Well I hope I've not offended Natita, my comments were intended as an encouragment to start a new thread.
RJB32482,
To find the ASME orifice areas you will need to look in the certification tables.
1. go back to the NB-18 table of contents, click the "Listing of Manufacturer and Assembler Certifications".
2. at the Listing of Manufacturer and Assembler Certifications table of contents, look in the left window pane and select the manufacturer of interest, for example Farris Engineering (TFO).
3. at the listing of devices designed by the manufacturer, find the device type in which you are interested and click on that device, for example "2600 & 2600S".
4. at the device details page, find the API orifice in which you are interested and read the Flow Area as the ASME area.
While on this page, you should also read the Certified Value listed which is the ASME discharge coefficient for the device. You must use the ASME discharge coefficient when using the ASME area. You must not mix the API and ASME values in the sizing equations, either use all ASME data or use all API data.
An example and brief description of the certification listings and tables can be found by going to the NB-18 table of contents and clicking the "Listing of Certified Device Types by Manufacturer".
Alternately, you can get the orifice information from a manufacturer. For example...
download the series 2600 catalog and look on page 10 of the catalog (that's 12 of 94 in the document).
Just remember, the API orifice designation is a defined standard, the ASME areas are not and vary somewhat between manufacturers for a given API orifice.