Certification methods as a mechanism for estimation of building sustainability

. The sustainable development concept is a universally recognized global trend that manifests itself in all aspects of society, including the construction industry. Rapid environmental and economic changes occurring at the international, and regional levels have necessitated the creation of a mechanism to provide an expert evaluation of the buildings` sustainability. In this regard, building certification methods have been developed to assess their energy efficiency and environmental friendliness. The purpose was to study certification methods BREEAM, LEED, and GZ Azeri as an estimation mechanism of building sustainability. The methods were used: descriptive review, comparative analysis, systematization, structuring, and generalization of available information on building certification. Results: the characteristic evaluation criteria of certification methods and their corresponding factors by sustainability spheres: environmental, social, and economic were analyzed. Technical characteristics of the certified buildings in Azerbaijan were considered. The benefits and drawbacks of the used certification systems were outlined, along with reasons for boosting the allure of certified buildings. Based on the comparative examination of the methods under consideration existing issues were divided into three categories: process, technology, and human-oriented. There are suggestions from experts on how to remove problems and overcome challenges.


Introduction
In the 21st century, sustainable development is the main guideline for society and is defined as development in which the needs of current generations are met without prejudice to the interests of future ones [1].According to the concept of sustainable development, the trinity of the following areas of society's activity is necessary: the environment, the social sphere, and the economy.Today, this concept has become a universally recognized global trend, which manifests itself in all sectors of life, including the building industry [2].Fig. 1 shows the relationship between the building industry's environmental, social, and economic areas.
Rapid changes in the environmental and economic spheres at the global and regional levels have necessitated the creation of a mechanism that provides expertise in the sustainability of the building industry.In this regard, methods for certifying buildings in accordance with their energy efficiency and environmental friendliness were created, therefore, building certification is considered as one of the tools on the way to the sustainable development of states [3].The building certification methods that first appeared in Europe and the USA at the turn of the 21st century most fully reflect the concept of sustainable development in the building industry.For the most part, certification methods evaluate the building and the surrounding landscape against a number of criteria, and according to the number of scored points, one or another level of environmental friendliness and energy efficiency is assigned [4].Only three certification methods have received international fame and recognition: the British BREEAM (1990), the American LEED (1998), and the German DGNB (2009).Over time, national assessment methods appeared in many countries, including Green Zoom Azeri (GZ Azeri) in Azerbaijan (2014).
For any country, the availability of sufficient energy reserves and natural resources is one of the major driving forces of its sustainable development [5].According to the report of the United Nations Program for 2022, buildings around the world during their life cycle spend approximately 40% of final energy, 12% of drinking water, account for 30% of global greenhouse gas emissions, and 40% of solid waste (http://www.unep.org/resources/emissions-gap-report-2022).In Azerbaijan, all these indicators (Fig. 2) are worse, 45% of the country's final energy is consumed by buildings, 23%-by transport, 25%-by industry, 7%-by other sectors of the economy (https://www.stat.gov.az/source/balance_ fuel/-2022).These figures highlight the energy-saving potential of buildings and the need for a higher degree of building sustainability in Azerbaijan [6].To effectively realize this potential, certification methods are used that clearly focus on assessing the degree of building sustainability.
If the concept of sustainable development is close and understandable to Europe and America, then for Azerbaijan it is still a new aspect of society, although interest in sustainable construction standards and building certification methods in the country is growing every year.In Azerbaijan, building certification began to gain popularity in 2014, when the first international BREEAM (UK) certificate was received, then in the same year, on the initiative of the Azerbaijan Green Building Council, based on LEED (USA), a national building certification system was created -GZ Azeri.To date, unfortunately, only a single building has been certified by GZ Azeri.
The goal of this research is to explore the experience of Azerbaijan on building certification methods such as BREEAM, LEED, GZ Azeri, to analyze the differences and similarities between them, to indicate factors for increasing the attractiveness of certified buildings, to identify the advantages and downsides of applied certification methods in the country, and to classify existing problems, obstacles and provide expert advice on how to overcome, eliminate them.The outcomes of this research will promote the development of a roadmap for the sustainability of the building industry in Azerbaijan.

Methods
In this paper, the following research methods were used: descriptive review, comparative analysis, systematization, structuring, and generalization of available information that was obtained from various sources, such as the expertise of the authors of the article, research reports, legal and technical standards, official documents of non-governmental and governmental organizations, press publications, interviews with representatives of the construction industry, assessments of other experts, as well as materials on building certification in Azerbaijan.
The authors are certified energy auditors of buildings by ENSI-Energy Saving International AS Norway and members of the team involved in the development of the first national building certification method, GZ AZERI.Currently, the authors continue to participate in the building certification process in Azerbaijan.The knowledge and experience of the authors, obtained as a result of the energy audit of buildings in Azerbaijan, proved to be effective in conducting this study.
The article discusses the building certification methods as part of the social and environmental areas (Fig. 3) in terms of sustainable development, taking into account the differences between the characteristics and benefits of energy-efficient, green and sustainable buildings as shown in Table 1.For sustainable buildings, all technical features are met.Table 1.Differences between the energy efficient, green and sustainable buildings [7].

Evaluation criteria of certification methods
Today, the building certification process is gaining popularity as the environmental impact of certified buildings is becoming more apparent and the use of certification methods is being encouraged due to their clear benefits in energy efficiency, resource efficiency and environmental friendliness [8].Although significant efforts have been made in Azerbaijan over the past ten years to certify some buildings, studies show that green construction is not widely practiced here, and the certification process is voluntary and still in its infancy.Despite the well-known advantages of building certification methods, today there are only three certified buildings in Azerbaijan, two of them according to BREEAM and one according to GZ AZERI.Two more buildings are under construction and are undergoing LEED certification.All buildings are public.Each certification method has its own characteristics and the certification scheme mainly depends on the purpose of the certification object [9].
According to the areas of sustainable development, the authors analyzed the characteristic criteria of certification methods and the corresponding evaluation factors based on the technical guidelines given in papers of [10] (Table 2).
Table 2. Evaluation criteria and their factors for spheres of building sustainability.Factors that could not be attributed to one or another comparative criterion were not taken into account, for example, project management, project optimization, etc.According to the given criteria for assessing sustainability, the main technical indicators of some buildings in Baku were analyzed and the results obtained were shown in the next part.

Technical characteristics of the certified buildings in Azerbaijan 4.1 BREEAM certification method
Office Building in White City of Baku (Fig. 4) is the first building in Azerbaijan that was certified in 2014 by BREEAM International New Construction with a GOOD rating, Certificate No 0057-2834 with a score of 48.5%.The building has:  Total area-40437 m 2 ;  Specific annual energy consumption for ventilation, heating, air conditioning, refrigeration and hot water supply-115.6 (kWh)/m 2 ;  Annual carbon footprint-44 kg/m 2 .
In addition to optimal architectural and design solutions, environmental principles for organizing construction processes were also implemented here (https://www.bakuwhitecity.com/en/newsd/85-baku-white-city-office-building-becomesthe-first-green-certified-asset-in-azerbaijan).The innovative technical features of the building are:  Building energy consumption is 19% less than the base model;  Reducing the specific energy consumption for heating, ventilation, and air conditioning (HVAC) systems relative to the baseline is 41% due to the usage of energy-efficient equipment and optimization of operation modes;  U-value of the façade is 1.1 W/(m2•0C), which provides efficient thermal insulation;  Thermal conductivity coefficient of external glazing is 1.8 W/(m0C), while for ordinary buildings-2.8W/(m0C);  Although the area of external glazing is 70% of the total surface of the building, it provides effective sound insulation  Heating system works with duplex burners;  Air conditioning is with VRV (Variable Refrigerant Volume) fourth generation;  All occupants have 100% outdoor visibility;  To ensure a healthy microclimate the facing and finishing materials used do not contain VOC (volatile organic compounds);  Due to the usage of LED (Light-Emitting Diode) lighting, it was possible to achieve visual comfort for employees and visitors;  Zoned automated lighting control promotes significant energy savings;  The energy-saving measures include applying heat meters to renters and using sensory plumbing fixtures;  The use of humidity sensors allows saving water during capillary irrigation of vegetation;  To prevent night light pollution, an optimal scheme of outdoor lighting with energysaving lamps was used;  The proximity of public transport stops ensures the accessibility of the building for pedestrians;  For the safety of pedestrians, the crossings located on the path of their movement are raised above ground level on the nearby territory of the building;  There is infrastructure for disabled people;  The presence of special paving stones helps to reduce the speed of passing vehicles;  There are bike racks and charging stations for electric vehicles;  The noise and light impact of neighboring buildings is minimized due to the optimal location of the building and the good sound insulation of its glass façade;  The biodiversity of the local landscape makes the building fascinating.
In 2016, the administrative building of the State Oil Fund of Azerbaijan passed the BREEAM certification (Fig. 5) and received a GOOD assessment at the "building in-use" stage.The requirements defined by BREEAM were considered during the construction phase.The total height of the building is about 209 m, it is the third tallest building in Azerbaijan.It has 24 ground floors and a two-story underground parking.The interior combines images of drawings from 9 national schools of carpet weaving.
The major building technical features are as follows:  Mechanical ventilation with heat recovery saves 24% of the annual energy balance of HVAC;  Ozone-friendly refrigerant is used for HVAC;  For the hot water supply system solar flat panels are used;  All engineering systems are environmentally certified;  The use of intelligent technologies based on the concept of integrated engineering systems provides automated management of the building infrastructure;  Management of all communication networks is carried out from a single center;  Heat supply is out by a system of heat pumps with an automated control unit;  54% of used building materials and structures are eco-friendly;  25% of building materials are manufactured locally and have ISO certification;  All insulating materials, finishing materials, coatings, and paints are made from natural raw materials;  10% of waste (concrete, glass, brick, mortar, metals, wood) was recycled and reused;  Automatic lighting control with motion sensor is provided;  Transport accessibility of the building is 280 m;  Collection and purification of stormwater is used;  Drainage water from the ventilation system is used for irrigation of nearby landscaping;  An automated landscape irrigation system with storm-water storage is provided for irrigation of the adjacent territory;  The fertilizers used for landscaping are environmentally friendly and ISO 9001 certified.

LEED certification method
The main building of the ADA University in Baku (Fig. 6) was commissioned in 2014 according to the LEED certification criteria, but it was not finally certified due to applying for certification so late-at the construction stage but not at the design stage, which is a strict requirement.
The following advanced technologies are applied here:  Geothermal energy is used to heat and cool the building by applying heat pumps on 290 vertical wells 130 m deep;  The building has a central air conditioning system with plate-type heat recovery that saves about 30% of energy consumption for HVAC;  Green roof is used;  The sensory plumbing fixtures have aerators with a water flow rate of 2-5 l/min, which is 2-3 times less than for conventional ones;  There is zonal LED lighting, which saves electricity by about 2.5 times and improves IAQ (indoor air quality);  The layout of the premises provides all learning areas with natural daylight;  There is a separate area for four groups of garbage;  The use of water coolers reduces the number of plastic bottles.

GZ Azeri certification method
Fairmont Hotel in Baku (Fig. 7) of the high-rise complex Flame Towers is the first building in Azerbaijan certified by the national building eco-standard GZ Azeri in 2017 at the beginning of the operation stage as New Construction.It was awarded the Platinum Certificate, with a score of 70% out of 90%.The Azerbaijani certification method is based on the international LEED and the Russian Green Zoom assessment systems.The authors of this work participated at all stages of the certification process.The assessment of the object was carried out according to 46 indicators by the methods of visual, instrumental, and documentary control and corresponding calculations.Confirmation of the compliance of the building indicators with the requirements was recorded by both local and international experts by photo fixations and instrumental methods directly on the building and with the help of relevant documents.Each score made by the experts had a documentary justification.
More than half of the assessed indicators had parametric values, which excluded the subjectivity of assessment and evaluation [11].The energy-efficient solutions allowed to reduce the hotel's annual operating costs by more than 2 times, heat consumption was reduced by 13%, and overall energy consumption was reduced by 23% compared to the base building according to the ASHRAE standard (https://www.ashrae.org/technical-resources/standardsand-guidelines).

Analysis of BREEAM, LEED and GZ Azeri
A comparative analysis of the three certification methods shows that, despite the differences in the assessment systems, the priority assessment criteria is Energy section, and all three methods have approximately the same sections: Energy efficiency, Water efficiency, Materials and resources, Indoor environmental quality, Site ecology, Innovations, and Regional features [12,13].The second-highest priority in BREEAM is the well-being and health of people, followed by the Indoor environmental quality, which means that this system has a greater social focus than LEED [9] and GZ Azeri.
BREEAM is more focused on the environmental criteria for evaluating a buildinglocation, transport accessibility and reducing the impact of transport on the environment.In both BREEAM and LEED, procedural performance takes priority over performance.For LEED, after Energy efficiency Materials and resources criterion is important, so LEED is more suitable for public buildings [14,15].The local certification method is more suitable for multifunctional buildings, including housing, but unfortunately, there are no certified residential buildings in Azerbaijan yet.
For all three methods, the assessment of the thermal and acoustic characteristics of building envelopes is identical [16,17].
Fig. 8 shows the percentage ratios of criteria for evaluating certification methods in three areas of sustainable development.It can be seen that the environmental sphere has the greatest importance for them, followed by the social sphere, and the economy which makes up a smaller part.For GZ Azeri, the economic sphere is more important than for the other two methods, which correlates with the fact that the cost of building certified buildings is 11-16% higher than conventional buildings and confirms the authors' many years of experience in the field of energy audit and certification of buildings.

Attractiveness of certified buildings
According to the authors' many years of experience in the field of energy auditing and building certification, although the cost of construction and operation of certified buildings is approximately 11-16% higher than for conventional buildings, the main factors contributing to increasing their attractiveness for investors and long-term tenants are:  High quality of the building as a construction structure as a whole;  High level of occupants` comfort;  The international image of the building;  Reduction of operating cost by 25-30%;  Saving resources and minimizing emissions and waste;  Increase in rent for premises by 2-16%;  Improved risk management;  Increase in the cost of sales by 8-35%;  Recoupment of construction-7-10 years.Also, the expediency of certification is dictated by the fact that the owners of buildings, fulfilling corporate goals, seek to attract additional attention to their property [18].For the E3S Web of Conferences 458, 07017 (2023) EMMFT-2023 https://doi.org/10.1051/e3sconf/202345807017state, building certification is the solution of national tasks for decarbonization, improvement of the quality of life and health of the population, and integrated development of territories [19].

Existing obstacles and their classification
The main obstacles to the implementation of building certification methods in Azerbaijan are:  For LEED certification, the documents are accepted only in English with imperial units of measurement and with the mandatory use of American standards like ASHRAE and others, but BREEAM can work with national building codes and standards (Table 1).
For LEED, applying for the certification process is possible only at the initial stage of project development.After the start of construction, the application for LEED certification is not considered (case of ADA University, Baku);  According to BREEAM, when creating a computer building model in an accredited calculation program of energy consumption, comparing the real energy consumption of a building with acceptable baseline values and indicators should be provided by experienced specialists, unfortunately, the experience of local specialists is insufficient;  To use only certified building materials and engineering equipment is necessary and information on their environmental impact during production, use, recycling, and disposal is obligatory.Local manufacturers do not have this data, but LEED strictly follows this rule;  Certification is a costly process, not only from an organizational point of view but also from a financial one.At present, the cost of certification in Azerbaijan is high and determined separately for each project.But it is obvious that as experience is gained in this area, this process will become more affordable.Qualitative research was applied to assess all the factors and challenges that mainly influence the development and adoption of the building certification process in Azerbaijan.All of them were grouped into three main categories: people-focused issues, technologyfocused issues, process-focused issues as shown in Table 3.

Conclusion and recommendations
The study and analysis of the main issues associated with the building certification methods used in Azerbaijan led to the following conclusion.Building certification as an effective tool for reducing human impact on the environment and promoting innovative energy and resource-saving technologies is relevant today [22].The completed complex of general and special research, the analysis of materials on the referent topic, and the experience of the authors as certified energy auditors show that:  The presence of a significant amount of natural resources determines the voluntariness of the building certification process and the passivity of officials and state organizations;  Cases of LEED and BREEAM application in Azerbaijan are due to their relative flexibility and adaptability to local building codes and practices;  The experience of applying international certification methods in Azerbaijan is gradually changing the attitude of project customers toward the organization and implementation of the construction process and stimulating further development;  The existing experience in building certification in Azerbaijan matters of great socioeconomic importance, but indicates an insufficient level of development of the real estate market in terms of compliance with international requirements;  An adequate strategy and methodology for the implementation of international and local certification methods has not yet been developed;  Further application of the national certification method GZ Azeri will be more successful and effective only with the support and facilitation of the state.Although some building owners in Azerbaijan are applying for certification, no building has been definitively certified in the last seven years.Only two buildings under construction are undergoing the process of LEED certification, and the authors are members of the expert working group.
To accelerate the building certification process in Azerbaijan and for further improvement of GZ Azeri, it is necessary to purposefully form the appropriate prerequisites:  Develop a specialized training course for local professionals depending on their skill level [20] and establish an appropriate training center in collaboration with international experts;  Create a consultation center and provide consultancy services to answer questions about building certification;  Develop a green building roadmap for Azerbaijan according to modern international requirements [23]. Introduce a specialized authority to monitor buildings' compliance with the requirements of green construction and energy efficiency of buildings;  Develop the legislative system related to green construction in general and introduce the legislative and economic incentives from the state through subsidizing, introducing a simplified taxation system, and paying part of the costs of certification. This research will help a wide range of international and local experts to better understand the emerging green building market in Azerbaijan and expand engagement with parties concerned both inside and outside of the country.The developers and owners can clarify and evaluate the goals, criteria, and standards of the three certification methods to better realize the factors influencing the choice of one or another certification method for a given building.The continuing relevance of the underlying principles and trends allows the article to claim to attract the attention of international experts for a comprehensive solution to the issue of accelerating the building certification process in Azerbaijan.Future research will focus on further improving the methodological foundations of the national certification method to involve more buildings in this process.

Fig. 3 .
Fig. 3. Buildings certification methods as part of the social-ecological system.

Fig. 6 .
Fig. 6.The main building of ADA University complies with LEED requirements. Low-potential thermal energy collection installation, circulation pumps, and other equipment have environmental certifications;

Fig. 8 .
Fig. 8.The percentage ratio of estimation criteria for the sustainability spheres: environmental, social, economic.