Hong Kong Regulations

BUILDING (PLANNING) REGULATIONS - REGULATION 31

Minimum requirements of window

(Past version on 30/06/1997).

(1) No prescribed window shall, for the purposes of regulation 30, be deemed
to face into the external air unless-

   (a)  it faces into a street which is not less than 4.5 m wide; or

   (b)  it faces into a space uncovered and unobstructed above the area
        delineated by the rectangular horizontal plane; and

   (c)  it is so placed that, if another rectangular plane, the base whereof
        is equal to and common with the base of the rectangular horizontal 
        plane, is inclined, above the rectangular horizontal plane, at an
        angle of 71 1/2 degrees from the horizontal where the window is in a
        room used for habitation or 76 degrees from the horizontal where the
        window is in a room used for the purposes of an office or as a
        kitchen, no part of the building, or of any other building within the
        site on which such building is erected, protrudes above such plane; or
        (G.N.A. 97 of 1962)

   (d)  where such window opens on to an area bounded on the side opposite the
        window by a boundary of the site on which the building is erected,
        such window is so placed that, if the rectangular horizontal  plane is
        projected to such boundary and, from the position at which it first
        intersects the boundary, another rectangular plane, the base whereof
        is parallel and level with the sill of the window and has a length
        equal to the length of the base of the rectangular horizontal plane,
        is projected, towards the site and above the
        rectangular horizontal plane, at an angle of 80 1/2 degrees from the
        horizontal where the window is in a room used for habitation or 83
        degrees where the window is in a room used for the purposes of an
        office or as a kitchen, no part of the building, or of any other
        building within such site, protrudes above such inclined plane:
        (G.N.A. 97 of 1962) Provided that, where there is a service lane or
        street less than 4.5 m wide adjacent to and parallel with such
        boundary, the boundary shall, for the purposes of this sub-paragraph
        be deemed to be at a position 1.5 m beyond such boundary. (L.N. 54 of
        1969)

(2) The rectangular horizontal plane shall be such that-

   (a)  it has an area of not less than 21 m2; and

   (b)  the minimum length of the base is not less than 2.3 m; and

   (c)  the minimum length of the sides at right angles to the base, between
        the wall in which the window is sited and any other wall or building
        opposite thereto within the boundary of the site on which the building
        is erected, is not less than 4.5 m; or

   (d)  where the window opens on to an area bounded on the side opposite to
        the window by a boundary of the site on which the building is erected,
        the minimum length of the sides at right angles to the base, between
        the wall in which the window is sited and such boundary, is not less
        than 2.3 m; or

   (e)  where the window opens on to an area bounded on the side opposite to
        the window by a boundary or the site on which the building is erected
        and there is a service lane or street less than 4.5 m wide adjacent to
        and parallel with such boundary, the minimum length of the sides at
        right angles to the base, between the wall in which the window is
        sited and a line 1.5 m beyond such boundary or, where such service
        lane or street is less than 3 m wide, between the wall in which the
        window is sited and a line drawn along the centre line of the service
        lane or street, is not less than 2.3 m. (L.N. 54 of 1969)

(3) For the purposes of this regulation-

        (a)	"base" (底邊), when used in relation to the rectangular 
horizontal plane, means that side of the rectangular horizontal plane common
with the line of the sill of the window; (L.N. 307 of 1998)

"rectangular horizontal plane" (矩形水平面) means a rectangular plane at
the level of the sill of the window having the minimum area and minimum
dimensions prescribed by paragraph (2);

"window" (窗) includes french window; and

   (b)  the sill of a prescribed window shall be deemed to be at a level 1 m
        above the level of the floor of the room for which the prescribed
        window is provided, whether or not the sill is at such level. (L.N. 54
        of 1969) (G.N.A. 83 of 1959; L.N. 294 of 1976)

"base" (底邊)

"rectangular horizontal plane" (矩形水平面)

"window" (窗)