Tips for Valves Best Practices: How to get the Most out of Valves
A successfully commissioned valve is crucial for trouble free performance. Unfortunately, the period between valve testing and commissioning is when the valve goes through lots of abuse and mishandling leading to non-performance. Here’s an overview of the steps that should be taken in order to safeguard ball valves and ensure performance.
One of the most widely used shut off valve in an oil & gas pipeline or installation is a ball valve. Owing to industry requirements and huge demands, the valves are produced by a large number of manufacturers, world over. API 6D / ISO 14313, which is the most relevant or applicable standard, sets out material & dimensional requirements, design features and testing norms for these pipeline ball valves. Valves are made to specific project orders, involving drawing and quality plan approvals as well as third party witness tests. Tests include a high pressure hydrostatic shell test and seat seal test and when specified also conducts low pressure pneumatic test, high pressure gas tests and specified functional tests.
The period between valve testing at the valve manufacturer’s facility and a successfully commissioned valve in the pipeline is crucial for proper and trouble free performance of the valve. There are lots of points to be taken care of after the pressure tests, by the valve manufacturer and the end–user, which influences the long term satisfactory performance of these valves. Needless to point out that a valve which is leaking or hard to operate or completely jammed creates havoc with all work plans and deadlines. Unless a valve is set right, the pipeline commissioning cannot move forward. But the paradox is that many a times even a good valve is made bad at the work site, due to lack of knowledge on correct handling procedures.
Critical points of awareness
Each of the following pointers needs to be taken into account at the valve factory after pressure testing to ensure proper functioning of a valve:
- Valve internal should be thoroughly cleaned and dried after a successful factory test, as accumulated cavity water can corrode valve internals
- It is important that the cavity is subjected to a dewatering oil treatment, which would displace all the sticking water particles from the crevices
- Valves with seat sealant injection facilities are filled with ‘First fill of the lubricant’, on both the seats. This not only protects the seat but also covers the crevice between the ball and seat rings from external ingress of foreign particles.