Comparing Estidama’s Pearls Rating System to LEED and BREEAM

Karim Elgendy

UPDATED – In April 2010 the Estidama program of the Abu Dhabi Urban Planning Council partially released the first version of its rating system suite, The Pearls Rating System for Estidama. The release included the design and construction portions of the the rating system suite which includes rating systems for buildings, villas, and neighborhoods.

Prior to its release Estidama has occasionally referred to the upcoming system as one that learns from its established predecessors, the British BREEAM rating system and the American LEED rating system (BREEAM stands for British Research Establishment Environmental Assessment Method, and LEED stands for Leadership in Energy and Environmental Design). The decision to learn from these rating systems was not only to learn from their mistakes but also to help create a system whose requirements are familiar to the market. On the other hand, the Estidama program asserted that the Pearls Rating System would not be a direct copy of either systems given the environmental and cultural differences of the Emirates

Given the debates that exist amongst practitioners and researchers on both sides of the Atlantic on the merits, shortcomings, and differences between BREEAM and LEED. An analysis of Estidama’s Pearls Rating System in comparison to these two established rating systems was necessary. The first version of the Pearls Rating System for Estidama will be compared to the latest version of the LEED rating system, LEED 3.0 (also known as LEED 2009), and the latest update of the BREEAM rating system, BREEAM 2008.

The comparison: An Introduction

To understand the differences between the three systems one must first understand their background and history. The Pearls Rating system is a government initiative developed by the Abu Dhabi Urban Planning Authority and has just been launched in 2010.

The British Research Establishment (BRE) was a government funded research body when BREEAM was conceived in 1990. BREEAM’s Mission was to provide relevant research and information to the building industry, about what kind of methods would best support environmental protection and sustainable development.

Finally, the United States Green Building Council (USGBC) is a national non-profit membership body, with around 20,000 member organizations. Since its inception in 1998, LEED has sought to change the construction market using a consensus approach. It has also adopted a commercial approach to marketing itself, attracting paying members and bringing in $24 Million a year. LEED is a registered trade mark and a brand name.

Estidama as a Design Guide

The first striking difference between The Pearls Rating System on the one hand, and LEED and BREEAM on the other, is that unlike its predecessors systems, the Pearls Rating System is not a standalone document, but part of the Pearls Design System, which includes a complementary design Guide and supplementary Application Guides for public works, parks and infrastructure. Like LEED and BREEAM, the Pearls Rating System for Estidama includes a number of rating systems assessing Buildings, Villas, and Neighborhoods.

The Pearls Rating System is also strongly linked to the Estidama Integrative Design Process (EIDP), which seeks to promote the new concept of Integrated Design process (IDP) as a design approach amongst design professional by encouraging design coordination at the early stages of the project. In fact, EIDP is not only part of the The Pearls Rating System, but it is also set to become part of the  development codes as a prerequisite for all projects types, requiring all projects to carry out a number of analyses before the design process is permitted to begin. These analyses include solar and contextual analyses, Energy efficiency design strategies including preliminary energy modeling, water budgeting, simple material strategies, and an analysis of potential for habitat connectivity. In doing so, Estidama is set to become one of the world’s most progressive Green Building Initiative, together with Cascadia Green Building Council in the United States, to formally adopt the Integrated Design Process, but the first to make it mandatory.

Estidama itself is also part of Abu Dhabi’s 20-year plan, known as Plan Abu Dhabi 2030, which attempts to redefine how a contemporary Arab city should look, to encourage sustainable growth, to encourage protection of the natural environment of sensitive coastal and desert ecologies, to re-emphasis the city’s stature as a capital city of the United Arab Emirates, and to enable the urban fabric and infrastructure to enforce the local values and culture of this Arab community. These broad goals are tied to Estidama through a number of key performance indicators measuring energy use, water use, waste generation, carbon footprint, and biodiversity amongst others indicators.

Pearls and the Building Code

The second striking difference between the Pearls Rating System (referred to as Pearls henceforth) is its integration into the Abu Dhabi development codes. Unlike the voluntary LEED and BREEAM systems which reference existing national codes and planning guides, the planning and building codes for the city of Abu Dhabi are currently being redrafted to integrate Estidama’s goals and Pearls requirements into them. Pearls includes requirements to comply with these new development codes which are mandatory requirements for a development to get planning and building permits. The designers of Pearls are perhaps making use of the fact that Abu Dhabi’s development codes are still developing, to integrate green building requirements into them. Such an integration would be more challenging in established and complex code environments such as those of the UK or the US. However, it must be noted that this integration has taken place in a more limited way in the case of  BREEAM where some parts of BREEAM have found their way into Part L (Energy section) of the British Building Regulations.

Under this arrangement between Pearls and the development codes -which will remain two separate processes- fulfilling the mandatory planning and building code submission requirements will include a number of prerequisites of Pearls, which satisfy the requirements for Pearls’ lowest rating level of One Pearl. Consequently, the lowest rating of One Pearl simply denotes that a building is legal and complies with the statutory development codes, but on the other hand it could be argued that under this arrangement every project in Abu Dhabi would have to have an element of sustainability simply by complying with development codes. In addition, the coordination of these documents also helps simplify the process of achieving a higher Pearls rating and paves the way for a smoother transition of the rating system from a voluntary rating system to an enforceable building requirement.

Credits and Requirements

As noted above, Pearls includes a number of code requirements which have been rewritten specifically for Pearls, and the satisfaction of these code requirements awards a project the lowest Pearls rating of One Pearl. This arrangement does not exist in either LEED and BREEAM.

In addition to these requirements, Pearls also includes requirements similar to LEED’s Prerequisites and BREEAM’s Mandatory Credits which do not award points but are mandatory for certification.

The Pearls Rating System, Like LEED and BREEAM, is also a point-based system that awards projects points for different credits that are grouped under a number of general categories. Points are added up to a final rating which ranges from One Pearl to Five Pearls. These 5 levels of certification compare to LEED’s 4 levels ( Certified, Silver, Gold, and Platinum) and BREEAM’s 5 levels (Pass, Good, Very Good, Excellent, and outstanding). It is expected that a very small number of buildings would achieve the highest rating of Five Pearls, whose bar is set intentionally high at 90% above benchmark compared to BREEAM’s 85% for outstanding, and LEED’s 73% for Platinum. The highest rating of Five Pearls requires a restorative, or a net positive, contribution to the environment in terms of energy, water, and improving diversity and health of living systems. Such requirements are much like – if not more challenging than- the progressive Living Building Challenge developed by the Cascadia Green Building Council.

Similar to LEED and BREEAM, Pearls is also designed as a weighted system, where the different credits have relative weights depending on their relative importance. This relative importance is understood differently between different rating system. For example, LEED is strong on occupant comfort, internal pollution issues (off-gassing etc), and heat island effects. LEED is also geared towards climates which use mechanical ventilation and air conditioning and where existing infrastructure promotes the use of cars as is the case in much of the United States whereas BREEAM responds to a built environment where natural ventilation is more prevalent and where a strong public transportation infrastructure exists. LEED also covers some areas not found in BREEAM where UK legislation takes over, for example environmental tobacco smoke control. BREEAM on the other hand is strong on pedestrian and cyclist safety, with much higher targets for cyclist spaces. It is also stronger than LEED on the social aspects of sustainability, and on acoustics.

The table below (Figure 1) demonstrates the general emphasis of the major categories of Pearls, BREEAM, and LEED and their relative weights in each rating system. It also shows that there is a considerable overlap between the three systems with each system having its on particularities (Integrated Design Process in the case of Pearls, Facilities Management in the Case of BREEAM, and Regional Priority in the case of LEED).

One can clearly notice an emphasis on water conservation in Pearls that far exceeds LEED and BREEAM. This emphasis is understandable given that the Emirates ranks third in the world in terms of the volume of sea water desalinated daily, at 4.7million cubic meters every day. Pearls also puts more emphasis on materials and Indoor Environmental Quality. This comes at the expense of the important energy credits which represent a smaller proportion of the rating system than they do in LEED and BREEAM ( 24% less). It also comes at the expense of  Site Selection credits and Innovation which represents a smaller percentage in Pearls than it does in BREEAM and LEED.

Figure 1. Rating systems comparison table. 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.

Assessment and Certification

Pearls approach to assessment can be described as a hybrid between BREEAM and LEED. BREEAM Assessment process depends on a competent assessor to issue the certification. This assessment method is very different from the web-based LEED Online system which reduces interaction and dialogue between building professionals and the USGBC to a minimum (mostly through online submissions of Credit Interpretation Requests). To compensate for this, the United States Green Building Council has chosen to encourage building professionals to obtain training on how to use LEED and to become accredited professionals in the use of the rating system. While this accreditation is not mandatory for a project to be LEED certified, American building professionals have embraced it with tens of thousands becoming LEED Accredited Professionals (LEED APs).

Pearls hybrid approach is much like BREEAM, in relying on a dedicated competent assessor for each project in its attempts to emphasize dialogue and an iterative design process. However, in addition to the role of the Pearls Assessor, it also requires the appointment of Pearls Qualified Professional (PQP), a new mandatory role. The Pearls Qualifies Professional must be a member of the design team and whose role is to facilitate the Pearls assessment during the design and construction stages, in a role similar to that of a LEED AP on a LEED project.

The Process

The general perception of LEED is that its requirements are generally less onerous than BREEAM. The targets set in BREEAM are perceived as exact, prescriptive, and linked to specific solutions, whereas in LEED it is more common to state the intention and leave it up to designers’ discretion as how best to comply. This meant that the LEED calculations methods and documentation became more rigorous, and consequently LEED requires more work to prove accreditation. This has led to the perception that LEED projects need to provide more extensive documentation than BREEAM.

In terms of documentation and tolerance, Pearls seems more in line with LEED than the stricter BREEAM. However, taken into consideration that the actual certification only takes place after a post-occupancy assessment, it appears that Pearls would be much more onerous than LEED since any alternative compliance path adopted by the designers must be demonstrated to work after occupancy, which is not the case with LEED.

Estidama also seems to have adopted parts of both of BREEAM in the design of the certification process of Pearls (Figure 2.)

Figure 2. Certification Processes of Pearls, BREEAM, and LEED

Pearls has three stages of rating. The first stage is during the design and construction phases. A Pearls Design Rating can be used to confirm that the proposed project design is consistent with the goals of Estidama. Once construction is complete as designed, a Pearls Construction Rating, will be provided. While these design and construction rating certificates can be used for marketing purposes, they must state that the rating advertised is a Design Rating or a Construction Rating and must not be used beyond their respective stages. As such, the construction rating does not constitute the final Pearls certificate. The third and final stage of rating, the Pearls Operational Rating, is only awarded after 2 years of at least 80% occupancy. The post-construction assessment, is designed to validate the Pearls Construction Rating, but it also has the powers to reduce or increase the rating. Previous draft publications from Estidama have indicated that the final certificate for Pearls Operational Rating was mandatory for the rating to be complete, however, since Operational portion of the rating systems has not yet been released, this is yet to be confirmed.

Similarly, BREEAM also has a two stage certification system which includes a design stage and a post-construction stage, but unlike Pearls, BREEAM does not require a post occupancy assessment except for its highest rating, BREEAM Outstanding, which has a mandatory requirement for a ‘BREEAM In Use’ certification within the first 3 years of operation.

LEED on the other hand, has an optional design submission at which no certificates are issued, and is the least of all three systems in terms of its post occupancy assessment. The new changes in LEED 2009 show a slow shift in the direction of post-occupancy assessment with the new requirement that the USGBC has access to projects’ Whole-Building Energy and Water Usage Data. However, the projects’ LEED ratings will not be tied to the information they provided, and the requirement is simply an authorization for the USGBC to access the usage data.


From the comparison above, it appears that while the Pearls Rating System is an independent rating system, it has many similarities with the LEED and BREEAM rating systems. Estidama appears to have picked certain elements from these two systems amongst other sources of inspiration, but still developed a system that is quite progressive and distinctly local. The degree to which market will embrace a system with such a high bar is yet to be determined as project teams engage with the system.

The Pearls Rating System’s emphasis on post-occupancy assessment indicates that it has learned lessons from other rating systems in designing a system that assesses results rather than intentions, and while performance assessment rating systems exists in the US and in the UK  (for example, the Energy Performance Certificates in the UK), their scope is limited to energy and are independent from the Green Buildings Rating systems.

Finally, the combination of enforceability of parts of Pearls and the incorporation of Pearls within Estidama’s larger development framework, together with Estidama’s efforts to promote an Integrative Design Process and the efforts by the market-driven Emirates Green Building Council, all have the potential to hasten the market’s adoption of green building practices at a faster rate than perhaps seen in the United States and the United Kingdom over the last 20 years.

Karim Elgendy is an architect and  sustainability consultant based in London. He can be contacted at: Karim [AT] Carboun [DOT] com

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