Chapter 13: Fire Resistive Structural Requirements

13-1.    Fire Resistance

13-1.1        For purposes of this chapter, every building or compartment shall be regarded according to its use or intended use, and where a building is divided into compartments intended to be used for different purposes, the requirements of each compartment shall be determined separately.

13-1.2        Every element of structure shall be required to have fire resistance for not less than the relevant period specified in TABLE 13.1 with regard to the building of which it forms part.

TABLE 13.1 Minimum periods of fire resistance

Types of Buildings or Compartment. Minimum period of fire resistance in hours for elements of structure.
Ground or upper storey Basement
i) Private dwelling house

 

1.5 1.5
ii) Private  dwelling house

 

0.5 1.5
ii) Institutional;

–        up to 92ft.(28m) high

–        up to 92ft.(28m) high

 

 

1

1.5

 

1.5

2

iii) Residential buildings other than private dwelling house

–        up to 2 storey high

–        up to 3 storey high

–        up to 92ft.(28m) high

–        up to 92ft.(28m) high

 

 

 

0.5

1

1

1.5

 

 

1

1

1.5

2

 

iv) Office Building

–        up to 25ft. (7.5m) high

–        up to 50 ft.(15m) high

–        up to 92ft.(28m) high

–        over 92ft.(28m) high

 

 

 

0.5

1

1

1.5

 

 

1

1

1.5

2

 

 

v) Mercantile Building

–        up to 25ft. (7.5m) high

–        up to 50 ft.(15m) high

–        up to 92ft.(28m) high

–        over 92ft.(28m) high

 

 

 

0.5

1

1

2

 

 

1

1

2

4

 

vi) Factory Buildings 

–        up to 25ft. (7.5m) high

–        up to 50 ft.(15m) high

–        up to 92ft.(28m) high

–        over 92ft.(28m) high

 

 

 

0.5

1

1

2

 

 

1

1

2

4

 

vii) Factory Buildings 

–        up to 25ft. (7.5m) high

–        up to 50 ft.(15m) high

–        up to 92ft.(28m) high

–        over 92ft.(28m) high

 

 

 

0.5

1

1

2

 

 

1

1

2

4

 

 

vii) Public Assembly Car Parks  

–        up to 25ft. (7.5m) high

–        up to 50 ft.(15m) high

–        up to 92ft.(28m) high

–        over 92ft.(28m) high

 

 

 

 

0.5

1

1

0.5

 

 

 

1

1

0.5

2

 

viii) Storage & Public Car Parks

–        up to 25ft. (7.5m) high

–        up to 50 ft.(15m) high

–        up to 92ft.(28m) high

–        over 92ft.(28m) high

 

 

 

0.5

1

2

4

 

 

1

2

4

4

 

13-1.2.1     If any part of a building is completely separated throughout its height, both above and below the ground, from all other parts by compartment walls in the same vertical plane, the fire resistance requirement of that part shall be determined solely by height of that part.

13-1.2.2     If any element of structure forms part of more than one building or compartment and the requirements of fire resistance in respect of one building or compartment differ from those specified for any other building or compartment of which the element forms part, such element shall be so constructed as to comply with the greater of greatest of the requirements specified.

13-1.2.3     Any elements or structure shall have fire resistance of not less than the minimum period required for any element which it carries.

13-2 Test of Fire Resistance

Every element of structure shall be capable of resisting the action of fire for the specified test of fire resistance period under the conditions of test appropriate to such an element in accordance with BS-476; Part 1: 1953and subject to modifications, if any.

  • External Walls

13-3.1        Any external wall which is situated within a distance of 4ft. (1.2m) from the relevant boundary, or is a wall of a building which exceeds 50ft (15.22 m) in height, shall be constructed wholly of non-combustible material apart from any external cladding.

13-3.2        Any steel beam or column, wherever forming part of or carrying, an external wall constructed of non-combustible material shall also be constructed wholly of non-combustible material.

13-3.3        Any part of a roof shall be deemed to be part of an external wall if it is pitched at an angle of seventy (70) degrees or more to the horizontal and covers a habitable space within the buildings.

  • Separating Walls and Fire Walls

13-4.1        Separating walls between two adjoining buildings shall form complete vertical separation and shall not have any opening except for the following:

13-4.1.1     Passage of a pipe through a separating wall if the pipe is not a flue pipe and has a diameter not exceeding 1 inch (25mm) if it is made of combustible material, and 6 inch (150m) if it is made of non-combustible material.

13-4.1.2     An opening which is necessary as a means of escape from fire, if the opening is fitted with a fire door which has fire resistance not less than the period required for the separating wall.

13-4.2        Any separating wall or fire wall which forms a junction with a roof shall be carried above the upper surface of the roof shall be carried above the upper surface of the roof covering to a distance not less than 15 inch (375 mm). A separating wall or fire wall shall not be required to comply with this requirement if:-

13-4.2.1     The roofs being separated by the wall are of non-combustible construction;

13-4.2.2     The buildings separated by the wall are residential, office or assembly buildings and do not exceed 40ft. (12.18m) in height.

13-4.3        if any external wall is carried across the end of a separating wall/fire wall shall be bounded together.

13-5.    Compartmentalization                                                        

Every floor of a building shall be divided as far as possible into compartments by means of appropriate fire resistant elements/measures for example fire walls and follows:

  • Separating one occupancy from another within the same building.

13-5.2        Separating part of a building from any other part of the same building which is used, or intended to be used, for a different function such as residential institutional, assembly, storage, commercial use etc.

  • Separating part of a building from any other part of the same building which is used, or intended to be used, for a different function such as residential institutional, assembly, storage, commercial use etc.
  • Dividing an institutional building except industrial building, into smaller compartments of an area not exceeding 3000Sq. yds. (2500sq.m).
  • Separating occupancy areas from common circulation areas.
  • Construction of Fire Walls

Fire walls shall be constructed in any manner or with any non-combustible material conforming to a minimum fire resistance of two (2) hours.

  • Openings in Fire Walls

13-7.1  Opening in fire walls may be fitted with a single or double leaf door with a minimum fire resistance for the following periods:-

13-7.1.1  Door giving access to an apartment from a common area – 0.5 hour

  • Any other case-1.5 hours
  • Except in case of fire doors giving access to occupancy areas from common circulation areas, all fire doors must open in the direction of escape.

 

13-8.    Direct Access for Ground Floor and Above                                     

13-8.1     Except for storey below the first storey, direct access for fire fighting shall be provided from the outdoors to every storey having its floor level less than 82ft. (25m) above ground by at least one unobstructed window or access panel for each 50ft. (15m) of wall, in each wall required to face a street.

13-8.2     An opening for access required in above clause shall be not less than 3.6ft.(1.1m) high by 2ft.(0.6m) wide, with a sill height of not more than 3ft.(0.9m) above the inside floor.

13-8.3     Access panels above the first storey shall be readily open able from both inside and outside, or the opening shall be glazed with plain glass.

14-9.Protected Shafts                                                                                  

13-9.1.1     Protected shafts shall be constructed only for stairway lift, chute, duct, or any other purposes which enable person, thing or air to pass between different compartments.                                                                    

13-9.2        There shall be no opening in shaft enclosures except the following:-

13-9.2.1     an opening for a pipe

13-9.2.2     an opening fitted with a door which has fire resistance of half hour or not less than half the period required in TABLE 13.1 whichever is more;

13-9.3        Any protected shaft containing a lift or lifts.

13-9.3.1     Shall be ventilated to external air by means of one or more permanent openings situated at the top of the shaft and having a total unobstructed area of not less than 1.5Sq.ft.(0.13Sq.m) for each lift;                     

13-9.3.2     Shall not contain any pipe conveying oil or gas or any ventilating duct;

13-9.3.3     May have an opening in its protective structure for passage of cables for the lift into the machine room provided that if the opening is at the bottom of the shaft the opening should be as small as practicable.

13-9.4        if a protected shaft serves as, or contains, a ventilating duct, the duct shall not be constructed of, or lined with, any material which increases the risk of spread of fire.

13-9.5        if a protected shaft consists of a stairway, it shall not contain any pipe conveying oil or gas, or a ventilating duct.

13-9.6        A shaft that does not extend to the roof of a building shall be enclosed with top construction of the same strength and fire resistance as that of the shaft enclosure. Such shafts shall be provided with non-combustible vents for the relief of smoke and gases in the event of fire, with an area not less than 10% of the shaft area.

13-9.7        All shafts that extend to the roof of a building shall be ventilated by a window in the side of the shaft of not less than 75% of the area of the shaft such window shall not be located within three 10ft. (3m) of an interior property line, and its sill level shall not be less than 2.5ft. (076m) above the finished roof level.

13-10.              Fire Resistant Doors

13-10.1      Any fire resistant door shall, if exposed to a test by fire and then fitted its frame, satisfy the requirements as to freedom from collapse and resistance to passage of flame for not less than the relevant period required.

13-10.2      The clearance between the leaf of the door and the frame or between leaves shall be as small as practicable.

13-10.3      If two separate doors (whether single or double leaf door) are installed on apposite sides of an opening, the required fire resistance may be achieved by the tow doors together or by either of them separately.

13-10.4      Wired glass, if used in fire resistant doors shall be of a maximum area 1Sq.ft. (0.1Sq.m) and shall not be less than 1/4th inch (6mm) thick.

13-11.Miscellaneous Provisions                                                      

13-11.1      If any part of an opening in an external wall of building other than a private dwelling house is directly above an opening in an adjoining storey, either:-                                                                     

13-11.1.1   The bottom of the upper opening shall be not less than 3ft. (0.91m) above the top of the lower opening and not less than 1.5ft.(0.56m) above the upper surface of the floor separating the storey; OR

13-11.1.2   A horizontal projection of non-flammable material is constructed between the two openings to project 1.5ft. (0.46m) form the wall.

13-11.2      Where a private dwelling house has an enclosed garage:-

13-11.2.1   The garage shall be constructed of non-flammable material having a fire resistance of not less than half an hour;

13-11.2.2   An opening in the wall separating the garage form the house shall at its lowest point be 4 inch (10cm) above the level of the floor of the garage and shall be protected by self-closing doors having a fire resistance not less than half an hour.

13-11.3      In premises with more than 400 persons seating capacity:-

13-11.3.1   The stage area shall be separated from the auditorium on either side of the proscenium opening by a fire resisting wall not less than 6 inch (150mm) thick, of block masonry or its equivalent, carried down to a solid foundation and up to least 3ft.(0.91m) above the roof level unless the roof is of fire resistant construction.

13-11.3.2.  Not more than two (2) opening shall be provided in the proscenium wall in addition to the proscenium opening. Such additional openings shall not exceed 20Sq.ft. (1.86Sq.m) area each and should be fitted with a door of minimum half an hour fire resistance

13-11.3.3.  A fire resistant curtain shall be provided to the proscenium opening.

13-12.Enclosures for Cinematographic Equipment                     

13-12.1      Cinematographic equipment shall be operated only within fire resistant enclosures located outside the auditorium.

13-12.2      The enclosure shall be constructed to have minimum two (2) hours fire resistance.

13-12.3      Two exits shall be provided to each enclosure. These shall be located outside the auditorium and fitted with self-closing doors with minimum fire resistance of half an hour. The door shall open outwards from the enclosure.

13-12.4      There shall be a minimum number of openings between the projection enclosure and the auditorium, and these shall be fitted with a gravity shutter of minimum half an hour fire resistance overlapping all edges of the openings by not less than 1 inch (2.5cm) when closed. There shall be provided a suitable device to close all shutters simultaneously from any projector head or from a point outside each exit door.

13-12.5      All enclosures shall be provided with adequate ventilation by suitable openings or shafts of non-flammable construction which shall lead to open air.

13-13.              Steel and Metal Structures 

13-13.1      All steel and other metal structural members shall be protected with non-combustible materials to provide the required fire resistance.

13-13.2.     Concrete fire protection on steel columns shall be reinforced and enclosed by wire mesh, metal clips or spirally would wire of not less than 12 gauge size with a pitch not more than 4 inch (10cm).

13-13.3      Where the fire resistant covering on columns is subject to damage moving vehicles or handling of merchandise, the fire proofing shall be enclosed up to a height of not less than 5ft. (1.5m) from the finished floor with a suitable metal covering of adequate strength.

13-14               Air conditioning Ducts                                            

13-14.1      All air-conditioning and ventilation ducts including supports shall constructed entirely of non-flammable materials.                                                    

13-14.2.     No air-conditioning or ventilation duct shall pass through a fire wall or separating wall.

13-14.3      Where ducts pass through floors or walls other than fire walls separating walls, the space around the duct shall be sealed with rope asbestos, mineral wool or other non-flammable material to prevent passage of flames and smoke.