Seal welding of vent holes on saddle plates welded to pipe, do they need to comply with NACE MR0175?

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Seal welding of vent holes on saddle plates welded to pipe. We have provided vent holes on saddle plates in accordance with ASME B31.3. We have used these saddle plates at support locations as a protective shield to pipe. Now we would like to close the vent hole by seal welding after completion of saddle welding with pipe and carrying out PWHT. Permanent closing of vent hole is required to avoid corrosion in offshore conditions. Service is crude oil with H2S, i.e., NACE MR0175/ISO 15156 is applicable. Kindly advise us about the acceptance of seal welding for these service conditions.


The ISO 15156 Maintenance Panel cannot provide guidance on the acceptability of seal welding in this application.
It is the responsibility of the equipment user to decide whether NACE MR0175/ISO 15156-2 is applicable to these seal welds. The applicability of this standard is described in Clause 1, Scope.
If this standard is considered applicable then the seal welds must comply with the requirements of NACE MR0175/ISO 15156-2, 7.3.3 or NACE MR0175/ISO 15156-3, 6.2.2.

This question is in relation to NACE MR0175/ISO 15156-2 Clause 7.3.3

Reference: ISO 15156 Maintenance Panel Inquiry #2005-21

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