Posted By Frank Hallett What are you actually testing Raiz? And under what circumstances? The answers will help us to come up with a set of sensible & relevant responses. Frank Hallett

Posted By George Wedgwood By 'hydrotesting' I take it that you are pressure testing the pipework hydrostatically? Using water to pressure test is the right way and so long as the correct pumps are used, no significant release of fluid can occur should a failure occur. However, there is always the possibility of (for example) flange bolts fracturing and these can fly out with considerable energy. Flanges should be suitably wrapped and any people in the immediate vicinity should be moved behind barriers that would stop such a missile - sandbags, walls or strong plywood screens should be adequate but the extent depends on the pressure and pipework arrangement. Best have an engineering assessment beforehand by an experienced person to check it out. You also have to comply with the Pressure Systems Safety Regulations 2000.