4 ms·

Things like threads sizes staying imperial makes sense to me. I believe they are now technically defined in mm, but obviously it's still based on fractions of

Things like threads sizes staying imperial makes sense to me. I believe they are now technically defined in mm, but obviously it's still based on fractions of an inch. In my view, there aren't any truly compelling reasons to switch from BSP to something based on natural metric measures. On the other hand, if we were to replace these pipe fittings with metric, we'd end up with a mixed system for realistically at least a century, if not a lot longer due to how long pipe systems last. The complexity (and also, in some cases, danger) of having to maintain both systems for so long would be incredible. It's similar to how in flying, we still use feet/flight levels, and actually a few places have migrated from metric to the more conventional imperial system. Imperial pipe fittings are pretty common across the entire world, in fact. I think most countries outside of UK/USA use BSP (often by a different name), but NPT is also sometimes used - and even BSP vs NPT is a huge pain.

dogma1138 4y ago
The problem is that BSP only applies to a specific types of pipes, soft water piping like PEX, gas and other pipes are often a mishmash of thread standards as they are not covered by BSP. So in reality there already is a mixed system which is often what causes a lot of headaches, what’s worse is that BSP is also a mixed standard it has both metric and imperial measurements for its standard threads however when you mix fittings that were machines using metric and pipes that were machined with imperial I’ve found that because of slight tolerance differences you often can get into a point where stacked tolerances becomes and issue.
perilunar 4y ago
> It's similar to how in flying, we still use feet/flight levels, and actually a few places have migrated from metric to the more conventional imperial system. It hasn't stopped the conversion of most other aviation measurements to metric. Runway dimensions, visibility and separation distances are in meters, temperatures are in Celsius, atmospheric pressure in hectopascals, fuel is in litres, mass is in kilograms. Frequencies are in Hertz. At least that's the case in Australia. Pretty sure Europe is similar.

dogma1138 4y ago

The problem is that BSP only applies to a specific types of pipes, soft water piping like PEX, gas and other pipes are often a mishmash of thread standards as they are not covered by BSP. So in reality there already is a mixed system which is often what causes a lot of headaches, what’s worse is that BSP is also a mixed standard it has both metric and imperial measurements for its standard threads however when you mix fittings that were machines using metric and pipes that were machined with imperial I’ve found that because of slight tolerance differences you often can get into a point where stacked tolerances becomes and issue.

perilunar 4y ago

> It's similar to how in flying, we still use feet/flight levels, and actually a few places have migrated from metric to the more conventional imperial system. It hasn't stopped the conversion of most other aviation measurements to metric. Runway dimensions, visibility and separation distances are in meters, temperatures are in Celsius, atmospheric pressure in hectopascals, fuel is in litres, mass is in kilograms. Frequencies are in Hertz. At least that's the case in Australia. Pretty sure Europe is similar.