By CWI7611 
Date 01-18-2014 18:14
Edited 01-18-2014 18:26
Yes, you are correct. DOT CFR Part 192 and 195 has lists of documents that have been Incorporated By Reference (be sure to read the explanation of what Incorporated By Reference means). Currently as of January 16, 2014 the 20th edition of API 1104 is still the listed edition therefore it is required that this edition be used for any work that is covered by DOT. Continuing to use an edition that has been replaced by a more current edition is not typically frowned upon as long as any additional work is in compliance with the current Incorporated edition.
Not all of API 1104 is Incorporated By Reference. Review relevant DOT parts and the API 1104 to see which Sections are referenced and within the 1104 which Sections may be referenced.
And as you mentioned your State regulations may also list of approved codes and standards. Sometimes state regulators may lag behind the Feds a little bit, but keep in mind that the Feds always trump the State. As long as you are using the most strict requirements from either standard you should be safe.
If it is your choice or if your requirements are that you use the latest edition there is no problem with that as long as you satisfy all the requirements of the current Incorporated By Reference edition.
Understand that not all editions of the API 1104 were Incorporated by DOT. It seems as though editions 12, 14, and 16 were never Incorporated. I could be wrong on the 12th edition however. Jumping ahead to use portions of the Standard may be futile if the edition is never incorporated. At times DOT did object to certain portions of the 1104 and did not Incorporate that edition. Occasionally the 1104 Committee has referenced different sections of the 1104 in sections that were Incorporated By Reference by DOT and this was where objections were raised. In other cases DOT simply did not have time to review and Incorporate those editions.
Some organizations such as ASME and API do have provisions for requiring compliance with their Standards. Compliance is required for "certification" or "stamping" of products manufactured in accordance with their requirements and these products must be manufactured in accordance with the latest editions.
If you want to know the date when you must stop using one edition and change to the other it depends on which regulatory agency you talk to. I believe DOT allows either 3 or 6 months after it is incorporated. I believe it is usually the same for some States after they adopt it but there may be a time lag between the Feds and State in adopting the Standard. As I said above, if you use the most stringent regulations (Sections) that are Incorporated By Reference you should be safe and in compliance with both agencies.
Have you tried contacting API themselves?
