Fire doors, like all fire safety systems are, if you’ll pardon the pun, a hot topic at the moment. We see, use and rely on fire doors almost every day of our lives and yet so much confusion and misunderstanding about what constitutes a fire door still prevails, even among those that should know better.
One of the first things that is drilled into those learning about fire doors is that you should never modify a fire door and its associated hardware, with the cardinal sin being to make a penetration in the door – to add a letterbox or spy hole for instance – as this will invalidate the door’s certification and, worse, make it simply not fit for the important purpose of holding back fire and smoke.
Of course many fire doors have a glazed panel in them – in fact, this can be an important safety feature, allowing building occupants and fire fighters to assess what may lie on the other side of the door before deciding to open it. But a glazing panel can constitute a point of weakness in the door – so how is 30- or 60-minute fire resistance achieved in a glazed fire door?
Obviously, the glass must be certified fire resistant glass and it should only be installed at the manufacturing stage of the door, as part of a certified glazing system. But what of the point where door and glass meet? Isn’t that a weak spot? It is vital that this is considered really carefully to ensure optimum performance in fire conditions. It requires a sealant that will hold the glass firmly in place without slumping in the extreme heat – and without allowing the glass to slump too. It also needs to stop heat transfer to the timber, so fire can’t take hold around the edges of the glazing aperture. It is important to take into account not just the glass type and size but all the other variables like frame type, frame and bead density when specifying the sealant to ensure the glazing upholds the door’s fire rating.
Here at Hodgson we are well known for our expertise in glazing sealants and fire-rated sealants are no exception. For example, our Firestrip intumescent strip sealant – we have 30 and 60 minute versions – is tested and approved to provide fire resistance to the passage of smoke and flames in timber doors and screens. It can be used with a wide variety of insulating and non-insulating fire glass types and what’s more, our technical team can happily advise you in the best solution for your fire door glazing sealing queries and ensure that the system you are installing is compliant and safe.
If you have queries or worries about sealing glazing panels in fire doors, get in touch with our tech team [email protected]