Windowless Rooms in Accordance with BS 5266 and Fire Safety Approved Document B
Understanding BS 5266 in Conjunction with Fire Safety Approved Document B for Windowless Rooms
Regarding the statement in Approved Document B fire safety volume 2-Buildings other than dwellings, Table 5.1
It states that “Areas requiring escape lighting” and includes “Underground or Windowless accommodation”
Table 5.1 Provisions for escape lighting
| Use of the building or part of the building | Areas requiring escape lighting |
|---|---|
| Residential |
All common escape routes(1), except in two storey blocks of flats |
| Office, industrial, storage and other nonresidential |
a. Underground or windowless accommodation b. Stairs either: • in a central core • that serve storey(s) more than 18m above ground level c. Internal corridors more than 30m long d. Open-plan areas of more than 60m2 |
| Shop and commercial, and car parks |
a. Underground or windowless accommodation b. Stairs either: • in a central core • that serve storey(s) more than 18m above ground level c. Internal corridors more than 30m long d. Open-plan areas of more than 60m2 e. All escape routes (other than the following exception) to which the public are admitted(1). The exception is shops that meet all of the following: • have a maximum of three storeys • have no sales floor of more than 280m2 • are not a restaurant or bar |
| Assembly and recreation |
a. All escape routes(1) b. Accommodation except for that which is open on one side to view sport or entertainment during normal daylight hours |
| Any purpose group |
a. All toilet accommodation with a minimum floor area of 8m2 b. Electricity and generator rooms c. Switch room/battery room for emergency lighting system d. Emergency control rooms |
|
NOTE: 1. Including external escape routes. |
It is the view of Zemper that:
Accommodation is defined as ‘a room, group of rooms, or buildings in which someone may live or stay’, therefore it includes any room that is regularly occupied, such as offices, hotel bedrooms, classrooms, laboratories etc. but not include walk in cupboards, storerooms less than 60m2 or any other room that is not routinely occupied.
Zemper considers that underground or windowless, covers any space without a reliable source of borrowed light as according to BS5266-1:2016, 3 Terms and definitions, 3.1 borrowed light.
“Light obtained from an adjacent reliable source that is expected to be available at all material times.”
NOTE: For example, from a local emergency luminaire
Defining Emergency Escape Lighting BS5266-1:2016, 3 Terms and definitions, 3.5 emergency escape lighting, States:
“That part of emergency lighting that provides illumination for the safety of people leaving a location or attempting to terminate a potentially dangerous process before doing so.”
Therefore in summary: any room that is regularly occupied and does not have borrowed light would need suitable emergency escape lighting.
The occupants should be provided with suitable escape lighting until they reach a planned place of safety.
For example, the escape route would have minimum 1 lux on the centreline, with minimum 0.5 lux on half the width of the route