Steel Door Institute
The #1 resource for commercial steel doors and frames
The Steel Door Institute (SDI) was established in 1954 as a voluntary, non-profit business association that develops quality and performance standards for steel doors and frames.
SDI’s standards are available without charge. Design professionals around the world specify these standards because they are concise and regularly updated with leading industry practices.
Only SDI Certified manufacturers undergo recurring audits to ensure compliance with our standards for strength, quality and consistency. By specifying SDI Certified, you can be assured you will receive a product that is well-constructed, tested, and evaluated to meet your specifications.