Correctly Specify Metal Building Assembler Qualifications

By: The MBCEA Technical Committee

As quality-assurance requirements become increasingly common in construction specifications, 
the MBCEA Technical Committee has observed instances in which the AISC Certified Erector 
Program is specified for work involving the assembly and erection of Metal Building Systems.

AISC 303, Code of Standard Practice for Steel Buildings and Bridges, expressly states that it “is 
not applicable to … metal building systems, which are addressed by … MBMA.” Accordingly, 
quality requirements for Metal Building Systems should recognize the standards and 
accreditation programs developed specifically for that industry rather than relying solely on 
credentials developed for conventional structural steel construction.

The AISC Certified Erector Program and IAS AC478 Accreditation both promote quality, safety, 
and professionalism. However, they were developed for different sectors of the steel construction 
industry and should not be treated as interchangeable credentials.

AISC Certified Erector Program

The AISC Certified Erector Program is an established quality-certification program developed 
for companies engaged in the erection of conventional structural steel, including structural steel 
framing, bridges, and similar structural steel applications.

The program evaluates an erection company’s quality-management system and its processes for 
performing structural steel erection, including applicable welding, bolting, inspection, personnel qualification, and documentation requirements.

IAS AC478 Accreditation

IAS AC478, Accreditation Criteria for Inspection Practices of Metal Building Assemblers, was 
developed specifically for companies engaged in the assembly and erection of Metal Building 
Systems.

The accreditation evaluates an assembler’s management system, quality-control procedures, 
safety program, personnel qualifications and training, equipment-management practices, project 
documentation, and documented erection procedures. It is administered by the International 
Accreditation Service and provides independent verification that an accredited assembler 
maintains systems and practices specifically applicable to Metal Building Systems erection.

IAS AC472 and IAS AC478 provide complementary, industry-specific quality-assurance 
programs for Metal Building Systems. AC472 addresses the inspection programs of companies 
that design and manufacture Metal Building Systems, while AC478 addresses the inspection 
practices of companies that assemble and erect them. Together, AC472 and AC478 provide a 
quality framework extending from design and fabrication through assembly and erection.

Recognizing the value of AC478, the MBMA endorses the program with the following statement 
on its website:

“MBMA encourages metal building contractors and erectors to pursue AC478 accreditation to 
demonstrate their commitment to quality, safety, organization, and professional qualifications.”

Guidance for Specifiers

Architects and engineers should select certification and accreditation requirements that 
correspond to the actual scope of work:

• For conventional structural steel erection, the AISC Certified Erector Program may be 
appropriate.
• For the assembly and erection of Metal Building Systems, IAS AC478 is the 
accreditation developed specifically for that work.

Some contractors perform both conventional structural steel erection and Metal Building 
Systems assembly and may maintain both credentials. Projects may also contain separate scopes 
for which different qualifications are appropriate. However, requiring the AISC Certified Erector 
Program for work limited to the assembly and erection of a Metal Building System may 
unnecessarily exclude qualified assemblers that maintain AC478 Accreditation specifically for 
that scope.

The MBCEA Technical Committee encourages design professionals to review project 
specifications carefully and align contractor-qualification requirements with the construction 
systems and scopes involved. Doing so preserves meaningful competition while ensuring 
contractors are evaluated under standards developed for the work they will perform.

The AISC Certified Erector Program and IAS AC478 Accreditation share the goal of advancing 
quality, safety, and professionalism. Each provides the greatest value when applied to the 
segment of the industry for which it was developed.

Learn more about MBCEA membership and read additional best practice articles.