Annex M(Clause 6.7.3)

Fire Protection Considerations for Venting in Industrial Buildings

M-1 Application

M-1.1 The provisions given below are applicable only to single storey industrial buildings (factories and storage buildings) covering large floor areas without sub-dividing/separating walls which are usually designed to meet modern production methods.

M-1.2 The requirements of fire and explosion venting of industrial buildings, as dealt with in this section, fall under two categories:

a) Smoke and fire venting, and

b) Explosion relief vents.

M-2.1 The basic considerations for formulating the design and other requirements for smoke and fire vents are as given in M-2.1.1 to M-2.1.20.

M-2.1.1 The smoke and hot combustion products from a fire, being lighter than the surrounding air, tend to rise, and on reaching the roof or ceiling spread out (mushroom) on all sides and form a layer which floats on top of the cold air beneath. In the absence of vents, this layer becomes progressively deeper until the whole building is filled with hot smoky gases. The time consumed for this to happen may be only a few minutes, depending on variables like, type of materials on fire, process/storage conditions involved, etc.

M-2.1.2 The hot gases at the roof level moved by convection currents contribute to rapid lateral spread of fire.

M-2.1.3 The provision of properly designed and suitably located vents in adequate number helps the speedy removal of smoke and hot gases, thereby preventing spread of fire, besides reducing risks of explosion of unburnt gases and reducing damage to the contents and structure of the building by heat and smoke. In addition, they facilitate firefighting operations, and minimise personal hazards to the firemen.

M-2.1.4 The time taken for accumulation of smoke and hot gases within a building on fire being very short, the venting devices installed shall be designed to operate in the early stage of the fire and must be automatic so as to ensure speed and efficiency in their operation.

M-2.1.5 The smoke and fire venting system shall be designed in such a manner as to keep the temperature of the combustion products from the fire as low as possible, preferably below approximately $150^{\circ}$ C.

M-2.1.6 Automatic venting systems are complementary to the fire extinguishing systems, and automatic sprinklers, where provided, should operate before the operation of the vents; otherwise, venting may delay sprinkler operation.

M-2.1.7 It is easier to vent a building of smoke than clear it of smoke once it has been filled.

M-2.1.8 Venting is particularly desirable in large area industrial buildings or warehouses, windowless buildings, underground structures or in areas housing hazardous operations. Automatic fire vents shall be provided for all industrial occupancies (including storage buildings) classified as medium hazard or above having floor areas exceeding $750 \, m^{2}$ , irrespective of whether they are compartmentalized or not.

M-2.1.9 These provisions do not cover other aspects, of ventilation (or lighting) designed for regulation of temperature within a building for personal comfort or meeting process needs.

M-2.1.10 Similarly, fire and smoke venting requirements as given here under are also not applicable to multi-storeyed buildings, as their requirements are different and more complex.

M-2.1.11 It is difficult to determine precise venting requirements on account of the many variables involved. For instance, the rate of combustion varies appreciably according to the nature, shape, size and packaging of the combustible materials as well as the size, height and disposition of the stacks of materials.

M-2.1.12 In industrial buildings of floor area less than $750 \, m^{2}$ and used as low fire hazard occupancies, conventional ventilators fitted high up near the eaves of the external walls may serve as vents for smoke and hot gases, provided care is taken to ensure that they are kept open at all times or are designed to open automatically in case of fire.

M-2.1.13 Extinction of fires by closing the doors and windows is not likely in the case of industrial buildings because of their large size, where sufficient air to sustain the fire at least in the initial stages can be expected to be present.

M-2.1.14 Of the two types of building ventilation, namely, vertical and horizontal, vertical ventilation is the one commonly adopted in the case of single storey industrial buildings.

M-2.1.15 Since 70 to 80 percent of heat produced in a fire is convective heat, the ventilation system has to be suitably designed to ensure early outflow of the heat and thereby minimise fire spread.

M-2.1.16 Combustible roof linings shall be avoided, as they themselves will contribute to the spread of fire, thereby multiplying the venting problems.

M-2.1.17 A wind blowing across a flat roof or a roof with a pitch under $40^{\circ}$ produces a negative pressure, that is, it tends to draw gases out of the building and so aids venting of hot gases. Wind blowing across a roof of pitch greater than $40^{\circ}$ will draw gases out on the leeward side, but oppose outward flow on the windward side of the roof.

M-2.1.18 For vents to work at full efficiency, the area of the inlets for cold air entering the compartment must equal at least the total area of the vents. Ideally, the inlets shall be as close to the ground as possible.

M-2.1.19 Where roof vents are installed in a single-storey building any neighbouring buildings, particularly those of more than one storey, will be subject to some degree of exposure hazard either from flying birds or radiation, or both, as a result.

M-2.1.20 If vents are to be installed, the size, design, number and disposition of the vents and the associated roof screens/curtain boards have to be assessed after careful analysis of the various factors stated under M-2.1.11, as well as other related factors like type of building construction, nature and height of roof, process hazards, exposure hazard, etc.

M-2.2.1 The estimated requirements for ventilation are largely based on the assumed build-up of the fire from the time of initial outbreak to the time of effective fire fighting action by fire brigade.

PART 4 FIRE AND LIFE SAFETY

M-2.2.2 The vent area required to be provided shall be approximately proportional to the perimeter of the fire area, because the entrained air forms the bulk of the vented gases.

M-2.2.3 The effective area shall be the minimum cross-sectional area through which the hot gases must flow out to the atmosphere.

M-2.2.4 No consideration shall be given to the increased air movement obtained by power operated fans, since it must be assumed that in the event of fire, power will be interrupted, or fans damaged by heat.

M-2.2.5 The total vent areas to be provided shall be as per the following ratios of effective area of vent openings to floor area for various occupancy classifications indicated:

a) Low heat release content — 1 : 150 (Sub-division G-1)

b) Moderate heat release — 1 : 100 content (Sub-division G-2)

c) High heat release — 1 : 30 to 1 : 50 content (Sub-division G-3)

M-2.3.1 Venting shall be accomplished by any of the types such as monitors continuous gravity vents, until type vents or sawtooth roof skylights.

M-2.3.2 Where monitor type vents are installed, wire glass or metal panels shall be used only if the sash is arranged to open automatically.

M-2.3.3 The use of plain thin glass for venting shall be avoided on account of its unpredictable behaviour during fire. However, if glass or other suitable plastic sheet materials with early disintegration characteristics are used, they should be designed for automatic operation.

M-2.3.4 Where monitors or unit type vents are used, the panels shall be hinged at the bottom and designed to open automatically. Both sides of the vents shall be designed to vent simultaneously to ensure that their effectiveness at the time of fire is not in any way impeded by wind direction.

M-2.3.5 Where movable shutters are provided for continuous gravity vents, these shall open automatically in the event of fire.

M-2.3.6 Unit type vents shall be of relatively small area, ranging between $1 \, m^{2}$ and $9 \, m^{2}$ , having light weight metal frames and housing with hinged dampers which shall be designed for both manual and automatic operation.

M-2.3.7 Sawtooth roof skylight shall be considered as

satisfactory for venting purposes only when designed for automatic operation.

M-2.3.8 Likewise, exterior wall windows shall not be reckoned as satisfactory means for venting of fire gases and smoke in industrial buildings. However, they may be reckoned as additional means of venting when, they are located close to the caves and are provided with ordinary glass or movable sash arranged for both manual and automatic operation.

M-2.3.9 Baffles shall not be installed inside vents, as they greatly reduce the effective area for venting.

M-2.4.1 The vents shall be automatic in operation, unless where specified in these provisions that they shall be designed for both manual and automatic operation.

M-2.4.2 The release mechanism shall be simple for operation and independent of electrical power, since electrical services may be interrupted by fire.

M-2.4.3 The automatic operation of vents shall be achieved by actuation of fusible links or other types of heat and smoke detectors, or by interlocking with operation of sprinkler system or any other automatic fire extinguishing system covering the area. Following their release, the vents shall be designed to open by a system of counterweights and associated equipment utilizing the force of gravity or spring loaded levers.

M-2.4.4 Automatic fire alarm system, where installed, shall be coupled to the automatic vents to ensure simultaneous operation.

M-2.4.5 Automatic sprinklers, where installed, shall operate before the vents open order to avoid any likely delay in sprinkler operation. However, heat actuated devices used for vent release shall be suitably shielded from sprinkler discharge so that water does not delay their action. Further, provision of operating the vents manually may also be provided.

M-2.4.6 Premises where height of roof apex is 10 m or more or where the materials handled or stored have high smoke producing characteristics, in addition to fusible links, the vent release mechanism shall be interlinked to smoke actuated automatic fire detectors to ensure early operation of vents.

M-2.4.7 Non-corrosive materials shall be used for hinges, hatches and other related parts to ensure long fail-safe operation of the vents.

M-2.4.8 In case of any doubts regarding the types of vents required to be installed for any particular occupancy, authorities having jurisdiction shall be consulted.

M-2.5.1 Vents shall be correctly sited to ensure their functional efficiency. Ideally, they shall be sited at the highest point in each area to be covered.

M-2.5.2 They shall, as far as possible, be located immediately above the risk to be protected so as to allow free and speedy removal of smoke and other combustion products in the event of fire.

M-2.5.3 The minimum dimension for an effective vent opening shall be not less than $1.25\mathrm{m}$ in any direction.

M-2.5.4 The spacing of the individual vent shall be based on the principle that more number of well distributed smaller vents are more effective than fewer number of badly located larger vents.

M-2.5.5 The maximum spacing between vents for the three occupancy classifications shall be as follows:

a) Low heat release : 45 m between centres content

b) Moderate heat release content

: 36 to 37 m between centres

c) High heat release content

: 22.5 to 30 m between centres, depending on the severity of fire potential.

M-2.5.6 Vents shall be placed in a sheltered situation where advantage can be taken of the prevailing wind. The design of the vent shall be such as to produce a suction effect. A wind blowing across a flat roof or one with a pitch of $40^{\circ}$ produces a negative pressure, that is, it tends to draw gases out of the building and so aids venting of hot gases. Wind blowing across a roof of pitch greater than $40^{\circ}$ will draw gases out of the leeward side, but oppose outward flow on the windward side of the roof.

M-2.5.7 Low level inlets, with total area not less than the total area of vents, shall be provided to permit outside air to be drawn in to aid automatic venting. These inlets, which may be in the form of doors, windows or such other openings, shall be designed for manual operation when desired.

M-2.6.1 Industrial buildings with large areas and having no subdivision/separating walls limiting the area of individual compartments to $750 \, m^{2}$ or less, shall be provided with roof screens or curtain boards.

These screens which extend from the roof downwards at specific intervals not only prevent lateral spread of heat and smoke in the event of fire below, but

substantially assist in early operation of automatic sprinklers and vents.

M-2.6.2 They shall be of sheet metal or any other substantially non-combustible material strong enough to withstand damage by heat or impact.

M-2.6.3 They shall be reasonably gas-tight, although small openings for passage of pipes, conduits, etc, shall be permitted.

M-2.6.4 They shall extend down from the roof/ceiling for a minimum depth of 2.2 m. Around specific hazards, the depth shall be 4 m. Where roof/ceiling height exceeds 15 m they shall extend down to within 3 m of the floor. For pitched sawtoothed roofs, they shall extend down to truss level dividing the roof into compartments.

M-2.6.5 In moderate hazard occupancies, the distance between the screens/curtain boards shall not exceed 75 m and the curtained areas shall be limited to a maximum of 4 500 m².

M-2.6.6 In high hazard occupancies, the distance between screens shall not exceed 30 m and the curtained area shall be limited to 750 m $^{4}$ .

M-2.6.7 The curtained roof area shall be so arranged that they effectively aid in the venting of smoke and hot gases through the automatic vents provided in each area.

M-2.6.8 In sprinklered buildings, the screens shall preferably be so located as to coincide with the individual sprinkler system areas.

M-3 Explosion Relief Vents

M-3.1 Industrial premises where combustible dusts can accumulate or where flammable gases, vapours or mists in explosive concentrations may be present are constantly exposed to explosion hazards. Pressures developed by such explosions may be of the order of $7 \times 10^{5}$ Pa and ordinary buildings will not be able to withstand the shock of such pressures. Hence, such buildings require explosion relief vents for preventing structural damage.

M-3.2.1 Most ordinary building walls will not withstand a sustained internal pressure as great as $6.9 \times 10^{3}$ Pa. Hence, explosion relief vents for buildings must be designed to operate at pressures well below those at which the building walls will fail.

M-3.2.2 There is a rise in pressure during an explosion within an enclosure even with open, unobstructed vents, and any delay in opening the venting devices increases that pressure.

PART 4 FIRE AND LIFE SAFETY

M-3.2.3 Structural damage can be minimised by locating hazardous operations or equipment outside buildings and cut-off from other operations by a pressure resisting wall. Such isolated processes or equipment shall be housed in single-storey buildings properly vented and a device provided at the inlet of the collector which will prevent an explosion from blowing back through the duct work and into the building.

M-3.2.4 Where highly hazardous operations cannot be located outside of main buildings they shall be segregated by pressure resisting walls and each such unit shall be ventilated outdoors. External walls may be of heavy construction, if equipped with suitable vents or high weight panels which blow out easily.

M-3.2.5 Operations or equipment involving explosion hazards shall not be permitted in basements or areas partially below grade.

M-3.2.6 Fire can be expected to follow an explosion in most occupancies, so that any fixed fire extinguishing equipment, like sprinklers, if installed, shall be such that only the minimum damage is caused to it.

M-3.2.7 For a given material, the finer the particle size of the dust, the more violent is the explosion. Some materials, such as aluminium powder, hydrogen, and acetylene, are difficult to vent effectively due to the rapid rate of pressure rise. Some slow burning materials, such as coal dust in a confined space, may do much damage because of the longer duration of their presence. Some dusts, such as magnesium, titanium and zirconium and several metal hydrides may react with and ignite in some common inert gases, such as nitrogen and carbon dioxide.

M-3.2.8 The maximum explosion pressure in a vented structure decreases as the size of the vent increases, but is independent of the rupturing pressure of a diaphragm.

M-3.2.9 The most effective vent for the release of explosion pressures is an unobstructed vent opening.

M-3.2.10 Pressure required to rupture diaphragms of the same area and material directly varies with the thickness of the material.

M-3.2.11 The slower the rate of pressure rise, the more easily can the explosion be vented.

M-3.2.12 The degree of venting required is directly proportional to the degree of explosion hazard.

M-3.2.13 Experience has shown that most explosions of dusts, vapours and gases do not involve a large part of the total volume of the enclosure, and frequently occur near the upper or lower limits of the explosive range. Consequently, such explosions are relatively weak compared with the optimum.

M-3.2.14 Rectangular unrestricted vents are as effective as square vents of equal area.

M-3.3.1 The explosion relief vents shall be any one or more of the following types, depending on individual requirements as assessed by the Authority. Open or unobstructed vents, louvres, open roof vents, hanger type doors, building doors, windows, roof or wall panels or movable fixed sash.

M-3.3.2 The effect or external wind pressure or suction on these devices shall be taken into consideration while designing and selecting the type of vents, since wind pressures may reach over $2 \times 10^{5}$ Pa in severe wind storms.

M-3.3.3 The type of vent for explosion relief for any occupancy shall be selected with life safety as the primary aim followed by minimum damage to property.

M-3.3.4 Where large hanger type doors of metal curtain doors in side walls are used as vents, care shall be taken to ensure that they are kept wide open during operations.

M-3.3.5 Where weather hoods are used to cover roof vents, they shall be as light as possible and lightly attached so as to enable them to be blown off quickly when an explosion occurs.

M-3.3.6 Doors and windows when used as explosion vents shall be installed to swing outwards. Doors shall have friction, spring or magnetic latches that will function automatically to permit the door to open under slight internal pressure.

M-3.3.7 Movable sash shall be of the top or bottom hinged or protected type. These shall be equipped with a latch or friction device to prevent accidental opening due to wind action or intrusion. Such latches or locks shall be well maintained.

M-3.3.8 Fixed sash shall be set in place with very light wall anchorages, or, if tight, shall be securely fitted and glazed with plastic panes in plastic putty.

M-3.3.9 Where the process is such that the whole of a building or a room may be desirable to arrange for a lightly constructed wall or roof to collapse and thus avert the worst effects of an explosion.

M-3.4.1 The required area of explosion vents shall ordinarily depend on the expected maximum intensity of an explosion in the occupancy, the strength of the structure, the type of vent closure and other factors.

M-3.4.2 Venting shall be planned in such a manner as to prevent injury to personnel and damage to exposure.

e)

In congested locations, substantial ducts or diverters shall be provided to direct the blast.

M-3.4.3 When ductwork is used, the ducts shall be of sufficient strength to withstand the maximum expected explosion pressure.

M-3.4.4 Where explosions are likely within duct and piping systems, they shall be vented by the use of suitable diaphragms designed to blow out at a predetermined pressure. There shall be no physical connection between ductwork system for more than one collector.

M-3.4.5 In large structures, the position of vents shall be relative to the point of origin of explosion, when it can be determined.

M-3.4.6 Where relatively slow explosions involving coal dust, chlorinated solvents, etc, are involved, light, hinged swinging panels may be preferred to diaphragm type of vents.

M-3.4.7 Obstructions of any kind blocking the vents from the risk covered shall be avoided, particularly where risks of rapid violent explosions are present.

M-3.4.8 Counter weights add to the inertia of the vents and so shall be avoided.

M-3.4.9 Various relieving devices, including devices actuated by detonators, shall start to open at as low a pressure as possible. They shall be of light construction, so that full opening can be quickly attained.

M-3.4.10 Vents shall be of such size and design as to prevent rupture of the protected device or apparatus.

M-3.4.11 Skylights or monitors with movable sash that will open outwards, or fixed sash containing panes of glass or plastic that will blow out readily under pressure from within, can be used to supplement wall vents or windows, provided resistance to their displacement or opening is kept as low as consistent with the requirements for structural strength.

M-3.4.12 Flexible plastic sheets when used for vent closures shall be installed in slotted frames in such a way that pressure from within bulges the sheets and releases them from the holding frame.

M-3.4.13 Fragile sheets made of plastic, when used for vent closures, shall be thin sheets that will crack or rupture under less pressure than single strength glass. For this reason use of transparent or translucent plastic sheets is more advantageous than use of glass in window sash.

M-3.4.14 If closed vents are used they shall be larger

in area than unenclosed vents to provide equivalent explosion pressure relief.

M-3.4.15 Small enclosures, such as machines, shall be vented more generously than buildings, because if an explosion occurs in a machine, its entire volume may be involved.

M-3.4.16 Vents for the protection of buildings and equipment shall be installed on the following basis:

a) Small enclosures of less than $30 \, m^{3}$ , machines and ovens of light construction: $1\,000 \, cm^{2}$ for each $0.3 \, m^{3}$ to $0.9 \, m^{3}$ .

b) For small enclosures of more substantial construction having reasonably high bursting strength: $1\,000\,cm^{2}$ for each $0.9\,m^{3}$ .

c) Fairly large enclosures of 30 to $700\mathrm{m}^3$, such as bins, silos, rooms, storage tanks, etc: $1000\mathrm{cm}^2$ for each $0.9\mathrm{m}^3$ to $1.5\mathrm{m}^3$. In these cases, attempt shall be made to the extent possible to predict the likely point of origin of the explosion in relation to the vent.

d) Large rooms and buildings over $700\mathrm{m}^3$ containing hazardous equipment comprising a small fraction of the entire volume:

1. For heavy reinforced concrete, walls: $100\mathrm{cm}^2$ for each $2.25\mathrm{m}^3$.

2. For light reinforced concrete, brick or wood construction: 1 000 cm² for each 1.65 m³ to 2.25 m³.

3. For lightweight construction such as prefabricated panels: $1000\mathrm{cm}^2$ for each $1.5\mathrm{m}^3$ to $1.65\mathrm{m}^3$.

Large rooms or building over $700\mathrm{m}^3$ containing hazardous equipment comprising a large part of the entire volume of a room or building shall be vented as generously as possible: $1000\mathrm{cm}^2$ for each $0.3\mathrm{m}^3$ to $1.05\mathrm{m}^3$.

f) In order to obtain these ratios, the size of the building or room must be limited. For some hazardous materials, such as hydrogen, acetylene, carbon disulphide, etc, these limits are extremely low.

g) Emphasis shall always be placed on segregating hazardous areas by means of firewalls or separating walls to prevent spread of fire.

h) Interior walls of light construction, such as tile, shall be avoided in hazardous locations, since they can cause injuries to personnel in the event of an explosion.

PART 4 FIRE AND LIFE SAFETY

LIST OF STANDARDS

The following list records those standards which are acceptable as ‘good practice’ and ‘accepted standards’ in the fulfillment of the requirements of the Code. The latest version of a standard shall be adopted at the time of enforcement of the Code. The standards listed may be used by the Authority for conformance with the requirements of the referred clauses in the Code.

In the following list, the number appearing in the first column within parentheses indicates the number of the reference in this Part.

IS No. Title

(1) 3808 : 1979 Method of test for non-combustibility of building materials (first revision)

(2) IS/ISO 834-1 : Fire resistance tests — Elements of building construction Part 1 General requirements

S/ISO 834-4 : Fire resistance tests — Elements of building construction: Part 4 Specific requirements for load bearing vertical separating elements

IS/ISO 834-5 : Fire resistance tests — Elements of building construction: Part 5 Specific requirements for load bearing horizontal separating elements

IS/ISO 834-6 : Fire resistance tets — Elements of building constructions: Part 6 Specific requirements for beams

IS/ISO 834-7 : Fire resistance tests — Elements of building construction: Part 7 Specific requirements for columns

IS/ISO 834-8 : Fire resistance tests — Elements of building construction: Part 8 Specific requirements for non-load bearing vertical separating elements

IS/ISO 834-9 : Fire resistance tests — Elements of building construction: Part 9 Specific requirements for non-load bearing ceiling elements

(3) 8757 : 1999 Glossary of terms associated with fire safety (first revision)

7673 : 2004 Glossary of terms for fire fighting equipment (first revision)

(4) 8758 : 2013 Code of practice for fire precautionary measures in construction of temporary structures and pandals (second revision)

(5) 9668 : 1990 Code of practice for provision

IS No. Title and maintenance of water supplies and fire fighting

3844 : 1989 Code of practice for installation and maintenance of internal fire hydrants and hose reels on premises (first revision)

(6) 1646 : 2015 Code of practice for fire safety of buildings (general) : Electrical installations (third revision)

(7) 9457 : 2005 Code of practice for safety colours and safety signs (first revision)

12407 : 1988 Graphic symbols for fire protection plans

(8) 11360 : 1985 Specification for smoke detectors for use in automatic electrical fire alarm system

(9) 655:2006 Specification for air ducts

(10) 1649 : 1962 Code of practice for design and construction of flues and chimneys for domestic heating appliances (first revision)

1642 : 2013 Code of practice for safety of buildings (general): Details of construction (second revision)

(11) 12777 : 1989 Method for classification of flame spread of products

(12) 1642 : 2013 Code of practice for safety of buildings (general): Details of construction (second revision)

(13) 16246 : 2015 Elastomer insulated cables with limited circuit Integrity when affected by fire — Specification

(14) 6044 (Part 1): Liquefied petroleum gas storage installations — Code of Practice : Part 1 Residential commercial and industrial cylinder installations

6044 (Part 2) : Code of Practice for liquefied petroleum gas storage 2001 Installations: Part 2 Commercial, industrial and domestic bulk storage installations

(15) 2175 : 1988 Specification for heat sensitive fire detectors for use in automatic fire alarm system (second revision)

IS/ISO 7240-5 : Fire detection and alarm 2003 systems: Part 5 Point-type heat detectors

IS/ISO 7240-7 : Fire detection and alarm systems: Part 7 Point-type smoke detectors using scattered light, transmitted light or ionization 2011

PART 4 FIRE AND LIFE SAFETY

PART 4 FIRE AND LIFE SAFETY

PART 5 BUILDING MATERIALS

BUREAU OF INDIAN STANDARDS

• FOREWORD
• ... 3
• 1 SCOPE
• ... 5
• 2 MATERIALS
• ... 5
• 3 SUSTAINABLE MATERIALS
• ... 5
• 4 NEW OR ALTERNATIVE MATERIALS
• ... 5
• 5 THIRD PARTY CERTIFICATION
• ... 6
• 6 USED MATERIALS
• ... 6
• 7 STORAGE OF MATERIALS
• ... 6
• 8 METHODS OF TEST
• ... 6
• LIST OF STANDARDS
• ... 6

National Building Code Sectional Committee, CED 46

This Code (Part 5) lists Indian Standard specifications for materials used in building construction. The Indian Standards for methods of tests, to ensure the requirements demanded of the materials in the various situations, are also included. This is with a view to ensuring the quality and effectiveness of building materials used in the construction and of their storage, which are as important as other aspects of building activity like planning, designing and constructing the building itself.

Historically, choice of building materials was determined by what was locally available, appropriateness to geoclimatic conditions and affordability of users. In the recent past, different initiatives have been taken in the areas of research and development, standardization, and development and promotion of innovative materials. A review of the recent trends indicates that the growth in the area of building materials covers emerging trends and latest developments in the use of wastes, mineral admixtures in cement and concrete, substitutes to conventional timber, composite materials and recycling of wastes, at the same time ensuring desired response of materials in relation to fire safety, long term performance and durability. In addition to these, nowadays, development of specific materials is being researched which may be structured and designed to meet needs to specially developed construction technologies in time to come, such as, for disaster prone areas or aggressive climatic and industrial situations.

To encourage use of appropriate materials, it may be desirable to have to the largest extent possible, performance oriented approach for specifications rather than prescriptive approach. The approach has been already adopted in some cases in development of standards, wherever found possible.

Indian Standards cover the requirements for most of the materials in use. However, there may be a gap between development of new materials and techniques of application and formulation of standards. It, therefore, becomes necessary for a Building Code to be flexible to recognize building materials other than those for which Indian Standards are available. This Part of the Code, therefore, since its first version, duly takes care of this aspect and explicitly provides for use of new or alternate building materials, provided it is proved by authentic tests that the new or alternative material is effective and suitable for the purpose intended. However, it is worthwhile that more and more emphasis is given to the satisfaction of performance requirements expected of a building material, so that a wide range of such new or alternate materials can be evaluated and used, if found appropriate.

As already emphasized, quality of material is quite important for their appropriate usage, whether it is a material for which an Indian Standard is available or a new or alternative material as defined in 4 of this Part of the Code. While continuing to emphasize on conformity of building materials to available Indian Standards, this Part recommends that the building regulating authority may also recognize the use of building materials conforming to other specifications and test methods (see 4.2), in case Indian Standards are not available for particular materials. Third party certification schemes available in the country for quality assurance of above materials can be used with advantage to ensure the appropriateness of these materials.

It is well recognized that buildings during their construction and subsequently in their operation consume lot of resources. The holistic approach for ensuring proper and sustainable developments is to take care of the concerned aspects affecting sustainability during the conceptualization, planning, design, construction, and operation and maintenance stages. The building material production, transportation and utilization assume a substantial component of the embodied energy that goes into a building. It is therefore important that sustainability of building materials is well understood and ensured in a building project. This Part of the Code recognizes this aspect and covers appropriate provision therefore.

This Part of the Code was first published in 1970 and subsequently revised in 1983 and 2005 as Part 5 of NBC 2005. The first and second revision of this Part incorporated an updated version of the list of Indian Standards given at the end of this Part of the Code. Also the list of building materials was completely revised to make it more user-friendly. This second revision of this Part, while basically retaining the structure of 2005 version of the Code, incorporates the following modifications:

PART 5 BUILDING MATERIALS

a) The clause on new/alternative materials has been extended to give examples of some potential new/alternative materials;

b) Recognizing the importance of sustainability in building construction and built environment, a new clause giving broad aspects relating to sustainable materials, has been added;

c) The list at the end of this Part has been updated to reflect the latest available Indian Standard specifications and methods of test.

d) In the above list, existing categories have been re-organized and some new categories have been added either under the existing principal categories or as separate principal categories. In the process, the categories such as, bricks, blocks and other masonry units; mortar (including sand for mortar); supplementary cementitious materials; mesh/net for mosquito/vector prevention; concrete door and window frame; other composite material doors and windows; fire check doors; stone flooring, etc, have been added.

e) The headings of some of the categories have been rechristened to more appropriately reflect the materials/products actually covered thereunder.

A reference to SP 21 : 2005 ‘Summaries of Indian Standards for Building Materials’ may be useful. This publication gives the summaries of Indian Standards covering various building materials, fittings and components except standards relating to paints.

All standards cross-referred in the main text of this Part, are subject to revision. The parties to agreement based on this Part are encouraged to investigate the possibility of applying the most recent editions of the standards.

For the purpose of deciding whether a particular requirement of this Part is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 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 Part.

PART 5 BUILDING MATERIALS

1 SCOPE

This Code (Part 5) covers the requirements of building materials and components, and criteria for accepting new or alternative building materials and components.

2 MATERIALS

Every material used in fulfillment of the requirements of this Part, unless otherwise specified in the Code or approved, shall conform to the relevant Indian Standards. A list of Indian Standard specifications as the ‘accepted standards’ is given at the end of this Part of the Code. At the time of publication of the Code, the editions indicated were valid. All standards are subject to amendments and revisions. The Authority shall take cognizance of such amendments and revisions. The latest version of the specification shall, as far as possible, be adopted at the time of enforcement of this Part of the Code.

3 SUSTAINABLE MATERIALS

Choice of building materials is important in sustainable design because of the extensive network of activities such as extraction, processing and transportation steps required for making a material, and activities involved thereafter till building construction and even thereafter. These activities may pollute the air, soil and water, as well as destroy natural habitats and deplete natural resources. One of the most effective strategies for minimizing the environmental impacts of material usage is to reuse existing buildings. Rehabilitation of existing building, and their shell and non-shell components, not only reduces the volume of solid waste generated and its subsequent diversion to landfills but also the environmental impacts associated with the production, delivery and use or installation of new building materials. However, the use of sustainable building materials is one of the best strategies in the pursuit of sustainable buildings.

An ideal sustainable building material is not only environment friendly but also causes no adverse impact on health of occupants, is readily available, can be reclaimed and recycled, and is not only made from renewable raw material, but also uses predominantly renewable energy in its extraction, production, transportation, fixing and ultimate disposal. Practically, this kind of ideal material may not be available and hence, when selecting sustainable materials, it may be

best to choose materials which fulfill most of these criteria. Sustainable building materials also offer specific benefits to the building owner and building occupants, such as, reduced maintenance/replacement costs over the life of the building; energy conservation; improved occupant health and productivity; lower costs associated with changing space configurations; and greater design flexibility.

The selection of sustainable building materials shall be made in accordance with Part 11 ‘Approach to Sustainability’ of the Code.

4 NEW OR ALTERNATIVE MATERIALS

4.1 The provisions of this Part are not intended to prevent the use of any material not specifically prescribed under 2. Any such material may be approved by the Authority or an agency appointed by them for the purpose, provided it is established that the material is satisfactory for the purpose intended and the equivalent of that required in this Part or any other specification issued or approved by the Authority. The Authority or an agency appointed by them shall take into account the following parameters, as applicable to the concerned new or alternative building material:

a) Requirements of the material specified/expected in terms of the provisions given in the standards on its usage, including its applicability in geo-climatic condition;

b) General appearance;

c) Dimension and dimensional stability;

d) Structural stability including strength properties;

e) Fire safety;

f) Durability;

g) Thermal properties;

h) Mechanical properties;

j) Acoustical properties;

k) Optical properties;

m) Biological effect;

n) Environmental aspects;

p) Working characteristics;

q) Ease of handling;

r) Consistency and workability;

s) UV resistance; and

t) Toxicity.

PART 5 BUILDING MATERIALS

Some of such new/alternative materials may be ferrocement, decorative concrete, polymer concrete, micro-concrete repair materials, dry-mix mortar, non-shrink grout, optical fibres, special materials for bunkers/blast resistant structures, artificial stones used in restoration of heritage structures, nanotechnology based advanced materials, aluminium composite panels, vermiculite based boards, exfoliated perlite, geopolymeric cement, pervious concrete, UPVC doors and windows, stainless steel insulated water tanks, etc.

For establishing the performance of the material/component, laboratory/field tests, and field trials, as required, and study of historical data are recommended. For sampling and frequency of tests for new or alternate materials, similar product standards shall be referred to.

The above materials would no longer be treated as new/alternative materials as soon as Indian Standards for the same are established.

4.2 Approval in writing of the Authority or an agent appointed by them for the purpose of approval of material, shall be obtained by the owner or his agent before any new, alternative or equivalent material is used. The Authority or their agent shall base such approval on the principle set forth in 4.1 and shall require that tests be made (see 8.1) or sufficient evidence or proof be submitted, at the expense of the owner or his agent, to substantiate any claim for the proposed material.

NOTE — For interpretation of the term ‘Authority’ (see also 8.1), the definition of ‘Authority having jurisdiction’ given in Part 2 ‘Administration’ of the Code shall apply.

5 THIRD PARTY CERTIFICATION

For ensuring the conformity of materials for which Indian Standards exist and for new or alternative building materials, to requisite quality parameters the services under the third party certification schemes of the Government, may be utilized with advantage.

6 USED MATERIALS

Utilization of used materials may not be precluded provided these meet the requirements of this Part for new materials (see Part 2 ‘Administration’ of the Code).

7 STORAGE OF MATERIALS

All building materials shall be stored on the building site in such a way as to prevent deterioration or the loss or impairment of their structural and other essential properties (see Part 7 ‘Construction Management, Practices and Safety’ of the Code).

8 METHODS OF TEST

8.1 Every test of material as required in this Part or by the Authority shall be carried out in accordance with the methods of test prescribed in relevant Indian Standards. In cases of methods of tests for which Indian Standards are not available, the same shall conform to the methods of tests issued by the Authority or their agent. A list of Indian Standard methods of test is given at the end of this Part of the Code as the ‘accepted standards’. Laboratory tests shall be conducted by recognized laboratories acceptable to the Authority.

8.1.1 The manufacturer/supplier shall satisfy himself that materials conform to the requirements of the specifications and if requested shall supply a certificate to this effect to the purchaser or his representative. When such test certificates are not available, the specimen of the material shall be tested.

Following are the Indian Standards for various building materials and components, to be complied with in fulfillment of the requirements of the Code.

In the following list, while enlisting the Indian Standards, the materials have been categorized in such a way as to make the list user friendly. In the process, if so required, some of the standards have been included even in more than one category of products, such as in the category based on composition as well as on end application of the materials. The list has been arranged in alphabetical order of their principal category as given below:

1. Aluminium and other light metals and their alloys

2. Bitumen and tar products

3. Bricks, blocks and other masonry building units

4. Builder's hardware

5. Building chemicals

6. Building lime and products

7. Clay and stabilized soil products

8. Cement and concrete (including steel reinforcement for concrete)

9. Composite matrix products (including cement and resin matrix products)

10. Conductors and cables

11. Doors, windows and ventilators

12. Electrical wiring, fittings and accessories

13. Fillers, stoppers and putties

14. Floor covering, roofing and other finishes

15. Glass

16. Gypsum based materials

PART 5 BUILDING MATERIALS

PART 5 BUILDING MATERIALS

IS No. Title

1838 Specification for preformed fillers for expansion joint in concrete pavements and structures (non-extruding and resilient type)

(Part 1): 1983 Bitumen impregnated fibre (first revision)

(Part 2): 1984 CNSL aldehyde resin and coconut pith

(Part 3): 2011 Polymer based

10566 : 1983 Methods of tests for preformed fillers for expansion joint in concrete paving and structural construction 11433 Specification for one grade polysulphide based joint sealant

(Part 1): 1985 General requirements

(Part 2): 1986 Methods of test 12118 Specification for two parts polysulphide based sealants

(Part 1): 1987 General requirements

(Part 2): 1987 Methods of test