-
1
- #1
Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
METRIC ! 52
- Thread starter ceesjan
- Start date
The one thing that comes to mind in reading through all these threads and that's the value of carrying units through all your calculations.
The example offered of the space probe going off course could never happen if the units were carried through.
I was taught early on to check for dimensional consistency at the end of every problem. I didn't really start to do it assiduously until I started doing chemistry and balancing redox reactions.
That's the biggest problem with Excel and lots of other programs I've seen - they let you mix units invisibly.
Regarding the change over to SI, I don't think it'll ever happen in public commerce, highway signs, etc. The average American just doesn't care to learn a new system of units and there's nothing in it for any politician who'd care to take up the banner. There are much better sound-bite issues available.
I presume that all engineers and scientists are "dimensionally bilingual".
The example offered of the space probe going off course could never happen if the units were carried through.
I was taught early on to check for dimensional consistency at the end of every problem. I didn't really start to do it assiduously until I started doing chemistry and balancing redox reactions.
That's the biggest problem with Excel and lots of other programs I've seen - they let you mix units invisibly.
Regarding the change over to SI, I don't think it'll ever happen in public commerce, highway signs, etc. The average American just doesn't care to learn a new system of units and there's nothing in it for any politician who'd care to take up the banner. There are much better sound-bite issues available.
I presume that all engineers and scientists are "dimensionally bilingual".
Congratulations to the Metric thread on reaching 100 posts. ![[wink]](/data/assets/smilies/wink.gif "[wink] [wink]")
HAZOP at
HAZOP at
When I started at school, we were still on the imperial system. Then metrication raised its head and we moved to the c.g.s system. Before long someone decided that this wasn’t right and we shifted to the kg.m.s system.
To say we have the SI system would be wrong. As other contributors have pointed out, most people work with a mix of units drawn from different systems. Even using cm instead of kilometres isn’t quite the same as using the SI system (a centimetre may be legit as an expression of length but what about when you calculate volumes? 1 cm3 is not SI, 0.001M3 is. Or is it? Then too, should it be 100ml or 1decilitre? Then add to the confusion by changing the names. The move from Fahrenheit to Centigrade was problem enough but change the name from Centigrade to Celcius, and Curies to Roentgens or whatever and you can confuse people even more. And what is the difference between 25C and 26C is it 1C or 1C ? is it because 1C is an actual temperature and 1C (one centigrade degree) is a difference in temperature…. but who is rigorous enough to make this distinction?
Now if life were as simple as just changing the road signs then I guess we’d all be in one unified system already. The speed limits don’t matter since no one takes any notice anyway and they become self-funding. Just install any speed sign in whatever units and follow it with a speed camera. In fact, in Europe speed limits are proving such a money-maker they have introduced variable speed limits on the Motorways, Autobahns, Autostrada, etc.. So one minute you’re legal and the next they dropped the limit on you, took your picture and made a cool £40. But that’s a political move and politicians won’t do it. It might cost votes (especially after Chancellor Kole bought it for a double whammy of (a) 1Duetsche Mark = 1 Ost Mark and (b) getting rid of Herr Titchmeyer, the Deutsche Bank and the Mark altogether for the Euro.
But if you give any retail business the choice they’d say let’s change. Let’s have lots of changes. Let’s have one after the other and don’t let’s try to do it all at once.
They know that the secret of any change is that the consumer pays.
Take plumbing, it changed in the UK many years ago. And guess what, 12mm and ½” are close, but not close enough. Any plumbing job became a nightmare in the UK as it gave plumbers the opportunity to change out whole plumbing systems because the new and old copper tubing didn’t match. “Change just one bit and you’re storing up problems for the future” they’d say. “Better to do it all now. Don’t know for how long we can get adapters”.
And note that the various adapters always seemed to be unreasonably expensive. “special” ½” to 12mm adapters always being more than ½” to ¾” or 12mm to 15mm. Or even than 12mm to 12mm straight connectors.
Another example, changing the weights to “metric” required every manufacturer to change from 1/2lb blocks of butter to the new metric equivalent size. Guess what, I’m sitting here debating whether to go and look at a block of butter to see what weight it really is sold in here! It looks the same (or does it?) I don’t know. …….
……………and I still don’t know, the wife takes the wrapper of and puts it in a dish. There, I actually went and checked. I think it is now 250gm (not 0.25kg). Some things went to odd values like 454gms (a pot of honey). Why 454? Is that a direct conversion? I doubt if any shopper knows (and how can the manufacturer say that this is approximately “30 servings”. The reason obesity is a problem is no one with an IQ of less than 180 can fathom out how many carbohydrates they’re eating per portion. Any diet is great but only if you have the first clue about how to measure your food factors. Food labeling is a nightmare.
While the poor consumer is struggling to figure out the difference between 1/2lb and whatever number of gms (250gm?) they now sell it in, they missed that the price per lb and price per kilo showed an amazing thing, it costs more when you buy per kilo.
Look at decimalization, (£1=240p to £1=100p) or any currency change. In Europe the coins have been withdrawn from circulation. Each one has been defaced. Then they have all been replaced with the new Euros. That costs money. I don’t know why they did it. It doesn’t make any sense at all, especially not for politicians except that each dreams of being President of Europe. But again, the consumer pays. Through taxation. Of course, some of the costs are recovered. The old coins are sold for scrap. One company in Scandinavia is turning them into ship propellers. I don’t know what other uses are being found. Who pays the balance of the costs? Helpfully, all those people with undeclared income stashed away in hard currency who couldn’t face walking into a bank with a suitcase full of old deutsche marks to trade for the new Euro (this was a serious problem in Germany, we are told) have helped contribute to the costs.
The currency change has, naturally enough, given the manufacturers another chance to hike the prices. Not just by rounding up when converting, this is small beer. For example convert 1 DM to Euros, it isn’t an exact conversion so naturally enough the sum is rounded up.
Now since many products are priced at $9.99 just to convince us its cheap where $10.00 makes us think it is expensive (I always fall for that one!); going from DM4.99 to E2.7445 goes to an intermediate E2.75 (a small gain) and then to a new E2.99 (a better gain). For the DM to Euro conversion notice that DM4.99 looks bigger than E2.99 because 4.99 is bigger than 2.99. This means it is easier to hike the price still further and hide it by fiddling with packaging sizes. So just change the package size and shape a bit and throw in a “Free” 20ml special offer. When the “Free” 20ml disappears no one will notice that the product costs 10% more after the currency change to before. Most people are pretty good at “size/weight recognition” when things are packed consistently. So always be sure to change the packaging. The fact that wine was sold in bottles where a bottle was 26floz was never a problem. It looked like a bottle. So just change to 75cl (not ccs) and change the bottle shape and who knows what they are buying?
More difficult is the conversion from Francs to Euros because the exchange is something like this: 4.99F = E8.2269. An immediate problem because 8.23 looks more than 4.99. Of course, the re-packaging trick works as well here. But while you may put less in the package to drop the price closer to E5, you may find it advantageous to not reduce the package size in direct proportion to the weight reduction. Buy an expensive box of chocolates some time and see what I mean. You’d be surprised what imaginative packaging can do to make 200gm of chocolates look like a 1kilo box, especially if the actual weight is printed just once in very small print.
So the trick is, never let the punter contend with just one conversion. Add a few more in and some repackaging tricks. There is even a fair chance some of them will get one of the conversions wrong, think they’ve discovered a big mistake of the manufacturers and stockpile two years worth of franks & beans. Then too, every change is an opportunity to sell $3 solar powered pocket converters at $9.99 a pop.
If you think this wouldn’t fool a 3-year-old, you’re wrong. My wife looks at the price per package and not the price per kilo (and shelf tags are very confusing since some show the price per kilo, some the price per 100gm and some nothing at all.) When we are in Europe she still converts the price to DM and using a 10 year-old conversion rate via Drachmas into Stirling. This is her sequential approach. She works things out according to the sequence of countries she has lived in, making no allowance for exchange rate changes. This is no more flawed, financially, than the EU approach to the Euro. Naturally, we don’t go shopping together. I spend the time trying to work out the prices only to find that while every other Mars pack has a shelf tag showing the price per 100gm the bag of fun size bars doesn’t have this so I never can decide whether to buy mars bars or not. I mention this because when there was only one size of Mars bar, the Mars bar price was used as a simple economic indicator in the UK. Now we have the “Footsie Index”. She, meanwhile is buying two loaves of bread for the price of one when we can only eat one (the ducks get the rest) but they just don’t offer half price bread. And how many pairs of red shoes can she really use? (none, it seems. She likes to shop for them, buy them and put them in the cupboard. I have never seen her wear them)
Letting illogical beings do the shopping unescorted is no great way to survive but it keeps the peace (Is a female Vulcan a contradiction in terms? Most illogical) but this is the key to change.
So believe me, even with the dumbest of finance directors, CEOs etc any half-way decent marketing guys can show a dozen or more ways to milk any change of units, currency, or anything else for a minimum 10% premium. All they ask is don’t do it all at once because that’s a clear 10% premium per change! And hey! The decimal change was a great earner. Why not now try binary? I can count to 10 on my fingers in decimal but to 1111111111 in binary (1023 in decimal?) The US has already started with a $1 (10000$) bill and a $2 (01000$) bill. They just need a $4 (00100$), $8 (00010$)$16 etc and we are half way there. Then label the old $5 bill 10100$ and the banks can get rich.
If we run out of changes, let’s do the whole thing over again, starting with the Babylonian hexadecimal system and cuneiform script. Bill Gates won’t like that, but I’m so fed up with having always to change the templates from Time New Roman to anything, anything else at all that Cuneiform will make a nice change.
So how about it? I’m game.
To say we have the SI system would be wrong. As other contributors have pointed out, most people work with a mix of units drawn from different systems. Even using cm instead of kilometres isn’t quite the same as using the SI system (a centimetre may be legit as an expression of length but what about when you calculate volumes? 1 cm3 is not SI, 0.001M3 is. Or is it? Then too, should it be 100ml or 1decilitre? Then add to the confusion by changing the names. The move from Fahrenheit to Centigrade was problem enough but change the name from Centigrade to Celcius, and Curies to Roentgens or whatever and you can confuse people even more. And what is the difference between 25C and 26C is it 1C or 1C ? is it because 1C is an actual temperature and 1C (one centigrade degree) is a difference in temperature…. but who is rigorous enough to make this distinction?
Now if life were as simple as just changing the road signs then I guess we’d all be in one unified system already. The speed limits don’t matter since no one takes any notice anyway and they become self-funding. Just install any speed sign in whatever units and follow it with a speed camera. In fact, in Europe speed limits are proving such a money-maker they have introduced variable speed limits on the Motorways, Autobahns, Autostrada, etc.. So one minute you’re legal and the next they dropped the limit on you, took your picture and made a cool £40. But that’s a political move and politicians won’t do it. It might cost votes (especially after Chancellor Kole bought it for a double whammy of (a) 1Duetsche Mark = 1 Ost Mark and (b) getting rid of Herr Titchmeyer, the Deutsche Bank and the Mark altogether for the Euro.
But if you give any retail business the choice they’d say let’s change. Let’s have lots of changes. Let’s have one after the other and don’t let’s try to do it all at once.
They know that the secret of any change is that the consumer pays.
Take plumbing, it changed in the UK many years ago. And guess what, 12mm and ½” are close, but not close enough. Any plumbing job became a nightmare in the UK as it gave plumbers the opportunity to change out whole plumbing systems because the new and old copper tubing didn’t match. “Change just one bit and you’re storing up problems for the future” they’d say. “Better to do it all now. Don’t know for how long we can get adapters”.
And note that the various adapters always seemed to be unreasonably expensive. “special” ½” to 12mm adapters always being more than ½” to ¾” or 12mm to 15mm. Or even than 12mm to 12mm straight connectors.
Another example, changing the weights to “metric” required every manufacturer to change from 1/2lb blocks of butter to the new metric equivalent size. Guess what, I’m sitting here debating whether to go and look at a block of butter to see what weight it really is sold in here! It looks the same (or does it?) I don’t know. …….
……………and I still don’t know, the wife takes the wrapper of and puts it in a dish. There, I actually went and checked. I think it is now 250gm (not 0.25kg). Some things went to odd values like 454gms (a pot of honey). Why 454? Is that a direct conversion? I doubt if any shopper knows (and how can the manufacturer say that this is approximately “30 servings”. The reason obesity is a problem is no one with an IQ of less than 180 can fathom out how many carbohydrates they’re eating per portion. Any diet is great but only if you have the first clue about how to measure your food factors. Food labeling is a nightmare.
While the poor consumer is struggling to figure out the difference between 1/2lb and whatever number of gms (250gm?) they now sell it in, they missed that the price per lb and price per kilo showed an amazing thing, it costs more when you buy per kilo.
Look at decimalization, (£1=240p to £1=100p) or any currency change. In Europe the coins have been withdrawn from circulation. Each one has been defaced. Then they have all been replaced with the new Euros. That costs money. I don’t know why they did it. It doesn’t make any sense at all, especially not for politicians except that each dreams of being President of Europe. But again, the consumer pays. Through taxation. Of course, some of the costs are recovered. The old coins are sold for scrap. One company in Scandinavia is turning them into ship propellers. I don’t know what other uses are being found. Who pays the balance of the costs? Helpfully, all those people with undeclared income stashed away in hard currency who couldn’t face walking into a bank with a suitcase full of old deutsche marks to trade for the new Euro (this was a serious problem in Germany, we are told) have helped contribute to the costs.
The currency change has, naturally enough, given the manufacturers another chance to hike the prices. Not just by rounding up when converting, this is small beer. For example convert 1 DM to Euros, it isn’t an exact conversion so naturally enough the sum is rounded up.
Now since many products are priced at $9.99 just to convince us its cheap where $10.00 makes us think it is expensive (I always fall for that one!); going from DM4.99 to E2.7445 goes to an intermediate E2.75 (a small gain) and then to a new E2.99 (a better gain). For the DM to Euro conversion notice that DM4.99 looks bigger than E2.99 because 4.99 is bigger than 2.99. This means it is easier to hike the price still further and hide it by fiddling with packaging sizes. So just change the package size and shape a bit and throw in a “Free” 20ml special offer. When the “Free” 20ml disappears no one will notice that the product costs 10% more after the currency change to before. Most people are pretty good at “size/weight recognition” when things are packed consistently. So always be sure to change the packaging. The fact that wine was sold in bottles where a bottle was 26floz was never a problem. It looked like a bottle. So just change to 75cl (not ccs) and change the bottle shape and who knows what they are buying?
More difficult is the conversion from Francs to Euros because the exchange is something like this: 4.99F = E8.2269. An immediate problem because 8.23 looks more than 4.99. Of course, the re-packaging trick works as well here. But while you may put less in the package to drop the price closer to E5, you may find it advantageous to not reduce the package size in direct proportion to the weight reduction. Buy an expensive box of chocolates some time and see what I mean. You’d be surprised what imaginative packaging can do to make 200gm of chocolates look like a 1kilo box, especially if the actual weight is printed just once in very small print.
So the trick is, never let the punter contend with just one conversion. Add a few more in and some repackaging tricks. There is even a fair chance some of them will get one of the conversions wrong, think they’ve discovered a big mistake of the manufacturers and stockpile two years worth of franks & beans. Then too, every change is an opportunity to sell $3 solar powered pocket converters at $9.99 a pop.
If you think this wouldn’t fool a 3-year-old, you’re wrong. My wife looks at the price per package and not the price per kilo (and shelf tags are very confusing since some show the price per kilo, some the price per 100gm and some nothing at all.) When we are in Europe she still converts the price to DM and using a 10 year-old conversion rate via Drachmas into Stirling. This is her sequential approach. She works things out according to the sequence of countries she has lived in, making no allowance for exchange rate changes. This is no more flawed, financially, than the EU approach to the Euro. Naturally, we don’t go shopping together. I spend the time trying to work out the prices only to find that while every other Mars pack has a shelf tag showing the price per 100gm the bag of fun size bars doesn’t have this so I never can decide whether to buy mars bars or not. I mention this because when there was only one size of Mars bar, the Mars bar price was used as a simple economic indicator in the UK. Now we have the “Footsie Index”. She, meanwhile is buying two loaves of bread for the price of one when we can only eat one (the ducks get the rest) but they just don’t offer half price bread. And how many pairs of red shoes can she really use? (none, it seems. She likes to shop for them, buy them and put them in the cupboard. I have never seen her wear them)
Letting illogical beings do the shopping unescorted is no great way to survive but it keeps the peace (Is a female Vulcan a contradiction in terms? Most illogical) but this is the key to change.
So believe me, even with the dumbest of finance directors, CEOs etc any half-way decent marketing guys can show a dozen or more ways to milk any change of units, currency, or anything else for a minimum 10% premium. All they ask is don’t do it all at once because that’s a clear 10% premium per change! And hey! The decimal change was a great earner. Why not now try binary? I can count to 10 on my fingers in decimal but to 1111111111 in binary (1023 in decimal?) The US has already started with a $1 (10000$) bill and a $2 (01000$) bill. They just need a $4 (00100$), $8 (00010$)$16 etc and we are half way there. Then label the old $5 bill 10100$ and the banks can get rich.
If we run out of changes, let’s do the whole thing over again, starting with the Babylonian hexadecimal system and cuneiform script. Bill Gates won’t like that, but I’m so fed up with having always to change the templates from Time New Roman to anything, anything else at all that Cuneiform will make a nice change.
So how about it? I’m game.
GregLocock
Automotive
There are 10 sorts of people. Those who understand binary, and those who don't.
Cheers
Greg Locock
Cheers
Greg Locock
Well, time for my rant on this subject I guess 
Being French, I'm indeed using metric system since I'm a kid. I learnt it at school and I'm using it in my every day life.
In my student life, I happened to go one year in Canada for my studies. Hence I had to deal with all your series of units and transform my Francs/Liter (was before 2002) in US$/Gallon for the car gas during my trip in US for spring break. Heck of a story it was! I let you guys have fun with this without your comp nor your calculator, because of course you do not travel with any of those when you go in holidays, do you? To help, you can use 1 US$ = 6.50 Francs (was around this at the time) and good luck to calculate by head ;-)
Now, do I care to have horsepower or watts for my engine specs? not really. HP is an old unit and people are used to it. I agree we should switch to Watts in regards of SI units. But let's be realistic! What does it change for customer to have Watts instead of HP? The real use is for the engineer, isn't it? Leave customer use their HP, most of them wouldn't know what Watts are anyway. For them, Watts are only related to their electric bill lol.
We however, as engineers, have to follow codes.
You guys in US use alot ASME, FAA, IEEE or whatever codes to design, manufacture etc your products, don't you? So why in the Hell wouldn't you use SI units?
I know it's related to your History and culture, and thus you won't leave your units easily. Hence I don't ask you to abandon them, just to work with SI ones. Just as I work in French and English on my papers because those are intended to be used by many countries. Papers intended to be use only inside my company are written in French. Do you see my point?
There are standards set for international understanding, and as engineer, I think we are educated enough to apply them as well as understand what they are and why they exist.
Just my 2 cents
Cyril Guichard
Mechanical Engineer
Being French, I'm indeed using metric system since I'm a kid. I learnt it at school and I'm using it in my every day life.
In my student life, I happened to go one year in Canada for my studies. Hence I had to deal with all your series of units and transform my Francs/Liter (was before 2002) in US$/Gallon for the car gas during my trip in US for spring break. Heck of a story it was! I let you guys have fun with this without your comp nor your calculator, because of course you do not travel with any of those when you go in holidays, do you? To help, you can use 1 US$ = 6.50 Francs (was around this at the time) and good luck to calculate by head ;-)
Now, do I care to have horsepower or watts for my engine specs? not really. HP is an old unit and people are used to it. I agree we should switch to Watts in regards of SI units. But let's be realistic! What does it change for customer to have Watts instead of HP? The real use is for the engineer, isn't it? Leave customer use their HP, most of them wouldn't know what Watts are anyway. For them, Watts are only related to their electric bill lol.
We however, as engineers, have to follow codes.
You guys in US use alot ASME, FAA, IEEE or whatever codes to design, manufacture etc your products, don't you? So why in the Hell wouldn't you use SI units?
I know it's related to your History and culture, and thus you won't leave your units easily. Hence I don't ask you to abandon them, just to work with SI ones. Just as I work in French and English on my papers because those are intended to be used by many countries. Papers intended to be use only inside my company are written in French. Do you see my point?
There are standards set for international understanding, and as engineer, I think we are educated enough to apply them as well as understand what they are and why they exist.
Just my 2 cents
Cyril Guichard
Mechanical Engineer
This is funny. Why is it even an issue which system is used. Ok so we use english here in the U.S. and everyone else uses metric. Once you learn both then it's no problem to use either. I know there are a lot of advantages to using the metric system because it makes more logical sense. But think about in the english system where the 1 lb mass is equal to 1 lb force. I would guess that some people would argue that that is a nice system. Each system has it's advantages and disadvatages which makes me believe that both systems aren't going anywhere.
CanEngJohn
Automotive
I am Canadian and born in '71. I grew up during the introduction of the metric system and had many a blank stare as I entered the world of automotive manufacturing. It took me about 6 months to become fully fluent in Metric and US units. I know without hesitation that 1 mil is 39.37 thou. And YES those extra digits ARE significant. I know people who use 40 and people who use 39. They are both wrong and have cost me tens of thousands of dollars in wrong parts for my machines. I know people who don't know what a thou is and people who growl at me to use imperial "cause the lathe ain't metric". I convert specs from lbf to Newtons and back again in my head these days(4.448 N/lbf). I have two different sets of allen keys. I know it is 454 g per pound and 2.2 lbs per kilo without thinking.
Bottom line here is that we are Engineers. We by nature have to be multilingual in measurement. Why you ask? Well when you are standing in front of a piece of assembly equipment the part needs to be long enough and strong enough to do the job. It really doesn't matter what unit you use to measure it.
"The cylinder needs to have a 0.002485 furlong stroke and be capable of working at 4137.19 Torrs." If the sales guy understands it great. If not you just wasted another $1200 bucks.
Also even Detroit is not willing to shell out the hundreds of billions it would cost industry to immediately convert all their equipment over. It would cost my current facility (1 plant of 500 ppl) just over 172 million to completely convert our equipment. And I am sorry but I cannot come up with a 1 year payback to justify it. And that is why many people still use the US units.
Oh yeah and butter here is sold in 454g blocks.
Bottom line here is that we are Engineers. We by nature have to be multilingual in measurement. Why you ask? Well when you are standing in front of a piece of assembly equipment the part needs to be long enough and strong enough to do the job. It really doesn't matter what unit you use to measure it.
"The cylinder needs to have a 0.002485 furlong stroke and be capable of working at 4137.19 Torrs." If the sales guy understands it great. If not you just wasted another $1200 bucks.
Also even Detroit is not willing to shell out the hundreds of billions it would cost industry to immediately convert all their equipment over. It would cost my current facility (1 plant of 500 ppl) just over 172 million to completely convert our equipment. And I am sorry but I cannot come up with a 1 year payback to justify it. And that is why many people still use the US units.
Oh yeah and butter here is sold in 454g blocks.
I have been an engineer for several years and have used both the metric and imperial units (my personal preference is the SI units). SI units have distinct advantages such as easier calculations and standards to remember. However, the US industry will not change to the metric system because of one reason alone COST. I was at conference on metriculation of units in the US the speaker said it cost the US industry billions of dollars to change over.
SI units do have an inherent ease of use but I remember being in school (Canada) hearing that we must always dimension our drawings in millimeters, for instance a room 13500 x 3600. The same instructors would howl in rage if the area of that room were given as 48600000 square millimeters.
SI, US, Imperial. Who cares!
As long as we know clearly what we are measuring. The problem is not the units used but how it is used. E.g. regarding prefixes: It is quite clear what MMSCF/bbl is for a an engineer (Million, in the refinery business) but if your are in a part of the world were it is not that obvious (which units of measure is used) and reads e.g. MSCF/h. Is it 1000's or millions that is used? a simple attached abbreviation list with prefixes, units and acronymes covered helps a lot.
Same with measures like gallons, is it UK or US gallons that is meant?. Another example is when engineers use percent e.g. for measuring concentration, is it weight, volume or mole % or what?
The main point is that we should be clear on what units we are referring to and e.g. explicitly mention if we are talking US or UK gallons (and not just gallons). If not we are destined to make mistakes which can cost a fortune.If one can fulfil this requirement I dont think it matters so much which system thats is used, since it is "crystal" clear what is meant if done thoroughly.
Regarding changing units. That will only occur if there is an obviouos advantage of doing so. E.g. if one would like to have the same product (e.g. a car) irrespective if it is produced in US or elsewhere in the world, with the same units of measure built into the car. At that point the manufacturer will decide which system to be used and as long as it is clear for the suppliers and the customer which system is used, so whats the problem?
It is only to accept that different parts of the world will use different system.
As long as we know clearly what we are measuring. The problem is not the units used but how it is used. E.g. regarding prefixes: It is quite clear what MMSCF/bbl is for a an engineer (Million, in the refinery business) but if your are in a part of the world were it is not that obvious (which units of measure is used) and reads e.g. MSCF/h. Is it 1000's or millions that is used? a simple attached abbreviation list with prefixes, units and acronymes covered helps a lot.
Same with measures like gallons, is it UK or US gallons that is meant?. Another example is when engineers use percent e.g. for measuring concentration, is it weight, volume or mole % or what?
The main point is that we should be clear on what units we are referring to and e.g. explicitly mention if we are talking US or UK gallons (and not just gallons). If not we are destined to make mistakes which can cost a fortune.If one can fulfil this requirement I dont think it matters so much which system thats is used, since it is "crystal" clear what is meant if done thoroughly.
Regarding changing units. That will only occur if there is an obviouos advantage of doing so. E.g. if one would like to have the same product (e.g. a car) irrespective if it is produced in US or elsewhere in the world, with the same units of measure built into the car. At that point the manufacturer will decide which system to be used and as long as it is clear for the suppliers and the customer which system is used, so whats the problem?
It is only to accept that different parts of the world will use different system.
Very interesting thread indeed.
I was fortunate enough to be born into a SI society, and thus "feel" in SI units. I have to agree with the defenders of the Imperial units: if one clearly specifies the units, no-one should feel uncomfortable.
In fact, how boring would life be if everyone spoke the same language? English is my second language, and I have lived a good life (so far) and certainly didn't make more mistakes in life (friendships etc.) as someone who speak the majority language of the world - probably Chinese. My point is, different units cannot change the science. In fact, the conversion from one set of units to another ceratinly increases the engineering "feel" and makes life interesting. It ceratinly also inspires different approaches to problems, which is a good thing.
Regards
GJdW
I was fortunate enough to be born into a SI society, and thus "feel" in SI units. I have to agree with the defenders of the Imperial units: if one clearly specifies the units, no-one should feel uncomfortable.
In fact, how boring would life be if everyone spoke the same language? English is my second language, and I have lived a good life (so far) and certainly didn't make more mistakes in life (friendships etc.) as someone who speak the majority language of the world - probably Chinese. My point is, different units cannot change the science. In fact, the conversion from one set of units to another ceratinly increases the engineering "feel" and makes life interesting. It ceratinly also inspires different approaches to problems, which is a good thing.
Regards
GJdW
For the sake of balancing readers' information, there is one site I found that considers butelja's funny story on railroad tracks a "rumor":
Rumor or not, I think butelja's message should be seriously considered.![[pipe]](/data/assets/smilies/pipe.gif "[pipe] [pipe]")
Rumor or not, I think butelja's message should be seriously considered.
The UK supposedly went metric in about '68 onwards as I recall. But we still use both units. We adapted because we had to. We are part of a much larger market and we needed to understand and not necessarily adopt other units.
I still work in Imperial and Metric. I'm 6'2" tall and weight 17 stone, my house is 500yds from the shops but I drive a 2litre turbo car.
I draw in mm and measure area in sq ft. I have a 32" TV set and buy drinks at the pub in pints. My car does 46MPG at a speed of 50MPH.
But when I go to France or Spain on holiday, I brush up on my schoolboy language training and communicate as best I can. I survive and its no big deal. The locals are generally very helpful and we haven't starved to death yet or ever not managed to buy our 60 litres of fuel.
Forces generated on pipe anchors are in kgF or KN. Pressure in PSI or Pa or Bar or kPA. I understand and use all of them fluently. Most people (Luckily for us English), learn English and speak it quite often better than we can. They adjust and adapt to the needs of the time.
We as engineers have the ability to do the same. We shouldn't be frightened to understand or use it, and it is probably in a global interest to have common units.
I'm sure that one day....(a long long time fom now), there will be some sort of standardisation. But in the mean time, I'm still using feet and inches and kG and fahrenheit and centigrade and NM.
Friar Tuck of Sherwood
I still work in Imperial and Metric. I'm 6'2" tall and weight 17 stone, my house is 500yds from the shops but I drive a 2litre turbo car.
I draw in mm and measure area in sq ft. I have a 32" TV set and buy drinks at the pub in pints. My car does 46MPG at a speed of 50MPH.
But when I go to France or Spain on holiday, I brush up on my schoolboy language training and communicate as best I can. I survive and its no big deal. The locals are generally very helpful and we haven't starved to death yet or ever not managed to buy our 60 litres of fuel.
Forces generated on pipe anchors are in kgF or KN. Pressure in PSI or Pa or Bar or kPA. I understand and use all of them fluently. Most people (Luckily for us English), learn English and speak it quite often better than we can. They adjust and adapt to the needs of the time.
We as engineers have the ability to do the same. We shouldn't be frightened to understand or use it, and it is probably in a global interest to have common units.
I'm sure that one day....(a long long time fom now), there will be some sort of standardisation. But in the mean time, I'm still using feet and inches and kG and fahrenheit and centigrade and NM.
Friar Tuck of Sherwood
Friar Tuck,
You missed one out - Even though our cars do 46MPG at 50MPH, we buy petrol in litres. Also, although legally shops have to sell weighed goods in kilo's, we always ask for a pound of carrots or quarter of a pound of cheese etc...
We also still have a few people here who moan about decimalisation (which took place in february 1971) as if it is a bad thing not to have to work in pounds shillings and pence (12 old pence in a shilling?, 20 shillings in a pound? 240 old pence in a pound - and don't even start on guineas which were apparently a pound and a shilling). Fortunatly I was born in 1972 so I missed out on all this.
In a similar manner (but less expensive than) the hubble telescope debacle, I spent a summer while at university working in an old cloth finishing machinery manufacturers in Salford (UK)where they managed to ruin a very expensive nylon roller they were turning because the drawing office of the company worked in metric and the machines downstairs on the shop floor were imperial. The two departments were in the same building and they still got it wrong. The D.O. expected the shop floor workers to convert every measurement prior to machining anything.
Regards
James Goodstadt
You missed one out - Even though our cars do 46MPG at 50MPH, we buy petrol in litres. Also, although legally shops have to sell weighed goods in kilo's, we always ask for a pound of carrots or quarter of a pound of cheese etc...
We also still have a few people here who moan about decimalisation (which took place in february 1971) as if it is a bad thing not to have to work in pounds shillings and pence (12 old pence in a shilling?, 20 shillings in a pound? 240 old pence in a pound - and don't even start on guineas which were apparently a pound and a shilling). Fortunatly I was born in 1972 so I missed out on all this.
In a similar manner (but less expensive than) the hubble telescope debacle, I spent a summer while at university working in an old cloth finishing machinery manufacturers in Salford (UK)where they managed to ruin a very expensive nylon roller they were turning because the drawing office of the company worked in metric and the machines downstairs on the shop floor were imperial. The two departments were in the same building and they still got it wrong. The D.O. expected the shop floor workers to convert every measurement prior to machining anything.
Regards
James Goodstadt
CanEngJohn,
[blue]I know without hesitation that 1 mil is 39.37 thou. [/blue]
1 mil is 1 thou. Don't ask me, 'mil' is a term your neighbours to the south use. How do they get from one thousandth of an inch to 'mil' in any rational step?
1 millimetre is 39.37 thou in England.
Mil is a slang term for millimetre over here in the UK. An American enginerr and I managed to tie ourselves in
knots over the difference in American and UK terminology.
------------------------------
If we learn from our mistakes,
I'm getting a great education!
[blue]I know without hesitation that 1 mil is 39.37 thou. [/blue]
1 mil is 1 thou. Don't ask me, 'mil' is a term your neighbours to the south use. How do they get from one thousandth of an inch to 'mil' in any rational step?
1 millimetre is 39.37 thou in England.
Mil is a slang term for millimetre over here in the UK. An American enginerr and I managed to tie ourselves in
knots over the difference in American and UK terminology.
------------------------------
If we learn from our mistakes,
I'm getting a great education!
- Status
Similar threads
- Locked
- Question