It means that anyone specifying or purchasing a steel door or frame from an SDI member company can be confident that the product has been tested and approved by the most respected laboratories in the country, and that it's backed up by a commitment to service and support you can count on.  SDI tests steel doors and frames for strength, quality, consistency, security, weather and fire resistance, wear and tear, and longevity. Testing is undertaken in conjunction with the top testing labs in the country like Underwriters Laboratories (UL), National Fire Protection Association (NFPA), American National Standards Institute (ANSI), and American Society for Testing and Materials (ASTM). In addition, SDI works alongside industry associations representing related products such as Door & Hardware Institute (DHI), Construction Specifications Institute (CSI) and the Builders Hardware Manufacturers Association (BHMA) to ensure compatibility with products used in conjunction with steel doors and frames.  Choose from the following links to view the Steel Door Institutes standards

Steel doors and frames manufactured by SDI member companies are available through a network of top distributors located throughout the United States. Local distributors in all major market areas ensure prompt delivery and quality service to the end user. Timely, accurate technical support is also available to architects, specifiers and construction teams online by visiting the Technical Assistance page on this site, or by contacting the SDI Technical Support staff at 440-899-0010.  Look for the SDI logo on steel doors and frames at your local distributor to ensure quality, strength and performance for years to come.