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How to Correctly Specify Steel Fire Doors

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How to Correctly Specify Steel Fire Doors

Specifying the right fire door can be a life or death responsibility. It can also be a difficult task if you don’t know what you are looking for. The correct specification, fitting and maintenance of a fire door is the responsibility of each and every person involved in the process. Don’t risk making any mistakes. Read this guide to make sure you know how to correctly specify steel fire doors.

Purpose of Fire Doors

Fire-resisting doors serve three main purposes in a building:

To restrict the initial development of a fire. A correctly fitted and functioning fire-resisting door can help to suppress a fire by restricting the amount of oxygen available to it.

To restrict the spread of fire. A closed fire-resisting door is designed to withstand a direct attack by fire for a specified period of time. This should restrict the spread of fire through the building, gaining time for evacuation of the premises, and for active fire protection resources such as sprinklers and firefighters to perform their functions.

To protect escape routes. The provision of protected escape routes is a requirement of Building Regulations. Any door opening onto an escape route or operating across an escape route is likely to be designated as a fire-resisting door, to ensure that persons using the route have protection from fire while they escape.

After evacuation, fire-resisting doors should continue to provide some protection for firefighters entering the building to extinguish the fire.

Fire Doors v Fire Exits

At Bradbury Group, we are often asked what the difference is between a fire door and a fire exit. A fire door is a door with a fire-resistance rating and is used to reduce the spread of fire and smoke between separate compartments of a structure and to enable safe egress from a building or structure. Fire doors should not be left open, unless certified fire door retainers are installed. Fire exits are external doors that serve as an emergency exit; sometimes they are used for general access and can be left open, however, they aren’t always fire-resistant.

Fire Door Accreditation

British Standards Institution

The British Standards Institution (BSI) is a service organisation that produces standards across a wide variety of industry sectors. Its codes of practice and specifications cover management and technical subjects, ranging from business continuity management to quality requirements, and they provide the standards which fire doors must adhere to. Fire doors are tested to BS 476-22 or BS EN 1634-1 to represent how they will function in a fire, and are awarded a respective rating.

There are a number of testing authorities which will test and certify a fire door to meet BSI standards, but the most widely utilised fire accreditation provider in the steel door industry is Exova.


CERTIFIRE is an independent third party certification scheme that assures performance, quality, reliability and traceability of fire protection products. Recognised by regulatory authorities worldwide, it is an internationally respected mark of fire safety, and one of the most authoritative in the industry. The fundamental benefit of CERTIFIRE is seated in giving the regulator, specifier, customer and end-user confidence with regards to the stated performance of the product, and provides an informed choice when purchasing or selecting the product.

For manufacturers of fire protection products and systems, CERTIFIRE offers the opportunity to differentiate products and processes from non-certified equivalents, thus helping to access markets worldwide. For architects, specifiers, contractors and building owners, CERTIFIRE provides assurance that fire protection products and systems, when correctly installed, will perform as required. Therefore avoiding costly mistakes and dramatically reducing risk.

Testing & Certification of Fire Doors

The building regulation relates to the entire door installation, and not just the door alone. Because of this, fire doors are not tested as individual leaves, but as a complete installation, along with frame, locks, latches and other essential ironmongery. Fire doors are rated by minutes, and their rating is denoted by a number, and prefixed by the letters FD. For example, most Bradbury fire doors are certified to FD240; providing 240 minutes of fire protection. To achieve this accreditation, Bradbury doors were subjected to a furnace test, withstanding temperatures in excess of 1100oC for over four hours.

Fire Door Assembly

To ensure the fire integrity of doorset, manufacturers can only use ironmongery that has successfully been tested in conjunction with their doorset, or has achieved an independent fire rating. When selecting ironmongery, be sure to check its fire accreditations, as this could limit the number of options available to you. Also, to comply with building regulations, all fire doors must be supplied with a self-closing device. As with other ironmongery, these must also have an independent fire rating, or have undergone testing by the manufacturer in conjunction with their doorset.

There are limitations to the maximum glazed area a certified fire door can contain, as well as restrictions on the type of glazing that can be used. Ceramic-based glass can offer fire resistance of up to 240 minutes, subject to the specification of the door.

The addition of thermal or acoustic ratings to a fire door may severely limit the options available to you, in terms of specification and suppliers. By increasing a door’s insulating or sound-reducing properties, the temperature differential between the inner and outer door skin causes the two to expand at different rates. This causes the door to bow, and makes it more difficult to achieve a fire rating – hence, the number of suppliers able to offer these in combination are limited.

Specification of Fire Doors

Steel fire doors are generally offered with a polyester powder coating; however, many architectural applications call for cladding or specialist finishes. It is important to check the lead times and independent fire ratings of the cladding or finish, as you may find yourself to be limited in terms of availability, when a project comes to the construction phase.

As well as correctly specifying a suitable fire door for your application, it is essential that you ensure the substrate or opening into which the door will be placed is compliant in terms of its construction, and is compatible with the specified doorset. The frame or lining should be constructed in a brick, block or masonry wall, or an appropriate timber stud/plasterboard lined partition, which provides an equal duration of fire protection as the door assembly.

Any voids between the frame or lining and the wall should be infilled with mineral fibre or intumescent paste. The gap between the door and the frame is extremely important and must be suitable for the intumescent seal fitted. In general, the gap should not exceed 3mm along the two long edges and across the top of the door leaf.

As with acoustic ratings, the addition of security certification to a doorset may limit the scope of specification available, as manufacturers need to undergo two rounds of testing; which, as discussed, can prove to be very expensive. The best way to proceed when specifying fire doors is to ask the manufacturer to provide a copy of their compliance certificates, to make sure that the doorsets are legally certified to perform as required.

Purchasing Fire Doors

The key to ensuring your fire door design criteria can be met is to source a manufacturer who offers a large scope of certified products. We are experts in the design and production of fire and security doors that comply with the most stringent third-party testing and certification standards. Bradbury’s M2MFD range of fire rated doorsets can be tailored to suit individual project requirements, with the widest scope of locking options, vision panels, and side and over panels available to UK specifiers.