I've recently been given some old BOC OA kit which includes an oxygen multi-stage regulator and resettable flashback arrestor and an acetylene multi-stage regulator and resettable flashback arrestor, as well as a welding/cutting torch.
The oxygen regulator is likely brass scrap as only rated for 206 bar inlet and IIRC the UK went to 230 bar maybe 20 years ago, all my current gas regulators such as oxygen, argon, and argon mix are 230 bar inlet or higher.
I was wondering if anyone knows whether the resettable flashback arrestors have wearing/ageing parts and whether they can be tested easily, also whether the acetylene regulator can be used for propane. The acetylene flashback arrestor is marked for 1 bar acetylene use or 3 bar propane. The acetylene regulator is marked for 15.5 bar inlet pressure. I've seen it said that acetylene regulators are OK for propane but asked a manufacturer and they said no, although they did mention on the side that was covering their arse for marked usage of the equipment.
A friend is looking to get a small oxy-fuel torch for use in glass blowing and some of these parts might be useful but I would want to make sure they are OK before handing them over or she can just buy a complete new set and I'll ditch the old stuff.
One other question, typical UK fitment of flashback arrestors is at the outlet of the regulator on the bottle, I understand the US fit them at the entry to the torch. In an application with an economiser is there a requirement for a flashback arrestor at the bottle and the economiser, or just at the bottle. My understanding currently is that the flashback arrestor at the bottle is all that is required, and currently only for systems which use 2 pressurised gases. One person I know has a flashback arrestor on a propane torch, which I think is unnecessary, as that entrains air by use of pressurised propane so a flashback can't occur.