FIRE SAFETY OF BUILDINGS (GENERAL):DETAILS OF CONSTRUCTION CODE OF PRACTICE

(  First Revision )

First Reprint OCTOBER 1998
UDC 699.812 : 11

@ BIS 1990
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

March 1990                                                                                                                                                                                                           Price Group 7

Fire Safety Sectional Committee, BDC 36

FOREWORD

This Indian Standard ( First Revision ) was adopted by the Bureau of Indian Standards on 20 June 1989, after the draft finalized by the Fire Safety Sectional Committee had been approved by the Civil Engineering Division Council.

The technical interpretation of fire safety of buildings is to convey the fire resistance of  buildings in terms of hours when subjected to a fire of known intensity. The fire grading of the building itself enables the correct amount of storage and class of materials, or appropriate ‘fire load’ to be apportioned for that particular application; the converse also holds good, thus, a building being required to accommodate a particular fire load for a given period would require the shell or fabric materials and construction to be designed accordingly.

Loss of life in fires is mainly due to smoke and hot gases being inhaled by occupants before actural flames have developed to a serious degree within the room concerned. Smoke and hot gases spread through doorways and ventilators which are normally impossible to keep closed. The essential requirements for fire safety in so far as materials and details of construction are concerned, arc that the flame smoke and hot gases should not spread so rapidly as to give the occupants insufficient time to escape. Should a fire occur, the construction should not further tend to spread the fire.

In order to reduce spread of fire, it is necessary that:

a) the fire should not spread rapidly from one room to another through the floors, partitions between rooms, and particularly between rooms and passages and staircases, that is, the ‘structural elements should have adequate fire resistance; and

b) the materials which are exposed to possible ignition, that is, wall and ceiling linings should not easily ignite, nor should the fire spread rapidly over the surface of the materials.

With a view to cover these aspects, this standard dealing with details of construction was first formulated in 1960. This revision has been based on useful information collected as a result of research in the country and abroad over the past 25 years.

The provisions given in this standard are those which are necessary at the time of construction of building new or addition or alterations for adopting fire safety measures. The provisions are applicable for all types of buildings including high rise buildings ( above 15 m in height ). The standard does not include other fire safety measures required to be adopted in the buildings of various occupancies in respect of provision of first-aid, fire fighting measures. alarm and extinguishing  systems, operation of fire lifts, etc; details of which are covered in relevant Indian Standards formulated/under formulation for each type of occupancy.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with 1S 2 : 1960 ‘Rules for rounding off  numerical values ( revised ); The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1 SCOPE

1.1 This standard lays down the essential requirements of fire safety of  buildings with respect to details of construction.

2 REFERENCES

The following Indian Standards are necessary adjuncts to this standard:

IS No.                                                                                                                                  Title

IS 655 : 1963                                                                                               Specification for metal air ducts

IS 941 : 1985                                                                                               Specification for blower and exhauster for fire fighting (second revision )

IS 1644 : 1988                                                                                            Code of practice for fire safety  of  buildings ( general ) : Exit requirements and personal                                                                                                                         hazard ( first revision )       

IS 1646: 1982                                                                                             Code of practice for fire safety of  buildings ( general ) : Electrical installation

                                                                                                                      ( first revision )                                               

IS 3809 : 1979                                                                                           Fire resistance test of structure ( first revision )

IS 4355 : 1977                                                                                          Specification for fire-resistant brattice cloth ( first revision )

IS 12459 : 1988                                                                                        Code of practice for fire protection of cable runs

IS 12777 : 1989                                                                                        Fire safety – Flame spread of products – Methods for classification

3 TERMINOLOGY

3.0 For the purpose of  this standard, the definition of various terms will be as under.

3.1 Fire Resistance

Ability of an element of  building construction, component for structure to fulfill, for a stated period of time, the required stability, fire integrity and/or thermal insulation and/or other expected duty in a standard fire resistance test ( see 1s 3809 : 1979 ).

3.2 Fire Separation

The distance in meters measured from any other building on the site, or from other site or from the opposite side of street or other public space to the building for the purpose of preventing the spread of  fire.

3.3 Fire Resisting Wall

The wall, either load bearing or non-load bearing. capable of specifying the criteria of fire resistance ( see 3.2 ) with respect to collapse, penetration and excessive temperature rise.

3.4 Separating Wall

The wall provides complete separation of one building from another or part of  a building from another part of the same building to prevent any communication of  fire or any access or heat  transmission to wall itself which may cause or assist in the combustion of materials of the side opposite to that portion which may be on fire.

3.5 Venting Fire

The process of  inducting heat and smoke to leave a building as quickly as possible by such paths that lateral spread of fire and heat is checked, fire fighting operations are facilitated and minimum fire damage is caused.

4 TYPES OF CONSTRUCTION

4.0 General

The design of any building and the type of materials used in its construction are important factors in making the building resistant to a complete burn-out and in preventing the rapid spread of fire, smoke or fumes, which may otherwise contribute to the loss of  lives and property.

4.1 The types of construction according to fire resistance are classified into four categories, namely, Type1, Type 2, Type 3 and Type 4 construction. The fire resistance ratings for various types of construction for structural and non-structural members should be as given in Table 1.

4.2 For buildings above 15 m in height non-combustible materials should be used for construction and the internal walls of  staircases should be of  brick work or reinforced concrete or any other material of construction with min-i mum of  2 hours rating. The walls for the chimney shall be of  Type 1 or Type 2 construction depending upon whether the gas temperature is above 200oC or less.

4.3 The fire resistance of an element of structure or combination of elements is determined from one of the following three methods. The fire test is done according to IS 3809 : 1979.

a) Information as established by research data ( see Note ).

b) Direct application of the results of fire resistance test on an element of structures.

c) On the basis for calculating the fire resistance of a structural element. ( This method is not applicable to columns or walls. )

NOTE – In the absence of research data available in this country, the data as arrived by Building Research Establishment ( UK ) ( see Guidelines for the Construction of Fire Resisting Structural Elements ) has been adopted in this standard. Therefore, while using this data it may be ensured that the

specification of material of construction are same as adopted in this Report. However, as and when data from indigenous source is available, the same will be incorporated in the standard.

5 WALLS

5.1 The fire ratings of some types of constructions for walls ( see Note below 4.3 ) are given in Tables 2 to 7. The specifications of materials should be so selected as to give these ratings.

Table 1 Fire Resistance Ratings of  Structural  Elements ( in Hours )

( Clauses 4.1 and 5.10 )


SI No.                                                                                 Structural Element                                                                 Type of Construction

                                                                                                                                               Type 1                    Type 2              Type 3            Type 4

  1              Exterior walls:                                                                                                    

                   a) Fire separation less than 3.7 m         i) Bearing                                     4                             2                       2                       1

                                                                                          ii) Non-bearing                           2                             1½                    1                        1

                   b) Fire separation of 3.7 m or                 i) Bearing                                      4                            2                         2                       1   

                   more but less than 9 m                         ii) Non-bearing                               1½                         1                         1                       1

                  c) Fire separation of 9 m or more        i) Bearing                                        4                              2                         2                       1

                                                                                      ii) Non-bearing                               1                             1                         1                       1 

     2           Fire walls                                                                                                             4                             2                        2                        2

     3           Fire separation assemblies ( like                                                                   4                             2                        2                       2

                  fire check doors )

    4            Fire enclosures of exit ways, exit way                                                              2                           2                        2                         2 

                  hallways, and stairways

      5          Shaft other than exit ways elevator                                                                  2                          2                         2                          2

                  hoist ways

      6          Exit way access corridors                                                                                1                             1                       1                           1

      7          Vertical separation of tenant                                                                            1                             1                       1                           1

                  spaces

    8            Dwelling unit separation                                                                                 1                              1                       1                           1

                  Non-load bearing partitions                                                                          <-At                      least                     an                        an

    9            Interior bearing walls, bearing           i) Supporting more                          4                              2                        2                           2

                  partitions, columns, girders, trusses   than one floor

                  ( other than roof trusses ) and              ii)Supporting one                         3                                1½                     1                          1

                  floor only                                                    iii) Supporting a roof                   3                                  1½                    1                         1

                  framing                                                      ‘only

                                             

   10          Structural members support walls                                                             3                                    1½                   1                         1

   11          Floor construction including walls                                                              3                                     1½                   1                         1

     12        Roof construction                          i) 5 m or less in height                        2                                      1½                  1                         1

                                                                             to lowest member

                                                                             ii) More than 5 m but                          1                                       1                    1                        1

                                                                              less than 6.7 m in

                                                                              height to lowest

                                                                               member

                                                                              iii) 6’7 m or more in                          0                                         0                 0                         0

                                                                              height to lowest

                                                                              member

 

Table 2 Masonry Walls: Solid ( Required to Resist Fire from One Side at a Time )
( Clause 5.1)


Nature of Constructioo and Materials                                              Minimum Thickness (mm), Excluding any Finish, for a Fire
                                                                                                                                           Resistance (Hours ) of        

                                                                                                                              Load Bearing                       Non-Load Bearing                            

                                                                                                     1          1½          2       3          4           1     1½         2     3         4

1 Reinforced* cement concrete                                             120     140        160    200    240

                                                                                                      (25)    (25)         (25)   (25)   (25)

2  Unreinforced cement concrete                                           150      175        —      —       —

3  No-fines concrete with:

a)  I3 mm cement/sand or gypsum/sand                                                                                          150   150    150     150      150

b)  13 mm lightweight aggregate gypsum                                                                                         150   150    150     150      150

      plaster

4   Bricks of clay:                                                                   

a)  Without finish                                                                    90        100         100    170   170          75       90      100      170     170

b)  With 13 mm lightweight aggregate                              90         90          90       100   100          75       90      90        90        100

      gypsum plaster

5    Bricks of sand lime:

a)   Without finish                                                                 90          100      100       190    190        75        90       100      170      170

b)   With 13 mm lightweight aggregate                          90           90         90          100    100       75         90       90        90         100

       gypsum plaster

6    Blocks of concrete:

a)   Without finish                                                               90            100      100         —       —         75        90        100     140         150

b)   With 13 mm lightweight aggregate                         90            90         90         100     100       75         75        75       90           100

       gypsum plaster

c)   With 13  mm cement/sand or gypsum/                                                                                         75          90        90      100          140   

7   Blocks of lightweight concrete:                                                                                                        

a)   Without finish                                                            90             100       100        140      150        75         75         75       125          140

b)   With 13 mm lightweight aggregate                      90             90          90          100       100       50         63        75          75             75

      gypsum plaster

c)   With 13 mm cements/and or gypsum/                                                                                            75         75       75           90            100

      sand

8    Blocks of aerated concrete:

a)   Without finish                                                          90             100       100        140          180         50        63      63           75          100

b)   With 13 mm lightweight aggregate                    90             90          100        100          150

       gypsum plaster

*Walls containing at least 1 percent of vertical reinforcement.

( ) Minimum thickness of actual cover to reinforcement.                 

 


Table 3 Masonry Walls: Hollows (Required to Resist Fire from One Side at a Time)

(Clause 5.1 )


Nature of Construction and Materials                                                                   Minimum Thickness ( mm ), Excluding any Finish, for a Fire

                                                                                                                                                                     Resistance ( Hours ) of

                                                                                                                                        Load Bearing                                      Non-Load Bearing

                                                                                                                               1       1½      2      3       4                       ½      1        1½       2     3       4

1 Bricks of clay:

a) Without finish                                                                                                170    170   170    200   200                75     100  100   170  170   200

b) With 13 mm lightweight aggregate                                                          100     100   170    170   170                75     75     90     100   100   170

gypsum plaster

2 Block’s of concrete:

a) Without finish                                                                                                                                                                90       125   125    140    140    150

b) With 13mm cement/sand or gypsum/                                                                                                                     90       125     125    140    140    140

sand

c) With 13 mm lightweight aggregate                                                          190     200    200    —     —                 75       90          90         100        125     125

gypsum plaster

3 Blocks of lightweight concrete:

a) Without finish                                                                                             100      100    100     —     —                 75          90         90       100       140     150

b) With 13 mm cement/sand or gypsum/                                                                                                                    75          75         75       100        140     140

sand

c) With 13 mm lightweight aggregate                                                                                                                          63          63         75        75           90       100                                                          

gypsum plaster


Table 4 Framed Construction, Load Bearing ( Required to Resist Fire from One Side at a Time )

( Clause 5.1 )


Nature of Construction and Materials/                                                                                    Minimum Thickness ( mm ) of Protection

Timber Studs at Centers not Exceeding                                                                                 for a Fire Resistance of 1 h

600 mm, Faced on Each Side with

1 Plasterboard layers with joints staggered, joints in outer layer                                                                 25

taped and filled – Total thickness for each face

2 One layer of 12’7 mm plasterboard with a finish of lightweight                                                                13 

aggregate gypsum plaster

3 Metal lath and plaster, thickness of plaster:

a) Sanded gypsum plaster ( metal lathing grade )                                                                                        22

b) Lightweight aggregate gypsum plaster                                                                                                        13


Table 5 Framed Construction, Non-Load Bearing ( Required to Resist Fire from One Side at a Time )

( Clause 5.1 )


Nature of Construction and Materials/Steel                               Stud                                                      Minimum Thickness ( mm ) of

or Timber Frame at Centre’s not Exceeding                        Construction                                            Protection for a Fire

600 mm, Facings on Both Sides of                                                                                                              Resistance of

                                                                                                                                                                              ½h        1 h        1½h     2 h

A) Dry lining with materials fixed direct to studs

( without plaster finish ):

1 One layer of plasterboard with taped and                           Timber or steel                                         127

filled joints

2 Two layers of plasterboard with joints                                  Timber or steel                                         19           25

staggered, joints in outer layer taped and

filled – Total thickness for each face

3 One layer of asbestos insulating board                                   Timber                                                   9

with transverse joints backed by fillers of                                    Steel                                                      12

asbestos insulating board not less than

9 mm thick, or by timber

4 One layer of  wood wool slabs                                                 Timber                                                      25

5 One layer of chipboard or of plywood                                       Timber or steel                                      18

B) Lining with materials fixed direct to studs, with

plaster finish:

1 Plasterboard of thickness:

a) with not less than 5 mm gypsum plaster                                                                                              95

finish                                                                                                 Timber or steel

b) with not less than 13 mm gypsum plaster                                                                                                                   127

finish

C) Wet finish:

1 Metal lath and plaster, thickness of plaster:

a) Sanded gypsum plaster                                                       Timber or steel                                    13

b) Lightweight aggregate gypsum plaster                             Timber                                                                                 13             19         25       

                                                                                                         Steel                                                                                    13


Table 6 Framed External Walls Load Bearing ( Required to Resist Fire from One Side at a Time )

( Clause 5.1 )


Nature of Construction and Materials                                                          Minimum Thickness ( mm ) of Protection

                                                                                                                                         for a Fire Resistance of 1 II

Timber studs at Centre’s not exceeding 600 mm

with internal linings of

1 Plasterboard layers with joints in outer layer                                                                      31

taped and filled, total thickness of plasterboard


 Table 7A Framed External Walls Non-Load Bearing Required to Resist Fire Only from

Inside the Building

( Clause 5.1 )


Nature of Construction and Materials                                                                                Minimum Thickness ( mm ) of Protection

                                                                                                                                                         for a Modified Fire Resistance of

                                                                                                                                                      ½ h       1 h           1 ½ h        2 h      3 h       4 h

A) Steel frame with an external cladding of non-combustible

sheets ( excluding sheet steel ), with a steel

supporting framework and internal lining of:

1 Metal lath and plaster, thickness of plaster:

a) Sanded gypsum plaster ( metal lathing grade )                                                          13           13

b) Lightweight aggregate gypsum plaster                                                                         10           13           15             15         15        19                                                                                    

2 Two layer of plasterboard with joints staggered

joints in outer layer taped and filled – Total                                                                         21          32

thickness

3 Plasterboard of thickness:

a) With not less than 5 mm gypsum plaster finish                                                        127

b) With not less than 13 mm gypsum plaster finish                                                       95

c) With not less than 10 mm lightweight aggregate                                                        95

gypsum plaster

4 One layer of asbestos insulating board with transverse                                             9            9             12           12           12            12    

joints backed by fillers of asbestos insulating

board not less than 9 mm thick, or by timber

5 One layer of wood/wool slabs without finish                                                                               50

6 One layer of compressed straw building slabs:

a) Without finish                                                                                                                  50                                           

b) With not less than 5 mm gypsum plaster finish                                                                      50

7 Aerated concrete blocks                                                                                               50             50             63        63         75         100      

8 Bricks of clay:

a) Without finish                                                                                                                75            75              90         90         100        100

b) With not less than 13 mm lightweight

aggregate gypsum plaster                                                                                                                                 75         75           90         90


Table 7B Framed External Walls Non-Load Bearing Required to Resist Fire Only from

Inside the Building

( Clause 5.1 )


Nature of Construction and Materials                                                                               Minimum Thickness ( mm ) of Protection

                                                                                                                                                    to Provide Sufficient insulation to Achieve

                                                                                                                                                    a Modified Fire Resistance of up to 4 h

B) Steel frame with an external cladding of sheet

steel fully lapped, steel bolted and fixed to steel

sheeting rails, with timber or steel supporting

framework and internal lining of:

1 Metal lath and plaster. thickness of plaster:

a) Sanded gypsum plaster ( metal lathing grade )                                                                                        13

b) Lightweight aggregate gypsum plaster                                                                                                       10

2 One layer of plasterboard with joints taped and filled                                                                              127

3 Plasterboard of thickness, with not less than 5 mm gypsum plaster                                                    95

,finish

4 One layer of asbestos insulating board with transverse joints backed                                                  9

by fillers of asbestos insulating board not less than 9 mm thick, or

by timber

5 One layer of wood/wool slabs                                                                                                                         25

6 One layer of compressed straw building slabs                                                                                           50

7 One layer of chipboard or of  plywood                                                                                                            18

8 Aerated concrete blocks                                                                                                                                   50

9 Bricks of clay                                                                                                                                                       75

10 Any internal decorative lining with a cavity fill independently                                                                   50

supported and retained in position of mineral fiber  insulating

material ( excluding glass ) at a density of 48 kg/m3


Table 7C Framed Walls Non-Load Bearing Required to Resist Fire Only from

Inside the Building

( Clause 5.1 )


Nature of Construction and Materials                                                                         Minimum Thickness ( mm ) of  Protection         

                                                                                                                                                    for a Fire Resistance of  1½  h

C ) Timber frame with external cladding of weather

boarding or external plywood, 95 mm with an

internal lining of:

1Plasterboard not less than 9.5 mm thick, finished with:

a) Gypsum plaster                                                                                                                                 13

b) Lightweight aggregate gypsum plaster                                                                                        10

2 Plasterboard not less than 12’7 mm thick, finished with:

a) Gypsum plaster                                                                                                                                10

b) Lightweight aggregate gypsum plaster                                                                                        10

3 One layer of asbestos insulating board with transverse joints

backed by fillers of asbestos insulating board not less than                                                        9

9 mm thick, or by timber                                                                                                                      12

 


5.2 The separating walls should be carried through the roof to a height of at least 60 cm above except in the case of reinforced brick/ concrete slab roof where it should be bonded flash ,with a top level of the slab. At the time of designing openings, particular attention should be paid to all such factors as will limit fire spread through these openings. Every opening in the wall should be protected by fire resisting doors having the fire rating of not less than 1 hour. Similar protection should also be done in other openings like rope races, motor alley ways, staircases. etc. of rating not less than 2 hours. However, for Types 1, 2. 3 construction, a doorway or opening in a separating wall of any floor should be limited to 5.6 m2 in area with a maximum height of 2.75 m and maximum width of 2 m.

5.3 When building(s) and/or compartment(s) are separated by separating wall(s) and there is a verandah on one or more sides of such building(s)  and/or compartment(s), it is necessary that the separating wall should be built out across the verandah and be carried through the roof of the same; otherwise the building(s) and/or compartment(s) should be regarded as having internal communication and, therefore, subject to danger of spread of fire.

5.4 When opening in walls are provided to allow cable, etc, the space around cables and the wall should be protected according to the provision given in IS 12459 : 1988. However, such space in case of openings provided to allow plumbing/ gas/steam pipes and similar services should be sealed with filler material of fire rating not less than that of the walls in which these are situated.

5.5 Where openings are permitted, they should not exceed three-fourths of the area of the wall in case of an external wall.

5.6 A separating wall should be supported in a vertical line by a similar separating wall through all story’s below. The separating wall should be carried and bonded to the floor of appropriate fire-resisting construction.

5.7 When a separating wall runs parallel to the axis of the north light opening or gabled roof, the screen wall should be carried through, and 60 cm above the top of the north light opening except in cases where the screen wall becomes of such a height that horizontal distance between the north light opening and the roof of the adjoining building and/or compartment or between two sloping faces of the two consecutive roofs at the level of the top of the screen wall, is at least 6 m.

If, however, the separating wall is at right angles to the axis of the north light opening or the gabled roof, the ‘saw tooth’ gaps should be bricked up and screen wall extended above the ridge of the north light or the gabled roof.

5.8 All separating walls should be built out to extend 15 cm beyond the eaves of the roof so as to effectively cut off the roofs of the parts so separated. The eaves should be cut away on each side of this extension of the separating wall. If there is an opening on both sides of the separating wall within 3 m of the wall, those on one side should be bricked up to full thickness of wall, or an alternative should be provided with fire resisting doors of fire rating not less than of 2 hours for walls of 4 hours rating and 1 hour for other rating.

5.9 Common wooden roof members (trusses, joists and purlins) should not pass through the separating walls but they may be embedded there in provided they do not extend more than 22.5cm into wall and are separated from the similar roof member in the adjoining building by at least 11 cm or solid wall material. A separating wall should be supported in a vertical line by a similar separating wall through all story’s below. The separating wall should be carried and bonded to the floor of appropriate fire-resisting construction.

5.7 When a separating wall runs parallel to the axis of the north light opening or gabled roof, the screen wall should be carried through, and 60 cm above the top of the north light opening except in cases where the screen wall becomes of such a height that horizontal distance between the north light opening and the roof of the adjoining building and/or compartment or between two sloping faces of the two consecutive roofs at the level of the top of the screen wall, is at least 6 m.

If, however, the separating wall is at right angles to the axis of the north light opening or the gabled roof, the ‘saw tooth’ gaps should be bricked up and screen wall extended above the ridge of the north light or the gabled roof. 

5.8 All separating walls should be built out to extend 15 cm beyond the eaves of the roof so as to effectively cut off the roofs of the parts so separated. The eaves should be cut away on each side of this extension of the separating wall. If there is an opening on both sides of the separating wall within 3 m of the wall, those on one side should be bricked up to full thickness of wall, or an alternative should be provided with fire resisting doors of fire rating not less than of 2 hours for walls of 4 hours rating and 1 hour for other rating.

5.9 Common wooden roof members (trusses, joists and purlins) should not pass through the separating walls but they may be embedded there in provided they do not extend more than 22.5cm into wall and are separated from the similar roof member in the adjoining building by at least 11 cm or solid wall material.

5.10 Partition is used for separating sections or rooms of a building but is not expected to have a fire resistance equa1 to any of the values. In fact, in practice it should not be considered otherwise than structure of light dimension and strength consistent with the purpose for which it is used. The minimum fire rating of the partition is given in Table 1.

6 COLUMNS AND BEAMS

6.1 The fire ratings of some types of construction are given in Tables 8, 9, 12 and 13 ( see Note below 4.3 ). The specifications of materials should be so selected as to give these ratings.

7 FLOORS AND ROOFS

7.1 The fire ratings of some types of construction is given in Tables 10, 11, 14, 15, and 16. The specifications of materials should be so selected so as to give these ratings.

Table 8 Reinforced Concrete Columns

( Clause 6.1 )


Nature of Construction and Materials                                                                     Minimum Dimensions ( mm ), Excluding any Finish,

                                                                                                                                                       for a Fire Resistance of

                                                                                                                                            ½  h          1 h         1 ½ h       2 h        3 h         4 h

1 Fully exposed                     Width                                                                               150   200   250   300    400    450

                                                 Cover                                                                               20     25     30      35      35     35

2 50 percent exposed          Width                                                                               125   160   200    200   300    350

                                                 Cover                                                                               20      25     25      25     30      35

3 One face exposed            Thickness                                                                      100   120   140     160   200    240

                                                Cover                                                                               20      25      25       25    25     25


Table 9 Concrete Beams

( Clause 6.1 )


Nature of Construction and Materials                                                        Minimum Dimensions ( mm ), Excluding any Finish,

                                                                                                                                                      for a Fire Resistance of

                                                                                                                             ½  h        1 h           1 ½ h         2 h         3 h          4 h

1 Reinforced concrete ( simply supported )            Width                           80         120          150            200       240         280

                                                                                        Cover                           20          30             40             60          70            80

2 Reinforced concrete ( continuous )                      Width                           80          80            120            150        200         240

                                                                                        Cover                          20           20             35              50          60           70

3 Prestressed concrete ( simply supported )        Width                         100         120           150           200        240         280

                                                                                       Cover                          25           40              55             70           80           90

4 Prestressed concrete ( continuous )                  Width                          80            100           120           150         200        240

                                                                                     Cover                           20             30             40              55           70          80


Table 10 Concrete Floors

( Clause 7.1 )


           Nature of Construction and Materials                                                              Minimum Dimensions (mm ), Excluding any Finish,

                                                                                                                                                           for a Fire Resistance of

                                                                                                                                                ½  h         1 h         1 ½ h          2 h        3 h           4 h

1 Reinforced concrete ( simply supported )      Thickness                                          75              95          110            125      150           170

                                                                                   Cover                                                  15              20           25               35         45             55

2 Reinforced concrete ( continuous )                Thickness                                           75             95           110            125       150          170

                                                                                  Cover                                                  15               20            20              25         35             45


Table 11 Concrete Floors: Ribbed Open Soffit

( Clause 7.1 )


Nature of Construction and Materials                                                      Minimum Dimensions ( mm ), Excluding any Finish,

                                                                                                                                                 for a Fire Resistance of

                                                                                                                            ½  h        1 h         1 ½ h       2 h      3 h         4 h

1 Reinforced concrete ( simply supported )          Thickness                    70          90          105        115      135       150

                                                                                        Width                            75          90           110       125      150        175

                                                                                       Cover                            15          25             35          45        55         65

2 Reinforced concrete ( continuous )                    Thickness                     70          90            105        115      135      150

                                                                                      Width                             75           80             90          110     125       150

                                                                                      Cover                             15         20               –             35        45          55


Table 12 Encased Steel Columns, 203 mm x 203 mm ( Protection Applied on Four Sides )

( Clause 6.1 )


Nature of Construction and Materials                                                                                          Minimum Thickness (mm ) of Protection

                                                                                                                                                                         for a Fire Resistance of

                                                                                                                                                              1 h       1 ½ h       2 h       3 h        4 h

A) Hollow protection ( without an air cavity over the flanges ):

1 *Metal lathing with trowelled lightweight aggregate gypsum plaster                                13           15          20         32

2 Plasterboard with 1.6 mm wire binding at 100 mm pitch, finished with

lightweight aggregate gypsum plaster not less than the thickness

specified:

a)‘9-5 mm plasterboard                                                                                                                10           15

b) 19 mm plasterboard                                                                                                                 10           13           20      

3 Asbestos insulating boards, thickness of board:

a) Single thickness of  board, with 6 mm cover fillets at transverse                                                   19          25

joints

b) Two layers, of total thickness                                                                                                                                               38      50

4 Solid bricks of clay, composition or sand lime, reinforced in every                                   50           50          50         75     100

horizontal joint, unplastered

5 Aerated concrete blocks                                                                                                           60            60          60

6 Solid blocks of  lightweight concrete                                                                                      50            50          50        60     75

Hollow protections ( with an air cavity over the flanges )                               

B) Asbestos insulating board screwed to 25 mm asbestos battens                             12           19                

C) Solid protections

1  Concrete, not leaner than 1 : 2 : 4 mix ( unplastered ):

a) Concrete not assumed to be load bearing, reinforced                                                     25           25            25       50     75 

b) Concrete assumed to be load bearing                                                                               50           50            50       75     75

2 Lightweight concrete, not leaner than 1 : 2 : 4 mix ( unplastered)                                25           25            25       40     60

concrete not assumed to be load bearing, reinforced

*so fixed or designed, as to allow full penetration for mechanical bond.

Reinforcement shall consist of steel binding wire not less than 2.3 mm in thickness, or a steel mesh weighing not less than 0’5 kg/m*. In concrete protection, the spacing of that reinforcement shall not exceed 200 mm in any direction.


Table 13 Encased Steel Beams, 406 mm x 176 mm ( Protection Applied on Three Sides )

( Clause 6.1 )


Nature of Construction and Materials                                                                 Minimum Thickness ( mm ) of   Protection

                                                                                                                                                  for a Fire Resistance of

                                                                                                                                     ½ h       1 h        1 ½ h      2 h        3 h         4 h

A) Hollow protection ( without an air cavity beneath the lower

flange ):

1 *Metal lathing with trowelled lightweight aggregate                                       13        13           15          20         25

gypsum plaster ( metal lathing grade )

2 Plasterboard with 1.6 mm wire binding at 100 mm pitch,

finished with lightweight aggregate gypsum plaster

not less than the thickness specified:

a) 9.5 mm plasterboard                                                                                       10         10         15

b) 19 mm plasterboard                                                                                        10         10          13         20

3 Asbestos insulating board, thickness of  board:

a) Single thickness of  board, with 6 mm cover fillets at

transverse joints                                                                                                                                19         25

b) Two layers, of total thickness                                                                                                                                  38        50

B) Hollow protection ( with an air cavity below the lower

flange ):

1 Asbestos insulating board screwed to 25 mm asbestos

battens                                                                                                                  9           12

C) Solid protection:

1 Concrete, not leaner than 1 : 2 : 4 mix ( unplastered ):

a) Concrete not assumed to be load bearing, reinforced                         25          25        25        25       50      75

b) Concrete assumed to be load bearing                                                    50          50        50        50       75      75

2 Lightweight concrete  not leaner than 1 : 2 : 4 ( mix )                             25          25        25         25       40      60

unplastered

*So fixed, or designed, as to allow full penetration for mechanical bond.

Where wire binding cannot be used, expert advice should be sought regarding alternative methods of support to enable the lower edges of the plasterboard to be fixed together and to the lower flange, and for the top edge of the plasterboard to be held in position. Reinforcement shall consist of steel binding wire not less than 2.3 mm in thickness or a steel mesh weighing not less than 0.5 kg/m*. In concrete protection, the spacing of that reinforcement shall not exceed 200 mm in any direction.

Concrete not assumed to be load bearing, reinforced.


Table 14 Timber Floors – Tongued and Grooved Boarding, or Sheets of Tongued and Grooved

Plywood or Wood Chipboard, of not Less than 21 mm Finished Thickness

( Clause 7.1 )


Nature of Construction and Materials                                                                Minimum Thickness (mm) of Protection

                                                                                                                                              for a Fire Resistance of

37 mm ( minimum ) timber joists with a ceiling of:                                                        ½  h        1 h        2 h

1 Timber lathing and plaster, plaster of thickness                                                             15

2 Metal lathing and plaster, thickness of plaster:

a) Sanded gypsum plaster ( metal lathing grade)                                                            15

b) Lightweight aggregate gypsum plaster                                                                          13         13          25

3 One layer of plasterboard with taped and filled joints                                                   127

4 Two layers of plasterboard with joints staggered, joints in outer layer taped

and filled total thickness                                                                                                         19         31                                                                           

5 One layer of plasterboard not less than 9.5 mm thick, finished with:

a) Gypsum plaster                                                                                                                    5

b Sanded gypsum plaster                                                                                                      13

c) Lightweight aggregate gypsum plaster                                                                           13

6 One layer of plasterboard not less than 12’7 mm thick, finished with:

a) Gypsum plaster                                                                                                                     5

b) Lightweight aggregate gypsum plaster                                                                           10

7 One layer of asbestos insulating board with any transverse joints backed by          9        12

fillets of asbestos insulating board not less than 9 mm thick, or by timber


Table 15 Timber Floors – Tongued and Grooved Boarding, or Sheets of  Tongued and Grooved

Plywood or Wood Chipboard, of not Less than 15 mm Finished Thickness

( Clause 7.1 )


Nature of Construction and Materials                                                  Minimum Thickness (mm ) of

                                                                                                                 Protection for a Fire

                                                                                                                     Resistance of

                                                                                                               1 ½ h          1 h         2 h       

37 mm ( minimum ) timber joists with a ceiling of:

1 Timber lathing and plaster, plaster of thickness                                           15

2 Metal lathing and plaster, thickness of plaster for:

a) Sanded gypsum plaster ( metal lathing grade )                                          15

b) Lightweight aggregate gypsum plaster                                                      13             13           25

3 One layer of plasterboard with taped and filled joints                                   127

4 Two layers of plasterboard with joints staggered,                                         22            31

joints in outer layer taped and filled total thickness

5 One layer of plasterboard not less than 9.5 mm thick, finish with:

a) Gypsum plaster                                                                                      5

b) Sanded gypsum plaster                                                                          15

c) Lightweight aggregate gypsum plaster                                                     13

6 One layer of plasterboard not less than 12.7 mm thick, finished with:

a) Gypsum plaster                                                                                     5

b) Lightweight aggregate gypsum plaster                                                     10

7 One layer of asbestos insulating board. with any transverse joints backed

by fillets of asbestos insulating board not less than 9 mm thick, or by timber  9           12

*Finished on top with 25 mm minimum thick glass fibber or mineral wool laid between joints.


Table 16 Timber Floors – Any Structurally Suitable Flooring of Timber or Particle Boards

( Clause 7.1 )


Nature of Construction and Materials                                                                      Minimum Thickness (mm ) of

                                                                                                                                     Protection for a Fire

                                                                                                                                           Resistance of

37 mm ( minimum ) timber joists with a ceiling of:                                                              ½ h                   1 h       

1 Timber lathing and plaster, plaster of thickness                                                                    15

2 Metal lathing and plaster, thickness of plaster for:                                                                

a) Sanded gypsum plaster ( metal lathing grade )                                                                   15

b) Lightweight aggregate gypsum plaster                                                                               13                      19

3 One layer of plasterboard with joints taped and filled and backed by timber                            127

4 Two layers of plasterboard with joints staggered, joints in outer layer taped

and filled total thickness                                                                                                       25

5 Two layers of plasterboard, each not less than 9.5 mm thick, joints between                           5

boards staggered and outer layer finished with gypsum plaster

6 One layer of plasterboard not less than 9.5 mm thick, finished with:

a) Sanded gypsum plaster                                                                                                   13

b) Lightweight aggregate gypsum plaster                                                                               15

7 One layer of plasterboard not less than 12.7 mm thick, finished with:

a) Sanded gypsum plaster                                                                                                   15

b) Lightweight aggregate gypsum plaster                                                                               13

8 One layer of asbestos insulating board with any transverse joints backed by

fillets of asbestos insulating board not less than 9 mm thick, or by timber                                12


7.2 In case of a building more than 15 m in height, all floors should be compartmented with area not exceeding 750) m2 by a separation wall with 2 hours fire rating, for floors having provision of sprinklers. The area may be increased by 50 percent. In long buildings, the fire separation walls should be at distance not exceeding 40 m. For departmental stores, shopping Centre’s and similar occupancies, the area may be reduced to 500 m2. Where this is not possible provision of the sprinklers should be kept with appropriate spacing.

7.3 A surface covering of non-combustible and non-toxic material should be laid directly on the incombustible floor. Wood flooring may be laid directly on such surface covering, or directly on such floor provided that in either case there is no intervening space and that any wood fillets for affixing such flooring is bedded not more than 2.5 cm in the non-combustible floor.

7.4 In the case of building used for storage purposes, the floor surface should conform to the above, in addition, it should be at least 15 cm above the ground level or the level of the door sills whichever is higher, and should slant towards the doors.

7.5 An opening through a floor should comply with the following:

a) At the time of designing openings particular attention should be paid to all such factors which will limit fire spread through these openings.

b) When opening in floors are provided to allow cable, etc, the space around cable and the floor should be protected according to the provision given in IS 12459 : 1988. However, such space in case of openings provided to allow plumbing/gas/steam pipes and similar services should be sealed with filler material of fire rating not less than 1 hour.

c)Openings for steam, gas and/or water pipes and electrical conduits, whether of iron or earthenware, should have a radial clearance, to allow for any heat expansion, not greater than 3 mm. 

d)The enclosure for staircases and hoists should be constructed entirely of brick, concrete or of reinforced concrete or similar material of construction having 2 hours rating. Every opening from the enclosure on to a roof used as floor or to any other part of the building should be fitted with a fire resistant door of rating not less than 1 hour.

e)If any staircase or hoist extends to the top store of a building the roof of which is not a roof used as a floor, the enclosing walls should be carried through and at least 45 cm above the roof of the building and a skylight or window glazed should be provided above the roof of the building. Alternatively, if the roof of the building is used as a floor. it should comply with (d), and this should also apply for any furnace or motor chamber communicating with the staircase or hoist enclosure.

7.6 Linings or false ceilings should not be permissible in buildings and in situations, where permitted, such additions should not detract in anyway from minimum fire rating of half an hour. In some cases, requiring provision of skylights, monitor lights or north lights in the roofs and where these are necessary. the glazing’s should be of glass in metal frames for fire rating of  half an hour minimum.

7.7 Composite roofs  may be used over 3 as addition to the roofs of buildings as a weatherproofing, but should not be considered as a roof in itself. that is, without the support of a noncombustible construction beneath, unless it is of not less than half an hour fire resistance.

8 AIR-CONDITIONING

8.1 Air-conditioning systems should be so installed and maintained as to minimize the danger of spread of fire, smoke or fumes thereby from one floor or fire area to another, or from outside into any occupied building or structure.

8.2 Air-conditioning systems circulating air to more than one floor area should be provided  with dampers designed to close  automatically in case of fire and there by prevent spread of tire or smoke. Such a system should also be provided with automatic controls to stop fans in case of fire, unless arranged to remove smoke from a fire, in which case these should be designed to remain in operation.

8.3 Air-conditioning system serving large places of assembly ( over 1000 persons ), large departmental stores or hotels with over 100 rooms in a single block should be provided with effective means for preventing circulation of smoke through the system in the case of a fire in air filters or from other sources drawn into the system even though there is insufficient heat to actuate heat sensitive devices controlling fans or dampers. Such means should consist of approved effective smoke sensitive controls.

8.4 Air-conditioning should conform to the following:

a) Escape routes like staircases, common corridors, lift lobbies, etc, should not be used as return air passage.

b)The ducting should be constructed of metal in accordance with IS 655 : 1963.

c)Wherever the ducts pass through fire walls or floor, the opening around the ducts should be sealed with fire resisting materials of same rating as of walls/floors.

d)As far as possible, metallic ducts should be used even for the return air instead of space above the false ceiling.

e)The material used for insulating the duct system ( inside or outside ) should be of flame resistant ( see IS 4355 : 1977 ) and non-conductor of heat.

f)Area more than 750 m2 on individual floor should be segregated by a fire wall and automatic fire dampers for isolation should be provided.

g)In case of more than one floor, arrangement by way of automatic fire dampers for isolating by ducting at every floor from the main should be made. Where plenum us used for return air passage, ceiling and its fixtures and air filters of the air handling units should be flame resistant [ see 8.4 (e)]. Inspection panels should be provided in the main trucking. No combustible material should be fixed nearer than 15 cm to any duct unless such ducting is properly enclosed and protected with flame resistant material. The fire dampers should be located in conditioned air ducts and return air ducts passages at the following points which will operate automatically and are simultaneously switch off air handling fans:

i) at the fire separation wall,

ii) where ducts/passages enter the central vertical shaft,

iii) where the ducts pass through floor, and

iv) at the inlet of supply air duct and the return air duct of each compartment on every floor.

In case of buildings more than 24 m in height in non-ventilated lobbies corridors. smoke extraction shaft should be provided. The  automatic fire damper should be so arranged so as to close by gravity in a direction of movement and to remain tightly closed upon operation.

9 SMOKE AND FIRE VENTING

9.1 Provision has to be made for venting which allows escape of  hot gases and smoke release by accidental burning of combustible material stored or are being processed inside a building, and will give ample time for all the inmates to escape before the roof collapses either in part or wholly in the event of fire. Provisions in this regard are essential for industrial buildings; details of which are covered in a separate Indian Standard. The provision in regard to the domestic buildings are given in 9.2. The form of vent should be a ventilator-cum-exhaust which in addition to the requisite grading of fire rating be easily open able.

9.2 Smoke venting facilities, where required for safe use of exits in windowless buildings, underground structures, large area factories, departmental store, domestic dwelling, theatres, cinemas, lecture halls, etc, or where required should be automatic in action.

9.3 Natural draft smoke venting should utilize roof vents or vents in walls at or near the ceiling level; such vents should be normally open, or if closed, should be designed for automatic opening in case of fire, by release of heat smoke sensitive elements, breakage of glass, or melting of plastic under the influence of  heat; or by other approved means.

9.4 Where smoke venting facilities are installed for purposes of exit safety, these should be adequate to prevent dangerous accumulation of smoke during the period of time necessary to evaluate the area served, using available exit facilities with a margin of safety to allow for unforeseen contingencies.

9.5 The discharge apertures of all natural draft smoke vents should be so arranged as to be readily susceptible to  opening by fire service personnel.

9.6 Power operated smoke exhausting systems may be substituted for natural draft vents

( see IS 941 : 1985 ).

9.7 In case of buildings more than 15 m in height the staircase should be ventilated to the atmosphere at each landing and a vent at the top, the vent openings should be 0.5 m in the external wall and top. If the staircase cannot be ventilated because of  location or other reasons, the provision should be made for pressurization ( 50 Pa ) to be separated automatically with the fire alarm. The roof of the shaft in the latter case should be 1 m above the surrounding roofs. ‘Glazing or glass bricks should not be used in the staircase.

10 SERF’JCE DUCTS

10.1 Service ducts should be enclosed by wails and doors ( if any ) of 2 hours fire rating; if ducts are larger than 1 m3 the floor should sea] them, but provide suitable openings for the pipes to pass through, with the gaps sealed.

10.2 A vent opening at the top of the service shaft should be provided between one-fourth and one-half of the area of the shaft.

11 BASEMENTS

11.1 Each basement should be separately ventilated. Vents with cross-sectional area ( aggregate.) not less than 2.5 percent of  the floor area spread evenly round the perimeter of the basement should be provided in the form of grills or breakable stall board lights or pavement lights or by way of shafts. Alternatively, a system of air inlets should be provided at basement floor level and, smoke outlets at basement ceiling level. Inlets and extractors may be terminated at ground level with stall board or pavement lights as before, but ducts to convey fresh air to the basement floor level have to be laid. Stall board and pavement lights should be in positions easily accessible to the fire brigade and clearly marked ‘SMOKE OUTLET’, or ‘AIR INLET’ with an indication of area served at or near the opening.

11.2 The staircase of  basements should be of enclosed type having fire resistance of  not less than 2 hours and should be situated at the periphery of the basement to be entered at ground level only from the open air and in such positions that smoke from any fire in the basement should not obstruct and exit serving the ground and upper store’s of  the building and should communicate with basement through a lobby provided with fire resisting self-closing doors of 1 hour fire resistance. If the travel distance exceeds 18.50 m, additional staircases should be provided at proper places.

11.3 In multi-level basements, intake ducts may serve al1 basement levels, but each basement and basement compartment should have separate smoke outlet duct or ducts. Mechanical extractors for smoke venting ( see IS 941 : 1985 ) from low basement levels should also be provided, with provision of automatic operation of system actuation of  heat/smoke sensitive detectors or sprinklers and also manually. Mechanical extractors should have an inter-locking arrangement, so that extractors should continue to operate and supply fans should stop automatically with the actuation of fire detectors. Mechanical extractors should be designed to permit 30 air changes per hour in case of fire or distress call. However, for normal operation, only 28 air changes should be maintained. Mechanical extractors should have an alternative source of supply. Ventilating ducts should be integrated with the structure and made out of brick masonry or RCC as far as possible and when this duct crosses the transformer area or electrical switch board, fire dampers should be provided. Basement/sub-basement should not be used for storage, cooking purposes, garage and shops unless provision is made for sprinkler system. If cut-outs are provided from basements to the upper floors or to the atmosphere all sides of the cut-out openings in the basements should be protected by automatic spray in the event of a fire.

12 CHIMNEYS

12.1 Over and above the provisions given in 4.2, the following previsions should be followed:

a) A clearance of at least 4 cm between the outer surface of the chimney and any adjacent combustible material forming part of a wall lining enclosing the chimney.

b)The fire resistance of  any structure surrounding a flew or flew pipe should be not less than that for external walls. In the case of flew pipe there should be an air space between it and the surrounding structure of sufficient width to permit access to the pipe for inspection and repair.

c)When a flew pipe passes though any other room or an enclosed roof space it should be protected by structure having a fire resistance equal to the external walls.

d)The chimney excluding the pot should be carried to a minimum height of 1 m above the highest point of its junction with the roof.

e)The outlet of a flew from domestic appliance having a roof covering should be at least 2.5 m in a horizontal plain from the roof of any structure built upon the roof or at least 0.6 m higher than any ridge within 2.5 m.

f)If the roof covering is not fire resistant, no flew outlet should be lower than the ridge for the highest point of the roof or less than 1 m above any ridge within 25 m.

g)Where a metal chimney passes through a roof covering which is not fire resistant, it shall be guarded by a suitable iron or metal thimble extending not less than 22.5 cm above and below roof construction and of a size to provide not less than 15 cm clearance on all sides of chimneys.

13 STAIRCASES AND LIFTS

13.1 Staircases

The details with regard to the provisions of staircases have been given in IS 1644 : 1988.

13.2 Lifts

13.2.1 The general requirements for the provision of lifts should be as follows:

a) Walls of lifts and enclosures should have a fire rating of 2 hours; lift shaft should have a vent at the top of area not less than 0-2 m2.

b)Lift motor room should be located preferably on top of the shaft and separated from the shaft by the floor of the room.

c)Landing doors in lifts and enclosures should have a fire resistance of not less than 1 hour.

d)The number of lifts in one lift tank should not exceed 4. Individual shafts in a bank should be separated by a wall of  2 hours fire rating.

e)Lift care door should have a fire resistance rating of not less than 1 hour.

f)Collapsible gates should not be used for  lifts and should have doors with fire resistance  of at least 1 hour.

g)In opening other than the lift lobby door  in the lobby enclosure wall should also have the minimum fire resistance of one hour.

h)Exit from the lift lobby, if located in the core of the building should be to a self closing stop door of minimum 1 hour fire rating.

j)Lifts should not normally communicate to the basement.

k)Suitable arrangements, such as providing slope in the floor of  lift lobby should be made to prevent water used during fire fighting, etc, on any landing from entering the lift shaft.

m) The sign should be posted and maintained at every floor at or near the lift indicating that in case of fire occupants should use the stairs unless instructed otherwise. The sign should also contain a plan for each floor showing the location of staircase.

13.2.2 Fire Lifts

13.2.2.1 Where applicable, fire lifts should be provided with a minimum capacity for 8 passengers with floor area of not less than 1.4 m2 and fully automated with emergency switch on the ground level. In general, building over 15 m in height should be provided with fire lifts. Each fire lift should be equipped with suitable inter communication equipment communicating with the control room on the ground floor of the building. The number and location of fire lifts in a building should be decided after taking into consideration various factors like building, population, floor. areas, section of  building ( comparmentation ), etc. The words ‘fire lift’ should be conspicuously displayed in IL luminous paint on the lift landing door at each floor level.

14 REFUSE AREA

14.1 In case of  buildings more than 24 m in height, refuse area of 15 m2 or an area equal to 0.25 m2 per person to accommodate the occupants of two consecutive floors, whichever is higher, should be provided as under. Refuse area should be provided on the periphery of the floor and open to air at least on one side protected with suitable railings:

a) For floors above 24 m and up to 39 m – one refuse area on the floor immediately above 24 m.

b) For floor above 39 m – one refuse area on the floor immediately above 39 m and so on after every 15 m.

15 REFUSE CHUTES

15.1 Refuse chutes should have an enclosure wall of non-combustible material with fire resistance of not less than 2 hours. They shall not be located within the staircase enclosure or service shafts, or air-conditioning shafts. Inspection panel and doors should be tight fitting with 1 hour fire resistance; the chutes should be as far away as possible from exits.

16 DRAINAGE

16.1 It is essential to make provision for drainage of any such water on all floors to prevent or minimize water damage of the contents.

The drain pipe should be provided on the external wall for drainage of water from all floors. On large area floors several such pipes may be necessary which should be spaced 30 m apart. The pipe should conform to relevant Indian Standards.

17 ELECTRICAL SERVICES

17.1 The electrical services should conform to the following ( see also IS 1646 : 1982 ):

a) The electric distribution cables/wiring should be laid in a separate duct. The duct should be sealed at every alternative floor with non-combustible materials having the same fire resistance as that of the duct. Low and medium voltage wiring running in shaft and above false ceiling should run in separate conduits.

b)Water mains, telephones lines, inter-corn lines. gas pipes or any other service line should not be laid in the duct for electric cables.

c)The inspection panel doors and any other opening in the shaft should be provided with fire doors having fire resistance of not less than 1 hour.

d)Medium and low voltage wiring running in shafts, and within false ceiling should run in metal conduit. Any 230 V wiring for lighting or other services above false ceiling should have 660 V grade insulations. The false ceiling including all fixtures used for its suspension should be of non-combustible material.

e)An independent and well-ventilated service room should be provided on the ground Boor with direct access from out-side or from the corridor for the purpose of termination of electric supply from the licenses service and alternative supply cables. The doors provided for the service room should have fire resistance of  not less than 2 hours.

18 FINISHES

18.1 There are certain aspects. Applicable to particular occupancies only. Which may Affect the spread of fire smoke or fumes and thus the Safe evacuation of the building in case of fire. Some such Aspects are as follows:

a) Interior finish and decoration;

b) Seating, aisles, railings and turnstiles in place of assembly;

c) Service equipment and storage facilities in buildings other than storage building; and

d) Hazards on stage, in waiting spaces, projection booths, etc, in theatres and cinemas.

 

18.2 The use of flammable surface finishes on walls ( including external facade of the building ) and ceilings affects the safety of the occupants of a building. Such finishes tend to spread the fire and even though the structural elements may be adequately fire resistant, serious danger to life may result. It is, therefore, essential to have adequate precautions to minimize spread of flame on wall, facade of building and ceiling surfaces.

Any materials used for various surfaces and

Décor should be such that the flame spread rating should not be more

Than the values given in 18.3 to 18.6 and in addition should not generate

Toxic smoke/fumes.

 18.3 Susceptibility to fire of various types of wall surfaces is determined

In terms of  flame spread (see IS 12777 : 1989).

18.3.1 In case of buildings more than 15 m in height, the interior finish

Material should not have rating exceeding Class 1.

18.3.2 The situation under which materials falling into various classes should be

Used in building construction is given below:

Class 1                                             Class 2                                                             Class3    

May be used              May be used in any situation,  except on               Should be used only in living rooms

In any situation           walls, façade of the building and ceilings of             and bedrooms ( but not in rooms

                                 Staircases and corridors                                       on the roof ) and only as a lining to

                                                                                                            Solid walls and partitions. Not on

                                                                                                            Staircases or corridors or facade of

                                                                                                            The building

NOTE – Paneling ( lining ) should be permitted in a limited area. It should not be permitted in a vestibule.

18.3.3 When frames, walls, partitions or floors are lined with combustible materials the surfaces on both sides of the material should conform to the appropriate class.

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986  to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of  BIS. This does not preclude the free use, in the course of implementing the standard, of  necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publications), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of ‘BIS Handbook’ and ‘Standards: Monthly Additions’.

This Indian Standard has been developed from Doc : No. BDC 36 (4208)

Amendments Issued Since Publication


Amend No.                                                 Date of Issue                                                                Text Affected


BUREAU OF INDIAN STANDARDS

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