Does ASME have any reference conditions for expressing gas volumes?

[mbeychok]

Does ASME have any standard reference conditions of temperature and pressure for expressing gas volumes? In one of their flowmeter test or design procedures? Or in any of their standards?

If they do have such conditions, what are they? And what is the title of the publication or standard or procedure in which those conditions are stated?

Thanks in advance,

Milt Beychok

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[zdas04]

In ASME 14.3, they cite 14.73 psia and 60F as "standard" for gas-measurement calculations. This is as good a number as any I suppose, but actual gas sales are still subject to contract terms which may or may not use the ASME standards.

For example, in the New Mexico side of the San Juan Basin the average atmospheric pressure is around 12 psia, but the state of New Mexico requires that all volumes be reported at 15.025 psia and many sales contracts are at 14.696 psia (the NIST "standard"). I will never understand all these different "standards", but I guess if I was supposed to understand them someone would publish a clear description. All I really need to know is that there are legitimate reporting requirements at different pressure bases and any system for flow measurement must be able to deal with multiple bases.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[mbeychok]

David:

Thanks for your response. That 14.73 psia is very widely used. Just do a search on google for "14.73 psia" and you get dozens of hits. The U.S. EIA (the Energy Information Agency) uses it in all of their reports about the natural gas industry. The Natural Gas Act in 18 CFR, Part 156, Section 156.4 also uses it. A good many of the various state agencies in the USA use it. The American Gas Association (AGA) Report 3 on orifice calculations uses it as well.

Considering that sea level atmospheric pressure is 14.696 psia, I really would like to know the history of how 14.73 psia became a standard.

If you (or any one else) knows of any other standard reference conditions published by the ASME, the API or the AGA, I would very much like to hear from you.

Milt Beychok

 

[katmar]

Milton,

I don't know where 14.73 psia came from, but it is almost exactly 30 inches of mercury. Could that be the reason for this number?

Actually there is no reason why the standards for temperature and pressure should be any different from any other arbitrary standard set by bureaucrats, and we probably should not frustrate our engineering minds by looking for logic in these choices. Perhaps God started this trend when he set pi to be 3.14159......

regards
Harvey

 

[JStephen]

I recall that ASHRAE gives the density of air at "standard" conditions- check the Handbook of Fundamentals to see what that is, if helpful.

 

[zdas04]

AGA 3 is ASME 14.3. Same committee, same words, same pictures. A lot of folks beside the EIA use that document as their source of gas measurement information so 14.73 psia is really widely used. I think the 30 inches of Hg is probably the answer, but it doesn't answer the question "why did as meticulous a group as this committee feel they had to make up their own standard?". Maybe this discussion should move to Engineering History.

David

 

[zdas04]

One should try to wake up prior to logging on.

I just looked at 14.3 and it is:

- API Manual of Petroleum Measurement Standards Ch 14, Section 3
- AGA Report Number 3
- GPA 8185
- ANSI/API 2530-1991

I knew that ASME 14.3 didn't look right in my first post, but skipped over my unease. I just did a search in the document and ASME is not involved.

David

 

[vzeos]

I agree with katmar about the 30.00 in of Hg, but I think it came from the manufactured gas industry.

The manufactured gas industry used a set of standard conditions that were closely related to the conditions of manufacture:

Gas temperature...................60F
Gas pressure........................30.00 in of Hg
Water vapor in the gas..........saturated at 60F

It is interesting to note that as of 1949, the natural gas industry did not have a standard pressure. The standard pressure varied by state. In Texas and Oklahoma it was 14.65 psia, in Louisiana it was 15.325 psia and in Kansas it was 16.4 psia. I conjecture that the natural gas industry adopted a common set of standard conditions between 1950 and 1960. This was the period during which, the construction of cross-country pipelines allowed natural gas to be delivered to cities such as Baltimore, Philadelphia, New York and Boston where manufactured gas would be completely replaced by natural gas. At this point it probably became practical to settle on one standard -- the utility's standard since it was already widely used.

 

[mbeychok]

Does anyone know if the ASME has any standard reference conditions for gas measurements? Perhaps in their publication "MFC-14M - 2003 Measurement of Fluid Flow Using Small Bore Precision Orifice Meters" (of which I don't have a copy)? Or any other ASME publication?

Milt Beychok