The LWF Blog

Passive fire protection for Building Professionals – Part 15

April 30, 2020 9:09 am

In LWFs 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 14, LWF looked at how the correct choice of components is essential for a correctly-functioning fire door. In part 15, we begin to discuss the fire resistance of walls and ceilings.

Passive fire protection consists of more than third-party accredited products. As it would be pointless to install a fire door of a good standard into a wall which was unable to offer fire protection, we now begin to consider the importance of fire-resistant construction in a building.

Together, fire-rated products such as fire doors and fire-resistant construction offer protection and form a compartment where fire and smoke cannot permeate for a given amount of time. Much passive fire protection is based on the use of compartments and many buildings are heavily reliant on passive fire protection to preserve life safety and protect property.

For this reason, it is essential that appropriate care and attention should be paid when constructing fire-rated walls. There are two main types of fire-rated walls to consider – masonry construction which traditionally erected with brick or block work affixed with mortar and/or concrete; or there is flexible wall construction.

Flexible wall construction is commonly referred to as ‘stud work’ and may use either wooden or metal studs to create a flexible walling system. The advantages of flexible wall construction are that it is cheap and quick to construct and it able to move with the building. Such flexibility may be important in areas where a high level of environmental difference is observed with regards to temperature or seismic conditions, and movement may be frequent. More commonly, however, flexible wall construction is used because of the cost/time benefit.

Masonry construction is more substantial and therefore offers the advantage of remaining in place for extended periods of time. While this is often a benefit, it may also be that flexible wall construction allows for substantial amendments to be made to the interior layout of a building without too much upheaval or cost.

The level of fire protection offered by interior flexible construction is inherently inferior to that of masonry constructed walls. The construction of flexible walls must be undertaken with a greater degree of care to ensure the appropriate level of passive fire protection is provided. In the past, simple wooden studs, lined with plasterboard were considered sufficient to offer 30-minute fire resistance, but this is no longer considered appropriate or sufficient.

In part 16 of this series, LWF will look more closely at the construction of flexible walls with fire-resistance in mind. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

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.

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