Hong Kong Regulations

BUILDING (CONSTRUCTION) REGULATIONS - REGULATION 17

Imposed loads

(1) The imposed load on any building, street, building works or street works
shall be the greatest applied load likely to arise from the intended use or
purpose of the building, street, building works or street works (including
forces exerted by the adjacent ground), but subject to this regulation-

   (a)  the minimum imposed load on a building or street shall be-

        (i)    the distributed load specified in column 3 of Table 1 applied
               uniformly on plan; or

        (ii)   the concentrated load specified in column 4 of Table 1 applied
               on plan over any square with a 300 mm side; or

        (iii)  the total load specified in column 5 of Table 1 applied on
               beams uniformly distributed over the span, whichever shall
               produce the most adverse effect;

   (b)  beams, ribs and joists spaced at not more than 1 m centres shall not
        be regarded as beams for the purposes of column 5 of Table 1;

   (c)  where a building is to support partitions but the position of the
        partitions is not indicated on the plan of the building, the weight of
        such partitions shall be regarded as imposed distributed load applied
        uniformly on plan and shall, in addition to other imposed loads, be-

        (i)    not less than 1/3 of the weight per metre length of the
               partitions uniformly distributed per square metre; and

        (ii)   not less than 1 kPa if the floor is used for office purposes.

TABLE 1

MINIMUM IMPOSED LOADS

1 2 3 4 5
Distributed load to be applied uniformly on plan Concentrated load to be
applied on plan over any square with a 300 mm side Total load to be applied on
beams, uniformly distributed over span Class No. Usage kPa kN kN 1 Floors for-
dormitories;
hospital wards, bedrooms, toilet rooms;
hotel and motel private sitting rooms, bedrooms, toilet rooms

2.0

2.0

12.0 2 Floors for-
domestic buildings;
hospital consulting rooms;
hospital operating theatres and X-ray rooms (equipment to be determined, but
not less than);
childcare centres and kindergartens

2.5

3.0

15.0 3 Floors for-
college and school classrooms, lecture rooms;
college and school laboratories (equipment to determined, but not less than);
offices for general use;
reading rooms without book storage;
recreational areas that cannot be used for assembly purposes, billiard rooms,
bowling alleys;
light workrooms, without central power-driven machines and storage

3.0

4.5

18.0 4 Floors for-
assembly areas with *fixed seating;
banking halls;
chapels, churches and places of worship (with fixed seating);
kitchens and laundries other than in domestic buildings (equipment to be
determined, but not less than)

*fixed seating means that the removal of the seating and the use of the space
for other purposes is unlikely to occur.

4.0

4.5

24.0 5 Floors for-
art galleries;
assembly areas without fixed seating;
dance halls;
department stores, supermarkets and shops for display and sale of merchandise;
footbridges between buildings, footpaths, terraces, plazas and areas used for
pedestrian traffic;
grandstands;
gymnasiums; hotel and motel bars, vestibules, lounges, public rooms, dining
rooms;
library rooms with book storage (excluding library stack rooms);
office for storage and normal filing purposes;
public halls and lounges;
restaurants, night-clubs, dining rooms subject to crowd loading, canteens and
fast food shops;
theatres and cinemas

5.0

4.5

30.0 6 Floors for-
boiler rooms (equipment to be determined, but not less than);
motor rooms, fan rooms and the like (equipment to be determined, but not less
than);
stages and television studios used as stages

7.5

9.0

45.0 7 Floors for-
workshops, factories and other buildings or parts of buildings of similar
category for industrial use -

   (a)  for light weight loads

   (b)  for medium weight loads

   (c)  for heavy weight loads

   (d)  for printing plants (equipment to be determined, but not less than)

5.0

7.5

10.0

12.5

9.0

9.0

9.0

9.0

-

-

-

- 8 Floors used for storage purposes for-

   (a)  library stack rooms, book stores

   (b)  cold storage

   (c)  paper storage in printing plants

   (d)  storage other than types specified in (a), (b) and (c), including
        storage in warehouse

* storage height shall be the height of the space between the floor and a
physical constraint to the height of storage formed by a ceiling, soffit of a
floor, roof or other obstruction.

3.5 for each metre of *storage height but not less than 10.0
5.0 for each metre of *storage height but not less than 15.0

8.0 for each metre of *storage height

to be determined, but not less than 2.5 for each metre of * storage height

to be determined, but not less than 9.0

to be determined, but not less than 9.0

to be determined, but not less than 9.0

to be determined, but not less than 9.0

-

-

-

- 9 Areas used for carriageways, floors, driveways and ramps used by vehicles-

   (a)  for car parking only, for vehicles not exceeding 2500 kg gross weight

   (b)  for vehicles not exceeding 4000 kg gross weight and inaccessible to
        fire-fighting engines

   (c)  for vehicles not exceeding 4000 kg gross weight but accessible to
        fire-fighting engines

4.0

7.5

7.5

9.0

15.0

75.0

24.0

45.0

150.0

   (d)  for vehicles not exceeding 12000 kg gross weight but accessible to
        fire-fighting engines

   (e)  for vehicles other than types specified in (a), (b), (c) and (d)

80 % of appropriate highway loading

appropriate highway loading 10 Flat roofs and sloping roofs up to and
including 10o -

   (a)  where no access is provided to the roof (other than such access as may
        be necessary for maintenance work)

   (b)  where access (in addition to such access as may be necessary for
        maintenance work) is provided to the roof

0.75

2.0

1.0

2.0

-

15.0 11 Pitched roofs (where no access is provided to the roof other than such
access as may be necessary for maintenance work) having an inclination to the
horizontal-

   (a)  of 30o or less

   (b)  of 75o or more

0.75
Nil

1.0
Nil

-
-

   (c)  more than 30o and less than 75o
linear interpolation according to the pitch 12 Stairs, landings and corridors
same as the floors to which they give access but not less than 3.0 and not
more than 10.0
4.5
-

(2) (a) Except as provided in paragraphs (b), (c), (d) and (e), in calculating
the total imposed load on any column, pier, wall or foundation, the
distributed imposed load on the roof and every floor carried thereby may be
subject to the reductions specified in Table 2.

   (b)  Where a single span of beam supports not less than 45 m2 of floor at
        any one level the distributed imposed load for the purpose only of
        determining the design of the beam may be subject to a reduction of 5%
        for each complete 45 m2 of that floor so supported but not more than
        20% in all.

   (c)  The reduction specified in paragraph (a) or (b), whichever is the
        greater, may be taken into account in calculating the total load on
        any column, pier, wall or foundation.

   (d)  For factories and workshops designed for a distributed imposed load of
        7.5 kPa or more the total imposed load shall not be reduced below that
        obtained if all the floors had been designed for a distributed
        imposed  load of 7.5 kPa without the reduction specified in Table 2.

   (e)  No reduction of the imposed loads shall be applied with respect to-

        (i)    plant or machinery which is specifically allowed for; or

        (ii)   floors of factories and workshops designed for a distributed
               imposed  load of less than 7.5 kPa; or

        (iii)  floors used by vehicles and floors used for storage purposes;
               or

        (iv)   office areas used for storage and filing purposes; or (v)
               forces produced by dynamic effects.

TABLE 2

REDUCTIONS OF TOTAL DISTRIBUTED IMPOSED LOADS

Number of floors (including the roof) carried by the member under
consideration Percentage reduction of total distributed imposed load on load
on all floors (including the roof) carried by the member under consideration 1
2 3 4 5 or more 0
10
20
30
40

(3) Protective barriers installed to restrict or control the movement of
persons shall be designed to resist the minimum horizontal imposed loads
specified in Table 3 when separately applied or the wind load (where
applicable), whichever shall produce the more adverse effects.

TABLE 3

MINIMUM HORIZONTAL IMPOSED LOADS ON PROTECTIVE BARRIERS TO RESTRICT OR CONTROL
THE MOVEMENT OF PERSONS

Uniformly distributed load to be applied at a height of 1.1m above floor level
Uniformly distributed load applied on the infill between floor and top rail
Concentrated load applied on any part of the infill between floor and top rail

Usage kN/m run kPa kN Areas where crowd load is not expected 0.75 1.0 0.5
Places of assembly and all panic barriers 3.0 1.5 1.5

(4) (a) Except as provided in paragraphs (b), (c) and (d), vehicle barriers
for car parks shall be designed to withstand an impact force of [10M / (100 +
db)] kN uniformly distributed over any length of 1.5 m and acting at bumper
height, where M is the gross mass of the vehicle in kg and db is the
deflection of the barrier in millimetres.

   (b)  Vehicle barriers for car parks which have been designed on the basis
        that any vehicle using them will not exceed a weight of 2500 kg shall
        be designed to withstand an impact force of [15000 / (100 + db)] kN
        uniformly distributed over any length of 1.5 m and acting at 375 mm
        above the floor level, where db is the deflection of the barrier in
        millimetres.

   (c)  Vehicle barriers for access ramps of car parks shall be designed to
        withstand 1/2 of the appropriate impact force determined in accordance
        with paragraph (a) or (b) acting at a height of 610 mm above the ramp.

   (d)  Opposite the lower end of any straight ramp intended for downward
        travel which exceeds 20 m in length the vehicle barrier shall be
        designed to withstand twice the appropriate impact force determined in
        accordance with paragraph (a) or (b) acting at a height of 610 mm
        above the ramp.

   (e)  Vehicle barriers in areas other than those covered by paragraphs (a)
        to (d) shall be designed to withstand the impact force appropriate to
        the vehicles using such areas.

(5) (a) Forces produced by dynamic effects shall be considered as additional
imposed loads in the design of buildings, streets, building works and street
works.

   (b)  The forces produced by dynamic effects in any workshop, factory or
        other building for industrial use may be determined on the basis of
        information about the particular building, but if not so determined
        shall be presumed-

        (i)    for the purpose only of determining the design of slabs and
               beams, to be an additional vertical imposed load of 2.5 kPa;
               and

        (ii)   for the purpose of determining the design of structural frames
               and foundations, to be an additional horizontal force (which
               may be assumed not to act together with the wind load) of 10%
               of the vertical imposed  load specified in subparagraph (i)
               acting simultaneously on the N number of floors which will
               produce the most adverse effects, where N is a whole number not
               less than 0.2 times the total number of floors subject to
               dynamic effects. (Enacted 1990)