Partially. I will try to explain it the way it was explained to me. This is only required in the API 1104 as far as I know.
Pipeline welders, years ago, used to get paid 8 hours for every test they made and passed. If they made four test welds in a day they were paid 8 hours for every test weld. That could easily happen when working on a job where there may be multiple diameters tests, socket weld tests, and o-let weld tests. Some owners may have required the welder to pass EVERY test or they were let go for failing one test even though they may have already have passed several tests already. This could end up costing the contractors quite a bit of money. As I understand it, the owners and contractors got together agreed that if the welder could layout, cut, fit, and weld the branch it would show his ability to use a torch and weld too. They agreed that if the welder could make the two welds on 12" pipe then they should be able to weld multiple joint designs, diameters, etc.. There is also a belief that this is a fabrication test. If you don't take the butt and branch test you cannot weld on fabrication. This restriction does not appear in the 1104. It's just that usually there will be multiple types of joint designs and diameters while fabricating and it's easier to track the welders if they all have the multiple qualification. If all the fabrication would fall within the single qualification as designated by the 1104 then the multiple qualification would not be necessary. This seldom happens.
Early on in some distribution areas they did make fittings, 90's, 45's, tees, Y's and what ever was required including orange peel plugs. I have seen one of those, orange peel plugs, and it was under quite a bit of pressure. Surprising what quality went into the fabrication of that cap or plug.
Today, as I understand it, the welder is only required to make the weld that is required to keep his job, make the butt weld and weld on all butt welds, fittings and pipe. But if you move outside of the API limitations you would have to make another test to weld in that particular situation, an example would be to move from a butt weld to a socket weld, different joint design. The butt and full sized branch weld allows a way around this. There are still some limitations with the multiple qualifications but they are few. The welder will get paid 8 hours for the test weld and if he goes immediately to work he gets paid for the number of hours in addition to the 8 hours.
There could be different reasons but this was the way it was explained to me by an individual who had been on the API 1104 Committee for many years. If someone can add to this jump in here and spread the word.
