LEED and BREEAM; Comparison between policies, assessment criteria and calculation methods A. Rezaallah & C. Bolognesi Department of Progettazione dell Architettura, Politecnico di Milano, Milan, Italy R. A. Khoraskani Department of BEST, Politecnico di Milano, Milan, Italy ABSTRACT: BREEAM and LEED are the two most widely recognized environmental assessment methods used globally in the construction industry today. Each has different strengths and weaknesses, with differing philosophies and business strategies. Generally it is not straightforward to compare the two. This article gives an overview about the BREEAM and LEED NC through their history, facts and characteristics. It provides an indication on the differences between their policies, practices and their approaches towards the global market. It looks at the BREEAM Offices 2008 and LEED NC (New Constructions and Major Renovations) 2009 main categories and factors they consider through their assessment process, and compares in detail their distinctions involving the priority and importance of these factors, among their different calculation methods and the process of certifying a building. 1 INTRODUCTION With so much attention being drawn towards the perils of our planet and the environmental impact that a global population is causing on natural resources, forward-thinking companies and individuals are developing new ways to solve human needs for new buildings and minimize the impact of these activities on environment. Among the different approaches and tactics that are being applied in order to describe, quantify and control these impacts, the most influential ones are BSA tools and methods accompanied by the new regulation worldwide for the building industry. There are some main categories that are being considered in designing a sustainable and green building; energy efficiency, CO 2 emission, material selection, water management and indoor environment quality and waste reduction are among them. The main aim of green design and refurbishment of a building is to have less impact on the environment, less use of natural resources and improve the health and overall quality of life of human beings. (Rezaallah 2012) 1.1 Regulations; Environment and Building Industry Initiatives to address the problem of energy consumption are not new. They have been developed in 1970s with the oil shock and energy crises that hit the capitalist economies hard. It was almost two decades after in 1990s with the growing sense of emergency and problem of climate change that global agreements focused on the problem of environment. The building sector has a considerable potential for cost effective energy savings, it means that by exploiting this potential the EU will have the possibility of consuming 30 percent less energy in 2020. Knowing all these facts, in addition to the problems that CO 2 emission causes on environment, and continuously rising prices of energy, the European countries are putting to act many regulations on regional, state and European levels for residential buildings. There are also international protocols and milestones like Kyoto protocol or 20-20-20 that needs to be fulfilled by
European nations. The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change (UNFCCC or FCCC), aimed at fighting global warming. The Protocol was initially adopted on 11 December 1997 in Kyoto, Japan, and entered in to force on 16 February 2005. Under the Protocol, 37 countries commit themselves to a reduction of four greenhouse gases and two groups of gases produced by them, and all member countries give general commitments. At conference, countries (including the USA) collectively agreed to reduce their greenhouse gas emissions by 5.2% on average for the period 2008-2012. This reduction is relative to their annual emissions in a base year, usually 1990. In 2007, the EU established what it described as the 20-20-20 objectives: a 20 percent decrease in CO 2 emissions; a 20 percent increase in energy efficiency; and increasing the percentage of energy generated from renewable sources to 20 percent. Green design and green refurbishment of the buildings will makes it much easier to reach these goals and meet the targets set for the future. 1.2 BSA Tools and Methods Building environmental assessment methods have emerged as a legitimate means to evaluate the performance of buildings across a broader range of environmental considerations. The increase in development and application of such methods has provided considerable theoretical and practical experience on their potential contribution in furthering green and environmentally responsible building practices. BREEAM and LEED are the two most widely recognized environmental assessment methods used globally in the construction industry today. Each has different strengths and weaknesses, with differing philosophies and business strategies. Generally it is not straightforward to compare the two. What might be applicable in one assessment method might not be relevant in another. 2 BREEAM (BUILDING RESEARCH ESTABLISHMENT ENVIRONMENTAL ASSESSMENT METHOD) 2.1 History and Overview The first certification system to assess the sustainability of the buildings was BREEAM, which was published in United Kingdom. The system was administrated and developed by BRE (Building Research Establishment) at the end of 1980s and introduced to the market in 1990. It was originally designed as a national system for office and residential buildings. The certification system is now used worldwide for a range of different building types. According to BRE, any building throughout the world can be assessed with BREEAM. 2.2 Market Penetration Although the certification system has been used in different countries around the world, the main focus is UK. In comparison with other certification systems worldwide, BREEAM has the highest number of registered (buildings that have applied for the certification) and certified buildings. A large number of these buildings in UK are residential buildings, which is the consequence of government regulations. (Ebert 2011) By 2009, 818,943 residential buildings and 22,972 other buildings were registered worldwide (BRE 2011) and more than 115,000 buildings had been certified in UK (BREEAM International 2009). Most of the certified buildings in UK are residential buildings. 2.3 Certification Schemes In UK, BREEAM have different certification schemes for different building types.
For non-residential buildings: BREEAM Offices BREEAM Retail BREEAM Industrial (factories and ware-houses) BREEAM Educational (schools) BREEAM Healthcare (medical facilities) BREEAM Courts BREEAM Prisons BREEAM Other Buildings (any building that is outside the standard categories for example laboratories, hotels, leisure complexes etc.) For residential buildings: BREEAM EcoHomes (refurbishment in England, new builds in Wales and Scotland) BREEAM Eco Homes XB (a tool for housing associations and etc.) The Code for Sustainable Homes (new single-family homes and apartments in England) BREEAM Multi-Residential (student halls for residence, sheltered housing, youth hotels and etc.) BREEAM Domestic Refurbishment (refurbishment of existing buildings) The scheme BREEAM International has been developed for buildings outside the UK and currently includes the following versions: BREEAM Gulf (all building types within the Persian Gulf region) BREEAM Europe (selected European countries; office and retail buildings) BREEAM Communities (urban planning / development) BREEAM International Bespoke (any building type) BREEAM In-Use (different existing buildings) 2.4 Assessment Criteria s There are ten main categories to be considered during the evaluation of credits in BREEAM 2011 sustainability assessment system, which is an updated version of BREEAM Offices 2008. Each category has some different criteria related to it and depending on the type of the building and certification schemes these criteria can be different and even some of them might not be considered. BREEAM has 76 criteria. Mandatory minimum performance standards are set for some of the categories, which they must be met, whatever Code level is sought. In the calculation process credits are not awarded for the mandatory criteria. The ten main categories are: Energy (Ene) Materials (Mat) Innovation (Inn) Waste (Wst) Pollution (Pol) Health & well being (Hea) Water (Wat) Transport (Tra) Management (Man) Land Use and Ecology (LE) 2.5 Certification Process Participation of an assessor is mandatory in all different BREEAM schemes and an assessor must submit the BREEAM report for the certification to BRE. The assessors are experts who have been trained and approved by BREEAM through formal educational courses and examination. They are responsible for performing an objective assessment and ensuring a consistent degree of quality within the process of certification. They corporate with the designing team and
construction team, they are trained to calculate the points in each different category and subcategories with the help of BREEAM calculator tools then they report it to the BRE, who validate the assessment and issues the certificate. 2.6 Calculation Methods The assessment process should proceed in a logical order through the environmental impact categories and criteria. It should begin with a check that the mandatory criteria for which no credits are awarded have been achieved The remaining tradable credits should be checked and confirmed so that they too contribute to the required sustainability level. If any of the standards for the non-creditable criteria are not met, then a zero rating will result, regardless of the other credits achieved, including the creditable mandatory criteria. For every category, the number of credits achieved is divided by the total available and multiplied by the category-weighting factor to give a percentage point score for the category. This number should be rounded down to two decimal places before the next step. The weighting factors show the contribution made by each category to the total performance recognized and rewarded by the BREEAM. It is important to note that weightings apply at the category level and not for individual criteria to avoid rounding errors. The rounded percentage point scores for each category are then summed to arrive at the Total percentage point s score for the building. The Total percentage point score must be rounded down to the nearest whole number. The sustainability Level is then derived from the Total percentage points according to the table. Table 1. BREEAM certifications Levels. BREEAM Rating Overall Achievement Unclassified < 30% Pass 30% Good 45% Very good 55% Excellent 70% Outstanding 85% 3 LEED (LEADERSHIP IN ENERGY AND ENVIRONMENTAL DESIGN) 3.1 History and Overview LEED is a certification program developed by USGBC (U.S. Green Building Council) at the end of 90s. The motivation to create this system was the demand for an assessment tool that can measure and compare the sustainability of the buildings. The aim of LEED green building rating system is to provide developers, owners and operators with information that assist them to apply different solutions and technologies to the building for sustainable design, construction and maintenance and to identify the sustainability measures of their building. 3.2 Market Penetration LEED was originally designed for the American market but now is in use worldwide. In April 2010, 27,696 commercial and office buildings were registered for a LEED certification. 5,462 of these buildings have been certified. The majority of these buildings are located in USA. The LEED for homes was introduced to the market in 2007 and by April 2010, 24,939 resi-
dential buildings were registered for certification. 5,988 of these buildings have been certified. (Ebert 2011) 3.3 Certification Schemes Currently LEED has ten different rating systems for different types of buildings, which are: LEED NC (New Construction and Major Renovations) LEED EB: O&M (Existing Buildings: Operational and Maintenance) LEED CI (Commercial Interiors) LEED CS (Core and Shell) LEED H (Homes) LEED for Schools LEED ND (Neighborhood Development) LEED Volume Certification LEED Retail: NC and CI (Retail: New Construction and Commercial Interiors) LEED for Healthcare Several countries around the world have adopted the LEED certification system and adjusted it to their specific conditions and requirements. Some of these countries are: India (LEED India) Italy (LEED Italy) Canada (LEED Canada) 3.4 Assessment Criteria The LEED sustainability assessment method is based on points, which are being given to individual credits. There are 43 different criteria in LEED. The credits are divided in to seven main categories. The weight of categories is slightly different between the rating systems. These categories are the same in all of the LEED rating systems except in LEED NA and LEED Homes. The seven main categories are: Energy and Atmosphere (EA) Water Efficiency (WE) Sustainable Sites (SS) Materials and Resources (MR) Indoor Environment Quality (IEQ) Innovation & Design (ID) Regional Priority (RP) 3.5 Certification Process For certifying a building with LEED in a similar way with BREEAM there accredited professionals who are helping to collect the evidences and sending the documentation to the GBCI (Green Building Certification Institutes) which is a non profit organization and a part of USGBC. Originally USGBC (U.S. Green Building Council) was the only responsible for all the aspects of LEED from developing the rating system to educating, examinations and issuing the certificates. Since January 2008 GBCI (Green Building Certification Institutes) is responsible for the entire certification process up to completing and awarding the certificates as well as LEED accreditation. For becoming a LEED accredited basic knowledge about the LEED and sustainable buildings, which will be tasted in an exam, is the first stage. The one who passes this stage successfully will become LEED Green Associate. As the second stage participating in a LEED project
or professional experience dealing with sustainability are the requirements for the exam. The ones who pass this stage successfully will become LEED Accredited Professional (AP). Then the AP has to specialize in a specific LEED rating system by taking another exam. Both of these titles are valid for two years and they are renewable by taking further exams or providing the evidence of additional training, working on a registered LEED project or publications regarding LEED or building sustainability. The highest accreditation level is LEED Fellow, which will be awarded to LEED APs that have maintained their title for at least 8 years and have professional experience in the green building sector for at least 10 years. LEED accreditation is not mandatory for preparing and submitting the documents to the GBCI (Green Building Certification Institutes) and cooperation with LEED AP is awarded one point in the assessment process. Working with an AP is beneficial for the design and construction team because of their knowledge and experience in the field, which will make achieving the target level easier. The role of the AP is to help gather the evidence and advise the client. The evidence is then submitted to the GBCI, which does the assessment and issues the certificate. 3.6 Calculation Methods Calculating the points for LEED is through checklists, which gives the design team a wide range of devices and technologies to consider using. The assessment is based on points and all LEED criteria are worth a minimum of 1 point. All LEED rating systems have 100 base points; Innovation in Design (or Operations) and Regional Priority credits provide opportunities for up to 10 bonus points. There are different topic areas included in the LEED assessment method and each of the topics has a unique goal. LEED guarantees minimum levels of sustainable practice through mandatory measures in different credit categories and there are no points for meeting the mandatory minimum requirements. All categories and criteria are listed with the number of available points. In LEED rating system is not possible to meet only a proportion of a criteria requirements, the requirements are either met or not. The only exception is made for three criteria; water use reduction, optimize energy performance and on site renewable energy. The number of credit awarded to these three criteria depends on the degree of fulfillment. In case of LEED, there is no multiplying system similar to BREEAM and points are awarded directly. Sum of all the points of all the categories is equal to total score. The four performance tiers according to the number of points earned indicate the level of sustainability performance of the building. Table 2. LEED certifications Levels (LEED NC 2009) LEED Rating Points Certified 40 49 Silver 50 59 Gold 60 79 Platinum 80 4 COMPARISON The two building sustainability assessment tools have their differences as well as similarities. Table 3 shows a detailed comparison between the main characteristics of these two systems, which are BREEAM Offices 2008 and LEED - NC (New Constructions and Major Renovations) 2009.
Table 3. Comparison of the two BSA system characteristics (Ebert 2011) BREEAM LEED Assessment Method BRE Environmental Method Leadership in Energy And Environmental Design Certification Body BRE USGBC Launch 1990 1998 Number of categories 10 6 Main categories Energy Energy and Atmosphere Materials Water Efficiency Innovation Sustainable Sites Waste Materials and Resources Pollution Indoor Environment Quality Health & well-being Innovation &Design Water Transport Land Use and Ecology Management Number of Criteria 76 43 Number of Mandatory Criteria 27 28 Weightings For each individual category No Weightings Calculation style In % With Points Result Unclassified Certified Pass Silver Good Gold Very good Platinum Excellent Outstanding There is a large overlap between the two systems assessment criteria. The table 4 (Elgendy 2010) demonstrates the general emphasis of the major categories of BREEAM and LEED and their relative weights in each rating system. It also shows that there is a considerable overlap between the two systems with each system having its on particularities (Facilities Management in the Case of BREEAM, and Regional Priority in the case of LEED). The table is for general comparison purposes only as it does not take into account point-less prerequisites. The names of some categories have been adjusted and some credits have been moved across categories to simplify the comparison. Table 4. Overlapping categories and their influences on each BSA tool Category BREEAM LEED Site Selection & Ecology 20.5% 24.5% Water 2.5% 5.5% Energy 33% 33% Materials 13.5% 13.5% Indoor Environment Quality 13% 14% Innovation 6.5% 6.5% Facility Management 12% - Regional Priority - 4% To categorize the level of sustainability of the buildings, LEED applies a scale of platinum, gold and silver, while BREEAM adopts a scale from pass to excellent. The different type of naming the certification levels can make the comparison between the two systems a bit complicated. A study by BRE (BRE, 2008) concluded that there are high levels of variation between the systems for the same grade or rating than might be expected. For example, BREEAM Excellent and LEED Platinum office building are not equivalent in terms of sustainability fea-
tures or environmental impact (BRE, 2008). LEED, when applied to UK buildings, rated those buildings higher than the UK BREEAM assessment method. Overall, BRE stated that none of the systems they examined (BREEAM, LEED and etc) traveled well in terms of comparison. One aspect that is very important to address in both of the certification systems is the operational performance. Both LEED and BREEAM need to clarify whether a high rating actually means an improvement in the building's efficiency and operational performance. They simply rate the 'asset' and do not consider how the building will operate in reality in future. LEED is ahead considering this matter, the owners of the buildings are mandate to provide them with the utility consumption data after five years and in case the owners don t provide the USGBC with such a data, they have to sign a waiver so that the USGBC will get the data from the utility providers. BREEAM 2011 has started to consider the post occupancy issue by emphasizing the commissioning the first year of occupation. It contains credits for 'seasonal commissioning', collecting and analyzing energy performance and consumption data for the first year; and providing extended aftercare. All the excellent and out- standing rated buildings have to complete the BREEAM In USE assessment in three years. There are some other significant differences between the two BSA tools. In general, LEED is slightly simpler and easier to use but this can also be considered a weakness if owners are pushing to improve environmental performance of the buildings. BREEAM is arguably stricter as it sets more absolute targets. LEED sets relative percentage reduction targets. For instance, in case of materials, LEED looks at the usage of local sources of the material and also percentage of recycled content, while BREEAM is more precise and considers the wider environmental impacts of building different elements by awarding the credits using the Green Guide to Specification and a 'responsible-sourcing' index. In case of water, BREEAM credits are based on cubic meters per person per year; LEED points are base on the water use reduction percentage. A 40% reduction in water use achieves maximum points under LEED, but only gets one or two credits under BREEAM. The main concern of the both BREEAM and LEED rating systems is to move towards internationalization. For being more easily accepted and adopted to the global market both systems have to work on their disadvantages. They are constantly trying to improve their weaknesses to optimize building performance and minimize environmental impact; provide a measure of a building s effect on the environment; and set credible standards by which buildings can be judged objectively. They are learning from each other s strength points. 5 ADVANTAGES AND DISADVANTAGES Both LEED and BREEAM building sustainability assessment tools have their own advantages as well as disadvantages. One of the aspects that makes the LEED more simple is the easy calculation method, which is done through a checklist that makes it very easy and transparent to calculate the points and evaluate the final score by sum of the points without any weighting. BREEAM is more complicated, more strict and accurate. The calculation of the points is through different calculators and is followed by various weighting scores for each category considered in the evaluation. This complex process makes the calculation less transparent, which is a disadvantage of BREEAM. For the international market the transparency is essential and BREEAM should try to make the calculation of the points more transparent for the market, developers and operators of the buildings. At the international scale the advantages and disadvantages of these two systems is very much dependent on the regional standards, lows and legislations. LEED is more dominated by ASHREA standards while BREEAM uses European and UK codes. Higher similarities between the regional standards and the code mentioned above will further assist the adaptation of the assessment tool for the regional purposes in the international market. Generally in this scene, BREEAM has more attention to the regional standards, laws and legislations. It tries to consider
the specific characteristic of different countries in accordance with their climatic situation. As an example BREEAM Gulf has been adapted for the local market. The weightings are changed so that water is the key issue, rather than energy as in the standard UK schemes. BREEAM also has long been able to adapt to local contexts. With BREEAM Bespoke, for example, the assessor can work with BRE to develop assessment criteria specially tailored to a building where it doesn't fit neatly into one of the existing schemes. (Parker 2009) Never the less LEED has also provided adaptability by using regional bonus for weighting different environmentally important factors for different regions in the USA. There are six regional priority credits available only for the USA. Also some individual national green building councils in other countries have developed some domesticated versions of LEED such as Canada and India. There are other countries such as Italy who are in the developing process. 6 CONCLUSION The main aim of these two methods is to encourage the mass of building stock towards higher levels of environmental performance. The two methods have their similarities as well as differences; they are improving and updating their judging criteria with legislative developments and current best practices. Since the main differences between the two systems arise from their policies and the bureaucratic environment of their origins, it is somehow unreasonable to praise one over the other and the decision to choose one over the other highly depends on the background and regional conditions of the projects. All of the comparisons and studies of different assessment tools proves that building certification in each country idealistically should be done by the country s specific certification system. These building sustainability assessment tools are supposed to adapt the local political, regional standards and laws, social and climatic conditions of each country. REFERENCES BRE, 10 things you might not know about the BRE Group [Homepage of BRE Global Ltd], [Online]. Available: http://www.bre.co.uk/page.jsp?id=1707 [2011,. BRE (2008) A Discussion Document Comparing International Environmental Assessment Methods for Buildings. BRE, Glasgow. BREEAM International 2009, BREEAM Europe Commercial 2009 Assessor Manual, BRE Global Ltd. BREEAM 2011, BREEAM New Construction Non Domestic Buildings Technical Manual 2011, BRE Global Ltd. BREEAM Offices 2008, BREEAM Offices 2008 Assessor Manual, BRE Global Ltd. Cheshire, D. 2011,, BREEAM versus LEED: the battle over green building assessment. Available: http://www.sustainablebusinessonline.com/news/news.asp?id=308. Ebert, T., Essig, N. & Hauser, G. 2011, Green building certification systems, 1st (edn), DETAIL, Munich. Elgendy. K, Comparing Estidama s Pearls Rating System to LEED and BREEAM, CARBOUN Middle East Sustainability and Environment, 2010. LEED 2009, LEED for New Construction and Major Renovations Rating System With Alternative Compliance Paths For Projects Outside the U.S., U.S. Green Building Council, Washington DC. LEED 2011, LEED 2009 for New Construction and Major Renovations Rating System With Alternative Compliance Paths For Projects Outside the U.S. (Updated November 2011) U.S. Green Building Council, Washington DC. Parker, J., BREEAM or LEED - strengths and weaknesses of the two main environmental assessment methods [Homepage of BSRIA Ltd], [Online]. Available: http://www.bsria.co.uk/news/breeam-orleed/[february 2009,. Parker, J., Model project - Herman Miller UK HQ [Homepage of BSRIA Ltd], [Online]. Available: http://www.bsria.co.uk/news/herman-miller/ [September 2009,.
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