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[Viral_Jim]

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! 

[STEMO]

When I saw the title, I thought your real name was Michael O'Leary.

[Doctor Gollum]

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

[STEMO]

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

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

[Doctor Gollum]

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

[Viral_Jim]

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  .

[Sir Tigger KC]

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.     

Oh and stand well back when you charge it up for the first time! 

[Viral_Jim]

Oh and stand well back when you charge it up for the first time! 

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!

[Doctor Gollum]

Put it another way, how many workshops have you seen using plastic piping for their compressors?

Would you use it for mains gas? 

[Andy B]

Problem solved ..... 

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

[Nick W]

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 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.

[dave the builder]

Indeed pressure rated ABS pipe can be used 1" is rated at 400 psi IIRC

speedfit plumbing pipe not so much 

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"

[Viral_Jim]

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.

[Kevin Wood]

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.

[Doctor Gollum]

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 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 

The compressor lines at work are all metal.