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南非土木工程施工标准 T部分 火灾防护系统 英文原文节选 20100079 3-20 |
TT16. PROVISION OF ESCAPE ROUTES
TT16.1 One or more escape routes shall be provided in any building.
TT16.2 Where the travel distance, measured to the nearest escape door, is not more
than 45 m, any such escape route -
in any single-storey building;
in any dwelling unit having such escape door at ground level; or
in and from any dwelling unit at first floor level where such dwelling
unit is served by an individual stairway to ground level;
shall not be required to include any emergency route and, in the case of any
dwelling unit contemplated in this subrule, such escape route shall not be required
to comply with the requirements of rules TT17 to TT30 inclusive.
(b) in any building of two or three storeys in height shall not be required to
any building of two storeys in height where the population of the
upper storey is more than 25 persons; or
any building of three storeys in height;
(a) (i)
(ii)
(iii)
include any emergency route: Provided that where such building is -
(i)
(ii)
with not less than two such escape routes and -
(i)
(ii)
such building shall be provided with not less than two such escape routes.
(c) in any building of a height of more than three storeys shall be provided
an emergency route shall form part of each such escape route;
any such emergency route shall include any stairway forming part
of the escape route and also that part of the escape route from the
lower end of the stairway to any escape door.
TT16.3 Where, in any building, the travel distance measured to the nearest escape door
is more than 45 m, not less than two such escape routes shall be provided and
an emergency route shall form part of each such escape route.
TT16.4 Where, in terms of subrule TT16.2 or TT16.3, emergency routes are required in
any building -
(a) such emergency routes shall be entirely independent from one another
and so situated that should any one of such routes become unusable or
inaccessible not less than one other such route may reasonably be expected
to remain accessible and usable;
(b) the travel distance measured to the nearest access door shall be not more
than 45 m;
(c) the path of travel to any access door shall be along a feeder route;
(d) any such feeder route shall lead in two different directions to two or more
independent emergency routes;.
(e) the exist door from any room shall lead directly into a feeder route: Provided
that -
(i) such exist door may lead into a dead-end corridor where the total
distance to be travelled from the furthest point in such room to an
access door or to a feeder route is not more than 15 m; or
(ii) such exist door may lead into any other room, where such other
room is within the same tenancy and the exit door from such other
room leads into a feeder route.
Commentary: All buildings must be provided with one or more escape routes that can be used in case
of fire or other emergencies. The two most important aspects are that the route should,
at all points, be wide enough to allow the population using such route to move rapidly
along it and it must not, at any time, be obstructed in any way.
SABS 0400-1990 182
The width of any escape route within a dwelling house (occupancy H4) or within an individual
dwelling unit in an occupancy H3 is not critical because of the small population
involved and the fact that the layout of the dwelling unit can be assumed to be well-known
to the occupants. In the case of any occupancy H3 where two or more dwelling units
open on to a part of the escape route which serves all of them, such common part of
the route must comply with all the requirements (including width) for escape routes.
The length of an escape route in an H3 occupancy may be controversial. The travel distance"
is of coursealways measured from the furthest point in any room in a dwelling
unit to the nearest escape door or access door but it is important to note that there may
be certain special circumstances that must be considered. In any dwelling unit at ground
level, whether an H4 occupancy or part of an H3 occupancy, any "exit" door from the
dwelling unit that leads to an approved open space may be regarded as an escape door
and the travel distance measured accordingly. In the case of a dwelling unit at first floor
level, such dwelling unit may be regarded as an independent unit where it is provided
with its own individual stairway leading to ground level outside the building and does
not share any part of an escape route with any other dwelling unit. However, because
an escape door must, by definition, be at ground level the travel distance must be measured
to an imaginary "escape door" at the foot of the stairway.
Where the travel distance, measured from the furthest point in any room to an escape
door, is less than 45 m there are no requirements (other than dimensions) for any escape
route and in many cases it will suffice to provide a single escape route. Where the
travel distance is more than 45 m or in any building of more than three storeys in height
it becomes necessary to provide emergency routes, and hence feeder routes, as part
of the escape routes and in all cases it will be necessary to provide at least two escape
routes.
To be fully effective, feeder routes and emergency routes should supply at least the degree
of protection envisaged in the deemed-to-satisfy rules given in this part of the code. This
is particularly important in the case of emergency routes which have to perform the dual
function of protection during evacuation of the building and during subsequent fire-fighting
operations.
The essence of any escape route that requires the incorporation of emergency routes
is that there should be at least two possible directions of escape. Where the exit from
any room leads into a dead-end corridor this is not possible and it becomes necessary
to reduce to the absolute minimum the distance to be travelled before either a feeder
route or an access door into an emergency route is reached. In this case,. account must
be taken of the travel distance both in the room in question and along the dead-end
corridor. This is of consequence both in itself and as part of the total travel distance to
a safe area.
In order to determine what provision is required for escape routes, proceed as follows:
(a) Check the travel distance from the furthest point in any room, measured along the
escape route, to the nearest escape door. Where this distance is less than 45 m or in
any building of not more than three storeys in height no emergency routes (and hence
no feeder routes) are required. With the exception of those cases contemplated in
subrule TTI 6,2(b), only one escape route need be provided but this must be dimensionally
adequate for the population to be served.
(b) Where the travel distance, measured in terms of (a) above, is more than 45 m, emergency
routes must form part of the two or more escape routes that must be provided
and these emergency routes should be as far apart as possible subject to the limitation
that the trave7 distance to the nearest access door to an emergency route must not be
more than 45 m ,
(c) Calculate the total population of each floor of the building. Note that in any occupancy
classified H3, the population within any individual dwelling unit is not, in itself, of consern
as the population figure required is used only in connection with the common part
of the escape route and not that part which is provided within each such dwelling unit.
(d) Using the population figure calculated in terms of (c), calculate the number and width
of the necessary escape routes bearing in mind that -
(i) the widths of all routes should be approximately equal;
(ii) because fire may prevent the use of a particular emergency route, one such route
is always discounted in determining the widths required for the remaining emergency
routes; and
(iii) in the case of a stairway only the population of the most heavily populated storey
need be taken into account in the calculation of width.原件下载： 
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