The LWF Blog

Fire Safety for Facilities Management Personnel – Structural Fire Protection – Part 160

July 25, 2022 12:05 pm

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 159, LWF looked at the self-closing mechanisms of fire resisting doors. In part 160, we continue to discuss fire doors and consider what checks should be undertaken on a regular basis.

When the structural integrity of a fire-resisting compartment or corridor is considered, providing that the walls, floors and ceilings are only penetrated using fire-stopping materials, the fire door is the greatest potential point of weakness.

To ensure that a fire-resisting door is functioning properly and will stop the passage of fire and smoke products as intended, regular checks must be made as follows:

  • No doors are to be wedged open, negating self-close mechanisms
  • No door is damaged with voids or holes created by the removal or change of hardware
  • Self-closing devices are operating as intended, even in the case of latched doors
  • The hinges for the door are not worn
  • The door fits into the frame well with no gaps of more than 4 mm between the door and frame or between the leaves of double doors
  • Intumescent seals and smoke seals are intact
  • Automatic door release mechanisms are working as intended
  • No storage, rubbish or any other item will impede the correct closing of the door or shutter that is held open under normal circumstances


Some fire resistant doors or walls may contain glazing, providing that the glazing does not reduce the overall fire resistance of the barrier. Normal glass would be inappropriate for use, as it shatters at an early stage of exposure to fire. Fire-resisting glass is available, the most commonly used is also the cheapest – Georgian wired glass.

Unwired glass is also available which is capable of affording set periods of fire resistance when installed correctly in suitable frames and channels. The cost of such glass is considerably more than Georgian wired glass, but the advantage in terms of aesthetic is often considered worthwhile. It is virtually indistinguishable from normal glass to the casual observer.

Georgian wired glass and some unwired glass does not provide significant insulation and, as a result, Approved Document B contains guidance on where these products cannot be used safely, such as in the enclosure of a protected stairway, in a single-stairway situation.

Some insulated glasses are available which contain intumescent interlayers to provide insulation in a fire situation, or which contain a heat-absorbing gel for the same purpose. These glasses are relatively thick compared with uninsulated products, but may be more suitable for use in fire-restricting construction.

In part 161 of this series, LWF will look at protection against flame spread over linings. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.


Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.


While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.


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