Can anyone tell me the difference between no hub couplings. I see that there are ones that have rubber gasket with a pipe clamp on each end, and then there are the ones that have the rubber gasket with a metal sleeve covering the entire length of the coupling.
I am using them in two applications, the first is on the waste line side of a tub P trap to join new PVC to old galvanized steel. The second will be to replace a sanitary tee on the sink drain, which will be new ABS to old galvanized steel.
I have yet to find a definitive answer on when to use which coupling. Seems like all the manufacturers make both.
thanks.
Replies
I think what you're asking is the diff. 'tween a no-hub (traditionally for cast iron connections), and a Fernco (brand name).
In my limited experience, space is usually the deciding factor. The thin rubber on a no-hub will allow one side to be rolled or flipped back once the other end is slipped on.
Because of the extreme thickness of a fernco, that same maneuver is impossible with one of their fittings. They're better utelized where you've got lots of end-to-end play. Enough even, to tap the fernco on to the pipe with a block of wood or something.
In either case, I've found it helpful to loosen the clamps enough to completely slide them off the fitting and out of the way while working with the rubber component. They're usually just in the way at that juncture.
As Smith says, "Hope that was clear as mud"
Good Luck.
sounds like what you will be needing is a mission coupling. They are spec's for steel to copper, pvc to steel . cast to copper etc. They are the type with the band over the entire coupling and generally have a FL orange sticker indicating what they are to fasten to.
james
What I understand is that the plain all rubber fernco is for use in accessible areas such as basement, crawlspaces, or chases.
If the fernco is to be buried, then the metal surround is used as a potection of the rubber from abrasion/penetration.
FWIW.......as heard on site from the plumbing subs! Other opinions please!
..................Iron Helix
You will find that some inspectors will require the type with the metal sleeve in most places, exceptions being where they are permanently accessible. There's a Kubrick movie about those fittings... Full Metal Jacket... or something?
Here the inspector will let you bury a Fernco inside a wall.
In my neck of the woods that uses the UPC.
We use the shielded couplings inside the building line & the non shielded outside the building line.
I can't find it in the code that says that's the way I have to do it, but if I do it differently I will get shot down by the inspectors.
Now I have to go ask the inspectors, where this ruling is---- dammit!