Is it legal to grease packing before testing a valve? API 598 (section 4.4.1) infers that the packing should not be greased because it is a "sealing surface." Also, MSSP-61 (4.1.2) also says that seat surfaces should be clean. It could be inferred that the packing should also be clean because it creates a seal on the stem of the valve. Some people in our company interpret this as strictly the seat of the valve and therefore it is perfectly fine to grease the packing to get the valve to pass a pressure test. Not having much experience in the industry, I ask others opinions interpreting this. That said, it's been my experience that certain types of packings and seals, particularly o-rings, NEED an initial application of a film lubricant to ease installation to AVOID future problems. Skipping the lubricant in this case is not in the owners' interest!Some valve manufacturers list the lubricants they use, so clients will know if these are suitable or if substitutions will need to be made. I've always presumed that if a lubricant was used, some of this stuff will end up on wetted parts inside the valve. Assemble the valve according to the manufacturer's assembly/service procedure. Unless you have a lubricated plug valve there should be no grease(Sealant) inside the valve.

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