how to convert some USA data to metric sistem ?

[rerednaw]

Maybe someine can explain me how much is:

1 gallon in liters
1000 BFt in m3
1000 BTU in Kw

in metric sistem ? i found some different data what gallon is from 3.8 to 4.5 liters

[populus]

One US gallon is 3.78 L. The confusion comes from the existence of a US Dry Gallon, which does not seem to be used any more.

One board foot is 0.00236 m^3  [NOTE: Corrected. See post below]

1000 BTU is 0.293 KWh. However, there are three different BTU units in use, so the conversion is approximate.

There are lots of online conversion calculators on the Web, like

WWW Unit Convertor

[Ernie]

1 Imperial (Canadian, British, Aussie, Kiwi, etc etc etc)Gallon = 4.54 litres

[rerednaw]

I find info http://www.census.gov/foreign-trade/www/sec9.html what board foot is 0.00236 m3 ... where is truth ?  I like our metric sistem
Den wich kind of BTU and BFT you use and how to convert it to metric system ?

[populus]

Your number is correct. One board foot is 0.00236 m^3.  I corrected my post above.

The odd thing is that the number I got (being lazy and not bothering to do the calculation myself) is from the USDA Forest Service. On further research, their conversion is based on raw logs:

"Although 1,000 board feet is theoretically equivalent to 2.36 cubic meters, this is true only when a board foot is actually a piece of wood with a volume 1/12 of cubic foot.  The conversion given here, 3.48 cubic meters, is based on the cubic volume of a log 16 feet long and 15 inches in diameter inside bark at the small end."  USDA Forest Service.

So I guess we use 0.00236m^3/bf for boards and 0.00348m^3/bf for logs.

Confusing?  Yes. Wood measurements in the US have always been confusing.

[OLD_ JD]

here a exemple of scalling in bf and metric.

one log of 12' whit 14" diameter at smal end = 100 bf in inter. scale table

same log mesure in metric will by scale like this

V= D^2  X  L X 0.07854

V= 36 cm(14") X 3.70m (12') x 0.07854 =10.46 dm^3

dm^3 is 10 time smaler them m^3...so it will be divide by 10 = 1.05 m^3

so 1,000 bf it shoud be 10.50 m^3 ....now we are completly lost

[populus]

Your calculations are a little off. 

dm^3 is not 10 times smaller than m^3, it is 10*10*10 smaller (i.e. a three-dimensional conversion), or 1000 times smaller.

Your formula is Huber's formula, but using the top end diameter.

Correcting the math:

V-36^2 * 3.66 *  0.00007854 = 0.36 m^3

(The 0.00007854 number is a unitless constant in Huber's or Smalian's  formula)

Using the log scale conversion, 1000 bf = 3.48 m^3, then 100 bf = .348 m^3

So the two methods give about the same result.

[SwampDonkey]

for hardwood and birch in my area, the marketing board uses 1 m^3 = 0.179 MFBM

But, I agree with populus, as his calculation is for what is called a stacked cubic meter. In my area we use 3.624 m^3(st)

[populus]

This discussion is a great example of why forest measurement is always so confusing, and needs to be as local as possible. The problem resides in the fact that trees are not cylinders and the standing tree is converted to wood in a non-linear way that is poorly predictable.  But it is compounded by the silly system of measurements used in the US. I have thought for a long time that the US would be better off moving to the metric system for forestry, and indeed for all measurements. When I do lab work or other research, temperature is in Celsius and weights and volumes are in SI (metric) units. As soon as I go to the log yard or the grocery store, everything reverts to the cumbersome and arcane English system (which, of course, the English don't use anymore).  Maybe I should simplify my life and emigrate to Canada!

[SwampDonkey]

Be glad to have ya.

[OLD_ JD]

humm...ok i my be wrong here but i still cant understand how it work

if dm^3 is 1000 time smaller and the Smalian formula is 0.00007854 to convers in m^3.....how come whit my calculator i have

v= 36 X 3.66 X .00007854 =0.0103484 M^3    ( i must do some wrong again)

on my exemple it was not a conversion ...it's how it shoud be scale in metric(if i can get it right )

if i use 3.70 meter in lenght is in scaling metric u always go some basic number ...like 8' log is 2.50 m, 10' is 3.10 m, 12' is 3.70m, 14' is 4.30m and 16' is 4.90m

here a link who propose some conversion and it confuse me even more

http://www.mesbois.com/

[populus]

Just a small error - you forgot to square 36. So the formula should be

v=36*36*3.66*.00007854=.37 (there is a round-off error difference between my original calculations and these)

And you are correct that in practice, you round log lengths. 

[KiwiCharlie]

G'day Guys,
Check out this web site for a great, free  , programme that literally has thousands of conversions all in one.  I use it a lot!  Its amazing.  You can even add your own formulas into it for future use.

http://www.savardsoftware.com/masterconverter/

Cheers
Charlie.

[sawmillsi]

Charlie,

This gets confusing for yong people like me (i'm 26) but my HP iPAC give me the conversion.

The american board foot is the same as our supe foot or 12"X12"X1" and there is 450 board feet per cubic meter.

1 US gal = 3.7854125 L

1 UK gal = 4.5461013 L

You could probably just stop at 1 decimal point though

Power confuses me full stop - I just go for the highest horsepower possible - V8's where ever possible!!!! Isn't BTU (british thermal unit) the amount of heat required to raise the temperature of 1lb of water 1 degree farenhieght? Isn't the metric equivilant the 'joules'?

What do you need that for?

Simon

Ps. I got that BTU stuff from my 'Macquarie dictionary' - Australia's national dictionary.

[KiwiCharlie]

Hi Simon,
Hypothetical senario - Im building a small but comfortable abode for me plus 1 plus 2 kids plus 1 dog that needs washing each time it gits out in the mud!  I want a gas hot water system but I need to how many BTU's to heat my required amount of water to get this mammoth task accomplished each day! Im a BTU man, but I know my dealer is a joule man, hence my need for a conversion factor, otherwise he looks at me like Im talking a foreign language.
I convert a lot from inches/feet to mm/m. 16' doesnt mean much to me, but 4876.8mm, I can see that in my mind straight away.
Im just glad theres so much good info out there that enables me to do these things! 
Now fractions and algebra - Ive never used that since I learnt it at school!   
Cheers
Charlie.

[sawmillsi]

Charlie,

How old are you? When did NZ change to the metric system?

If I can understand 16" and I was born in 1978 (Australia changed to the metric system in 1967) you should be able to.

1 BTU = 1059.67 joules I think.



The volume of a log depends largely on species, grwoth conditaions and location and age and structure of the tree it was cut from - in short what was is the logs shape?

Was it a cylinder, a cubic paraboloid, a quadratic paraboloid, a cone, a neiloid etc...

You can then use extremely complicaed form volume equations to give the approximate volume (the only true way is to de-bark it carefully and put it in water etc...).

Or you can assume it is a quadratic paraboloid and use either Smalian's formula or Huber's formula or Newton's formla - all that show the approximate volume is nearly identical (I have the formulas if you want them).

The trees I have been working with in Angola (western africa), I have assumed to be a secong degree paraboliod (infact I asked a inventory specialist what they were).

But it dosn't matter normally cause when I am milling, I just take the average diameter at both ends and work out an average radius and use the good 'ol pi*r^2*L (where pi=3.141, r=radius and L=length of the log).

Simon

[sawmillsi]

sorry about the spelling, i'm used to MS word

i mean a second degree paraboloid

if you find any others just let me know

Si

[Cedarman]

There are two ways of looking at the conversion of english to metric and vice versa. One is the arithmetical way where numbers are crunched with the calculator by some formula. The other is to treat metric and english like languages. If you are always translating you will never get the hang of it. You must simply use both until they become natural. In other words you have to think in French to speak French. You must think in metric to comprehend it.  If you look at a log and it looks 16 feet you've got it in english. But look at it again and think in meters. You have to have your minds eye calibrated in both feet and meters and be able to switch back and forth.

Back many years ago when there was a push to convert from english to metric all the teaching was done to get the kids to convert an english measurement into metric instead of getting kids to estimate in mm, cm, m km etc. They never got the kids past conversion. And kids hated it. Who wants to carry around all those conversions in their head. Just start thinking in metric.  Ask a good mechanic to give you nut sizes in metric. Most can look at it and say 10mm, 12mm etc because they have got there minds eye to thiink in metric.

When we measure cedar logs, I use a cedar log conversion chart to convert diameter to inches. Its only good for cedar, but that is what everyone in the cedar business uses.  Are there not scales for measuring logs in cm and getting cubic meters based on diameter and species?  So why not measure in metric to begin with?
Now if the measurement is already done in english and you need to convert to metric you have to first find the proper formula like has been suggested in earlier posts. So I assume there is another party needing a metric measurement.  They should be the ones to tell what is the proper scale for there purposes.

[KiwiCharlie]

G'day Simon,
Why should I be able to??    Im 10 years older than you, if that means anything.  NZ started changing over to metric in '69.
The only imperial I use are the timber sizes ie 4x2.  And thats because its what I grew up with.  I still buy a 3m 4x2.
Just like Cedarman (and I) said - I can "see" 3m easily.
I thunk yous musst b heaps moor cleverer than me.
Charlie.

[sawmillsi]

 

Nah, I just didn't have a chance - i had to learn both (people ring me up and ask for a 8"x1" 2.4m long???)

Simon