You should ensure the steel fabricator is certified by international regulatory authorities, such as The American Institute of Steel Construction (AISC). The AISC certification demonstrates that they have passed an audit and review and are legally qualified for the position. It ensures that the steel fabricator has the necessary skills, knowledge, and experience to produce quality steel products.
They must also hold a CWI qualification, which stands for Certified Welding Inspector. The latter is a national welding and steel industry standard developed by the American Welding Society. It denotes high-quality work that complies with steel industry requirements. Some states may additionally have their own set of local requirements.