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Why it is not okay to prop open fire doors in in a COVID-19 world

I have witnessed an alarming number of facilities propping open, or even worse, disconnecting arms on door closing devices to keep fire doors open and touch free during the COVID-19 pandemic.

You MUST not do this. EVER.

Fire doors are a critical life safety system that when closed maintain a buildings fire compartmentation and delay the spread of toxic gases during a fire. They allow people to escape in the event of fire and afford time for the emergency services to access the building to extinguish the fire.

Fire doors only work if they are fully closed and/or latched flush into the frame under the pressure of a controlled door closing device.

“But I’ve had a risk assessor advise otherwise”

They are wrong, and here’s why…

To risk assess, you need to know the risks. Right? And to know the risks you must have a good working knowledge of the subject matter, which in this case is fire doors.

To understand fire doors, we first need to know some basic principles of fire door assembly/ fire doorset design.

A fire door is an engineered system consisting of door leaf, frame, architectural hardware (closer, hinges, locks & latches, operating furniture etc…) glazing system and sealing system (fire and smoke sealing) that when installed correctly, AND CLOSED FLUSH into its frame will resist the passage of fire and smoke, as tested, for a specified period time e.g. 30 minutes / 60 minutes.

Fire doors leaves are generally made from engineered particle board core with densities greater than 510kgM3 for 30 minute doors and greater than 650kgm3 for 60 minute systems. The core is then framed, glued, lipped, glazed and finished with decorative surface material to suit the intended application.

Timber is subject to considerable distortion by humidity and fluctuations in moisture content. Ideal state for a fire door is 12% moisture content for it to remain stable i.e. to not twist, warp or bow.

Hinges when used on fire doors must be selected on their load bearing capacity. When door closers are used on fire doors that load bearing capacity must be increased by 30% to take into the account the forces applied through the door leaf under its opening and closing cycle (normal use).

When door closers with backchecks are used the increased load bearing capacity is adjusted by +75%! To take into account the significant forces applied through the door leaf during normal operation.

There are three opposing forces on a door leaf during operation.

  1. The door closer wants to pull the door closed from the head of the door leaf. (against the hinges and the user)
  2. The user pushes and pulls the door leaf at its central leading-edge position. (against the closer and the hinges)
  3. The hinges keep everything pulled in at the hinge side. (against the user and the door closer forces)

Over time these opposing forces cause a timber door leaf to warp, bow and twist, and eventually prevent the door from closing flush into its frame. Add in moisture fluctuations and humidity variables found in all buildings (especially this time of year) this twisting and bowing effect happens very quickly. It’s not uncommon to see this twisting effect happen over a very short period of time e.g. weeks or even days.

A door leaf that does not close fully into its frame because it has warped, twisted, or bowed is not a functioning fire door system and must be replaced. It will not perform as intended or as tested.

So, what has this got to do with propping open fire doors?

When you prop open a fire door using a wedge or chock forced between the door leaf and floor, the opposing forces applied through door leaf are constant and dramatically increased. Add into the mix fluctuating moisture content and humidity variables found  in every building and the door WILL, without doubt, distort out of shape.

A door leaf that is bent out of shape will not close flush into its frame. A fire door leaf that does not close flush into frame is no longer a fire and smoke resisting system.

And that is why you should NEVER, EVER prop open a fire door.

Author: Brian Ferguson

Brian Ferguson CertFDI, DipFD, DipGAI, MInstAI, RegAI is the Owner and Director of FD Fire Door.

www.fdfiredoor.co.uk

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