Technical Booklet E Fire Safety·Page 14
Protected stairways as places of relative safety
Defines protected stairways as places of relative safety where people can proceed to a place of safety, with smoke and flames excluded by fire and smoke-resisting construction, appropriate smoke control systems, or both.
A protected stairway is considered to be a place of relative safety within which people can proceed at their own pace to a place of safety. Smoke and flames must be excluded from protected stairways by fire and smoke-resisting construction or by an appropriate smoke control system or both.
The ultimate place of safety is the open air clear of the effects of the fire.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet E - Fire Safety.pdf