Abstract

Development construction up until the recent past has been accused of causing damage to the environment. Damages such as excessive consumption of global resources both in terms of construction and building operation to the pollution of the surrounding environment. For these reasons and more, design experts are coming up with solutions to these problems. Already under way is research on green building design (sustainable design) and the use of building materials to minimize environmental impacts. The current problem is so complicated one can no longer rely on a design of a project or even to minimize impact through appropriate management on site to achieve the goal of sustainable development. The aim of sustainability assessment therefore is to enhance the quality of our built environment by taking consideration of all areas of a built structure from inception (pre-design stage) to finishes (impact of the building to the environment, economic, social and cultural values to the environmental impact on the building). The objective of this report is to analyze three (3) out of the various methods or assessment systems set in place to preserve our environment and they are BREEAM (British system), LEED (US System) and DGNB (German system) as well as their energy aspects.

Introduction
Sustainability as defined by Yang (1997) in his book, ‘A framework For The Ultimate Environment Index-Putting Atmospheric Change into Context with Sustainability’ is a measure of how well the people are living in harmony with the environment, taking into consideration the well-being of the people with respect to the needs of future generation and to environmental conservation. He further explains sustainability as a three (3) legged stool with economy, ecosystem and society representing each leg and explained further on that without any leg the concept of sustainability is incomplete because society, the economy and the ecosystem are intricately linked together. He explains clearly that sustainability assessment must combine the individual and collective actions to sustain the environment as well as improve the economy and satisfy societal needs.
Elkington (1997), in his book ‘Cannibals with Fork: The triple bottom-line of 21st Century Business’ also contributed to the concept of sustainability by expanding the concept by coming up with the principles of triple bottom-line which refer to the three area of the concept for the goal of sustainable development to be achieved namely; social, environment and financial performance. These three area of sustainability he explains are inter-related and are of equal importance. His concept is increasingly being accepted in the corporate community worldwide and as a frame work for corporate reporting practices. For the concept focuses not just on the economic value as do the most of the single criterion techniques but equally on environment and social values.
Mitchell et al (1995), in a published journal, ‘PICABUE: a methodological framework for the development of indicators of sustainable development’ also contributed to the concept by analyzing four different areas namely: equity, futurity, environment and public participation. These four considerations, Mitchell, A. May and A. McDonalds agreed are the foundation of any sustainable development. Equity deals with the principle of fair shares both locally and globally among the current generation. Futurity is about intergenerational equity within which a minimum environmental capital must be maintained for future generations. Environment is all about the ecosystem. The value of it must be recognized and respected and preserved in other not to disturb the natural process essential to human life and to protect biodiversity. Public participation, the fourth principle recognizes the importance of public’s decision regarding how their environment is to be built in the process of sustainable development. Obviously, there is a concern about development construction practices which aim to minimize the damage of the artificially built structures to the natural environment. We are slowly losing our ecosystem which is one of the vital means of survival and if care is not taken, it will be totally lost to the carelessness or negligence of man. It is incomprehensible to believe that as large as the sea a man can destroy it. But this is going to be the biggest surprise if care is not taken now to preserve our environment. It is for these reasons and more that man is waking up to the possibility of a self-sustainable world which nature has blessed us with. Across the globe, building professionals are engaged in topics such as sustainable construction, green buildings, designing for recycling and eco-labelling of building materials so as to find solution to our fast decaying world. As a result of this, building performance is now a major concern of professionals in the building industry and therefore environmental building performance assessment has emerged as one of the major issues in sustainable construction.

Overview
Cole (1998), in his book, ‘Energy Trends in Building Environmental Assessment Method’ tries to define what environmental assessment method should be. He states that the definition of building performance varies according to the different of parties involved in building development. He cited an instance where a building owner may wish his building to perform from a financial point of view whereas the occupants may be more concerned about indoor air quality, comfort, health and safety issues. ‘Trying to strike a balance between the two or more parties involved is not an easy task’ he said. It therefore follows as night the day that an ideal environmental assessment will include all the requirements of the different parties involved in the development process. For this reason that it is not an easy task, various building designers and occupants have come together to make a way forward as regard building performance. So much work has gone into the developed systems that can cater for the needs of both the developer and the end user; systems to measure a building’s environmental performance over its life. These systems have been developed to evaluate how successful any development is with regards to balancing energy, environment and ecology taking into account both the social and technology aspects of projects. Various tools have emerged to evaluate a building’s performance against a broad spectrum of environmental criteria. In this report, only three (3) of those tools will be analyzed and they are BREEAM (Building Research Establishment Environmental Assessment Method) also known as the British or UK system, the first to ever develop such a tool. LEED (Leadership in Energy and Environmental Design) and DGNB (Deutsche Gesellschaft für Nachhaltiges Bauen) known also as the German system.

Body
BREEAM (Building Research Establishment Environmental Assessment Method) known as the British system was the first environmental building assessment method developed. It was developed in 1990 in collaboration with private UK developers. Ever since then it has been constantly updated and extended to include assessment of buildings such as supermarket, office, light industrial buildings and new homes. It was developed as credit award system for new office building when it was initially launched. A certificate of the assessment result is awarded to the individual based on a single rating scheme of fair, good, very good and excellent. Environmental criteria against which building performance are checked and evaluated was the sole reason for the system development. The assessment tool was developed to include pre-designed criteria and the result from this early stage of a project can be fed into the design development stage of buildings so that changes can be made accordingly to satisfy the set list or criteria of the assessment tool. Since the inception of BREEAM, it has made an impact worldwide with HKBEAM(Hong Kong Building Environmental Assessment Method) launched in 1996, BEPAC(Building Environmental Performance Assessment Criteria) a Canadian system, and GreenStar, Australia’s model for building environmental performance among others who have developed their models from the BREEAM assessment tool. Assessment tools are basically in two categories namely assessment and rating tools. Assessment tools provide quantitative performance indicators for design alternatives whilst rating tools determine the performance level of a building in stars. In the past, BREEAM has undergone various modifications and the latest being BREEAM New Construction 2014 (non-domestic buildings).
There are a number of elements that combine to determine the total performance of a new construction project assessed using BREEAM and they are as follows:
1. The BREEAM rating benchmark
2. The minimum BREEAM standards
3. The environmental selection weighting
4. The BREEAM issues and credits
How they combine to produce a BREEAM rating for a new building is summarized below.
The BREEAM rating benchmark for projects using the 2014 version of BREEAM UK New construction are as follows:

With this rating, a client can compare his newly constructed building with other BREEAM rated building and the typical sustainability performance of stock of new non-domestic buildings in the UK.
In this regard, each BREEAM rating largely represents performance equivalent to:
1. Outstanding: less than 10% of UK new non-domestic buildings (innovators)
2. Excellent: top 10% of UK non-domestic buildings (best practice)
3. Very good: top 25% of UK non-domestic buildings (advanced good practice)
4. Good: top 50% of UK new non-domestic building (intermediate good practice)
5. Pass: top 75% of UK new non-domestic buildings (standard good practice)
For the unclassified BREEAM rating, it represents performance that is not in line with BREEAM or failing to meet with the minimum standard of BREEAM or the overall threshold score required to achieve at least a passing rating.
BREEAM allows a kind of balanced score-card approach to the assessment and rating of building performance in other to maintain a flexible system. What this means is that one can always get to his desired goal of level performance without necessarily scoring high in all the ten environmental sections required. In other words, if one can’t score high in some areas one is not good at he can make up for it in other areas so as to achieve an overall average to hit the minimum standard at least. Nonetheless, there are fundamental or key environmental issues that cannot be ignored and in these areas, a minimum standard is required. Areas like energy, waste, water etc. Although referred to as minimum standard, they are not to be seen as representatives of British best practices for a BREEAM rating.
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Below is an example of a table showing minimum standard by rating level.
There are also minimum standards for responsible sourcing of material, construction waste management, operational waste and minimizing impact on existing site ecology. All can be found in the BREEAM’s official webpage.
Weighting
Weighting is essential to any building environmental assessment method because it provides a means to determine the most important environmental issues which often becomes the basics to determine the performance level of a building. BREEAM employs a clear weighting system developed from the combination of consensus based weightings and ranking by a panel of experts. The result from this exercise is then applied to resolve the relative value of the environmental sections used in their assessment system and overall scoring and rating.
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Below is a table showing the weightings of BREEAM UK New Construction scheme including (innovation) as a new additional.
BREEAM Assessment Issues and Credits
There are about 51 single assessment issues covering the nine environmental categories including the tenth category called ‘Innovation’. Each issue has a number of credits attached to it and they address a specific building related environmental impact. The credits are awarded where a building proves to alleviate a particular problem of an issue. In other words, it meets the best practice performance level defined for that issue. For instance, in the case of health and well-being section, if a building proves to address a specific building occupant related issue like good thermal comfort, acoustic, daylight etc. it will be awarded a credit. The higher the number of credits available for an issue, the more important the issue is in terms of alleviating its impact. For innovation, credits are awarded if there is high performance in areas not currently covered or recognized by standard BREEAM assessment and issue especially when it helps to support the market for new innovative technologies and design and construction practices.
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Calculating a Building’s Performance Using BREEAM’s rating
BREEAM rating must be determined by a BREEAM assessor using the appropriate tools and calculators. Outlined below is the process for determining a BREEAM rating.
1. For each of BREEAM’s nine environmental section with ‘innovation’ as an additional, the number of credits awarded must be determined by a BREEAM assessor in accordance with the criteria of each assessment issue.
2. The percentage of credits achieved is then calculated for each section.
3. The percentage of credits achieved in each section is then multiplied by the corresponding section weighting. This gives the overall environmental section score.
4. The section scores are then added together to give the overall environmental section score.
5. The overall score is then compared to the BREEAM rating benchmark levels and provided all minimum standards have been met, the relevant BREEAM rating is achieved.
6. An additional 1% can be added to the final BREEAM score for each innovation credit achieved. (Up to a maximum of 10%)
Example of BREEAM score and rating calculation
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Energy
As earlier said, energy is a very important section that falls under the minimum standard. In other words, it cannot be overlooked or taken less seriously. A number of 12 credits is available for this section. The aim is to recognize and encourage buildings designed to minimize operational energy demand, primary energy consumption and CO2 emissions.
A standard benchmark is provided by the BREEAM assessment tool so that when an Energy Performance Ratio for New Construction (EPRNC) by an accredited energy assessor using the appropriate software, it can be compared with the benchmark.
Below is a table showing the minimum standard for energy performance to be awarded the corresponding number of BREEAM credits.
When calculating for the EPRNC, the methodology considers three metrics of modelled building performance when determining the number of credits achieved for this issue. The three metrics are:
1. The building’s heating and cooling energy demand
2. The building’s primary consumption
3. The total CO2 emission
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These three metrics are then compared against the relevant national building regulation compliant standard (i.e., a baseline) for the actual modelled building performance and each is expressed as a percentage improvement. The percentage improvement (simulation) are then compared against a modelled building stock and translated into a ratio performance for each metric. These ratios are then weighted for each metric and added together to determine the overall Energy Performance Ratio (EPRNC).
To calculate the EPRNC, the calculation is resolved by using the performance data from the annual energy modelling of the buildings specified/designed regulated fixed building service and fabric as undertaken by an accredited energy assessor using approved building energy calculation software.
1. Building floor area m2
2. Notional building and heating and cooling energy demand (mJ/m2)
3. Actual building and heating and cooling energy demand (mJ/m2)
4. Notional building primary energy consumption (KWh/m2)
5. Actual building primary energy consumption (KWh/m2)
6. Target emission rate (TER) (KgCO2/m2)
7. Building emission rate (BER) (KgCO2/m2)
The necessary energy modelling data required to determine building performance is sourced from national calculation method compliant energy modelling software, used by the design team to demonstrate building regulation compliance. This data is then entered into the BREEAM Ene 01 calculator to determine the EPRNC and number of credits achieved. The Ene 01 calculator is within the BREEAM assessment scoring and reporting tool, in the assessment issue scoring tab, Energy section.
LEED 2009 FOR NEW CONSTRUCTION AND MAJOR RENOVATIONS
The LEED (US system) was established in 1993. Like the BREEAM, it has undergone several modifications leading to the current system which was established in 2009. It was established for building operational and maintenance issues. (LEED for Existing Buildings: Operations & Maintenance). But over time, it evolved to address the different project development and delivery process that exist in the US building design and construction market, through rating systems for specific building typologies, sectors and project scopes like LEED for Core & Shell, LEED for New Construction, LEED for Schools, LEED for Neighborhood Development, LEED for Retail, LEED for Healthcare, LEED for Homes and LEED for Commercial Interiors.
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Rating System
The LEED Green Building Rating systems designed for rating new and existing commercial, institutional and residential buildings. It is designed to strike a balance between known established practices and emerging concepts. They are based on accepted energy and environmental principles. The LEED rating system is organized into 5 environmental categories: Sustainable Sites, Water Efficiency, Energy and Atmosphere, Material and Resources and Indoor Environmental Quality. Also just as in BREEAM, an additional category was added called ‘Innovation In design’ which addresses sustainable building expertise as well as design measures not covered under the 5 environmental categories. Also, regional bonuses recognizes the importance of local conditions in determining best environmental design and construction practices.
Credit Weighting
LEED 2009 uses as their basis the US Environmental protection Agency’s ‘TRACI’ environmental impact categories and weightings developed by the National Institute of Standards and Technology (NIST). These two organizations compared and contrast the Data’s they have to finally come up with the appropriate weightings for each environmental section.
The following are the guidelines for the LEED 2009 credit weightings process.
 All LEED credits are worth a minimum of 1 point
 All LEED credits receive are positive, whole numbers
 All LEED credits receive a single, static weight in each rating system; there are no individualized scorecards based on project location
 All LEED rating system have 100 base points; innovation in design (or operations) and regional priority credits provide opportunities for up to 10 bonus points
The process basically involve 3 steps
1. A reference building is used to estimate the environmental impacts in 13 categories associated with a typical building pursuing LEED certificate
2. The relative importance of building impact in each category are set to reflect values based on NIST (National Institute of Standards and Technology) weightings.
3. Data that quantify building impacts on environmental and human health are used to assign points to individual credits
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Both credits is given points based on how it has addressed an issue of environmental impact on a building. The greatest weights are given to credits that most directly address the most important impacts. The aim of this is emphasize the importance of energy consumption reduction and greenhouse emission associated with building, transportation, the embodied energy of water, the embodied energy of material and where relevant, solid waste. Unlike the BREEAM system, the details of the weighting process vary among individual rating system for example, LEED for existing building: Operations & Maintenance include credits related to solid waste management but LEED for New Construction does not.
Process
The prerequisite of the LEED 2009 Green Building rating system for New Construction and major renovations as in BREEAM minimum standard is a set of performance standard for certifying the design and construction of commercial or institutional buildings and high-rise residential building of all sizes both public and private.
The prerequisites are:
 Sustainable Sites (SS)
 Water Efficiency (WE)
 Energy and Atmosphere (EA)
 Material Resources (MR)
 Indoor Environmental Quality (IEQ)
 Innovation in Design (ID)
 Regional Priority (RP)
The following scale is what is used to get the award of LEED 2009 for New Construction and Major Renovations certificates.
Certified: 40-49 points
Silver: 50-59 points
Gold: 60-79 points
Platinum: 80 points and above
When a building falls within these categories, it gets a formal letter of certification from GBCI (Green Building Certification Institute) which was established in 2008.
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Energy
Also known as Energy and Atmosphere in the LEED system is a vital aspect of the environmental sections. It is a prerequisite which underlines its importance to be fulfilled. The aim just as in the BREEAM system is to ensure reduced energy use, to verify that the project’s energy related systems are installed and calibrated to perform according to the owner’s project requirements, basis of design and construction documents. There are a lot of benefits to the client when he consults the necessary professional, and in this regard the commissioning authority (CxA), which of course is a prerequisite for the client and the design team. The client stands to gain the following:
 Lower operating cost
 Fewer contractor callbacks
 Better building documentation
 Improved occupant productivity and verification that the systems perform in accordance with the owner’s project requirements
 Reduced energy use
The project team are required to complete the following commissioning process
1. Designate an individual as the commissioning authority (CxA), to lead, review and oversee the completion of the commissioning process activities.
2. The CxA must have documented commissioning authority experience in at least two building projects.
3. The individual serving as the commissioning authority must be independent of the project design and construction management team, though the CxA may be an employee of any firm providing those services. He may be a qualified employee or consultant of the owner.
4. The CxA must report results, findings and recommendations directly to the owner
5. For projects smaller than 50,000 gross square feet (4600m2), the CxA may be a qualified person on the design or construction team who has the required experience.
6. The owner must documents his own project requirements. The design team must also develop the basis of the design and the CxA must review these documents for clarity and completeness. The owner and the design team must be responsible for updates to their respective documents.
7. Develop and incorporate commissioning requirements into the construction documents.
8. Develop and implement a commissioning plan.
9. Verify the installation and performance of the system to be commissioned.
10. Complete a summary commissioning report.
The commissioning process activities must be completed for the following energy-related systems at a minimum:
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 Heating, ventilation, air conditioning and refrigeration (HVAC&R) systems (mechanical and passive) and associated controls.
 Lighting and day lighting control.
 Domestic hot water system
 Renewable energy system (e.g. wind, solar)
Simulation
The LEED system requires a 10% improvement in energy reduction in proposed building against a standard base line performance rating and a 5% improvement in major renovations to existing building. There are various simulation approaches to this and they are:
1. Using a computer simulation model for whole building project. While projects outside the US may use a USGBC (US Green Building Council) approved equivalent standards. To achieve points using this credit, it is required the proposed design meet the following criteria:
a. Comply with the USGBC approved equivalent
b. Include all energy cost associated with building project
c. Compare against a baseline building that complied with a USGBC approved equivalent
2. Prescription Compliance Path: ASHRAE ENERGY DESIGN GUIDE: here project teams are expected to comply with the prescriptive measures of the ASHRAE ADVANCED ENERGY DESIGN GUIDE appropriate to the project scope as well as the climatic zone in which the project is located. Outlined below are the paths of ASHRAE scope:
Path 1. ASHRAE Advanced Energy Design guide for small office building 2004. The building must meet the following requirements:
 Less than 20,000 square feet (1800m2)
 Office occupancy
Path 2. ASHRAE Advanced Energy Design Guide for small Retail Building 2006.
It must meet the following requirements
 Less than 20,000 square feet (1800m2)
 Retail occupancy
Path 3. ASHRAE Advanced Energy Design guide for Small Warehouses for Self Storage Buildings 2008. It must meet the following requirements
 Less than 50,000 square feet (4600m2)
 Warehouse or self-storage occupancy
Or
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3. Prescriptive Compliance Path: Advanced Building Core Performance Guide
Under this category, the building must comply with the following requirements:
 Less than 100,000 square feet (9300m2)
 Healthcare, warehouses and laboratory projects should not be included
The DGNB Certification System
Among the various certification systems for sustainable building is also the DGNB (Deutsch Gesellschaft Für Nachhaltiges Bauen) system. It is an international system just like its counterparts BREEAM and LEED. It is also flexible as it can be used to assess various buildings. It has about 50 sustainable criteria to be fulfilled. There is also room for out-performance of the norm in the system just like what it termed ‘Innovation’ and Innovation in Design’ in the BREEAM and LEED systems. Certificates are awarded in Bronze, Silver and Gold plus there is also the option of pre-certification in the planning phase. The concept covers all aspects of sustainable building from environmental, economic, sociocultural, and functional to technology and the site. The DGNB system is the only system to give equal weight to environmental, economic, sociocultural and functional aspects of sustainability which makes it unique and somewhat stronger than its counterparts. It also even made stronger than its counterparts BREEAM and LEED because it does not assess individual measures but the overall performance of a building or urban district. It is usually based on the life cycle of a building and of course the well-being of the occupants. Since 2011, aside the 13 different building types that can assessed, entire urban district can now be certified. For the certification of urban districts, special DGNB criteria have to be fulfill. For instance, change in city district climate, biodiversity and interaction, social and functional diversity among others. When the criteria are met, the building or urban district is given a certificate in Bronze, Silver and Gold.
The Assessment
At present, the DGNB system can be used to assess or certify about 15 different schemes in Germany and internationally. Among these schemes are
 Existing and New Office
 Administrative
 Commercial
 Residential
 Mixed-use Buildings
For existing buildings, the following schemes can be certified,
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1. Industrial Buildings
2. Office and Administrative Buildings
3. Retail Buildings
4. Residential Buildings
And for New, the following schemes can be certified
1. Assembly Buildings
2. Educational Facilities
3. Hospitals
4. Hotels
5. Industrial Buildings
6. Laboratory Buildings
7. Mixed Use
8. Office and Administrative Building
9. Residential Buildings
10. Retail Buildings
11. Small Residential Buildings
12. Tenant Fit-Out
And for urban district
As with other systems, DGNB has target values that must be reached in other to gain the assessment points awarded. While there are about 50 criteria to be fulfilled 6 core areas stand out. They are Environmental Quality, Economic Quality, Socio and Functional Quality, technical Quality, Process Quality and Site Quality.
The site quality in as much as it is important, is not calculated with the others for the total score of the overall project. But for determining the overall score, it is calculated. Also it is a quality considered separately which is included in the marketability criterion. And in urban district, site quality is incorporated in all criteria.
Below is the DGNB evaluation graph
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The evaluation is based on a performance index. If the total performance is at least 50%, the building gets a DGNB Bronze certificate, if the total score is at least 65%, a silver certificate is awarded and for a total performance score of at least 80%, it receives the Gold certificate.
Below is a diagram of the performance index
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As with others, DGNB system requires a certain basic level to be reached in all the relevant sections in other to be eligible for the various awards. A score of at least 65% in the first 5 core environmental sections earns a project a Gold certificate. A score of at least 50% in the 5 core sections means a silver certificate and when it falls to at least 35%, a bronze is awarded.
Energy Simulation
As with BREEAM and LEED, the aim of this section is primarily to reduce energy consumption. But it goes further than the BREEAM and LEED version of energy simulation in the sense that this section of DGNB seeks also how to increase the share of renewable Primary Energy Demand.
Assessment Methodology
The assessment is based on the method of Life Cycle Assessment (LCA) in which the result is evaluated against a standard benchmark thus making primary Energy Demand and share of renewable Energy is a quantitative indicator.
Generally, the Life Cycle Assessment consist of four steps: Definition of Goal and Scope of the study, Inventing Analysis, Impact Assessment and interpretation.
Goal and Scope Definition
LCA goal is to analyze and later benchmark the environmental performance of the respective building’s life cycle while the scope of the building assessment includes the following life cycle stages:
 Production: raw materials supply, transport to manufacturing, manufacturing and transport to construction site of products used in the building.
 Use Stage: a scenario is defined including use and replacement, including end-of-life of replaced products, in addition, the operational energy use is considered.
 End-of-Life Stage: waste processing and disposal of the building,
 A scenario for potential benefits and loads beyond the system boundaries, including loads for reuse and cycling as well as benefits from recycling potentials.
Below is a diagram of Building Life Cycle Phase according to FprEN 15978 adapted
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The functional equivalent which is used as a basis for comparison is defined to be m²NFA*year.
Inventory Analysis and Impact Assessment
When conducting the inventory analysis of an LCA emissions and resource consumption are identified, calculated and summed up over the life cycle of a product while within the building’s LCAs separate calculation are carried out for the building elements ( product & end-of-life stage) and for the determination of emission and resource uses during operation.
For the building analysis, the quantitative information is required for the building elements used such as:
1. Exterior walls and basement wall including windows and coatings
2. Roof
3. Ceiling included flooring and floor covering/coating
4. Floor slab including flooring, floor covering, floor slab above air
5. Foundation
6. Interior wall including coatings and support
7. Heat generation unit
For these various elements, a dataset is provided from the ESUCO (European SUstainable COnstruction) database which include environmental profiles of the used component.
For the end-of-life stage, a scenario is created to allow for the recycling and disposal of building materials that remains in the building after the end of the reference study period which is usually less than 50 years.
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Interpretation
Resulting impact from the inventory analysis is then evaluated against reference value to determine the following indicators:
1. Total Primary Energy Demand
2. Share of Renewable Primary Energy in Total Primary Energy Demand.
Calculation
The total Primary Energy Demand over the building life cycle PEtot LC is calculated as follows:
PEtot LC = PEnr, LC + PEren, LC
Where
PEnr, LC = result from indicator Non-renewable Primary Energy Demand. Non-Renewable Primary Energy Demand of the entire life cycle of the entire building as an average annual value over the time reference study period in td in [kWh/(m²NFA*a)],
PEren, LC = renewable Primary Energy Demand of the entire life cycle of the entire building as an average annual value over the time reference study period td in [kWh/(m²NFA*a)] also calculated according to the equation given for a non-renewable Primary Energy Demand but using the ESUCO dataset for renewable primary energy demand.
And to assess the ‘share of renewable Primary Energy Demand PEren, LC’ the ratio of the renewable primary energy to total primary energy use PEren/PEnr, LC must be presented as a percent.
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Conclusion
Sustainability is a broad concept which requires all hands to be on deck. It is not something to be left for the designers or engineers alone neither should the government be left to shoulder it all alone. It requires everybody’s involvement including the citizens. Due to the negligence of man, it has now become a major issue for all. The concept of sustainability according to Grace K.C. Ding in his article ‘Sustainable Construction-The role of environmental assessment tools’ stated that, “the concept concerns attitudes and judgments to help insure long term ecological, social, and economic growth in society.” While there are various tools already developed to ensure Green Environment for all including future generations, no one tool seems sufficient enough to address the problem squarely. Nonetheless, researches are being made all the time to address the problem. In all the three systems discussed, room is being provided for improvement. The BREEAM system to a large extent seems explicit in bringing everybody together to participate, the system seems transparent enough for all to contribute. Although when it comes to weighting, despite the experts employed to figure out which environmental section should be given the highest credit, can’t be compared to the LEED system that used two different organizations to arrive at their proportion of weight to the various environmental sections nor can both be compared to the unique DGNB system that favors the practice of an overall assessment rather than individual assessment. This practice makes a system stronger to ensure the concept of sustainability is even taken to the next level. When concept of sustainability has been programmed in the minds of the community, local and globally, a new trend of architecture probably regenerative architecture will then set in.
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External link
www.sciencedirect.com
www.usgbc.org
www.breeam.org
http://www.dgnb-system.de
http://www.openhouse-fp7.eu