Quite often this venting is through the threads- so there is a rule that five or more threads must be engaged.
I admit I know little about haz location stuff but this is a bit confusing and you are right, I never did realize it.
I would think that the rule would be to limit the number of threads engaged but still, when tightly made up even dry a threaded connection will not leak even under considerable pressure. How can this be reliable?
-Hal
