Golden welds is a concept that is used in conjunction with pipeline lay and repair. The golden weld is an accepted weld without solid (and more tangible) proof of strength, for example a break test or load test.
Before a pipeline is put into use, it is often pressure-tested with water (a hydrotest) to a level above the working pressure of the pipeline. But, to save time, the user of the pipeline sometimes give construction of the various parts of the pipeline system to different contractors. The different contractors will then test their own system before handing it over to the owner.
So, for example, the Europipe-II pipeline was laid from Emden,Germany to the middle of the north sea, and from Kårstø,Norway to the same location - both pipelines could have been laid by different vessels or even different contractors. The same pipeline segments have also been pressure tested and found acceptable by the owners. Now the owner will want to connect the pipelines without having to test the entire system again. Because of the previous tests, all components in the system are now ok, except the final weld between the two systems. It is here that the "Golden weld" concept comes into play.
In short: In the pipeline industry it is accepted that you don't pressure test a system component (eg. a weld) if you can prove by inspection and calculation that it is strong enough.
Inspection is often stated to be at least:
For non-magnetic pipelines one can use liquid penetrant
instead, and if one uses automatic ultrasonic testing, one isn't required to do the others. Note that these are the rules of Det Norske Veritas
,DnV ("the norweigan truth", a certify
ing body), and so might not be applicable in all areas. The defects that are discovered during inspection need to be smaller than the maximum stated in the calculations.
Even though this example features a subsea pipeline, golden welds are also popular for large systems where different contractors are involved. A rather extensive example of golden welds (-=-) in a pipeline system could be:
Oil well -=- Platform production system -=- Platform riser -=-
Subsea pipeline -=- Shore crossing -=- Refinery -=- Distribution system