Non-wetted parts NACE requirements

[nickypaliwal]

1) For the Non-wetted parts in a piping or valve suchas external bolts, do we need NACE compliance?

2) Is valve gland flange considered for NACE requirement in a sour service ?

3) Why does wetted parts under compressive stresses such as Trim of a valve needs to follow NACE requirements ?

 

[OGMetEngr]

1) If those parts have the potential to be "exposed" to sour fluid in the event of a leak (e.g. - embedded under insulation), then the bolting should also be NACE compliant.
2) See answer to #1. You don't want a minor leak to turn into a major one.
3) Materials oftentimes have internal stresses originating from manufacturing processes, welding, etc. This residual stress is at-times enough to facilitate cracking due to sour fluids.