This is what our site team have found behind a frame of an existing fire door in a live hospital ward. The wall has been loosely filled with timber off-cuts and newspaper!
Fire stopping correctly between the back of door frames and the wall sub-structure (behind the architraves) is a critical part of a fire door-sets function. As important as the door leaf itself, fire stopping enables the door-set to restrict the passage of cold smoke and fire for the specified period of time.
Yet it is one of the main areas where we constantly find it neglected, or worst still not carried out at all. All fire door-set installations and existing fire door assemblies that are being maintained must have fire stopping between the back of frame and sub-structure. This must be carried out as per the manufacturers installation instructions and as per BS 8214 (2016).
Not having the correct materials behind the architraves means fire-doors are totally ineffective for what they were designed for. This is why all fire door-sets should be installed by third party accredited installers.
Materials that should be used vary depending on the depth of the void, it’s not just a case of filling up the gaps with something inflammable! Intumescent material and intumescent mastic as specified in the fire door-sets’ installation instructions or the fire certificate data sheet should be used to fill any gaps.
Gaps up to 10mm – intumescent mastic tested to BS 476: Part 20: 1987 and EN1366-4
Gaps between 10mm and 20mm – non-combustible mineral fibre material for linear joints which is then encapsulated with intumescent mastic as above.
Gaps in excess of 30mm – timber packer infills the same density as the frame.
Once this work has been completed and the installation detail has been checked, architrave should then be fitted as they often form an integral part of the fire door assembly and its ability to provide effective passive fire protection.
What should should never, ever, ever be used is random timber off-cuts and rolled up newspaper!!