EEMUA PUB NO 199
On-Line Leak Sealing of Piping: Guide to Safety Considerations
|Publication Date:||1 January 2000|
Certain leaks from pressurised piping may be effectively contained by on-line sealing methods involving injection of elastomeric compounds. The methods, originally developed for application to leaking steam or condensate systems, may also be applied to process piping leaks but additional precautions are usually necessary. Because of the inherent risks, such methods should only be carried out by trained personnel working to an agreed procedure. Also, since leakage indicates deterioration of the pressurecontaining material, all repairs by these methods should be regarded as temporary. It is therefore essential that records of such repairs are maintained.
This publication is applicable to industrial piping in which leaks are to be temporarily sealed whilst in service by the injection of a suitable compound. It gives guidance on the limits of application of the technique, the factors to be considered when evaluating the feasibility of its use, and the preparation and execution of the procedure. It also provides the information necessary for an appropriate multi-skills team to conduct a detailed risk assessment in order to decide whether the technique should be applied in a particular case.
Injection techniques should not be used for the repair of cracks as effective penetration by the sealant is unlikely to be achieved. Neither are the techniques suitable for repairs to special joints such as those employing pressure energised gaskets or lens rings. In these cases the sealant pressure may affect the alignment of the gasket or lens ring and cause the joint to fail.