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I'm building a spunding valve and can't locate an adapter from female flare to male pipe thread. Until I can, I'm planning on using reinforced PVC tubing to connect the valve/gauge assembly to the gas disconnect. The tubing will be attached by 1/4" barb and hose clamps.

How much pressure could this setup survive?

I'm planning on maintaining 10 or 15psi toward the end of fermentation, but I imagine that if I'm not careful, the pressure could shoot up without my knowledge. I'd like to avoid projectiles, if possible.


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up vote 2 down vote accepted

The link to the tubing you posted says the tubing rating is 250psi, and a barb with a clamp would surely tolerate at least 60psi, but I don't think figuring out the maximum pressure the system can safely handle is the way to go.

Instead, ensure that your adjustable valve has a maximum pressure so that it that opens when the pressure goes above a threshold regardless of how tight you screw it. 30psi might be a safe bet, and far lower than the breaking point of any of the components in the valve assembly. You can then test this safely and verify the valve opens as expected - and know for sure that the rest of the valve assembly can also tolerate the pressure.

I have the morebeer pressure relief valve and that opens at around 20psi even when screwed right down.

PS: (Here's a FFL x MPT adapter) FFL x MPT adapter

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This is good advice on safety. One thing I'd add is to make sure that you have a backup burst-valve somewhere on the vessel itself. If you're using a corny, for example, make sure that the emergency valve on that is in good working order. – MalFet Feb 19 '13 at 2:00
Good points - you know, I was going to mention about cornies and the pressure relief valve, but cut that paragraph for brevity! – mdma Feb 19 '13 at 2:11
I'll test it for 60 psi but try not exceed 30 in practice. Thanks for the link @mdma but shipping to Canada from that supplier is stupidly expensive. I'm going to to try to find it locally. – Tobias Patton Feb 19 '13 at 3:33
I get my stuff shipped to Norway from there - a small flat rate box for about $20. Just order plenty of stuff in one go and it works out ok. – mdma Feb 19 '13 at 3:36

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