Exposing the Gap in Fire Door Testing: Why UL1784 Falls Short on Bottom Seals

Whether residential or commercial, fire safety is an essential aspect of a building’s design.

Fire doors are crucial components that can help prevent the spread of smoke and fire so occupants have as much time and clear pathway to egress during a fire emergency. The UL 1784 testing standard evaluates the performance of fire doors and specifically examines the effectiveness of their seals in restricting air leakage.

Nevertheless, the standard is not designed specifically for elevator hoistway openings, it does not address the bottom seals of fire doors.

This article explores this critical gap in the fire door testing methodology and examines the implications for fire door performance in real-life situations.

The Artificial Bottom Seals Dilemma

UL 1784 testing allows the use of artificial bottom seals when assessing fire doors. The standard permits covering the bottom gap of the door during testing with an impermeable material like tape or a sheet. According to UL 1784 Section 5.4.5, the artificial seal is applied to the test sample's bottom six inches (152.4 mm).

This practice is based on the original development of air leakage tests for side-hinged doors. The tests were designed with the assumption that smoke would start accumulating near the ceiling and gradually descend. Additionally, door undercuts, which serve HVAC purposes, were considered in the development of the standard.

Consequently, the standard allows the use of artificial bottom seals during testing to accommodate air leakage tests.

Implications in Real-World Scenarios

The use of artificial bottom seals in fire door testing can lead to a false sense of security regarding fire door testing performance. In actual situations, smoke and fire can spread rapidly,with any gaps in door seals potentially leading to devastating consequences. While smoke does tend to accumulate at the ceiling before moving downward, relying on this assumption in testing may not fully represent the conditions encountered during an actual fire event in front of the elevator hoistway opening.

Furthermore, door undercuts designed for HVAC purposes may inadvertently create pathways for smoke and fire to spread between rooms. When artificial bottom seals are used during testing, the UL 1784 standard may not accurately reflect the performance of fire doors in real-life situations, which raises concerns about the doors' effectiveness in preventing the spread of smoke and fire during emergencies.

The Promise of Smoke Guard Products

Smoke guard products offer a potential solution to the limitations of the UL 1784 testing standard. These products are specifically designed to address the bottom gap sealing in fire doors and are generally more effective in restricting the spread of smoke and fire than traditional fire doors that rely on artificial bottom seals during testing.

Smoke Guard's M2100

The M2100 Elevator is an example of a solution that provides smoke and fire protection by fully sealing at the top and bottom. It uses fire-resistant materials that can withstand high temperatures for an extended period of time.

The M2100 Elevator is constructed to meet the UL 1784 standard, which measures the air leakage performance of fire doors and smoke guards. This means that it can effectively prevent smoke from entering through gaps between the curtain and the floor. This is important for ensuring safe exit paths during emergencies and limiting the spread of smoke.

The Smoke Guard's M2100 provides better protection than traditional fire doors and similar products. This is because it focuses on sealing the bottom of the curtain, which is often overlooked in fire door testing. Having a tight and complete seal at the bottom of the curtain helps prevent the spread of smoke and fire in real-life situations. On the other hand, fire doors may not provide the same level of protection at the bottom seal during actual use.

Smoke Guard's M200 and M400

Elevator curtains are specifically designed to provide extensive protection in the context of elevator shafts by meeting or exceeding code regulations. The bottom seal construction in these curtains plays a crucial role in offering superior protection.

The smoke detectors in the elevator landing area are linked to the M200 and M400 curtains. If there is a power loss or an alarm goes off, these curtains will deploy on their own. Their bottom seal is constructed to fit snugly against the floor or elevator landing area. This design helps prevent smoke from entering the elevator shaft. As a result, the spread of smoke between floors is limited and occupants of the building are safer.

The superior protection provided by Smoke Guard's M200 and M400 elevator curtains' bottom seal construction is especially important considering that elevators often serve as a means of vertical transportation in a building. During a fire event, smoke may spread rapidly between floors through elevator shafts if not properly sealed. By addressing this concern with an effective bottom seal, Smoke Guard elevator curtains help maintain safe egress pathways and contribute to overall building safety.

Suggestions for Enhancing UL 1784 Testing

To address the limitations of the current UL 1784 testing standard, several changes should be considered:

First, the standard should require drop-down or deployable bottom seals to help ensure that all fire doors are tested under conditions that more closely resemble real-world situations. This modification would eliminate the use of artificial bottom seals and provide a more accurate assessment of fire door performance in preventing smoke and fire spread.

Second, it is crucial to revisit the allowance for artificial bottom seals in the UL 1784 standard to ensure that fire doors are tested under conditions that accurately reflect their real-world performance. By removing this allowance, manufacturers would be prompted to develop innovative and effective solutions for sealing the bottom gap in their products.

Third, promoting continuous research and development in fire door design and testing is essential to ensure that testing standards keep pace with technological advances and our understanding of fire safety. Collaboration between testing organizations, manufacturers and industry experts could help identify and address potential shortcomings in the testing process and ultimately lead to more robust standards.

Enhance Your Building's Safety with Smoke Guard's Superior Fire and Smoke Protection Solutions

Don't leave your building's safety to chance. Choose Smoke Guard's superior fire and smoke protection solutions to secure your property and ensure the well-being of its occupants. With our cutting-edge products, you can trust that you are investing in reliable and effective solutions that address the weaknesses in traditional fire door testing.