Thank you, I should have included that their is a purge on this SS pipe. which would prevent oxidation of the root as well. the contractor uses this type of ring so they can get out of the 100% coverage of RT now they are required to have 60% coverage, I personally don't see the need to weld the ring prior to insertion, but it is a requirement. I have review some film of these joints and their is complete fusion their must be some reason for this requirement. thanks.