading to a lack of adhesion between the wrap material/resin and the pipework. It was also considered that inadequate pressure being applied during the wrap application contributed to the premature failure of the repair which was identified as a contributory factor.
The lesson learnt is to always ensure the pipe having the wrap applied is brought up to the correct temperature, as per manufacturers guidance prior to application of the wrap.
A method statement for the application and quality assurance of each temporary repair shall be available. This shall include, but not be limited to, acceptable environmental conditions for application, acceptable surface temperature ranges, surface preparation requirements, wrap lay up procedure and curing procedure and controls. No deviation from this method statement shall be allowed without prior recourse to the repair vendor. Where required additional heat sources such as heat blankets can be utilised to bring pipework surface temperatures within the required range. This should be included as part of the repair application method statement.
Maintain strict adherence to the specification, design, application and close out (including acceptance by the duty holder) of any designed composite repair.
Use of heat blankets in all Temporary Repair situations is recommended to ensure the pipework is up to recommended temperature before application.