https://steeldoor.org/firerateddoors/
See how commercial fire-rated doors are made and tested. Fire-rated doors and frames play a vital role in keeping people safe and minimizing property damage during a fire. Hollow metal is the only door material widely available with a 3 hour label.

SDI member manufacturers have been certified to provide quality fire-rated doors and frames. View their products at http://www.steeldoor.org/gallery-prod....