That's an interesting question. I guess it's partly the fact that chemical industry is very large-scale, often with one company in charge (think Shell or Total)

That's an interesting question. I guess it's partly the fact that chemical industry is very large-scale, often with one company in charge (think Shell or Total). The realities of having one organisation in charge of many large operations across many countries probably gives higher reward on standardisation. This is a bit like coding to "Google style guidelines" or whatever. The big organisation has more incentive to fund standardisation, but the small people can benefit from that effort, too. The magnitude of impact also means that many industrial plants fall under government regulation, and in the safety field specifically there is a lot of knowledge sharing. I think there is also a component about the inflexibility of real matter that factors into this. It's much harder to attach two incorrectly sized pipes together than it is to write a software shim, so the standardisation of pipe sizes and gets pushed up to the original manufacturers, where it also happens to be more economical to produce lots of exact copies than individually crafted parts.