AGA3 formula

  • Thread starter Leong Kam Fatt / ATD SEEMAL
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Leong Kam Fatt / ATD SEEMAL

Who know the formula for AGA3 flow calculation.

from : psi and C or
kPa (absolute) and C.

to flow.

KF Leong
AGA Report no 3
The "Orifice Meter Constants Handbook E-2" from American Meter lists the equations based on the above mentioned report.
They are the same as in your Spink.
If there is no binding contract between you and your Client, I recommend you go by ISO-5167.
So easier to use because it is massflow, directly.
The only delicate part (as well as with AGA.3) is the evaluation and then eventually the correction
for rho (masse volumique of the gas) depending upon the variation in % of the constituants.

When purchasing gas on contract it is recommended you lab test periodically.

Canadian meter used to provide calibrated meter run at ±.25%
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> Who know the formula for AGA3 flow calculation.

I've been down this path before myself.

Your best bet is to purchase the AGA-3 document.
AGA = American Gas Association...

From memory, there were several formula options available; iterative and something else.

I recommend purchasing the book, because you will always be guaranteed that you are using the 'latest' formula (because they are amended from time to time), and there are usually several standard tables of data in the documents that you can use for inhouse and client FAT testing. After all, your client will need you to test and verify against known valid data - and where else would you go bu the AGA-3 documentation!!!?

Have a look on the AGA website ( They have options for paper copies and electonic downloads...

From memory the AGA-3 document I purchased several years ago was approx AUS$200

All the best.