Bill Hooper asks why not keep the cubic decimeter, cubic metre, cubic
millimetre etc. which are strictly SI.
I ask why are milliliter, liter, and other types of liter (cubic decimeter)
quantities so commonly used in grocery stores, in gasoline stations and many
other places? L is an accepted unit which is approved for use with the SI even
though it is not strictly SI since it's so commonly used worldwide. Why have a
mixture? So why not use kL for very large quantities to be consistent?
As for the person who asked about the metric quantities marked on containers,
it really didn't matter because the visual quantity (bottle etc) was sufficient
information to make a decision to purchase. This is what the President of a
Consumer organization found back in the 1970s. Nothing new! However,
unit-pricing was very important to the buyer.
Regards, Stan Doore
----- Original Message -----
From: Bill Hooper
To: U.S. Metric Association
Sent: Thursday, June 28, 2007 1:24 PM
Subject: [USMA:38949] Re: Indefinite postponement
On 2007 Jun 28 , at 4:14 AM, G Stanley Doore wrote:
... why not adopt kL for the cubic metre to be consistent with other kilo
uses.
Why not? Because -
- (1) it is unnecessary. since there is already a name for that size; namely,
the cubic metre,
- (2) the kilolitre and the litre are not coherent with the other units of
the SI; in any calculations done involving other SI units, care must be taken
to use only coherent SI units or else the answers will be wrong.
The kL is simple and understandable for all to use, but it doesn't preclude
the use of scientific notation by scientists.
Paraphrasing Doore's comment above: "The cubic metre is just as simple and
understandable as the kilolitre (perhaps simpler and more understandable) and
doesn't preclude the general public from using it."
The kL/s would be particularly useful in stream flow and kL for lake volume
in hydrology, and for other applications in which large volumes are involved.
And, it does not preclude the use of L/s and L for smaller volumes. Also, Nm3
(Normal metre cubed) and barrels used in oil and gas reporting should be
replaced with kL to make the SI volume unit universal and consistent in the oil
and gas industry.
Everything stated for the kilolitre in the above paragraph is just as true
for the cubic metre, including the fact that use of the cubic metre does not
preclude using the litre for smaller volumes.
I need to ask what is meant by "normal metre cubed". Is that any different
than a cubic metre? Regardless, there is no reason to use "Normal metres cubed"
in place of cubic metres.
Contrary to what Doore suggests, use of the kilolitre is NOT an SI unit (nor
is the litre) and using it to make things "consistent in the oil and gas
industry" would make the "things" inconsistent and not coherent with the rest
of SI. It is more important to keep SI consistent (and coherent) than it is to
cater to one particular industry that wants special dispensation to measure
things differently.
Bill Hooper
72 kg body mass*
Fernandina Beach, Florida, USA
* plus or minus a kilogram or so.
