TECHNICAL COMMITTEE: NATIONAL BUILDING CODE SECTIONAL COMMITTEE, CED 46 ADDRESSED TO: 1. All Members of Civil Engineering Division Council, CEDC 2. All Members of National Building Code Sectional Committee, CED 46 and Panel for Sustainability, CED 46:P19 3. All others interests. Dear Sir/Madam, Please find enclosed the following draft: Doc. No. Title CED 46(7830) Draft Amendment No. 1 to National Building Code of India 2005 (SP 7:2005) (to incorporate a new Part 11 Approach to Sustainability) Kindly examine the draft and forward your views stating any difficulties which you are likely to experience in your business or profession if this is finally adopted as Part of the National Building Code of India. Last Date for comments: 15 March 2013 . Comments if any, may please be made in the format as attached, and mailed to the undersigned at the above address. You are requested to send your comments preferably through e-mail to [email protected]. In case no comments are received or comments received are of editorial nature, you may kindly permit us to presume your approval for the above document as finalized. However, in case of comments of technical nature are received then it may be finalized either in consultation with the Chairman, Sectional Committee or referred to the Sectional Committee for further necessary action if so desired by the Chairman, Sectional Committee. This document is also hosted on BIS website bis.org.in. Thanking you, Yours faithfully, (D.K. Agrawal) Sc ‘F’ and Head (Civil Engg) Encl: as above Telefax: 011 23235529 DRAFT IN WIDE CIRCULATION Reference Date CED 46/T-24 07 December 2012 FORMAT FOR SENDING COMMENTS ON THE DOCUMENT [Please use A4 size sheet of paper only and type within fields indicated. Comments on each clause/sub-clause/ table/figure, etc, be stated on a fresh row. Information/comments should include reasons for comments, technical references and suggestions for modified wordings of the clause. Comments through e-mail to [email protected] shall be appreciated.] Doc. No.: CED 46(7830)WC BIS Letter Ref: CED 46/T-24 Dated: 07 December 2012 Title: Draft Amendment No. 1 to National Building Code of India 2005 (SP 7:2005) (to incorporate a new Part 11 Approach to Sustainability) Name of the Commentator/ Organization: ______________________________________ Clause/ Para/ Table/ Figure No. commented Comments/Modified Wordings Justification of Proposed Change For BIS Use only Doc No. : CED 46(7830)WC December 2012 BUREAU OF INDIAN STANDARDS DRAFT FOR COMMENTS ONLY (Not to be reproduced without the permission of BIS or used as an Indian Standard/as an amendment to National Building Code of India) Draft AMENDMENT NO. 1 TO NATIONAL BUILDING CODE OF INDIA 2005 (SP 7:2005) Add a new part, Part 11 Approach to Sustainability, as enclosed. (CED 46) For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 1 Draft NATIONAL BUILDING CODE OF INDIA PART 11 APPROACH TO SUSTAINABILITY BUREAU OF INDIAN STANDARDS For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 2 IMPORTANT EXPLANTORY NOTE FOR USERS OF CODE In this part, where reference is made to `good practice’ in relation to design, constructional procedures or other related information, and where reference is made to `accepted standard’ in relation to material specification, testing, or other related information, the Indian Standards listed at the end of this section may be used as a guide to the interpretation. At the time of publication, the editions indicated in the above Indian Standards were valid. All standards are subject to revision and parties to agreements based on this section are encouraged to investigate the possibility of applying the most recent editions of the standards. In the list of standards given at the end of this part, the number appearing in the first column indicates the number of the reference in this part. For example: a) good practice [11(3)] refers to the Indian Standard given at serial number (3) of the above list given at the end of this Part 11, that is IS 456:2000 Code of practice for plain and reinforced concrete (fourth revision) b) accepted standard [11(7)] refers to the Indian Standard given at serial number (7) of the above list given at the end of this Part 11, that is IS 9142:1979 Specification for artificial light-weight aggregates for concrete masonry units. c) accepted standard [11(10)] refers to the Indian Standard given at serial number (10) of the above list given at the end of this Part 11, that is IS 1725:1982 Specification for soil-based blocks used in general building construction d) good practices [11(11)] refers to the Indian Standards given at serial number (11) of the above list given at the end of this Part 11, that is IS 401:2001 Code of practice for preservation of timber (fourth revision) and IS 1141:1993 Code of practice for seasoning of timber (second revision) For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 3 C O N T E N T S FOREWORD 1 SCOPE 2 TERMINOLOGY 2.1 to 2.38 3 APPROACH TO SUSTAINABILITY 3.1 The Need for Sustainable Development 3.2 Elements of Sustainability 3.3 Life Cycle Sustenance 3.4 Technology Options 3.5 Energy Efficient Design and Processes 3.6 Reduced Embodied and Operational Energy 3.7 Integrated Water Management 3.8 Operation and Maintenance of Services 3.9 Monitoring Compliances 3.10 Corporate Governance 3.11 Disaster Preparedness 4 APPLICABILITY OF THIS PART 5 IMPLEMENTATION OF THIS PART 6 SITING, FORM AND DESIGN 6.1 General 6.2 Site Design and Development 7 EXTERNAL DEVELOPMENT AND LANDSCAPE 7.1 Landscape Design 7.2 Rainwater Harvesting 7.3 Water Elements and Irrigation Practices 7.4 External Access Design 7.5 External Lighting Design 8 ENVELOPE OPTIMIZATION 8.1 Building Envelope 8.2 Envelope Optimization Methods 8.3 Renewable Energy Integration in Envelope 9 MATERIALS For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 4 9.1 General 9.2 Materials and Recommended Sustainable Alternatives 9.3 Construction Phase Material Storage and Handling 9.4 Construction Waste Management 10 WATER AND WASTE MANAGEMENT 10.1 General 10.2 Planning and Design of Water Management System 10.3 Planning and Design of Waste Water System 10.4 Water and Waste Management During Construction 10.5 Process Water Requirement and Effluent Treatment 10.6 Planning and Design of Solid Waste Management System 10.7 Integrated Approach to Water Supply, Water Waste and Solid Waste Management 11 BUILDING SERVICES OPTIMIZATION 11.1 General 11.2 Concept Development 11.3 Natural and Mechanical Ventilation Strategies 11.4 Passive Heating Techniques 11.5 Passive Cooling Techniques 11.6 Pre-Cooling of Ventilation Air 11.7 Low Energy Mechanical Cooling Techniques 11.8 HVAC System 11.9 Electrical System 11.10 Lighting 11.11 Lifts and Escalators 11.12 Good Installation Practices 11.13 Commissioning and Handing Over 11.14 Operation and Maintenance 11.15 Ongoing Performance 11.16 Renewable Energy 12 CONSTRUCTIONAL PRACTICES 12.1 Pre-Construction Pre-requisites 12.2 Planning for Construction 12.3 Preparation of Construction Management Plan 12.4 Planning, Monitoring and Control of Environmental Descriptors 12.5 Work Execution Procedures 12.6 Effective Use of Water 12.7 Construction Waste Management 12.8 Post-construction Closeout 12.9 Heritage Buildings and New Construction 12.10 Alternate Use, De-construction, Dismantling and Demolition 12.11 Disaster Risk Mitigation during Construction For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 5 13 COMMISSIONING, OPERATION, MAINTENANCE AND BUILDING PERFORMANCE TRACKING 13.1 General 13.2 Commissioning and Handover 13.3 Operation and Maintenance 13.4 Building Performance Tracking (Measurement and Verification) 13.5 Operator Skills and Training 13.6 Control-System Maintenance ANNEX A DESIGN STRATEGIES AS PER CLIMATE ZONES FOR VARIOUS SEASONS ANNEX B PRESCRIPTIVE METHOD FOR ENVELOPE OPTIMIZATION ANNEX C TRADE-OFF METHOD FOR ENVELOPE OPTIMIZATION ANNEX D WHOLE BUILDING ANALYSIS METHOD FOR ENVELOPE OPTIMIZATION LIST OF STANDARDS For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 6 BUREAU OF INDIAN STANDARDS WIDE CIRCULATION DRAFT (FOR COMMENTS ONLY) (Not to be reproduced without the permission of BIS or used as an Indian Standard/as a Part of National Building Code of India) Draft NATIONAL BUILDING CODE OF INDIA: PART 11 APPROACH TO SUSTAINABILITY (Draft SP 7: 2005 - Part 11) ICS: 0.120; 91.040.01 National Building Code Last Date for Comments Sectional Committee, CED 46 15 March 2013 FOREWORD Ancient civilizations used to build edifices using locally available materials, with great skill, and in harmony with nature. Basham in ‘The Wonder that was India’ describes how palaces in Mauryan dynasty in second century B.C., were exquisitely built from carved wood of local deodars. In later years the monasteries, temples and dharmashalas were built with locally available stones; these have withstood the ravages of time. Edwin Arnold in ‘The Light of Asia’ describes Vishramvan, the palace built with local marble and alabaster for prince Siddharth. The epic Mahabharata describes palace built by Vishwakarma. Kashi Vishwanath Temple in Varanasi, was built more than a thousand years ago. Many other ancient monuments in all parts of India are classic examples of sustainable buildings. The Taj Mahal, built more than four hundred years ago, can accommodate 10 000 people with no suffocation, as the stone jalis in the facia induce air movement and enable natural ventilation. The fort in Mandu has elaborate rain water harvesting techniques. Havelis in northern India were invariably built around a central courtyard, which brought day light in all nooks and corners, but the heat was kept out. Many forts and havelis have elaborate provision for evaporative cooling, using khas-screens and rain water stored at higher plateaus. Sustainable building has been the way of life in India. Less than a hundred years ago, industrial revolution came to India and changed many of these traditional sustainable practices in Indian buildings. The insatiable thirst for progress and comfort-at-any-cost, altered the equation with nature for ever. Concrete, steel, glass and later plastics became the dominant construction materials, beyond stone and wood of yesteryears. Power supply, artificial lighting, water supply and disposal, and thermal environmental control within built environment, were desired and obtained. For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 7 The new civilizations grew along the river banks, always regarding rivers as sacred. With the industrial revolution, untreated water, effluents from chemical industries and organic waste were discharged into rivers and water bodies, destroying our precious sources of water for domestic use. In addition, the unsustainable development of buildings and industries have led to huge construction waste and solid waste during their operation, which today have become a major problem. Modern buildings in India consume about 25 to 30 percent of total energy, and up to 30 percent of fresh potable water, and generate approximately 40 percent of total waste. India is now entering the phase of rapid urbanization. Various studies indicate that by 2050, the built foot print of India may become four times the current mass, which may pose a major challenge in preserving our fragile environment. Although the present energy consumption per capita in India is a fraction of that of most developed nations, but with its projected growth, unless enough measures are taken, it may lead to acceleration of environment degradation, contributing to increased carbon footprint leading to global warming and climate change. Sustainable buildings have demonstrated reduction in energy and water consumption to less than half of the present consumption in conventional buildings, and complete elimination of the construction and operational waste through recycling. The Indian way of life is aparigraha (minimum possession), conservation (minimum consumption) and recycling (minimum waste). These three attributes are the guiding principles for sustainable buildings as well. With these attributes and its rich heritage, India can make a substantial contribution in this field and eventually lead the world on the path of sustainability. Developed nations’ approach to sustainability generally concentrates on energy conservation through high technology innovations, and use of products, materials and designs with lower embodied energy. Their green ratings are based on intent, which implies expert inputs and simulation. Indian construction industry will do better using our traditional wisdom and practices, building in harmony with nature through regional common knowledge, consuming as little as necessary, applying low cost technology innovations, using recycled materials, and recognizing performance (not intent) through easily measurable parameters wherever feasible. Aiming towards such objectives, the National Building Code Sectional Committee, CED 46 reviewed the present contents of the Code. The Sectional Committee observed that, in the Code, due considerations have been given to these important dimensions in building planning, design and construction and during operation through provisions of effective utilization of natural light and ventilation; increased use of renewable energy, material selection including recyclability and reusability aspects; use of low gestation plantations and agriculture and industrial wastes; design approach; proper management practices; efficient electrical and other building services and plumbing services; energy conservation; rain water harvesting; etc. All these have been duly interwoven throughout the Code addressing both the embodied energy and the operational energy involved, as also showing sensitivity towards the concerns such as ozone depletion, global warming, etc. The Committee, however, felt that in keeping with the present needs as well as likely future scenario, For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 8 it may be appropriate to completely review all such aspects and give them a special and separate identity in the form of Part 11 of the Code covering sustainability approach to buildings. This Part 11 ‘Approach to Sustainability’ provides a comprehensive set of requirements, intended to reduce the negative impact of buildings on the natural environment. It can be readily used by the owners, developers/builders, architects, engineers, building services engineers and other building professionals as well as by manufacturers of building materials apart from the Authorities concerning land and building development, government and private construction agencies and academic and research institutions. The intent of this Part is to highlight sustainability measures including those referred to in different Parts/Sections of the Code as may be required as well as to define comprehensive sustainability standards for the building construction and related built environment. The approach to sustainability is founded on principles consistent with this Code, to adequately protect public health, safety and welfare and to provide requirements that do not unnecessarily increase construction cost nor restrict the use of new materials, products or methods of construction. The benefits of incorporating measures listed in this Part 11 are not only environment friendly, but also result in much better health and productivity of occupants, at minimal additional initial cost over the cost of conventional buildings, while substantially reducing the life cycle cost. This minimal additional cost is offset during a few years usage of the buildings, and vast advantage in cost is accrued during the life cycle of the building. The measures of sustainable buildings described in this Part of the Code set performance thresholds and incorporate features that allow Authority to customize requirements according to local geographical conditions, environmental priorities and agenda. These are not specific to any rating system and are not intended to provide a single metric indication of overall building performance. The flexibility of these provisions allows the practitioners to easily exercise their engineering judgment in holistically and objectively applying the underlying principles of sustainability to a development or building facility, considering its functionality and required comfort level. The information contained in this Part has been brought in coherence with the provisions contained in other parts of the Code, as also the concerned Indian Standards on various areas. In preparation of this Part, efforts have been made to take into cognizance the various latest applicable practices followed in the country and abroad, relevant to sustainability in buildings. This has been done by taking into consideration the publications of the American Society for Heating, Refrigeration, Air-conditioning Engineers; Bureau of Energy Efficiency, India; Indian Green Building Council; Indian Society for Heating, Refrigeration, Air-conditioning Engineers; International Organisation for Standardisation; and The Energy and Resource Institute. For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 9 WIDE CIRCULATION DRAFT (FOR COMMENTS ONLY) (Not to be reproduced without the permission of BIS or used as an Indian Standard/as a Part of National Building Code of India) Draft NATIONAL BUILDING CODE OF INDIA: PART 11 APPROACH TO SUSTAINABILITY (Draft SP 7: 2005 - Part 11) ICS: 0.120; 91.040.01 National Building Code Last Date for Comments Sectional Committee, CED 46 15 March 2013 1 SCOPE 1.1 This Part covers the parameters required to be considered for planning, design, construction, operation and maintenance of buildings and relating to land development from sustainability point of view. 1.2 This Part is a supplement to all other Parts/Sections of the Code and shall be read along with the same. 2 TERMINOLOGY 2.0 For the purpose of this Part, the following definitions shall apply. 2.1 Authority Having Jurisdiction – The authority which has been created by a statute and which, for the purpose of the Code/Part, may authorize a committee or an official or an agency to act on its behalf; herein after called the authority. 2.2 Biodiversity – The variability among living organisms from all sources including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within spaces, between species, and of ecosystems. 2.3 Building Environment – The surrounding in which a building operates, including air, water, land, natural resources, flora, fauna, human beings and their inter-relations. 2.4 Building Performance – Ability of a building to fulfil required functions under intended use conditions or behaviour when in use. For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 10 2.5 Built Environment – The collection of man-made or induced physical objects located in a particular area or region. NOTE – When treated as a whole, the built environment typically is taken to include buildings, external works (landscape areas), infrastructure and other construction works within the area under the consideration. 2.6 Disaster – It is a catastrophe, mishap, calamity or grave occurrence in any area, arising from natural or man-made causes, or by accident or negligence which results in substantial loss of life, or human suffering or damage to, and destruction of, property or damage to or degradation of environment, and is of such a nature of magnitude as to be beyond the coping capacity of the community of the affected area. 2.7 Ecosystem – Community of biological organisms and their physical environment, functioning together as an interdependent unit within a defined area. NOTE – For the purpose of this definition, humans, animals, plants, and micro-organisms are individually all considered biological organisms. 2.8 Embodied Energy – The sum total of energy that is used to extract, process, package, transport and install the material in the building. NOTE – Embodied energy data is often collected using input and output analysis. 2.9 Emissivity (E) – It is the ratio of the rate of heat emitted by a surface as compared to that of an absolutely black surface under similar conditions. It varies with the temperature of the emitting surface. 2.10 Environmental Impact – Any change to the environment, whether adverse or beneficial, wholly or partially, resulting from environmental aspects of a building. 2.11 Green Roof System – An assembly that supports an area of planting/landscaping, built up on a waterproofed substrate at any level that is separated from the natural ground by a human made structure. 2.12 Heat Island Effect – A phenomenon in which urban air and surface temperature are higher than nearby rural areas due to the replacement of natural land cover with pavement, building, and other infrastructure. 2.13 Horizontal Sun Angle (HSA) – The horizontal angle between the normal of the window and the Sun azimuth angle at a given time (see Fig. 1). For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 11 FIG. 1 HORIZONTAL AND VERTICAL SOLAR ANGLE FORMULATION 2.14 Indoor Air Quality (IAQ) – The nature of air in the area where one works or lives that affects the health and well being of building occupants. 2.15 Indoor Environment Quality (IEQ) – The condition or state of the indoor environment. 2.16 Life Cycle Assessment (LCA) – A method of evaluating a product by reviewing the ecological impact over the life of the period. NOTE – At each stage, the product and its components are evaluated based upon the materials and energy consumed, and the pollution and waste produced. Life stages include extraction of raw materials, processing and fabrication, transportation, installation, use and maintenance, and reuse/recycling/disposal. 2.17 Non-Renewable Source – Resource that exists in a fixed amount that cannot be replenished on a human time scale. NOTE – Non-renewable resources have the potential for renewal only by the geological, physical and chemical processes taking place over hundreds of millions of years. Non-renewable resources exist in various places in the earth’s crust. Examples include iron ore, coal, and oil. 2.18 Renewable Resource – A resource that is grown naturally, can be replenished, or cleansed. NOTE – Sustainable use of renewable resource implies that the rate of growth, replenishment, or cleansing takes place at a rate equal to or greater than the current rate of For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 12 depletion of that resource. Examples include trees in forest, grasses in grassland, and fertile soil. 2.19 Reuse – Using a material, product or component of the waste stream in its original form more than once. 2.20 Recycling – Process to turn the materials, that would otherwise become waste, into valuable resources. 2.21 Skylight Roof Ratio (SRR) – The ratio of the total skylight area of the roof, measured to the outside of the frame, to the gross exterior roof. 2.22 Solar Heat Gain Coefficient (SHGC) – The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward through conduction, convection and radiation (see Fig. 2). FIG 2 MECHANISM OF SOLAR HEAT GAIN 2.23 Solar reflectance index (SRI) – A measure of material’s ability to reject solar heat, as shown by a small temperature rise. NOTE – SRI of standard black surface (having reflectance of 0.05 and emittance of 0.9) and a standard white surface (of reflectance 0.8 and emittance 0.9) are taken as 0 and 100 respectively. 2.24 Sustainability – The state in which components of ecosystem and their functions are maintained for the present and future generations. NOTES 1. Sustainability is the goal of sustainable development and can result from the application of the concept of sustainable development. 2. In building construction, it relates to how attributes of activities, materials/products or services used in construction work, or use of construction works, contribute to the maintenance of ecosystem components and functions for future generations. 3. While the challenge of sustainability is global, the strategies for sustainability in building construction are local and differs in context and content from region to region. For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 13 4. ‘Components of ecosystem’ includes plants and animals, as well as humans and their physical environment. For humans, this includes a balancing of key elements of human needs namely the economic environmental, social and cultural conditions for societies’ existence. 2.25 Sustainable Buildings – A building that provides the specified building performance requirements while minimizing disturbance to and improving the functioning of local, regional, and global ecosystem both during and after its construction and specified service life. NOTE – A sustainable building optimizes efficiencies in resource management and operational performance; and, minimizes risks to human health safety and the environment. 2.26 Sustainable Development – Development that meets the need of the present without compromising the ability of future generations to meet their own. 2.27 Thermal Absorptivity – A factor indicating the relative amount of radiation absorbed by a surface as compared to an absorbing black body under the same conditions. Its value is dependent upon the temperature of the source and of the receiving surface. 2.28 Thermal Capacity – The amount of heat necessary to raise the temperature of a given mass by 1 ºC. Numerically, the thermal capacity per unit area of surface is the sum of the products of the mass per unit area of each individual material in the roof, wall or floor surface multiplied by its individual specific heat. 2.29 Thermal Conductance (C) – The thermal transmission of a single layer structure per unit area divided by the temperature difference between the hot and cold faces. It is expressed in W/m 2 K (Watt per square meter-degree Kelvin). NOTE – Thermal conductance is a measure of the thermal transmission per unit area through the total thickness of the structure under consideration. Thermal conductivity on the other hand refers to unit thickness of material. Further, this term applies only to a single layer of material and not to a composite insulation or to a structure made up of several layers of materials or medium. 2.30 Thermal Conductivity (K) – The quantity of heat in the steady state conditions flowing in unit time through a unit area of a slab of uniform material thickness of infinite extent and of unit thickness, when unit difference of temperature is established between its faces unit is W/mK (Watt per meter-degree Kelvin). NOTE – Thermal conductivity is a characteristic property of a material and its value may vary with a number of factors, including density, porosity, moisture content, fibre diameter, pore size, type of gas in the material, mean temperature and outside temperature range. The conductivity value varies from 0.03 W//mk for insulators to 400W//mk for metals. Materials with lower conductivity are preferred, as they are better insulators and reduce the external heat gains from the envelope. 2.31 Thermal Reflectivity – The ratio of the reflected heat to that of the total heat incident on a surface at a certain mean temperature range. For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 14 2.32 Thermal Resistance (R) – Thermal resistance is reciprocal of thermal conductance. For a structure having plane parallel faces, thermal resistance is equal to thickness (L) of the structure divided by thermal conductivity (K). L R = ------- K NOTE – The usefulness of the quantity is that when heat passes in succession through two or more components of the building units, the resistance may be added together to get the total resistance of the structure. 2.33 Thermal Resistivity (1/k) – The reciprocal of thermal conductivity. It is expressed in mk/W. 2.34 Thermal Transmittance (U) – Thermal transmission through unit area of the given building unit divided by the temperature difference between the air or other fluid on either side of the building unit in steady state conditions. It is also called as U-value. Its unit is W/m 2 k. NOTE – Thermal transmittance differs from thermal conductance in so far as temperatures are measured on the two surfaces of a building unit in the latter case and in the surrounding air (or other fluid) of the material on the two sides, in the former case. Thermal conductance is a characteristic of the building unit whereas thermal transmittance depends on conductance and surface coefficients of the building unit under the conditions of use. 2.35 Vertical Solar Angle (VSA) – The angle that a plane containing the bottom two points of the window and the centre of the Sun makes with the ground when measured normal to the shaded surface (see Fig. 1). 2.36 Visual Light Transmittance (VLT) – The ratio of total transmitted light to total incident light. 2.37 Volatile Organic Compound (VOC) – The carbon compounds (excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate) which participate in atmospheric photochemical reactions. The compounds vaporize at normal room temperatures. 2.38 Waste – Substances or objects which the holder intends or is required to dispose off. 3 APPROACH TO SUSTAINABILITY 3.1 The Need for Sustainable Development Building construction, occupancy and additions/alterations including preventive and curative maintenance are always energy centric. Large amount of elementary form of energy in the form of water, natural materials, air, etc are consumed for the purpose. While, these elements and their use are inter-dependent and there is need for integrated approach of considering them all together in general design development For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 15 and construction practice, the approach towards utilizing them is independent of each other. With increasing urbanization and rapid rise in people’s economic level and consumption pattern in many parts of the country, there is an increasing trend to consume more natural resources per capita. This is evident from the aspirational lifestyles and resulting in changing tastes and expenditure patterns of individuals and societies. This is equally witnessed from modern construction trends and changing sky lines of cities. This is constantly putting tremendous pressure on fragile ecosystem by over exploitation of natural resources adversely affecting biodiversity of our planet. Realizing this fact, there are efforts for a changing approach towards nature initially from ‘humanization of nature’ to ‘naturization of human’ and more recently towards sustainable development. The concept is to ensure that every living being on earth will have equal opportunity to utilize the natural and man made resource for survival and to develop for mutual benefits for all time to come. The inclusive aspect of development will come into sharp focus while deciding on choices. To achieve this, it is important to accept major challenge in controlling and judiciously using natural resources to shrink ecological foot print, famously known as carbon foot print, a measure to understand our consumption patterns. The way to achieve this is by holistically planning our growth needs, one of which is construction and combining them with need based economy, but at the same time without compromising on functionality and essential comforts. The basic components of building facility, their inter-correlation, tradeoffs and effect on surrounding micro-climatic conditions have to be understood, to achieve the harmony between buildings and ecological surroundings. It is necessary to assess the association of various factors involved, rationalizing the impacts of construction on neighbourhoods or building micro-climatic conditions for sustainability of built environment. 3.2 Elements of Sustainability The generalized design process towards sustainability should comprise the following steps: a) Set the design parameters to be implemented above benchmarking standards given in this Code. b) Make the basic performance requirements and set standards, applicable/ selectively adaptable to the climatic zone and geological conditions in which the construction is proposed. c) Have deep understanding of requirements of performance and human comfort, considering building type and use, quality of building and plumbing services desired, etc in buildings. d) Question the need, identify their optimum levels in long term scenario, and take the design provisions to that level only. e) Ensure what is sustainable today, remains that way in decades to come, and ensure the required performance levels of systems designed. For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 16 f) Ensure that sustainability is not only in parts, but also a holistic effort. g) Make efforts to maximize the use of traditional wisdom in design, wherever applicable, as it represents the knowledge about the long-term behaviour of materials and technology and their strengths as well as weaknesses. h) While having an open approach, assess new materials and technologies for their long-term impact in the context of the country and its development priorities, before accepting them for use. i) Take decision making processes to measurable levels wherever feasible, in order to make judicious choices. j) Take the savings’ benchmark targets closer to the minimum consumption standards; undertake value engineering exercises for deciding among the options. This process emphasizes the requirement of bottom up approach which invariably considers microclimatic conditions around. NOTE – The ‘bottom up approach’ concentrates more on how little is consumed; pursue our understanding of sustainability; uses low technology innovations, materials and practices; recognizes performance to be more important than intent; and necessitates the use of common knowledge and common sense in design decisions. On the contrast, the ‘top down approach’ concentrates more on how much energy is saved; accepts the understanding of sustainability may not be developed indigenously more readily; uses high technology innovations, materials and practices; is driven by green brand and accompanying recognitions based on intent; and necessitates expert inputs and simulations. The design process itself can play a significant role in creating built environment respecting all principles of sustainable development. This has to take into account the various climatic zones like hot-dry, warm-humid, composite, temperate and cold climates as well as sun path movements and annual wind directions. This should also reflect the aspirational needs of barrier free environment by differently abled people including by people under various age groups. Functional requirements of buildings have to also measure up to the required comfort levels demanded for all types of user requirements. 3.3 Life Cycle Sustenance The process flow from concept, design, construction, commissioning, operation and maintenance, and also decommissioning and disposal at the end of useful life of structure, should be planned and important steps chalked out for sustainable development. This should also take care of possible reuse/recycle of materials/ components/structure or part thereof. 3.4 Technology Options The consequential building envelope to create harmonious development with neighbourhood and building environments poses one of the biggest challenges in selection of building materials, technologies and practices. It may be a combination of natural and manmade materials with least embodied energy and also leading to use of fast renewable resources. The trade-off between choice of the materials and For BIS Use only Doc No. : CED 46(7830)WC December 2012 Draft NATIONAL BUILDING CODE OF INDIA 2005: PART 11 APPROACH TO SUSTAINABILITY 17 technologies and their effect on environment has to be balanced. As a holistic approach, all efforts should be made towards: a) Encouraging and harnessing building materials out of agricultural, industrial and bio-wastes, which has an enormous scope. b) Encouraging indigenous environment-friendly and acceptable cost-effective technologies and practices in identifying and pursuing sustainable developments. c) Identifying and encouraging appropriate technologies for more research and development applications. d) Making building construction more indigenous, more adaptable to climatic zones of India and also executionable to achieve the basic provisions for sustainable development. e) Encouraging use of traditional technologies and local vernacular design and construction practices, which have stood the test of time which may be blended with the modern technology applications. 3.5 Energy Efficient Design and Processes All efforts need to be made towards optimum and efficient use of energy sources for life sustenance. The increasing thrust on using non-fossil fuel energy for all needs have to be given priority consideration. The tapping of renewable sources of energy for lighting, heating, cooling and ventilation needs, deserve special attention. For example, an improved day light factor will reduce the day lighting needs by means of supplementary lighting. India with over 95 percent of the clear design sky available, the design has to fully utilize the associated benefits. While deciding on the energy choices, life cycle cost analysis including tangible and intangible benefits should be made and not look at the onetime initial capital expenditure alone. 3.6 Reduced Embodied and Operational Energy All designs, materials and technologies, construction practices should be selected and employed aimed at reducing the overall embodied and operational energy involved in construction and operation of the built facility. 3.7 Integrated Water Management Considering an ever increasing demand for water, efforts are needed to substantially reduce water consumption in buildings. Integrated and sustainable water management focusing on least anthropogenic water discharge from human activities should be pursued. The use of water conserving fixtures, landscaping, rain water harvesting, aquifer recharging and waste-water recycling need to be given due consideration. 3.8 Operation and Maintenance of Services This should involve use of efficient building and plumbing services components and fixtures tailor-made to meet sustainability objectives and creating sufficient
Posted on: Fri, 31 Jan 2014 17:38:58 +0000
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