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Chat Area => General Discussion Area => Topic started by: Viral_Jim on 12 October 2021, 10:52:15

Title: Running air lines in a garage... push fit?
Post by: Viral_Jim on 12 October 2021, 10:52:15
I'm nearing the end of the house project and I have some 22mm BPEX pipe left over and a few push fittings.

Next house will be one that I stay in for a while and I want to plumb compressed air in around the garage (not least so the compressor can make its noise somewhere else). I was wondering if I can use a) the pipe and b) the push fittings for air. The pipe seems to be oil resistant and rated to 175psi @23 degrees but I am less sure what effect the oil will have on the fittings.

I don't mind spending the money to buy other stuff if required, but if I can use what I have then why not!  :y

Title: Re: Running air lines in a garage... push fit?
Post by: STEMO on 12 October 2021, 12:29:24
When I saw the title, I thought your real name was Michael O'Leary. ;D
Title: Re: Running air lines in a garage... push fit?
Post by: Doctor Gollum on 12 October 2021, 12:55:58
Not your brightest idea. ;)

The pipe may be rated to over ten times mains water pressure, but the push fittings won't be. Put another way, the pipes are intended not to burst if frozen, but the fittings blow apart, from experienced, at about - 10°C. Not sure how much pressure the ice exerts, but it's not going to be 175 psi, not even close.

If you're going to the trouble, then do it properly, or build an insulated box for the compressor :y
Title: Re: Running air lines in a garage... push fit?
Post by: STEMO on 12 October 2021, 14:25:50
Not your brightest idea. ;)

The pipe may be rated to over ten times mains water pressure, but the push fittings won't be. Put another way, the pipes are intended not to burst if frozen, but the fittings blow apart, from experienced, at about - 10°C. Not sure how much pressure the ice exerts, but it's not going to be 175 psi, not even close.

If you're going to the trouble, then do it properly, or build an insulated box for the compressor :y
As the water in pipes freezes, it expands, creating as much as 2,000 pounds of pressure per square inch

 ::)

https://www.propertycasualty360.com/2015/03/02/the-big-freeze-5-signs-your-pipes-are-frozen-and-how-to-thaw-them/?slreturn=20210912092457
Title: Re: Running air lines in a garage... push fit?
Post by: Doctor Gollum on 12 October 2021, 17:14:32
It expands 9% by volume. If the pressure exceeds 175 psi then that pipe will fail, ergo that pipe will never see 2,000 psi ;D
Title: Re: Running air lines in a garage... push fit?
Post by: Viral_Jim on 12 October 2021, 20:08:19
On pressure alone, I don't have any concerns as both pipe and fittings are rated to 12 bar by the manufacturer (having read their website more closely). The other thing worth understanding is how hot the air can be coming off the compressor (Boyles law and all that jazz) as the pressure rating drops as the temperature increases (ratings of 8bar @90 degrees for pipe and fittings). As I've never had a compressor before I don't know how hot the air can get.

Having read around, online information seems to fall into 2 camps. The first is 'use only copper or specialist air fittings or the world will end' second camp basically reckons anything will do as long as it's pipe  ::).
Title: Re: Running air lines in a garage... push fit?
Post by: Sir Tigger KC on 12 October 2021, 20:44:56
I've no idea what I'm talking about so do your own due diligence.  ;)

So I reckon the pipe would be OK, but I'd be dubious about the push fits.  :-\  I think I'd use brass compression joints instead.  :y   

Oh and stand well back when you charge it up for the first time!  ;D
Title: Re: Running air lines in a garage... push fit?
Post by: Viral_Jim on 12 October 2021, 20:48:16
Oh and stand well back when you charge it up for the first time!  ;D

100%. I'll be outside with my fingers in my ears?

Tbh, having looked at my compressor closely (hardly used it since I've had it), it's got twin outputs, so the number of fittings I'm going to need is so small I may as well but the real deal. Speedfit air rated are up to a fiver a go, but that's hardly breaking the bank if I only want two or three!
Title: Re: Running air lines in a garage... push fit?
Post by: Doctor Gollum on 12 October 2021, 21:04:55
Put it another way, how many workshops have you seen using plastic piping for their compressors?

Would you use it for mains gas?  :D
Title: Re: Running air lines in a garage... push fit?
Post by: Andy B on 12 October 2021, 21:11:04
Problem solved .....  :y

https://vevor.co.uk/products/air-hose-reel-3-8-65ft-20m-auto-1-4bsp-retractable-line-compressor-wall-mount?gclid=Cj0KCQjw5JSLBhCxARIsAHgO2Sczeb5uBkA2tEI3v_uK-jcMNPQ7j-Meo1KBYoQN0IhyIqQ75ojvdTkaAsFdEALw_wcB
Title: Re: Running air lines in a garage... push fit?
Post by: Nick W on 12 October 2021, 21:18:39
Put it another way, how many workshops have you seen using plastic piping for their compressors?



Lots. It's easier and cheaper than using steel pipe.


HERE  (https://kcair.co.uk/services/compressor-services/installation?gclid=Cj0KCQjw5JSLBhCxARIsAHgO2Sf9-te3peWJdJCOybi55uqUtq5pKJ2BQ-l7yGu9O2TYKxOr2FQAyqAaAr5aEALw_wcB)is just one supplier(the first one on the search page)


There was a recent Edd China Youtube plumbing his air system with plastic pipe and fittings.
Title: Re: Running air lines in a garage... push fit?
Post by: dave the builder on 12 October 2021, 21:33:52
Indeed pressure rated ABS pipe can be used 1" is rated at 400 psi IIRC

speedfit plumbing pipe not so much  :D

as for "mains gas" ,that is low pressure anyway , but you have to use TRAC pipe, copper etc , the DNO use MDPE  on the network "gas grid"

Title: Re: Running air lines in a garage... push fit?
Post by: Viral_Jim on 12 October 2021, 21:58:56


There was a recent Edd China Youtube plumbing his air system with plastic pipe and fittings.

Thanks, I'll look for this! At least his video is likely to have some experience/knowledge/research behind it. :y
Title: Re: Running air lines in a garage... push fit?
Post by: Kevin Wood on 12 October 2021, 23:13:29
I have a feeling you can get Speedfit, etc. fittings designed for use on airlines if you're worried.

Possibly, they just have different rubbers designed to be oil resistant.

If the pipes are mounted such that they're not going to cause injury or demolish the place if a fitting lets go, then I'd be inclined to suck it and see, TBH.
Title: Re: Running air lines in a garage... push fit?
Post by: Doctor Gollum on 13 October 2021, 02:09:58
Put it another way, how many workshops have you seen using plastic piping for their compressors?



Lots. It's easier and cheaper than using steel pipe.


HERE  (https://kcair.co.uk/services/compressor-services/installation?gclid=Cj0KCQjw5JSLBhCxARIsAHgO2Sf9-te3peWJdJCOybi55uqUtq5pKJ2BQ-l7yGu9O2TYKxOr2FQAyqAaAr5aEALw_wcB)is just one supplier(the first one on the search page)


There was a recent Edd China Youtube plumbing his air system with plastic pipe and fittings.
Fair enough  :y

The compressor lines at work are all metal.
Title: Re: Running air lines in a garage... push fit?
Post by: TheBoy on 13 October 2021, 06:25:09
Given my history of things going wrong in the garage, I decline to advise either way ;D
Title: Re: Running air lines in a garage... push fit?
Post by: Marks DTM Calib on 13 October 2021, 08:05:04
I wont even use push fit on water  ;D

But water fittings for an airline is questionable, airlines often have oil in them and you need seals in the fittings capable of withstanding exposure to the oil.
Title: Re: Running air lines in a garage... push fit?
Post by: Keith ABS on 13 October 2021, 19:35:15
 On a site a few years ago, all the mains water in the building was being preasure tested overnight after being pumped up to 20bar. It dropped to -17c overnight. every fitting blew out and it flooded the floor being tested. Plastic pipe and fitting specialy designed for air are made. I would strongly advise going that route. The old way was to use steel threaded pipe and in some small establishments, copper pipe. Plastic is now the norm