After repeated failures due to corrosion, they took a commercial valve and under the direction of an experience ME modified it by creating a new, sturdier valve body made from a different alloy and thicker pipe on the discharge side. It has worked well. My question is: How does that affect the legality of using that valve and are there any methods to have the valve tested and stamped to approve it for service, or is that even possible? The legality of the changes that you have made to this valve basically depend on what the changes are, and what part of the world you are in. Here in Europe all valves supplied must meet the requirements of the Pressure Equipment Directive. If you have changed the pressure boundary in any way then you must document what you have done and show that it meets recognised standards. Using ANSI standards I would say that you should produce a fully documented technical appraisal of the valve. For this you will have to check the pressure/temperature ratings, the body wall thickness, and flange dimensions. You should also produce some bonnet thickness calculations and carry out a body hydraulic valve test. Overall it could be cheaper to purchase a new valve.

MORE NEWS