Working for a safer world

During a fire, closing the door, could have a potentially life-saving impact.

Underwriters Laboratories is a nonprofit organization dedicated to advancing the UL public safety mission of creating safer living and working environments for people everywhere through the discovery and application of scientific knowledge.


We conduct rigorous independent research and analyze safety data, convene experts worldwide to address risks, share knowledge through safety education and public outreach initiatives, and develop standards to guide safe commercialization of evolving technologies. We foster communities of safety, from grassroots initiatives for neighborhoods to summits of world leaders.


Our organization employs collaborative and scientific approaches with partners and stakeholders to drive innovation and progress toward improving safety, security, and sustainability, ultimately enhancing societal well-being.


Over a decade of research conducted by our UL Firefighter Safety Research Institute (FSRI) proved that a simple behavioral change, closing the door, could have potentially life-saving impact during a fire. Spreading this crucial fire safety message with first responders and the public has become an essential part of advancing the UL mission, working for a safer world.

A striking visual comparison of natural and synthetic furnishings.

See the impact that synthetic furnishings have in time-to-flashover.

A comparison of an open door bedroom and a closed door bedroom in a fire.

See for yourself what a closed door can do. The bedrooms in this video are side by side, adjacent to the burning living room.

Why is the Close Your Door message so important now? Because fires have become more dangerous than ever.


Modern synthetic construction materials, home furnishings, and contemporary layouts allow fire to spread and become toxic much faster – like three minutes or less to get out faster.


But a closed door can slow the spread, reduce toxic smoke levels, improve oxygen levels and decrease temperatures dramatically – and that could make a life-saving difference in your home.