The world has a lot of different standards for a lot of things, but I have never heard of a place with the default screw thread direction being opposite.
So does each language have a fun mnemonic?
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Acetylene does, gas lines are standard pipe.
Suppose it’s cause natural gas runs at like, 1-3 psi, while a fresh tank of acetylene is 5,000?
Least in the US
It’s also torches and everything after the regulator, which run at much lower pressure. At least in NZ
I think it might be because they’re connected and disconnected regularly so misconnection is a common problem, even with colour coding. Gas work on houses involves actually putting the fittings on pipe and is done by people who should be concentrating more on that rather than on what they’re about to weld/cut.