Does anyone have a link to any law or standard that allows or prohibits
their use?

Was having a discussion with a mechanic yesterday and the wrench was
saying that it was easier to use a compression fitting than double
flaring and he didn't have a problem using them; my position was that if
I needed to replace a hard line where it was easier to cut and splice in
the middle than rerun the whole thing that I would always use a double
flare and a union, because of the impossibility of the fitting blowing
apart under pressure save for a failure of the tubing itself. the
discussion was prompted because he was looking at a repair I'd done on a
friend's vehicle when the rear brakes had failed; the hose to the rear
axle had failed and replacement required replacement of both the axle
lines and the back half of the rear body line due to rust, and he'd
noticed that the one splice that I'd done was a double flare union.

However when I went to research the issue I see a lot of opinions that
"it's illegal" to use compression fittings but no links to actual
references nor could I find anything in the pertinent safety inspection
standards (NB: I'm not a vehicle inspector nor have I ever been, so I
don't know if there is an "unwritten rule" that compression fittings =
failure.) If anyone has any knowledge of this issue I'd appreciate your
input esp. if it is specific to VA, MD, or DC.

I also certainly hope that the mechanic was referring to a good steel
Swagelok fitting (which is at least rated for the pressures used in an
automotive brake application) and not the brass ones like you'd use to
hook up an icemaker!

nate

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