Question about metric 6

[murdof]

Hi guys,

we are a company (ACE-Hellas SA) that has a software for static and dynamic analysis plus design of structures.

The question though is the following:

Currently we are looking for partners to promote our software all over the world.
Our software supports only metric and not imperial units.
I see that in US there are a lot of talks about adopting officially the metric system.
For us to support imperial units is not so easy - as we have to recreate all forms and calculations, so it will take a lot of time.

Do engineers in US work with metric or imperial units for the static and dynamic analysis?

We want to see if we should try to promote the software in the US as well.

Thanks!

 

[Archie264]

BA,

Thanks for the explanation. I suppose it might be inevitable that this turn into a SI vs Imperial debate but suffice it to say you've hit on two of my annoyances with SI for structural engineering applications: (1) a slipped digit doesn't easily reveal itself and (2) people incorrectly using kilograms as a unit of "force". My third quarrel with it is that I find SI dimensions to be difficult to read quickly. For example, I've seen dimensions such as this: "60000". Quickly, is that 6 meters, 60 meters or 600 meters? I guess those who work with it regularly have no problem but discretely different units such as feet and inches are much easier to read quickly...for me.

I'm now wearing my flame-resistant suit...

 

[Archie264]

PS: I think for certain scientific applications metric is superior but that's when dealing predominately with units of mass, not force. Just my opinion.

 

[77JQX]

I'll just leave this here:

Metric System Thriving in Nation's Inner Cities

 

[Archie264]

 

[IRstuff]

Apparently, there are benefits to inner city education; who'da thunk?

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[hokie66]

Archie,
BA has done a good job of answering your question to me (while I was asleep). I don't even like centimetres for rainfall or dressmaking, but I can't do anything about it. In structural engineering in Australia, we only use multiples of 1000, which is really what metric is about. Dimensions are all in mm. Europeans, particularly the French, use cm, but they do a disservice to the concept.

 

[Archie264]

Hokie66,

Thanks. I know the bulk of the world uses SI so it can't be all bad.

 

[Ron]

The metric system was sanction by the US Congress in the 1860's or 1870's....seems like implementation is going a bit slowly.

 

[Archie264]

...any day now...

 

[dik]

I quite clearly stipulate that shop drawings must be prepared in the units of the project... I have no difficulty designing in either... I like the Imperial system because of the different units... less likely to make an error due to the unusual units... with SI, it's easier to slip a decimal place... other than government projects, few projects I've been involved with are SI. Mostly alterations to larger facilities, where the original facilities are in Imperial...


Dik

 

[drawoh]

Archie264,

Most English flat head screws have 82[°][ ]heads. Some English flat head screws have 100[°][ ]heads.

Metric flat head screws have 90[°][ ]heads.

--
JHG

 

[BAretired]

On metric drawings, we are encouraged not to use decimal points or commas to delineate numbers. Instead we are encouraged to use a space where required. The number 60000 should not appear on a metric drawing. Instead, it should should read 60 000.

On structural or architectural drawings, it is not usual to dimension anything to a precision of less than one millimetre. Where smaller dimensions are needed, micrometres or nanometres should be used, but I have never seen either used on structural drawings.

BA

 

[IDS]

It seems ironic to me that mainland Europe, including France, commonly uses such peculiar units as kgf/cm^2 for stress, but the countries following the UK tradition use "proper" SI units as a matter of course.

To be fair, the Eurocodes do use SI units, but even they adopt the peculiar practice of designating millistrain as 0/00, which at the moment makes no sense at all to me.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[Tomfh]

in Australia, we only use multiples of 1000, which is really what metric is about.

Do you know why they teach centimetres in school?

I've never been able to figure that out.

 

[hokie66]

Tomfh,
No, I don't know how that started or why it can't be changed.

BA,
Do you have a reference for that? Where would you start? You mentioned 1200 x 2400 above, but don't like 60000. I see the point, but it is just the number of zeroes that is the problem? Is it 24000 or 24 000?

 

[BAretired]

hokie,
To be consistent, I probably should have said 1 200mm x 2 400mm but felt there was no danger of misreading 1200mm x 2400mm as there are only two zeros involved. Similarly, 24000 is easier to read than 20000. So, yes it is really the number of zeros which causes the reader problems. The whole object is to dimension in such a way that it cannot easily be misinterpreted by the reader.

I did have a reference years ago, but have not been able to find it tonight. The comma and decimal point are discouraged because they have different meanings in different parts of the world. The folowing discussion is of some interest but is not necessarily authoritative:

http://forums.autodesk.com/t5/Drafting-Techniques/metric-dimension-style/td-p/1692220

BA

 

[BAretired]

I found the following reference from NIST (National Institute of Standards and Technology). They are using a space and a decimal point in Item #16. The decimal point is not required on structural drawings as one millimetre is precise enough for most applications.

http://physics.nist.gov/cuu/pdf/checklist.pdf

BA

 

[hokie66]

I haven't seen the space convention used, perhaps because it is seldom needed to prevent misinterpretation. Grated, it is easy to read, say 60240, but not as easy to read 60000. I will continue to leave out the space. Writing 'mm' is redundant if that is the only unit used.

 

[BAretired]

I agree that writing "mm" is redundant.

BA

 

[apsix]

Learning centimetres in school is essential for those aspiring to become dressmakers or pizza chefs.