steel flat face flange to steel raised flange?
steel flat face flange to steel raised flange?
(OP)
I am putting together a calibration stand and I have a pump with a 3" 150# steel flat faced flange for the suction side and I have a steel raised face flange and gasket to mate to it. Is this ok since its steel to steel or will I be setting myself up for leaks?





RE: steel flat face flange to steel raised flange?
RE: steel flat face flange to steel raised flange?
RE: steel flat face flange to steel raised flange?
ASME B16.5 is the flange construction standard. It deals mostly with geometry, i.e., hole pattern, etc.
The flat faced flange is intended to be used with a full face gasket and won't necessarily have the same surface finish requirement as the Raised Face flange. But just because it's not "required" doesn't mean that's not what it IS. Give it the old fingernail test to see how similar they are.
RE: steel flat face flange to steel raised flange?
As far as the primary concern of bolting up a raised face flange to a flat face flange, that's only really a problem when one of the two is made from a brittle material like cast iron. You'll be fine, provided you torque the flange stud bolts to give (approximately) even and correct tension.
RE: steel flat face flange to steel raised flange?
Aramid/Buna-N Flange Gasket Full Face, rated 1000psi
RE: steel flat face flange to steel raised flange?
RE: steel flat face flange to steel raised flange?
In B31.1, I think it is Table 12, but that is from "senior" memory so don't trust it (I am not at my company compuer so I can't look it up.)
rmw
RE: steel flat face flange to steel raised flange?
This is to prevent the relatively thin & brittle 125 CI flange from being sprung into a gap, while bolting-up - possibly cracking the flange.
250 CI flanges have a raised face, and they can be bolted directly to 300 steel flanges with their raised faces intact, using ring gaskets. The 250s are so heavy that unless the pipefitter has superhuman strength, they cannot crack during bolt-up.
RE: steel flat face flange to steel raised flange?
RE: steel flat face flange to steel raised flange?
RE: steel flat face flange to steel raised flange?
RE: steel flat face flange to steel raised flange?
Mating raised to flat face is only a problem in certain material combinations. It is not always necessary to machine off the raised face, which was the point of this thread.
RE: steel flat face flange to steel raised flange?
Goulds has a particularly strong statement in their literature warning against this practice (unless, of course, the pump metallurgy is DI.)
rmw
RE: steel flat face flange to steel raised flange?
-Deal with it.
RE: steel flat face flange to steel raised flange?
OK, I think that's permission to take this otherwise resolved thread a little off topic!
Hey, if you want to specify an expensive practice even when it's unnecessary in a particular set of circumstances, I don't have a problem with that- unless you're unwilling to PAY for it in cost and schedule.
When the spec calls out an unnecessary practice, which is not followed because it makes no sense, and this is called out during inspection as a defect- "repairing" that "defect" is a little irksome, especially when the client themselves are inconvenienced by the delay. The trouble is, the person who wrote the spec is seldom available to give their opinion about whether or not the "defect" is acceptable!
When the spec calls out a practice that is physically impossible, or will render their resulting unit inoperable, that gets a little comical. And when one company's spec calls out a practice as mandatory, and another company's spec calls out the SAME practice as prohibited, that gets a little comical too.
I can tell you that it's far easier to get people to follow rules that make sense, especially when a little explanation is given in a guidance document as to why a particular practice is called out.
RE: steel flat face flange to steel raised flange?
Another oddity: I recently had a pump co build a pump with a 250# inlet and 250# outlet but they wouldn't put a RF on the 250# flanges (to which I was bolting a 300# flange.) The same pump company on the other hand sold us a different model pump with 125# RF flanges. Go figure. I thought I was reading a typo when I first saw it.
If you are making this determination for your own plant or process, you can make rational decisions that make sense for the situation based on good engineering principles. On the other hand, if you are making a product for sale to the public, then some end user can hire a consultant who has no sense, but who can read and quote from a code book and hang you out to dry with your customer. Been there. Once they find something to sink their teeth into, it seems to start a feeding frenzy where they will then go after and find all kinds of obscure stuff that amounts to nothing but that won't go away. They bill by the hour you know.
rmw
RE: steel flat face flange to steel raised flange?
rmw
RE: steel flat face flange to steel raised flange?
Alternatively, draw the P&ID with the notation, "125# FF (NOTE 1)", and then for NOTE 1 at the bottom left of the P&ID, state:
"OFF-SPECIFICATION FLANGE FOR LINE CLASS xxxx"
Then let the piping guys figure it out - which indeed they can.
Regards,
SNORGY.
RE: steel flat face flange to steel raised flange?