Hydrogen Piping Components: What an ASME B31.12 RFQ Must Define

Introduction

Hydrogen is increasingly central to global energy transition strategies, and the U.S. Department of Energy notes that pipelines are a key hydrogen-delivery pathway. Approximately 1,600 miles of hydrogen pipelines currently operate in the United States, primarily owned by merchant hydrogen producers and concentrated near large users like petroleum refineries and chemical plants. As hydrogen projects expand, EPC engineers and procurement managers must understand the specific requirements for piping components under ASME B31.12, the code dedicated to hydrogen piping and pipelines.

This guide focuses on what an RFQ must define when sourcing seamless steel pipes and socket-weld forged fittings for hydrogen service. It is not a substitute for the code, but a practical checklist to help you avoid common pitfalls.

Understanding ASME B31.12

ASME B31.12, titled "Hydrogen Piping and Pipelines," is applicable to piping and pipelines handling gaseous hydrogen, gaseous hydrogen mixtures, and liquid hydrogen service. The code applies up to and including the joint connecting the piping to associated pressure vessels and equipment, but not to the vessels and equipment themselves. It also covers the location and type of support elements, but not the structure to which they are attached.

The code is organized into parts:

• Part GR – General Requirements: definitions, materials, welding, brazing, heat treating, forming, testing, inspection, examination, operation, and maintenance.
• Part IP – Industrial Piping: requirements for components, design, fabrication, assembly, erection, inspection, examination, and testing.
• Part PL – Pipelines: requirements for components, design, installation, and testing of hydrogen pipelines.
• Mandatory Appendices I through IX and Nonmandatory Appendices A through F.

Each part must be used in conjunction with Part GR but is independent of the other parts. The joint connecting piping governed by two different parts must be subject exclusively to the requirements of one part. The code is not intended to be applied retroactively to existing hydrogen systems.

Key Considerations for RFQ

When preparing an RFQ for hydrogen piping components, you must define the following:

1. Service Condition and Code Part

Specify whether the component is for industrial piping (Part IP) or pipeline (Part PL). This determines design, material, and testing requirements. Include operating pressure, temperature, and hydrogen concentration (pure or mixture). For liquid hydrogen service, additional low-temperature requirements apply.

2. Material Specification and Qualification

Hydrogen service can cause embrittlement of steel and welds, as noted by the DOE. Therefore, material selection is critical. The RFQ must specify the exact material grade and standard (e.g., ASTM A106 for seamless pipe, ASTM A105 for forged fittings). However, do not assume that a conventional material is automatically hydrogen-qualified. The design code, service conditions, material performance, welding, and testing all require project review. The supplier must demonstrate that the material and manufacturing process are suitable for hydrogen service, often through additional testing or documentation.

3. Design and Fabrication Requirements

Reference ASME B31.12 for design and fabrication. The RFQ should require compliance with the applicable part (IP or PL) and any additional project specifications. Include requirements for welding, heat treatment, and forming. For socket-weld forged fittings, ensure that the fitting dimensions and ratings meet the design conditions.

4. Inspection and Testing

Define the required inspection and testing, such as hydrostatic testing, NDT (RT, UT, PT, MT), and material traceability. The RFQ should specify whether third-party inspection is required and which standards apply (e.g., ASME V for NDT). For hydrogen service, additional leak testing may be necessary to control permeation and leaks.

5. Documentation

Require material test certificates (MTCs) per EN 10204 3.1 or 3.2, and any hydrogen-specific documentation. The supplier must provide evidence of compliance with ASME B31.12, including design calculations and test reports.

Procurement Checks

Before issuing an RFQ, verify the following:

• Supplier capability: Does the supplier have experience with hydrogen piping components? Ask for references and case studies.
• Material availability: Confirm that the specified material is available in the required sizes and quantities.
• Code compliance: Ensure the supplier is familiar with ASME B31.12 and can provide documentation of compliance.
• Quality system: Check if the supplier is certified to ISO 9001 or similar, and if they have a quality manual that addresses hydrogen service.

Common Risks and How to Mitigate

• Hydrogen embrittlement: This is a primary concern. Mitigate by specifying materials with proven resistance, controlling hardness, and using appropriate welding procedures.
• Permeation and leaks: Hydrogen molecules are small and can leak through seals and welds. Specify leak testing and use appropriate gasket and joint designs.
• Inadequate documentation: Without proper MTCs and code compliance certificates, the component may be rejected during inspection. Require full documentation upfront.
• Blending research vs. approval: The DOE discusses blending hydrogen into natural gas pipelines as a research area. Do not assume that a component is approved for hydrogen service just because it is used in natural gas. Always verify against ASME B31.12 and project specifications.

RFQ Inputs: What to Include

Your RFQ should include:

• Project name and location
• Applicable code and edition (e.g., ASME B31.12-2023)
• Part (IP or PL) and service conditions (pressure, temperature, hydrogen concentration)
• Material specification and grade
• Size, schedule, and end connections (e.g., beveled for butt weld, socket weld)
• Quantity and delivery schedule
• Inspection and testing requirements
• Documentation requirements (MTCs, NDT reports, etc.)
• Any special requirements (e.g., low-temperature toughness, hardness limits)

Inspection and Documentation Points

During inspection, verify:

• Material traceability: MTCs must match the material markings on the components.
• Dimensional compliance: Check against ASME B16.9 for butt-weld fittings or ASME B16.11 for socket-weld fittings, as applicable.
• Visual and NDT results: Ensure no cracks, porosity, or other defects.
• Hydrostatic test certificates: Confirm test pressure and duration.
• Marking: Components must be marked per MSS SP-25 or as specified.

Conclusion

Hydrogen piping requires careful specification and verification. ASME B31.12 provides the framework, but the buyer must ensure that every component meets the code and project requirements. By defining service conditions, material qualifications, and inspection needs in your RFQ, you can reduce risks and ensure safe, reliable operation.

For sourcing, consider our seamless steel pipes and socket-weld forged fittings, which can be supplied with the necessary documentation. Always verify hydrogen suitability with your engineering team.

Sources

• https://www.asme.org/codes-standards/find-codes-standards/b31-12-hydrogen-piping-pipelines
• https://www.energy.gov/eere/fuelcells/hydrogen-pipelines