Civil Engineering Reference
In-Depth Information
Table 9.6
Suggested total actual travel distances
Purpose group
Escape - single
Escape - more
direction
than one direction
Residential institutions (care homes, etc.)
9 m
18 m
Hospital wards (high dependency patients)
15 m
30 m
Hotels, fl ats other residential
18 m
35 m
Offi ces
18 m
45 m
Schools (with seating - halls, etc.)
15 m
32 m
Shops
18 m
45 m
Factories and warehouses
25 m
45 m
Assembly (primarily for disabled persons)
9 m
18 m
Table 9.7
Minimum number of exits
Table 9.8
Minimum widths
No. of occupants
No. of exits
No. of occupants
Width of exits
1-60
1
1-60
750 mm
61-600
2
51-110
850 mm
601
3
111-220
1050 mm
221
1050 mm plus 5 mm/person
In addition to the requirement to limit travel
distances, it is also necessary to consider the fl ow of
people through the exits from buildings. The Approved
Document B provides guidance on the number and
widths of exits that are required to provided an adequate
means of escape.
In practice this means that when planning or assess-
ing the means of escape for a particular situation, there
must be adequate numbers and widths of exit as well as
adequate directions and distances of travel.
NB wheelchair users require a minimum of 900 mm width
Although it is important to consider the number and
widths of exits when considering the travel distances
(particularly when considering the adequacy of alternative
routes that result in increased travel distances), it is also
important to consider the appropriate evacuation time.
It is also essential to take into account those that
may need to make use of wider exits, corridors and
open plan offi ces with designated routes, such as those
using wheelchairs, walking aids, etc.
Minimum number of escape exits
In terms of the numbers of exits that are required, this
is based on a simple correlation between the numbers
of people likely to need to escape and the number
of doors.
The fi gures within the tables should be used in
conjunction with the travel distance fi gures and should
also be used with the same caution.
The use of refuges
Stage 2 of an escape route normally ends when the
occupants reach an adjoining fi re resisting compartment
for refuge, or a protected stairway which leads to ground
level. Descent to ground level is Stage 3 travel, but this
may not take place immediately. It may be more appropri-
ate for people to take refuge in another part of the building
separated from the fi re by a series of compartment walls.
The Codes of Practice for escape for disabled
persons and guidance on homes for the elderly, and the
guidelines for new and existing hospitals (NHS Firecodes),
Minimum widths of escape routes and exits
In terms of the width of the escape exits this again is a
simple correlation between the numbers of persons who
are likely to make use of the exits and the width of the
doors and corridors.
