Temperature rise- In specific scenarios, these doors don’t just act as barriers to fire but also prevent excessive heat transfer to safeguard building occupants during evacuations. These specialized doors, termed “temperature rise doors,” possess both an hourly rating and a temperature rise rating. The temperature rise ratings can be 250 degrees F, 450 degrees F, or 650 degrees F. This rating illustrates the maximum temperature increase, beyond the ambient, on the non-fire side during the initial 30 minutes of a standard fire test. Notably, a 250-degree F rating is seen as the most rigorous, thus fulfilling specifications even if they call for 450 or 650 degrees F.
Smoke and draft control- Certain doors, like 20-minute doors in corridors with fire resistance ratings or smoke barriers, might also undergo smoke infiltration tests as per UL 1784, the Standard for Air Leakage Tests of Door Assemblies and Other Protective Openings.
How do they withstand all of those tests? The materials they’re made of, including:
- A core of fire-resistant material (like vermiculite, gypsum, or ceramic).
- A layer that prevents heat transfer.
- Seals that expand with heat, blocking the gaps around the door.