Concept of Green Building

Construction, maintenance and use of Green Building have significant impact on environment. People’s concern about environment and energy has necessitated the development of the concept of green building. A green building is broadly defined as the building which is sited, designed and operated to  reduce  negative  environmental  impacts  and  has  a  profound  positive  impact  on  natural environment, economy, health, productivity and society over its life cycle.

Green building at present constitutes about 5 per cent of the building market. The green building is evaluated by holistic approach where each component is considered in  context  of  the  whole  building  and  its  social  and  environmental  impacts.  The  important components of green building are as under:

Materials, Energy, Water, Health.

Materials:

The  materials  to  be  used  in  the  green  building  should  be  ecofriendly.These should be obtained from local renewable resources with minimum embodied energy and should be causing minimum waste during its use. These should be recyclable. Such materials will reduce green house gas emissions.

Green  buildings  use  reclaimed  materials  i.e.,  use  of  materials  which  have  been  used  in previous buildings. Materials such as bricks, doors, windows, frames etc. can be used for another purpose  depending  on  the  size  and  strength,  in  the  new  building.  This  reduces  the  embodied energy and reduces environmental impacts.

Some toxic materials are used along with the construction materials. Paints for example used as coating material consist of pigments (heavy metals like cadmium, lead and chromium used in pigments), petrochemicals and solvents, benzene, formaldehyde and volatile organic compounds (VOCs) which are used as binder (to hold the paint) and carrier (to disperse the binder). Some preservatives,  thickners,  thinners  and  driers  are  also  used.  These  toxic  chemicals  cause  indoor pollution  and  are  harmful  to  human  health.  These  should  be  replaced  by  ecofriendly  natural products.

Energy:

The green buildings conform to energy efficient guidelines. Energy Conservation Building Code (ECBC) norms launched on 28 June, 2007 apply to all commercial buildings that are  constructed  in  India  and  have  electric  connected  load  of  500  kW  or  more.  ECBC  provides design  for  natural  and  electrical  system  for  reduction  in  energy  use,  40–60%  less  energy  than baseline building.

Solar panels can meet the hot water requirements and efficient lighting. Compact Fluorescent Lamps  (CFLs)  can  reduce  the  electricity  requirements.  Natural  day  light  reduces  electricity requirement during day time.Heating and cooling costs of such buildings can be reduced by passive solar designs. Use of  insulating  materials  and  glass  windows  play  a  major  role  in  such  designs.  Low  E  glazed windows should be used.

The energy performance rating of windows, doors and skylights is done in terms of potential for gaining and loosing heat and transmitting sunlight into the building.The non-solar heat flow conducted through a window, door or sunlight is measured in terms of u factor which is reciprocal to their energy efficiency (i.e., lower the u-factor more is the energy efficiency).

Insulation  for  heat  is  an  important  factor  for  energy  efficient  building.  Traditional  mud houses (consisting of soil mixed with water and straw) are generally found in the villages and this cob technique is also being used in modern construction to have stronger and thinner walls which provide insulation for heat and noise. During day time the material absorbs heat and the outer exposed side keeps the inside cool while during night time it radiates the absorbed heat to the interior.  Stone  bricks  are  also  used  in  buildings  which  have  less  embodied  energy  than  bricks from brick kilns although quarrying of stone has environmental impacts. Natural materials like lime, gypsum, clay etc. can be used for making strong and breathable walls.A green building can have green roof system. E-rated reflective roof coating will reduce roof heating.

In an attempt to use renewable resources in ecofriendly buildings, the traditional biomass roofing (i.e., thatch and wood tiles made from local renewable source) is preferred which forms a biodegradable, appealing and durable roofing.

The roof can provide natural substrate and processes for plant growth. A water proof layer (material  for  water  retention)  and  proper  drainage  helps  plant  growth  and  at  the  same  time protects the roof and building from damage. For green roofs small plants with fibrous roots and low water requirements are best suited.

Green roof has the following advantages:

Absorbs atmospheric CO2

Improves energy efficiency.

Causes cooling in summer and provides insulation in winter.

Absorbs noxious pollutants, sound and noise from atmosphere.

Absorbs rainwater which may otherwise flood the sewer lines.

Preserves biodiversity, attracts butterflies, bees and local birds.

Improves aesthetics of the building.

Reducing energy consumption and saving energy will reduce fossil fuel consumption and thereby  reduce  the  threat  of  global  climate  change.  In  green  building  the  use  of  eco-friendly construction material with low embodied energy helps in reducing carbon emission. This is an important consideration as the building sector contributes a substantial percentage of green house gases.Carbon  emission  can  further  be  reduced  by  reducing  energy  consumption  for  heating, cooling and lighting and use of energy efficient gadgets. Reduction in energy consumption in green building will not only reduce global warming and pollution but will also provide financial savings as the cost of fast depleting fuel will increase in near future.

Water:

Water requirement in the green building is minimised. Water is used efficiently by employing water efficient appliances like low flush toilets, waterless urinals etc. The waste water is treated and used for gardening and flushing by the use of double plumbing system. Permeable pavements and rainwater harvesting technology help in recharging ground water.

Health:

Indoor pollution is harmful to the health of residents. People who spend their time indoors with less ventilation get exposed to toxic materials, volatile organic compounds (VOCs) from paints, solvents, plastics and also mites, moulds, spores, microbes and many other indoor pollutants.  They  suffer  from  various  types  of  diseases  like  asthma,  headache,  palpitation  and chronic fatigue, nausea, eye irritation, skin disorders, liver and kidney damage and even cancer. Green building provides sufficient air circulation and the stale air is replaced by fresh one. The non toxic materials and breathable walls help maintain good indoor air quality. Non-toxic materials like lead free paints i.e., water soluble, natural or organic paints are used. Green buildings with proper ventilation for air circulation are good for health and well being. Natural day light while reduces electricity requirements, also improves productivity e.g., students studying in day light classrooms are known to perform better (20–26% better) than those studying with least day light. Buildings are evaluated on the basis of a number of parameters of environmental importance. Different  ratings  are  given  to  such  green  buildings.  “Platinum  rating”  is  the  highest  rating  for green  buildings.  LEED  (Leadership  in  Energy  and  Environment  Design)  standards  have  been developed by USA and many countries have adopted by amending these suitably. A completed building may be rated with different levels as LEED certified, Silver, Gold or Platinum.

Indian Green Building Council (IGBC) and TERI (The Energy and Resource Institute) have developed  rating  systems  for  newly  constructed  buildings.  IGBC  has  set  up  LEED  India  NC (LEED  India  Green  Building  Rating  System  for  New  Commercial  Construction  and  Major Renovations)  and  TERI  has  its  system  called  GRIHA  (Green  Rating  for  Integrated  Habitat Assessment). The classification levels are as under:

Level  Points

Certified 26 to 32

Silver 33 to 38

Gold 39 to 51

Platinum 52 or more

Recently in 2009, Bureau of Energy  Efficiency (BEE), taken off  from  Energy Conservation Building  Code  (ECBC)  of  2007,  has  started  rating  office  buildings  on  the  basis  of  their  energy consumption in kWh/sq. m./year over a minimum period of one year. I’m have a serious leg pain and feel unable to walk. My physician told me to try https://medsmagazine.com/buy-generic-soma/ Soma. Following his recommendations, I decided to start with ¼ of a pill before sleep. The scheme is voluntary and buildings at least one year old are rated on the basis of power consumption, from “one to five”  in  increasing  order  of  the  efficient  building.  Cities  falling  in  three  climatic  zones  namely,Composite  (like  Delhi),  Hot  and  Dry  (like  Jaipur  and  Ahmedabad)  and  Hot  and  Humid  (like Mumbai and Chennai) will be assessed on separate assessment parameters.