I spent (wasted?) considerable time trying to sort out the API rules for density adjustment, which they call volume correction factors. They want to sell the standard for $500, but I think I have pieced together the algorithm from scraps here and there. At least it checks to 4 sig. fig. with some calculators on the web, the 5th digit may be off a unit or two.
The draft calculation on ships and weighing road tankers is certainly done as at least a cross-check. However, the total load is often divided among multiple customers and they use (hopefully precise) flowmeters. They go to a lot of trouble measuring density and adjusting the volume to what it would be at a standard temperature, which is 60 °F in the US. ISO originally used the same equations but adjusted parameters for 15 °C. There was pressure for 20 °C tables as well and the equations didn't fit. Now ISO may call it 15.5555 °C, but corrections must now be calculated as a chain, actual --> 60 °F --> alternate standard temperature, or backward through the same chain. Commercial sales are always temperature adjusted. In the US, retail sales are generally not, although there is some pressure for it. The in-ground tanks have a pretty stable temperature through the year, nearly equal to the location's average annual temperature. However, when a road tanker delivers fuel, it will be either hot or cold relative to what remains in the tank. It is best not to refuel right after a delivery from a hot tanker. Barring that, time of day won't matter much. ________________________________ From: Pat Naughtin <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Thu, June 10, 2010 11:02:14 PM Subject: [USMA:47681] Re: Oil Spill Technical Team Using SI Dear Gene, I agree with you and I suspect that this is how the oil people actually measure quantities of oil. After all it is so easy to do using the Plimsoll line in ships or running a road tanker over a weigh bridge. This also allows for the differences in the density of crude oil. I recall an urban legend about buying petrol (in litres) in the mornings before it expanded due to the rising temperature each day. Cheers, Pat Naughtin Author of the ebook, Metrication Leaders Guide, see http://metricationmatters.com/MetricationLeadersGuideInfo.html Hear Pat speak at: http://www.youtube.com/watch?v=_lshRAPvPZY PO Box 305 Belmont 3216, Geelong, Australia Phone: 61 3 5241 2008 Metric system consultant, writer, and speaker, Pat Naughtin, has helped thousands of people and hundreds of companies upgrade to the modern metric system smoothly, quickly, and so economically that they now save thousands each year when buying, processing, or selling for their businesses. Pat provides services and resources for many different trades, crafts, and professions for commercial, industrial and government metrication leaders in Asia, Europe, and in the USA. Pat's clients include the Australian Government, Google, NASA, NIST, and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com/ to subscribe. On 2010/06/11, at 05:13 , <[email protected]> <[email protected]> wrote: >For incompressible fluids e.g. oil (and even for methane) kilograms or metric >tons of mass are easier to visualize and would be better than any unit of >volume, and kg/s is best for rate of flow, liquid or gas. > >---- Original message ---- > >Date: Thu, 10 Jun 2010 09:23:44 -0700 (PDT) >> >From: "John M. Steele" <[email protected]> >> >Subject: [USMA:47649] Re: Oil Spill Technical Team Using SI >> >To: "U.S. Metric Association" <[email protected]> >> > >> > I can envision 1 L or a few, I can't envision 3 >> > million. Would not 3000 m³ be a lot better than >> > throwing in "big counting words" in lieu of a >> > suitable unit or prefix? >> > >> > I will probably take flack for this one, but SAE >> > metric practice is to use the cubic dekameter for >> > large amounts of water, such as irrigation, where >> > traditional measure would be the acre-foot. In that >> > notation, the leak would be 3 dam³/day. >> >... >> > >> >
