The LWF Blog

Fire Safety for Facilities Management Personnel – Fire Resistance – Part 65

September 28, 2020 12:43 pm

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 64, LWF looked at how fire develops inside buildings, before beginning to consider fire resistance. In part 65, we continue to discuss fire resistance.

BS EN 1363-1 provides the general requirements for fire resistance testing. A fire resistance test involves exposing areas of construction, such as walls, floors, ceilings, doorsets and glazing systems to heat from a furnace in accordance with a time/temperature curve. The curve is intended to represent and simulate the environment in a post-flashover fire.

BS 476-21 provides detailed test requirements and the criteria for whether the item passes or fails the test.

Load-bearing construction elements may be tested for three performance parameters under the standards:

Loadbearing capacity – the ability of the element to support its test load without excessive deformation. This is especially important for floors and ceilings which must not collapse to allow for safe evacuation of a building during a fire situation.

Integrity – the item’s ability to contain fire without collapse or the development of holes or cracks through which flame could pass. This element is particularly important to avoid the spread of fire from one compartment to the next, or from one building or storey to the next.

Insulation – the ability of the element to resist heat passage from the exposed to the unexposed face. Convected heat can cause fire to start in an adjoining area if this is not considered, plus, fire in the storey below could heat the floor of the escape route to a dangerously high level, making escape dangerous.

The examples given are not exhaustive and there are very many applications and reasons why each test is essential when considering fire-resistance and construction materials.

Non load-bearing elements are, of course, not tested for loadbearing capacity.

The test results will indicate the performance of the construction element in units of time, based on the standard time/temperature curve.

The minimum period of fire resistance specified is usually 30 minutes, although there are a few exceptions – one of them being cross corridor smoke stop doors. 30 minutes fire resistance is considered normal for the protection of escape routes from a building to a place of safety outdoors. However, some buildings and projects may require longer periods of fire resistance for parts of the construction, either in the building regulations or as a requirement of the insurer.

In part 66, LWF will begin to look at the causes of fire and where statistics on fire can be found in the United Kingdom. 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.