API 16A "Pressure Containing Weld"

[jennin77]

API 16A weld definitions:
3.1.73 weld, full penetration: A weld which extends throughout the complete wall section of the parts joined.
3.1.74 weld, non pressure containing: A weld the failure of which will not reduce the pressure-containing integrity of the component.

What is your interpretation of "pressure containing integrity"?
Is a seal weld of a NPT plug a pressure containing weld in your optinion? I would consider it is not, but I cannot find any support to my assumption.
Any help with that?

Thanks