The LWF Blog
Fire Safety for Facilities Management Personnel – Means of Escape – Part 114September 6, 2021 11:48 am
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 113, LWF discussed means of escape and some escape ideas which are not acceptable. In part 114, we continue to discuss means of escape and the idea of alternative escape routes.
A situation within a building where escape is only available in one direction should be avoided, where possible. It can be unavoidable in limited circumstances, but it should always be at the forefront of effective building design that an occupant of the building, situated at any position within the building, may find their escape route cut off by fire and an alternative route should be available.
An alternative escape route is one which is sufficiently separated from the first by either direction or space, or by fire-resisting construction. The purpose is, of course, that one viable escape route will be passable if the first is not.
When considering a room or storey of a building where escape routes are not physically separated by fire-resistant construction, the two exit points should be sufficiently separated by direction. The minimum ‘angle of separation’ is 45 degrees, measured from an opposite point in the room. The point behind this rule is to avoid a situation where a fire can prevent egress via both exits.
Equally, if both exits were placed on different walls, but close together in a corner, that would be unacceptable for the reasons given above.
An escape route must lead to a place of safety. This is invariably outside and a safe distance from the building. However, with high-rise buildings being much utilised in built-up areas, the distance between the top floor of a multi-storey building and the ultimate place of safety outdoors may be considerable. It is important, therefore, to provide a place of relative safety inside the building, and that is often a protected stairway. Protected stairways are a separate compartment to the surrounding spaces they pass through and so allow a period of safety for occupants while they exit the building.
Building occupants feel most confident using the most familiar escape route to them and will revert to that route wherever possible. Most commonly, that is also the same way they entered the building. Alternative escape routes should be obvious to all occupants, not complicated in any way that is not essential and accept that ultimately, building occupants may still be reticent to use them.
Employees working in buildings should be taken through alternative escape routes during fire drills to ensure they are familiar with them and any fire safety training that takes place should also address any and all suitable escape routes from the building.
In part 115 of this series, LWF will look at the various design codes in use. 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.