What’s in a name eh?
British Standard Pipe — as the name suggests a thread series originally intended for joining ferrous pipework and incidentally now adopted as the ISO standard. The designation is derived from the nominal bore of the pipe.
I suspect the appellation “Gas” is historic. As it happens I’m just old enough to have lived with gas lighting, there are even some redundant bits buried under the plaster in my current hovel.
How times have changed! It’s not that long ago gas lighting was, in towns at least, almost universal, now it’s almost forgotten. It would be hard to overestimate the impact that the introduction of gas lighting, both public and domestic, must have had on people’s lives. Probably this is where the use of “gas” crept in; we are fond of verbal shorthand, “gas” is just easier to say just like we say “bus” rather than “omnibus”. The point is that the pipe is just a means to an end; it is what it carries that is the thing and it is just happened to be gas that had the most impact on people’s lives.
Steel pipes can and are used for transporting almost any fluid, it is not that long ago that there was even a compressed air service that was commercially piped under the streets of London!
I don’t wish to start an argument with bitza1927 but other than the existence of two versions of the BSP thread, the parallel (“G” designation) and conical (“R” designation), I am unaware of a gas thread as such. I suspect the “slight difference” referred to is in fact the conical “R” type that seals on the thread rather than relying on a gasket.
If ‘yer knows different please elaborate!