It seems logical to me to post questions regarding a structural welding code; D1.1, D1.2, D1.5, etc. under the heading D1. Likewise, any questions relative to the ASME B&PV Code or Pressure Piping Codes can be posted under ASME.
General questions relating to WPSs and PQRs as they apply to other welding standards, i.e., API 1104, D17.1, D14.X, etc. can be posted under the general heading Certification and Qualification.
I don't know that there a any hard and fast rules about where the question has to be posted, but it is nice when they are posted under a somewhat logical heading.
Al