GAS has been contacted by several clients about the use of Method 19 to calculate mass emissions

The API has been making phone calls and discussing the improper use of this allowed test method.  Please be assured that this problem will not affect any tests performed by GAS as we use Method 2 in lieu of Method 19.

Below is brief breakdown of the problem in question, and a link to the EPA’s stance on the issue.

We are given a choice to use Method 2 or Method 19 to produce volumetric stack flow rate in order to calculate mass emissions.  Method 19 will use fuel and Method 2 will use the velocity of the gas coming out of the stack.  If you use Method 19, it is assumed that you will also have a calibrated fuel meter and a fuel analysis done that day.  Calibration papers are to be turned in with the report.  The flow and fuel BTU are used to calculate your BTU/HP-HR, and combining the three you can work to obtain your volumetric stack flow rate (for mass emissions calculations).  It is our understanding that the problem is coming from these flow numbers being calculated and not using a calibrated fuel meter or having a same day fuel analysis.  Instead a manufacturers supplied BTU/HP-HR is possibly being used to calculate fuel flow and obtain the volumetric stack flow rate in that manner.  When doing so a burn rate for that engine is being used that is not realistic for units in the field, thus producing mass emissions numbers that will almost always be lower than if you used Method 2 or the calibrated fuel meter.

Implementing the use of Method 2

GAS has been implementing the use of Method 2 for many years to avoid this problem and provide faster, more efficient testing.  By using Method 2, we obtain volumetric stack flow rate using real time pressures, temperatures, velocity readings (from pitot tubes), and stack information.  Fuel data is not required and is irrelevant when using this Method. We still provide it by back calculating our volumetric stack flow rate, but it is not used in any of your emissions data, and is only provided because most producers like to see it.

Here is a link to the EPAs stance on this issue:

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