UL 793:2020 PDF Download

The UL 793:2020 standard outlines requirements for two types of roof vents: mechanically-opened and gravity-opened. Mechanically-opened vents consist of a body frame, damper covers and hatches, and operating mechanisms with heat-responsive devices and springs. Gravity-opened vents consist of a body frame and nonmetallic drop-out panel.

These vents are designed to be manually operated or automatically activated in the event of a fire to remove smoke and heat from a building. The automatic operation does not rely on electrical power or other energy sources that may be disrupted during a fire. Instead, it relies on the activation of a heat-responsive device or the shrinking and falling of a plastic cover due to fire exposure.

It is important to note that these vents are not intended for general building ventilation purposes but specifically for smoke and heat evacuation during fires. The UL 793:2020 standard sets the requirements to ensure the effectiveness and safety of these automatically operated roof vents.