148 THE BUILDING CONSERVATION DIRECTORY 2025 CATHEDRAL COMMUNICATIONS FIRE DOORS THAT FIT ROBIN RUSSELL LISTED BUILDINGS embody history, architectural and cultural significance. Yet the need to adhere to modern fire safety regulations is imperative and so tends to trump any wish to prevent the alteration of listed buildings. Even historic gems must meet modern fire safety standards to protect their occupants. There’s no way this article is meant to be a definitive guide to what you need to do. All solutions are unique to each specific example and you must always ask the controlling authority. Very generally, there needs to be a safe means of escape from any room. Rooms opening off that escape route need to be separated from it by walls and doors which protect the route from smoke and flames for a set period, typically 30 minutes, to allow people to get out of the building. The building may also be compartmentalised to stop the spread of fire from one part of the building to another. Existing partitions, plasters and timbers which are in good repair may be sufficient to provide the protection required, especially in listed buildings. Where further enhancement is needed, options range from thin coverings like intumescent paints and papers, to thicker ones like fire-resistant plasterboard. Any gaps and holes may be plugged appropriately, especially, for example, penetrations for plumbing or light fittings, and there are many proprietary intumescent products for ducts, conduits and other openings. Door openings are a particularly obvious weak point in any compartmentation strategy. Gaps between the frame and the door must seal to limit smoke passing and to delay the spread of the fire for the required period. Smoke is of course a major killer. Intumescent seals and a cold smoke seals may be let into the door or the frame. These come in various forms and experimentation to find the best may be needed. Where gaps are greater than 4mm (or the width that intumescents can seal when heated), timber fillets may be applied to the frame or the door to reduce the gap. Upgrading existing doors to meet the requirements can be complex, and the process can have a significant impact on both their appearance and their historic significance. Historic England’s Guide to the fire resistance of historic timber panel doors (http://bc-url.com/fire-doors) outlines some of the options and gives four main reasons why historic doors and doorframes can fail fire resistance tests (BS 476: Part 22 and BS EN 1634-1 and 2): • when heated the door may distort at its junction with the frame, particularly the top corners, allowing the passage of flames • there may weakness in the door construction, particularly at the junction of panels with the frame or in joints in the panel • thinner parts of the panel or frame may burn through, particularly where large items of door furniture are fitted • burn-through may also occur at the gap between the door edge and the frame. NEW FIRE DOORS Where the existing doors are relatively recent additions and of little historic value, the simplest option may be to replace them. In some cases it may also be necessary to replace earlier doors which are too poor to upgrade or where upgrading would have too great an impact on their character. Integrating new fire-resistant doors into listed buildings presents a unique set of challenges. Unlike modern buildings, where One of the new fire doors at Gotham House: the intumescent strips are hidden behind a thin veneer. (All photos: Robin Russell)
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