Unit Systems

[nh3simman]

I have many engineering text books that were written by well known authors in the US.

Some of these, as far back as the early 80's, used SI units exclusively.

As I read the posts, I notice that a lot of people are still using Imperial units. ASHRAE even publishes the handbooks in SI and Imperial, so there is obviously a demand.

What is the position in the US with unit systems?

Do other countries use Imperial?

[lana]

I think that's only for US. As far as I know everywhere is SI, which should be.
Actually it is how we are used to them. Nobody can say which one is better. The problem is the whole world must use the same units, whichever it is.
Cheers

[US Iceman]

What is the position in the US with unit systems?


It's mixed, if you will pardon the pun.

Some of us learned the old system, then SI came around. Therefore we have to work through both unit systems, but I have to say I am more familar with, and have a better intuitive grasp of Imperial units.

The situation is beginning to change but there is a lot of inertia to overcome.

[nh3simman]

The situation is beginning to change but there is a lot of inertia to overcome.

Do you think that existing machinery keeps the the Imperial system in place? I'm thinking of things like pipe sizes, bolt sizes...

We have some old fin presses where the tube pattern is still quoted in imperial. Even fin spacing is still expressed in fins/inch. The younger guys here have never seen an inch but they quote 10 fpi.

[Brian_UK]

..... The problem is the whole world must use the same units, whichever it is.
CheersI don't see why that should be although it would, of course, make life easier albeit a bit boring.

At the moment you could say that the Far East has decided on a third set on units but depends how you look at it.

It started with Imperial (psi), moved on the SI(bar) and now we have kPa as well :(



Do you think that existing machinery keeps the the Imperial system in place? I'm thinking of things like pipe sizes, bolt sizes...

We have some old fin presses where the tube pattern is still quoted in imperial. Even fin spacing is still expressed in fins/inch. The younger guys here have never seen an inch but they quote 10 fpi.

I like pipe sizes in Imperial, it seems easier than having decimal points of millimetres. Whether the whole world will ever manage to get together and resize everything into whole number sizes is a completely different ball game.

With some things (10fpi) I sometimes wonder whether it matters at all. It's almost an 'expression' as against a dimension.

Some things are just numbers, what the exact size is is irrelevant almost.