The American Society of Mechanical Engineers (ASME) Section IX is a globally leading standard for qualifying welders, welding operators, and procedures for welding, brazing, and plastic fusing.
Appendix L in this Section IX provides a legally supported and internationally recognized method for qualifying welders under both the ISO and ASME systems using a single test coupon.
This test coupon must meet the requirements of ISO 9606-1:2012 or ISO 14732:2013, along with the additional conditions outlined in Appendix L of ASME Section IX. These additional requirements pertain to:
- L-200: Administrative requirements
- L-300: Technical requirements
- L-400: Testing requirements
These additional requirements will be summarized in this article. This approach accelerates the qualification process and offers an efficient, fully compliant solution for internationally operating companies. It enables them to deploy welders globally without compromising quality or regulatory compliance.
What is Appendix L?
Appendix L is a non-mandatory annex within ASME Section IX. It provides a method to simultaneously qualify welders and welding operators in accordance with ISO 9606-1 and ISO 14732, as well as the ASME Section IX framework, without requiring a separate full performance qualification procedure under ASME Section IX.
What does this mean in practice?
If the test coupon meets both the requirements of ISO 9606-1 or ISO 14732 and the requirements of Appendix L, then ISO 9606-1 or ISO 14732 certificates and an ASME IX certificate can be issued directly based on these test results.
This provides companies with a practical and efficient route because:
- Dual qualifications (ISO and ASME) are no longer necessary, provided the ISO qualification meets the additional requirements described in Appendix L.
- The most efficient route to qualify the welder or operator is through mechanical testing, as this avoids the exceptions stated in paragraph L-400 regarding NDE examination.
It is important to understand that Appendix L is optional. It is not a mandatory part of ASME Section IX, but an approved alternative route that companies may follow to better align international qualifications.
European Pressure Equipment Directive
For companies in America, Europe, and other regions dealing with ASME Section IX in combination with the European Pressure Equipment Directive (PED), Appendix L offers significant advantages:
- It is possible to invite an independent party (notified body) to witness the qualification test, as required under PED.
- This notified body can assess and approve the qualification, regardless of whether it was performed according to ISO 9606-1, ISO 14732, or via the Appendix L route within ASME IX.
This creates a harmonized approach that complies with both American and European regulations, enhancing efficiency and reducing costs.
Additional Requirements of Appendix L
Administrative Requirements – Summary (L-200)
- Use of a welding procedure: The welder must work according to a valid welding procedure.
- Full supervision by the organization: The welding of the test coupon must be fully supervised by the qualifying organization. This responsibility may not be outsourced.
- Authorized personnel: Supervision, inspection, evaluation, and acceptance must be performed by personnel who meet the requirements of QG-106.
- Execution of testing: Testing may be performed by third parties, but the organization remains responsible for compliance with ASME IX.
- Certification of the qualification document: The qualification record must be certified by the organization(s) that supervised the welding, in accordance with the internal quality system.
- For PED applications the Notified Body also may sign the qualification document.
Technical Requirements – Summary (L-300)
- Essential variables and qualification ranges: The qualification record must specify the essential welding parameters and the qualified ranges.
- Difference between ISO and ASME IX: The measured values are consistent with ISO 9606-1 or ISO 14732, but the qualification ranges under ASME IX differ and must be documented separately.
- Selection of base and filler materials:
- Use test material with a P-number (QW-420).
- Use filler material with an F-number (QW-432).
- This ensures compatibility within the ASME IX system.
- Flexible documentation:
- Forms may be freely designed.
- ISO and ASME ranges may be documented on separate or combined forms, depending on the organization's preference.
Testing Requirements – Summary (L-400)
- Mechanical testing according to ISO: Test results from ISO 9606-1 or ISO 14732 are accepted by ASME IX, provided they meet ISO requirements.
- Fracture tests according to ISO 9017: These are not accepted under ASME IX.
- NDE techniques according to ASME IX:
- May only be applied to test pieces with a minimum thickness of 6 mm (1/4 inch). Radiographic examination must comply with QW-191.1
- Ultrasonic examination must comply with QW-191.2
- Qualification of NDE personnel must comply with QW-191.4
- Acceptance criteria for NDE: ISO criteria are valid, except for linear slag indications: Maximum flaw length equals test coupon thickness / 3 (t/3)
- Minimum thickness for ultrasonic testing: Ultrasonic testing
Looking Ahead
Appendix L of ASME Section IX provides a legally sound and internationally recognized method for qualifying welders using a single test coupon.
By applying this appendix, companies can achieve cost savings, greater flexibility, and global deployability without compromising quality or safety.
For organizations operating in a globalized industry, Appendix L is a strategic tool that unites compliance and efficiency.
Following the successful implementation of Appendix L in ASME IX, which enables welder qualification through a single test coupon, a new initiative is quietly gaining momentum within the international welding community.
A group of experienced welding engineers, active across both ISO and ASME domains, is currently working on a draft for a new appendix. The goal: to enable welding procedure qualification on a single test coupon that satisfies the requirements of both ISO 15614 parts and ASME IX.
This harmonized approach could significantly reduce duplication in qualification efforts, streamline documentation, and simplify compliance with international regulations such as the European Pressure Equipment Directive (PED). For globally operating welding companies, the potential benefits mirror those already realized through Appendix L: reduced costs, increased efficiency, and greater flexibility in project execution.
If successful, this new appendix could mark a major step forward in aligning international welding standards and supporting the industry's growing need for cross-border compatibility.