Tuesday, August 13, 2019

Fire Door Gap Size Allowances - Am I protected?

For me, it’s that time of year again, annual facility fire door inspections.  I already know that the majority of these doors are going to fail, primarily due to door gap size allowances being exceeded. Current codes, NFPA 80, requires a maximum door gap allowance of ⅛” around the top and vertical perimeters of a fire rated door.  They allow up to ¾” door gap allowance at the bottom perimeter of the door. 

As I walk through the facility with my tablet and door gap gauge, I have to be prepared for the litany of questions that I will inevitably receive from facility managers. The primary question being, “How do I know that gap measurement is sufficient?”

In March of 2018, the NFPA’s Fire Protection Research Foundation published a report to answer the question of how did the gap size allowances come to be, and are the current gap allowances the best practice. The study included a literature review of more than 100 published documents and media, and computer modeling.  This report, Influence of Gap Sizes around Swinging Doors with Builders Hardware on Fire and Smoke Development, can be viewed in its entirety.

This study and report made some of the following conclusions:

“From this information a great deal of information and data was collected that directly reveals that the gap sizes around swinging doors have a significant effect on the fire development.”

“A significant amount of work was done to trace the historic record of the prescriptive gaps sizes included in NFPA 80. It was revealed that the first inclusion of these gaps sizes was added in 1959. Initially, requirements were based on the mounting of doors; however, in 1967 the requirements switched to being based on the door construction. There is no evidence to suggest that this was done from a fire performance perspective, however the test reports from that time period indicate that the prescriptive gap sizes are in the vicinity of what was found during full scale testing.”

Aegis Fire Door Gap Gauge