Final answer:
A welding supervisor under CSA Standard W47.1 must have a minimum of three years of experience if no experience reduction has been granted due to additional education.
Step-by-step explanation:
Under the Canadian Standards Association (CSA) Standard W47.1, which is concerned with the certification of companies involved in fusion welding of steel, a welding supervisor is required to have a minimum of three years of experience, assuming that no reductions have been granted based on additional education or experience. This experience helps ensure that welding supervisors are adequately prepared to oversee the quality and safety of welding operations in accordance with the rigorous standards set out by the CSA.