Civil Engineering Reference
In-Depth Information
➤
A door or doors that lead to another compartment
enclosed by fi re resisting construction - see
pro-
gressive horizontal evacuation
above
➤
An open staircase (accommodation stairs) where
the length of the stair is included in the total travel
distance
➤
Any ramps conforming to BS 8300, at a gradient of
no more than 1:12
➤
Any moving walkways where the distance is
included in the total travel distance and the walkway
is designed not to stop suddenly
➤
Any wicket doors and gates (except from high risk
areas), provided that:
➤
They are not to be used by members of the
public
➤
Not more than 10 persons are expected to use
them in an emergency
➤
They provide an opening at least 500 mm wide,
with the top of the opening not less than 1.5 m
above the fl oor level and the bottom of the
opening not more than 250 mm above the fl oor
level.
Generally unacceptable means of escape
- the follow-
ing are not normally acceptable as means of escape, but
they can be used in certain situations where their reliabil-
ity can be demonstrated to the appropriate authorities:
Figure 9.42
Escalators are generally unacceptable as a
means of escape
➤
Lifts, except for an appropriate evacuation lift for the
evacuation of disabled people in an emergency
➤
Fixed ladders, except those in plant rooms which
are rarely used and accommodate fewer than 10
able bodied people
➤
Portable ladders and throw-out ladders, e.g. rope
ladders from upper rooms
➤
Appliances requiring manual operation/manipula-
tion, e.g. fold-down ladders
➤
Power operated or manually operated sliding doors,
except where they are designed to 'fail safe' in the
open position on loss of power
➤
Security grilles and shutters (roller, folding or slid-
ing), loading doors, goods doors, sliding doors and
up-and-over doors, unless they are capable of being
easily and quickly opened
➤
Wicket doors and gates at exits from high risk areas
➤
Escalators
➤
Wall and fl oor hatches
➤
Window exits.
Stairways
A fundamental aspect of any means of escape in multi-
storey buildings is the availability of suffi cient numbers
of adequately wide, protected escape stairways.
Figure 9.43
Typical modern escape stairway
