The LWF Blog

Passive fire protection for Building Professionals – Part 7

March 5, 2020 11:29 am

In LWF’s blog series on passive fire protection for building professionals and contractors and those with an interest in structural fire protection issues, we aim to give an overview of the important role passive protection plays in the overall fire safety provision of a building. In part 6, LWF continued from part 5’s look at third-party accredited products and contractors. In part 7 and 8, we will discuss fire doors and the important role they play in protecting lives and property from fire.

Fire-resistant construction in a building is comprised of protective firewalls and ceilings which are intended to restrict the spread of fire and smoke from the compartment of fire origin for a fixed period of time. It is common for compartments in buildings to have either 30, 60, 90 or 120 minute rating for fire resistant construction.

In order for the compartment to be effectively fire-resistant, all apertures must be filled with fire-stopping products, as smoke and fire can spread through even the smallest gap in fire protection. The largest aperture in that protection will be the doorway, where fire doors must be used and as a general rule of thumb, should have an equal level of fire-resistance to the walls and other fire-stopping products of that compartment.

The average image of a fire door is probably that of an emergency exit door, however, fire doors come in wide range of sizes and types. A small simple fire door can measure 750 mm wide by 1.8 m high, while large doors can be as large as 4 m x 4 m. Fire doors can be made of a variety of materials – timber, composite or metal being most typical.

Timber composite fire doors are the most popular and should be tested as per BS 476, Part 22 ( and BS EN 1364. ( The standards lay out the specification for the passage of flame, the prevention of excessive heat transfer, the stability and the integrity of the door, which relates to the prevention of fire penetration of the door.

Passive fire protection can be thought of as a system of fire-resistant components which work together to prevent the spread of fire and smoke. The key element, however, is that they are designed to work together. A fire door should be constructed of components individually tested to the relevant standards, however, if they have not been tested to work together effectively, the end product may not be reliable and the level of fire resistance intended for the compartment may not be achieved. This subject will be explored in more detail in the next blog in this series.

In part 7 of this series, LWF will continue to discuss fire doors and the important role they play in passive fire protection provision.

In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please do not hesitate to contact this office on free phone 0800 410 1130.

Lawrence Webster Forrest are fire engineering and fire risk management consultants who have over 30 years’ experience in providing fire safety advice to Architects, Developers, Contractors and End User Clients.

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.

Share this post