UHI Effect: Impact on Sustainability

Urban Heat Island (UHI) Effect arises due to absorption of incident radiation from the sun by built surfaces of tall buildings, roof, concrete structures and asphalt roads and then releasing it in the form of heat. The term “urban heat island” describes the built-up areas that are significantly hotter than the surrounding open, natural or rural areas. It occurs on the surface and in the atmosphere. The built surfaces are made of high-percentage of non-reflective and water-resistant construction materials. These materials act as heat sinks that absorb the radiated heat and store it for long time.

The UHI Phenomenon

Lack of sufficient wind, change in thermal properties of the surface materials and lack of evapotranspiration rate in urban areas cause the urban heat island effect. On the other hand, green, wooded and open spaces composed of vegetation and moisture trapping soil use large proportion of absorbed radiation and release them through evapotranspiration process. As evaporation causes cooling effect, the released water vapour contributes to cool the air in the vicinity. On a hot summer day, the urban surfaces are exposed to high temperature of   50–90°F (27–50°C) hotter than the air, where as the temperature of the shades or green open areas surrounding the urban surfaces remain close to air temperature. These changes in temperature between two areas create an “island” of higher temperature in the urban landscape. Normally the temperature difference of higher than 10 degrees forms heat islands.

Impacts on Sustainability

The increase in temperature in urban areas due to UHI effect can have negative impacts on three pillars of sustainability, i.e. environment, people and economy. Some of the negative impacts include:

  • Increase in energy consumption – Increase in temperature leads to increase in demand for cooling, which subsequently puts pressure on electricity supply during the peak periods of demand.
  • Increase in emission of air pollutants and GHGs – As more electricity is needed to cool the surfaces, demand on energy supply leads to emissions of air pollutants and greenhouse gases from the power plants. Even use of ozone depleting refrigerants such as CFCs in the air-conditioning system cause depletion in stratospheric ozone layer. Elevated temperature also promotes the formation of ground-level ozone.
  • Demand on water – As the surface and air get hotter, people consume more water for both indoor and outdoor usage and it puts pressure on water supply.
  • Ecosystem – Hot surfaces transfer the absorbed heat to water features such as rivers, streams, ponds, lake etc. increase the surface water temperature and alerting the aquatic  ecosystem structure and functions
  • Quality of life – Elevated day and night temperatures along with higher air pollution can cause respiratory diseases, discomfort, heat stress and decrease productivity and increase heat related mortalities.

UHI Effect in the UAE

UHI is quite common in cities located in the temperate zone. However, a very few studies are done so far to find how cities in semiarid and arid areas act as urban heat islands. UAE consists of seven emirates and weather here is tropical desert climate. Out of seven emirates, Dubai, Abu Dhabi and Sharjah have experienced a rapid rise of high and low intensity urban areas in recent years.

Dubai the most populated and developed emirate and a very few studies indicated that its urban climate is mostly affected by land use changes, vegetation cover, and expansion of built of areas. It was thought that cities in arid region have possibility to act as daily urban cool islands (UCI). However, there are not many studies done so far to establish this. Rather some studies indicated that Dubai has seen 64.8% change in land cover and a 1.5 degree C rise in land surface temperature (LST) in past 10 years. These are the common indicators of UHI.

Mitigation Measures

Studies have found that the mean daily temperature increase is consistent with increase in urban development. The composition of land cover features can significantly influence the magnitude of land surface temperature.  Hence, increase in percent of vegetation is the most essential driver of reducing the land surface temperature and hence the UHI effect. Therefore, proper management of green space is needed to mitigate the UHI effect in the urban cities of arid and semi arid countries. The heat island effect can be reduced by using following strategies.

  • Build small – Minimise building footprint and maximise open space
  • Minimize hardscape – Design driveways, roads, parking space and hardscape areas smartly by using permeable materials or surfaces such as vegetated roofs, porous pavement and grid pavers. Use open grid pavement system, which is at least 50% pervious and locating the parking space under the building will help reducing the urban heat island effect.
  • Use of reflective materials – Use high reflective materials with high solar reflective index (SRI) values for roofs and non-roof exterior surfaces.  The SRI value is the combined value of reflectivity and emmitance.
  • Shading – Provide shading with existing tree canopy or new trees or with other structures. The surfaces can also be coved by solar panels that produce renewable energy. Shading with some architectural features of SRI of at least 29 will also help to reduce the heat island effect.
  • High albedo cool roof and green roofs: Combination of high albedo cool roofs (roofs with controlled SRI) and vegetated roof surface can reduce heat island effect significantly.

Conclusions

The composition of land cover features can significantly influence the magnitude of land surface temperature.  Hence, increase in percent of vegetation is the most essential driver of reducing the land surface temperature and hence the UHI effect. Therefore, proper management of green space is needed to mitigate the UHI effect in the urban cities of arid and semi arid countries.

Tips to Improve Indoor Air Quality

Indoor air pollution is considered as one of the top environmental risks to public health worldwide due to increasing number of building-related illnesses. Studies have found that concentration of indoor pollutants is significantly higher indoors than they are in outdoor environment, which is two to five times and sometimes hundred times higher than outdoor levels. As most of the people spend 80% to 90% of their lives indoor, indoor air quality has significant implication on sustainability.

Decreased indoor air quality can affect quality of life of the building occupant, increase health risks and increase the liability for building owner, decrease the productivity of occupants and reduce the resale value of the building. Poor indoor air quality can cause “sick building syndrome”, which is a medical condition linked to poor health and absenteeism.

Poor indoor air quality is due to many factors including but not limited to improper building design, inadequate ventilation, off-gassing of volatile organic compounds (VOCs) from furniture, carpets, paints and coatings, cleaning products, and from human respiration. Airborne particles such as lints, dust, dust mites, mold, bacteria, pollen and animal dander also contribute to poor indoor air quality. Indicators that are used to measure the indoor air quality include total particulate matter, total volatile organic compounds (TVOCs), formaldehyde, carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), air temperature, relative humidity (RH). Concentration of CO2 in the indoor environment indicates whether ventilation is sufficient or not.

In the Middle East region, most of the people live in enclosed air-conditioned indoor environments. With rapidly growing population, increase in number of vehicles on the road, high temperature level, ever increasing construction activities, regular sandstorm, concentration of air contaminants in the region is among the highest worldwide. Indoor environment also reflects outdoor air quality and pollution. Transport of outdoor contaminants to the indoor environment can result in occupant exposure to outdoor pollutants that have serious health impacts. In addition, there are many sources of indoor pollutants present in building materials, cleaning products, indoor mold and legionella growth, and emission from interior furnishings, finishing and equipments.

Tips to Improve Indoor Air Quality

Indoor air quality is influenced by concentration of outdoor air pollutants as well as indoor source of pollution, characteristic of building and habits of occupants. Appropriate building design and mechanical system and control strategies as well as changing occupant behaviour can improve indoor air quality and health and comfort, performance and productivity of building occupants. There are a host of strategies to improve the indoor air quality.

Appropriate design: Building envelop, orientation, and location of air intake, location of mechanical ventilation systems can contribute to indoor air quality. Hence, these factors should be considered during the design stage of projects to control the main source of pollutants for the whole building.

Whole house mechanical ventilation: Properly designed and sized ventilation system can supply adequate outdoor air to indoor. In most of the green building rating systems, industry standards such as ASHRAE Standard 62 or Ventilation for Acceptable Indoor Air Quality are commonly followed.

Mixed mode ventilation: Use of combination of mechanical and natural ventilation systems in buildings, such as automated window controlling systems and operable windows, can help in maintaining healthy indoor air quality.

Air quality management during construction: During the construction phase, molds can develop due to exposure of building materials with moisture. Dust and particulates can easily accumulate on building materials if they are not protected. The air quality during the construction period can be protected by protecting the building materials from dust and particles and moistures.

High efficiency air filters: Filters prevent transports of outdoor VOCs, dusts, particulates and ozone indoors. Use of good particle filter such as high MERV rated filters in ventilation equipment are found to be the most effective filters in filtering outdoor dust and particulates out.

Maintenance schedule for HVAC filters: Dirty filter can cause sensory irritation. Hence, appropriate maintenance schedule can prevent this to happen.

Use of low emitting materials: Use of materials that have low VOC content for products such as indoor carpets, rubber flooring, sub-floor materials, ceramics and ties, plasterboards, or other sealants and adhesives.  Also internal construction materials with low formaldehyde content can be helpful.

Conduct building flush out: Flushing out of indoor contaminants thoroughly in buildings before occupancy will help replacing dirty indoor air with fresh outdoor air.

Green cleaning program: Select cleaning materials that are made of low emitting materials and employ a green cleaning program to reduce contaminant exposure.

Carbon dioxide monitors: Install CO2 monitors in ventilation system and integrate them to regulate the supply of fresh air according to the building occupants demand. By doing so, if the CO2 concentration increases beyond a set point, then the airflow automatically increases. 

خواص الأبنية الخضراء

المبني الأخضر هو المبنى الذي يراعي الاعتبارات البيئية في كل مرحلة من مراحل البناء، وهي التصميم، التنفيذ، التشغيل والصيانة، والاعتبارات الرئيسية التي تراعى هي تصميم الفراغات وكفاءة الطاقة والمياه، وكفاءة استخدام الموارد، وجودة البيئة الداخلية للمبنى، وأثر المبنى ككل على البيئة.الفرق الرئيسي بين المباني الخضراء والمباني التقليدية هو مفهوم التكامل، حيث يقوم فريق متعدد التخصصات من المتخصصين في البناء بالعمل معا منذ مرحلة ما قبل التصميم الي مرحلة ما بعد السكن لتحسين خواص الاستدامة البيئية للمبنى وتحسين الأداء والتوفير في التكاليف.

المباني الخضراء توفر العديد من المزايا للعديد من الجهات المعنية بصناعة البناء، بما في ذلك سكان المباني والمجتمع ككل.المباني الخضراء تشمل في العادة جودة هواء أفضل، اضاءة طبيعيه وفيرة، توافر اطلالات، ومكافحة الضوضاء والتي تفيد شاغلي المبنى، مما يجعل هذه المباني مكان أفضل للعمل أو المعيشه.

من السمات الاساسية في المباني الخضراء التشديد على حماية التوازن البيئي الموجود، وتحسين البيئات التي قد تكون قد تضررت في الماضي. عادة ما تشيد المباني الخضراء في الأراضي الحساسة بيئيا، مع أخذ التدابير اللازمه لاستعادة الحياة النباتية. والمباني الخضراء أيضا تستفيد من أقل قدر ممكن من المواد، من خلال تصميم جيد واهتمام بإزالة المواد غير الضرورية في التشطيبات. وبالإضافة إلى ذلك، بناء تلك المباني يرشد في استخدام المواد وكذلك إعادة تدوير المياه.

كفاءة استخدام الطاقة هي واحدة من أهم العوامل في تصميم المباني الخضراء. من الاختيارالدقيق للنوافذ، والعزل جيد للحفاظ على درجة حرارة الهواء، عزل مواسير التكييف، والوضع الصحيح لعوازل البخار والهواء، واستخدام الطاقة النظيفة في التدفئة والتبريد، تجعل المبنى كفء في استخدام الطاقة. استعمال الطاقة المتجددة، مثل طاقة الرياح، والطاقة الشمسية أو الطاقة الحيوية، لتلبية الاحتياجات من الطاقة تقلل إلى حد كبير من البصمه الكربونيه لهذه المباني.

البيوت الخضراء تشدد على الحفاظ على الماء باستخدام أنظمة أكثر كفاءة لضخ المياه واعادة استعمالها، ترشيد المياه يعد خاصية أخرى مميزة للمباني الخضراء والتي تساعد في تخفيض الاثار الضارة لاستعمال المياه على البيئة المحيطة كالبيئات البحرية مثلا.

وقد أسهمت الزيادة في الأمراض التنفسية والحساسية والمواد الكيميائة التي تطلق الغازات في الهواء، في زيادة الوعي على أهمية الهواء داخل المنازل. المباني الخضراء تركز ايضا على تقليل الأمراض التنفسيه والحساسية عن طريق تحسين الهواء داخل المنازل عن طريق التحكم في مصادر التلوث وتقليلها والقضاء عليها من خلال التنقية والترشيح.

تعد منظمات LEED (Leadership in Energy and Environmental Design), BREEAM (BRE Environmental Assessment Method) وايضا Green Globes أشهر منظمات التقييم والتقدير في العالم. الاستدامة اصبحت من أهم الاهداف في منطقة الشرق الأوسط، فدول مثل قطر والأمارات العربية المتحدة ولبنان اصدرت نظم خاصة بهم لتقييم المباني الخضراء، تشتمل على الخصائص الاجتماعية والاقتصادية والبيئية والثقافية في العمارة. النظام الشامل لتقييم الاستدامة القطري GSAS يعد من أشمل النظم العالمية للتقييم، بينما النظام التقييم الخاص بأبوظبي  PRSحصل على مكانة خاصة في قطاع المباني الخضراء العالمي.

الخلاصة

لتلخيص ما سبق، المباني الخضراء ليست تقدم فقط استدامة انشائية وبيئية، ولكن ايضا تقدم الكثير من المنافع والفوائد لمالكي المباني ومستخدميها. فتكاليف البناء المنخفضه وتكاليف التشغيل المنخفضه والراحه المتوفرة والبيئة الداخلية الأفضل صحيا، بالاضافة لتكاليف صيانة أقل وعمر افتراضي أطول، كل هذا يعد من خصائص المبنى الأخضر

 

ترجمة: طه واكد – مهندس مدني مهتم بشؤون البيئة – مصر

شريك مؤسس في مشروع دقيقة خضراء  –  معد وكاتب حلقات دقيقة خضراء عاليوتيوب

للتواصل عبر taha.waked@gmail.com   أو admin@green-min.com

Green Buildings Certification in MENA – Issues and Challenges

Green building rating systems are increasingly gaining attention in the building industry in the MENA region. During the last 15 years, there has been a regional trend in developing and applying green building ratings systems. In several countries such systems have been developed in an attempt to follow the international green movement. For example, the Pearl Building Rating System (PBRS) was founded in UAE in 2007, the Green Pyramid (GPRS) and ARZ Building Rating System in Egypt and Lebanon respectively were founded in 2008, the Edama was proposed in Jordan in 2009 and Qatar Sustainability Assessment System (QSAS) was founded in 2010. 

A new study compared four regional rating systems in the Middle East, in addition to LEED and BREEAM. The study found that the problem with most emerging rating systems is that they imitate the LEED or BREEAM rating systems and are not enough adapted to local environmental, cultural, historical, societal and economic context. Thus certification systems must be adapted to meet the needs of the Middle East regional climate, social, environmental and economic conditions.

The study, conducted in 2013, compared four rating systems (GPRS, SI 5281, QSAS and PBRS) and a cross analysis study was used to answer questions about the strength and weakness of the systems. The four systems use score point system for assessment. The four tools provide programs involving the building life cycle process – pre-design, design and post-design (occupation). There are many common criteria and categories between the four examined rating systems; such as limiting the consumption of energy and water in the building, improving the environmental quality in both indoor and outdoor, resources and material conservation, service quality, and site strategies. The four rating systems operate from an ecological foot print minimisation paradigm. At the same time, each rating system focuses on certain aspects more than the other ones according to the country’s local context. Surprisingly, there is no agreement on weighing the different environmental criteria.

Problems of Rating Systems

The study found that the examined rating systems are proposing theoretical models that needs to move to effective market implementation politically (government) and economically (NGOs & private sector). The rating systems require more adaptation to local and regional context. Rating systems should differentiate themselves from well-established rating systems.  For example, the study believes that water scarcity should be the most important category together with human wellbeing. Already LEED and BREEAM programs are considered the most fairly comprehensive in scope – from registration to calculation to building certification. In the case of the four rating systems, the initiation approaches were bottom down and not bottom up approaches.

Therefore, the uptake and market penetration is slow compared to LEED or BREEAM. In the four countries, there is no encouragement/engagement in the form of working out incentives or law enforcement to apply the four rating systems except for PBRS. In fact, each country in the region is looking to achieve those criteria individually. The entry of the LEED and BREEAM rating system into the Middle East property market coincided with increasing demand for regional and local ratings systems. As a result, different systems were developed under serious time pressure in the last ten years. The four compared systems are based on American and British standard. In the same time, there are currently no standardisation efforts working at local level to quantify and assess sustainability.

Towards Harmonised Systems

Green Building Councils in the Middle East will have a long way; they have to manage to position themselves as leaders promoting green buildings in the countries where they operate. By comparing and evaluating the four rating systems lesson could be learned and problem could be avoided. Therefore, the study author believes that a harmonised system within the Middle East would have distinctly better chances if the following issues are addressed:

Institutional Setting

Since the oil embargo of 1973, Western countries developed local codes and standards, which are revised annually, for the built environment. Those codes correspond to their context and are strongly linked to practice and buildings industry. However, in the four examined countries, the (b) local codes and standards are still not mature when compared to American or British ones. So there is a regulation problem on the institutional level. More importantly, (b) energy and water are heavily subsidized in most of the four countries.The comparison revealed that the certification rates are low and the feesstructure is very high (registration, certification, auditing).

Thus the whole political regulation landscape regarding resources efficiency is contradicting with the rating systems scope and objective. Therefore, it is important to address the (a) efficiency regulations and (b) subsidies policies on the institutional level and avoid the dependence on Western standards, codes and rating systems. This should be done through facilitating the adjustment and upgrading for the specification of environmental assessment factors in a dynamic, flexible and simple way.

Scientific Rigour and Priorities

Developing an assessment framework should be based on in-situ building performance research and technical knowledge. Technical rigour is very important in this case, for example setting benchmarks and measuring the performance. Furthermore, the investigated rating systems are located in hot climates, with scarce water resources which require a different approach and credits focus. Issues like solar protection, water conservation, life style, solar cooling and urban planning should be more strongly addressed in future developments. This includes advancing environmental footprint issues, like climate change.

Regionalisation

The assessment framework should suite the local context of each country in the Middle East, depending on its culture, issues, stakeholders, practices and institutions. Surprisingly, SI 5281 is the only rating system that was written in a native language, thus it is essential for each country, to design its own indicators to serve its goals in local language. This includes the development of local criteria to quantify the social part of sustainability that includes tradition and culture.

Providing a Platform

Multi-stakeholders should participate in developing rating systems, since they require participative and collaborative work process. Experts, designers, elected officials, working group, agency players, and others should be introduced as key participants in this process. The building industry should be encouraged to get into sustainable track to achieve a real transformation, regarding water and energy. There is a need to link those rating systems to grass root initiatives rather than developing them within academia or elite practicing companies.

According to the study, the examined certification systems need strong adaptation to meet the needs of the Middle East regional climate, social, cultural, environmental and economic conditions. Also there must be a harmonisation effort between regional rating systems aiming to develop and implement a common, transparent regional building assessment methodology. Otherwise, there will be a proliferation of immature systems without accumulated and unifying experience. 

Conclusion

There is still a long way before those examined systems examined become mature and widely usable.  Despite that the development of the examined rating systems is intended to facilitate the assessment of sustainable design in MENA; they fail to suit the local context culture issues, resources, priorities, practices and economic challenges. The GPRS, QSAS and PBRS systems neglect the interpretation of essential local sustainability measurements in their assessment set and normative standards. The study concludes that the existing rating system needs to increase the technical rigor and to put more weight on the most important categories, mainly water, IEQ, pollution and energy. The study suggests a number of recommendations to develop a harmonised green building assessment system in the MENA region. The usefulness of rating systems in the future depends on their flexibility and ability to measure the merits of buildings.

Note: The original version of the article can be viewed at this link.

District Cooling Perspectives for the Middle East

District cooling produces chilled water in a centralized location for distribution to buildings like offices and factories through a network of insulated underground pipes. The chilled water travels to different buildings, where the water circulates through refrigeration coils or uses absorption technology to enter the air-conditioning system. During winter, the source for the cooling can often be sea water, so it is a cheaper resource than using electricity to run compressors for cooling.

What is District Cooling

District cooling provides effective control over internal temperature of a building, requires less maintenance than a standalone air-conditioning system, consumes lesser space and reduces noise pollution. The effect of district cooling systems on the environment is minimal because of the reduction in carbon dioxide emissions, use of eco-friendly refrigerants and implementation of rigorous health and safety standards.

The Helsinki district cooling system in Finland uses waste heat from CHP power generation units to run absorption refrigerators for cooling during summer time, greatly reducing electricity usage. In winter time, cooling is achieved more directly using sea water. The adoption of district cooling is estimated to reduce the consumption of electricity for cooling purposes by as much as 90 percent. The idea is now being adopted in other Finnish cities.

The use of district cooling is also growing rapidly in Sweden and in a similar way. District cooling is very widespread in Stockholm, the capital of Sweden. In fact, approx. 7 million square meters of commercial space in Stockholm is connected to the district cooling grid. The Stockholm district cooling grid currently consists of different systems with capacities ranging from 3 MW to 228 MW. The district cooling network in Stockholm is currently 76 kilometers long.

District Cooling Prospects in the Middle East

There is tremendous potential for the utilization of district cooling systems in the Middle East. The constant year-round heat coupled with expensive glass exteriors for hotel, airports and offices etc result in very high indoor temperatures. The combination of distributed generation of power and utilization of waste heat can provide a sustainable solution to meet the high demand for refrigeration in the region. District cooling systems can provide cooling solutions to commercial buildings, hotels, apartment blocks, shopping malls etc.

The world’s largest district cooling plant, Integrated District Cooling Plant (IDCP), was installed in The Pearl-Qatar in 2010. IDCP will service more than 80 apartment towers, beachfront villas, townhouses, shopping complexes, offices, schools and hotels throughout the Island, ultimately supplying more than 130,000 tons of refrigeration to the Island’s estimated 50,000 residents.

Despite paramount importance of air conditioning in Middle East countries, regional governments have failed to incorporate it in policy and planning which has lead to the evolution of an unregulated market for cooling systems.  Most of the cooling methods employed nowadays are based on traditional window units or central air cooling systems where consume copious amount of power and also damage the environment.

District cooling has the potential to provide a viable solution to meet air conditioning requirements in the Middle East. Low energy requirement, peak saving potential, eco-friendliness and cost-effectiveness are major hallmarks of district cooling networks. District cooling can play a vital role in fostering sustainable development in Middle East nations. Apart from providing cooling needs, district cooling can reduce the need for new power plants, slash fossil fuel requirements and substantially reduce greenhouse gas emissions from the region.   

Green Roofs in MENA – Prospects and Challenges

Green roofs are emerging technologies that can provide a wide range of benefits to communities interested in enhancement and protection of their environment. The major benefits of green roofs are reducing energy use as well as air pollution and greenhouse gas emissions, enhancing stormwater management and water quality, decreasing heat island effect by regulating temperature for the roof and the surrounding areas and providing aesthetic value and habitats for many species.  

According to a 2013 MENA renewable energy status report, the Total Primary Energy Supply (TPES) in Middle East and North Africa has reached about 800 million tons of oil.  This equates to a 15% increase in energy demand since 2007. Increased energy consumption in the region is due largely to population growth, with related increases in demand for liquid fuels and electricity for domestic use and devices, heating, cooling, and desalination of water.  With heating and cooling being a reason for the increasing demand on fossil fuels, there is enormous opportunity for investment in green roofs as a way to stabilize or reduce energy consumption in the MENA region.  

Enhancing Stormwater Management and Water Quality

Stormwater is rainwater and melted snow that hits impervious surfaces and runs off into streets, lawns, sidewalks, and other sites. The main concern with stormwater is it can pick up debris, chemicals, dirt, and other pollutants and flow into a storm sewer system or directly to a lake, stream, river, wetland, or coastal water. In many places around the world, including MENA region, anything that enters a storm sewer system is often later discharged untreated into a nearby waterway polluting the same waters we swim, fish, and drink from.

In addition, stormwater runoff can cause flooding and an overflowing of sewer sanitary systems causing serious water quality impairments. In developing countries like Morocco and Algeria, where countrywide stormwater management and municipal waste management systems are deficient, stormwater runoff is a big problem. Rainwater flows from roofs straight onto streets carrying things like petrol, household garbage, bacteria, fertilizers and pesticides to nearby receiving waters.

According to an EPA study, green roofs are capable of removing 50% of the annual rainfall volume from a roof through retention and evapo-transpiration. By reducing the amount of impervious surfaces within a developed zone, green roofs reduce the amount of stormwater runoff.   Also, because green roofs absorb water, they delay the time at which runoff occurs, resulting in decreased stress on sewer systems at peak flow periods.

For conventional non-living roofs with a slope of 2%, a 96% runoff rate is observed.  On the other hand, intensive green roofs may have as low as a 15% runoff rate.  The benefits green roofs have regarding stormwater runoff could be amplified by more green roofs in a close-knit area and using green roofs with a deeper substrate layer. Nevertheless, if implemented, countries in the MENA region in which stormwater management systems are not in place could greatly benefit from the use of green roofs to help reduce hazardous runoff and subsequent contamination of water supplies. 

Decreasing Urban Heat Island Effect

Since the built environment tends to be constructed from materials that are impermeable and non-reflective they tend to absorb a significant proportion of the sun’s radiation and release it as heat. Because urban areas are densely populated with buildings, they tend to be hotter than the surrounding areas, a phenomenon known as heat island effect.  Urban heat islands have many negative impacts such as an in increase energy demand for cooling, an increase in air pollutants and greenhouse gas emissions, and impaired water quality.

The heat island effect causes internal temperatures of buildings to rise which subsequently increases the demand for air-conditioning to moderate the buildings internal temperatures.  This in turn leads to higher emissions from power plants, as well as increased smog production as a result of warmer temperatures.  Additionally, hot rooftop surfaces transfer their excess heat to stormwater causing the runoff water to be much warmer than the streams, lakes, and other waterways it enters.  In many cases dealing with this rapid change in temperature causes stress to aquatic ecosystems.

Urban heat island effect is especially worrisome for areas like Middle East and North Africa, where out of a population of 300 million, 170 million people reside in urban areas. Furthermore, according to UN projections the MENA population will reach 430 million by 2020, of which 280 million are expected to be urban.  In order to combat the potential for the heat island effect in the MENA region, communities can utilize green roofs. 

The vegetative surfaces of green roofs utilize a relatively large proportion of the absorbed radiation in the evapo-transpiration process and then release water vapor into the air which helps to cool air temperatures.  Additionally, the shade provided by trees and other shrubbery greatly helps to reduce the rooftop temperatures and the overall heat island effect. 

Roof Lifespan

Rooftop vegetation moderates the factors that accelerate a rooftops breakdown such as extreme temperatures, UV radiation, and cold winds, thus dramatically expanding the life of a roof.  According to a study in Germany, a vegetated roof on average can be expected to prolong the service life of a conventional roof by at least 20 years. The result of this is not only cost savings to the building’s owner but also a reduction of landfill wastes. 

Habitats for Species

One of the more altruistic aspects of green roofs is the creation of wildlife habitats. Green roofs can provide habitat (food, shelter, water and breeding grounds) for many different species. Because of their high density, cities severely restrict green space and threaten or destroy habitats so the creation of such green space assumes particular importance in these areas.  Urban habitats are often seen as too degraded and depauperate to support biodiversity. 

Various recent studies in Europe have indicated that green roofs in large cities have high potential as habitat for species negatively impacted by land-use changes. For example, in Basel, Switzerland, surveys of birds, spiders and beetles on green roofs found high diversity levels for all groups, including many species considered rare or threatened.

For modern Middle Eastern citiies like Dubai, Jeddah, Cairo, Beirut and Tehran, creation of habitats for species could be very valuable.  Across the MENA region natural habitats are few and far, and green roofs can provide living space for plants and animals, especially for species such as invertebrates and birds. 

Aesthetic Value

Green roofs have the ability to significantly improve the beauty of buildings, the visual and environmental diversity which can have positive impacts psychological well-being. Studies across several countries have all shown the correlation between daily contact with nature and human well-being. In fact, the results of a large survey in the Netherlands showed that the amount of green space in the residential environment was positively related to the health condition people said they experienced in their daily life.

When people have contact with green space research has indicated a positive effect in levels of stress, health levels due to green space encouraging a higher level of use of the outdoor spaces, and mental well-being due to positive psychological effects plants and nature has on humans.

Current Scenario

While green roofs in Northern Scandinavia have been around for centuries, in North America green roofs are still a relatively new technology. In Europe, these technologies have become very well established mainly due to governments and legislatives financial support.  This support has led to the creation of a vibrant, multi-million dollar market for green roof products and services in Germany, France, Austria and Switzerland among others.

Currently, implementation of green roofs is rare in the MENA region.  However, there is a definite market potential as the benefits of green roofs address many of the major environmental concerns of this area.  Furthermore, the concrete architecture in the Middle East is ideal for a green roof implementation.  The structural soundness of concrete buildings has the potential to support the weight load of both intensive and extensive roofs. The swift progress of green buildings industry in the Middle East  promises a deeper penetration of green roofs in domestic as well as commercial constructions in the years to come.

However, one issue that may surface is that roofs are often fully accessible and are often used to dry laundry or to hold social events like weddings and other celebrations.  This may pose an issue for home owners if their green roof takes up too much of their roof to perform their daily functions.  An intensive roof may be more suitable for homeowners in this region as they lend well to daily visits and offer space to hold social functions.

Conclusion

Due to their extensive range of environmental and economic benefits, particularly their insulation and cooling properties, ability to significantly reduce rainwater runoff and urban heat island effect, as well as improve air quality and their value in promoting biodiversity and habitat in urban areas, green roofs have become important elements of sustainable and green construction in many countries.  While the green roof industry is growing in popularity, the industry is still young with many areas needing advancement.

The major barriers to green roof expansion in the Middle East include a lack of governmental support, high installation costs, lack of awareness and education about green roofs, and limited data quantifying green roof benefits.  However, with proper support these barriers can be easily overcome through research and innovation in design by the green roof industry. 

 

References

  1. After the Storm". (2013). 2013, from http://water.epa.gov/action/weatherchannel/stormwater.cfm#what
  2. Akbari, H. (2005). Energy Saving Potentials and Air Quality Benefits of Urban Heat Island Mitigation. 1-19. http://www.osti.gov/scitech/servlets/purl/860475
  3. Beattie, D., Berghage, R., Jarrett, A., O’Connor, T., Razaei, F., & Thuring, C. (2009). Green Roofs for Stormwater Runoff Control (pp. 81). National Risk Management Research Laboratory Office Of Research And Development: EPA.
  4. Bryden, J., Riahi, L., & Zissler, R. (2013). MENA Renewables Status Report. In L. Mastny (Ed.), (pp. 21). REN21 Secretariat, Paris, France.
  5. Colla, S. R., Packer, L., & Willis, E. (2009). Can green roofs provide habitat for urban bees (Hymenoptera: Apidae)? . Cities and the Environment 2(1), 1-12. http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=1017&context=cate
  6. Dinsdale, S., Pearen, B., & Wilson, C. (2006). Feasibility Study for Green Roof Application on Queen’s University Campus: Queens University.
  7. Dunnett, N. (2006). Green Roofs For Biodiversity: Reconciling Aesthetics With Ecology. Paper presented at the Fourth Annual Greening Rooftops for Sustainable Communities Conference, Boston.
  8. Green Roof Benefits. (2013).   Retrieved 12/9/2013, from http://www.greenroofs.org/index.php/about/greenroofbenefits
  9. Hermy, M., Mentens, J., & Raes, D. (2006). Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century? Landscape and Urban Planning, 77, 217–226. Retrieved from www.sciencedirect.com website: http://www.floradak.be/downloads/eng.pdf
  10. The Future of Green Roofs.   Retrieved 12/18/2013, from http://www.hrt.msu.edu/greenroof/future/index.html
  11. The social role of green space – health, education and enjoyment of life. (2005).   Retrieved 12/18/2013, from http://www.thesteelvalleyproject.info/green/intro/people-2.htm#well
  12. Urban Challenges in the MENA Region. (2013).   Retrieved 12/14/2013, from http://goo.gl/IT8rWo 
  13. What Is an Urban Heat Island? (2013).   Retrieved 12/14/2013, from http://www.epa.gov/hiri/about/index.htm

Green Buildings and the Middle East

The Middle East region faces a unique set of challenges in terms of sustainable buildings and cities. For example, water shortage is mitigated by costly desalination and we are faced with high water consumption which leads to a higher carbon footprint and ultimately impacts climate change. Middle Eastern countries are at the top of the list of largest per capita ecological footprints. Qatar has the highest per capita level of carbon dioxide emissions, at 44 metric tons per person annually. Kuwait is second with 30.3 tons, followed by the UAE with 22.6. Therefore, integrating energy efficiency is a critical need.

Benefits of Green Buildings for Middle East

The benefits of green buildings for the Middle East are not only environmental, but also economic and social. Long-term operating costs are lowered via reduced energy consumption, reduced emissions, improved water conservation and management, temperature moderation, and reduced waste. Avoiding scarce natural resources, like water, opting instead to recycle, can cut down building costs by an estimated 10 percent.

With a third of the world's energy being utilised in construction and building operation, the concept of green buildings is becoming more and more popular worldwide. General construction work uses excessive amounts of energy, water and raw materials and tends to generate large amounts of waste and potentially harmful atmospheric emissions. As a result, companies are facing demands to build environmentally friendly and eco-efficient buildings, while minimising their actual impact on the environment.

Green buildings do not require complex processes and costly mechanisms. Affordable green technologies include tankers to store and harvest rainwater to cut water consumption, intelligent lighting systems to cut electricity use, natural ventilation and a ground source heat pump that reduces heating and cooling costs. Energy efficiency is another cornerstone of green building. Careful window selection, building envelope air sealing, duct sealing, proper placement of air and vapour barriers, use of clean energy-powered heating/cooling systems all contribute towards an energy efficient building.

Use of renewable energy, such as solar, wind or biomass energy, to meet energy requirements can significantly reduce carbon footprints of such buildings. Other green trends that are currently being advocated include carbon neutral communities, public transport and no-car cities, self-sustaining urban planning, on-site water treatment plants, and cultural sensitivity incorporating traditional design elements.

Green Building Trends in Middle East

The Middle East region has made great progress in the field of green buildings in recent years. Sustainable building design is gaining popularity in the Middle East with designers and construction firms finding the most eco-friendly ways to get buildings made. Sustainability is now a top priority in the region and countries like Qatar, UAE and Lebanon have come up with their own green building rating system to incorporate socio-economic, environmental and cultural aspects in modern architecture. Qatar's Global Sustainability Assessment System (GSAS) is billed as the world's most comprehensive green building rating system while Abu Dhabi's Pearl Rating System (PRS) has carved a niche of its own in global green buildings sector.

United Arab Emirates and Qatar are spearheading the sustainability trend in the region, having the highest share of green buildings in the Middle East and North Africa. There are about 1,200 green buildings in MENA that have a Leadership in Energy and Environmental Design (LEED) accreditation. Of these buildings, 65 per cent (802) are located in the UAE. Qatar is ranked second on the list, with 173 green buildings, followed by Saudi Arabia (145), Lebanon (25) and Egypt (22).

The number of LEED-registered buildings has increased rapidly across the region, especially in GCC, in the past few years. Some of the notable examples of green buildings in the Middle East are Masdar City in Abu Dhabi, KAUST in Saudi Arabia and Msheireb Downtown Doha in Qatar. Masdar City promises to be a model for green cities all over the world. The King Abdullah University of Science in Saudi Arabia employs many forward-reaching green features while Msheireb Downtown Doha promises to be the world's largest sustainable community with 100 buildings using an average of a third less energy.

If Middle Eastern industries embrace 'green building' technologies instead of conventional ones, they could significantly help in tackling environment problems in addition to long-term financial returns. Although the MENA region still lags behind other markets in terms of overall sustainability, 29% of firms in this region have over 2 million square feet of green projects planned in the next 3 years, by far the highest of any region. Green building systems technologies can serve as catalysts for smartly shaping urbanization, ensuring energy security, combating climate change, and opening new diplomatic and economic opportunities. 

نظم تقييم المباني الخضراء في الشرق الأوسط

الأبنية الخضراء لا تساهم فقط في بيئة أفضل وطرق بناء مستدامه، ولكنها تجلب ايضا الكثير من المنافع والفوائد لمالكي المباني ومستخدميها. فتكلفة الانشاء أقل، وتكلفة التشغيل أقل، وسبل الراحه أكثر، والبيئة الداخلية أكثر صحة، والعمر الأفتراضي أطول وتكاليف الصيانة أقل في المبنى الأخضر.

توجد العديد من النظم لتقدير وتقييم المباني الخضراء حول العالم، مثل LEED  و BREEAM . فالاستدامة الان تعد هامة جدا في منطقة الشرق الأوسط ودول مثل قطر والامارات لديهم انظمتهم الخاصة بهم لتقييم المباني لتشمل السمات الاجتماعية والبيئية والاقتصادية والثقافية في العمارة الحديثة

نظام تقييم الاستدامة الشامل (قطر)

ان نظام تقييم الاستدامة الشامل (GSAS) المعروف رسميا باسم نظام تقييم الاستدامة القطري (QSAS) تم تطويره في عام 2010 بواسطة منظمة الابحاث والتطوير الخليجيه (GORD) بالتعاون مع مركز T.C. Chan  في جامعة بنسيلفنيا ويهدف الي انشاء بيئة حضرية مستدامة لتقليل التأثيرات البيئية للمباني وفي نفس الوقت تحقق احتياجات المجتمع.

توصف GSAS  كأكثر نظام تقييم شامل للمباني الخضراء في العالم بعد تحليل دقيق لأربعين كود للمباني الخضراء من حول العالم. أهم مميزات نظام GSAS  انها تأخذ في الحسبان السمات الاجتماعيه والاقتصادية والبيئية والثقافية للمجتمع، والتي تختلف في مناطق العالم. الكثير من بلدان الشرق الأوسط مثل السعودية والكويت والأردن والسودان، أبدو اهتمام شديد في اتخاذ GSAS  ككود موحد للمباني الخضراء في المنطقة.

 

المعاير الخاصة بشهادة GSAS  تنقسم الي 8 أقسام:

قامت قطر بادراج QSAS في كود البناء القطري 2010 والان يجب على كل مشاريع القطاع العام والخاص الحصول على شهادة GSAS. تضم GSAS 140 آليه تقييم للاستدامة، وتنقسم إلى 8 أقسام تشمل الاتصال الحضري والموقع والطاقة والماء والمواد والبيئة الداخلية والقيمة الاقتصادية والثقافية والإدارة والتشغيل. كل قسم من النظام سوف يقيس خاصية معينه في التأثير البيئي للمشروع. كل قسم ينقسم إلى معايير محدده تقيس وتحدد موضوع بعينه. ثم يعطى درجة لكل قسم حسب درجة التوافق.

نظام التقييم اللؤلؤي (أبو ظبي)

ان نظام التقييم اللؤلؤي PRS  هو نظام تقييم المباني الخضراء لإمارة أبو ظبي، صمم ليدعم الاستدامة من التصميم للتنفيذ إلى التشغيل يشمل المجتمعات والمباني والفيلات، ويعطي ارشادات ومتطلبات لتقييم الاداء المتوقع للمشروع من منظور الاستدامه.

ان نظام التقييم اللؤلؤي هو مبادرة من الحكومة لتحسين الحياة لمن يسكن في أبو ظبي من خلال التركيز على العادات الثقافية والقيم الاجتماعية، نظام التقييم مفصل بدقه على مناخ أبو ظبي الحار والذي يتميز باحتياج الطاقه العالي لتكييف الهواء، معدل البخر العالي، سقوط المطر القليل، وندرة المياه الصالحة للشرب.

الأقسام المتنوعة في نظام التقييم اللؤلؤي

يوجد في نظام التقييم اللؤلؤي العديد من مستويات الشهادات، بدءا من واحد الي خمس لؤلؤات. مطلوب على أقل تقدير شهادة بلؤلؤه واحده لتطوير أي مشروع داخل أبو ظبي. يقسم النظام اللؤلؤي الي سبعة أقسام منها اعتمادات اجبارية واعتمادات اختيارية. للحصول على دجة لؤلؤه واحدة يجب على الأقل ان تتحقق جميع الاعتمادات الاجبارية.

نظام الأرز لتقييم المباني (لبنان)

نظام الأرز هو نظام أقل شهرة لتقييم المباني، وهو أول نظام مباني خضراء لبناني كمبادرة لكود دولي مع نظام اعتماد تديره جمعية المباني الخضراء اللبنانية (LGBC). انشأ هذا النظام ليدعم نمو وتبني استخدام المباني المستدامة في لبنان، مع تركيز على التقييم والتقدير البيئي للمباني التجارية

نظام الأرز لتقييم المباني تم تطويره بواسطة خبراء لبنانيين من LGBC بالشراكة مع مؤسسة التمويل الدولية، ويهدف الي تحقيق أقصى قدر من الكفاءة في التشغيل وتقليل الأثر البيئي. نظام الأرز هو منهج قائم على الأدلة لتقييم المباني ومدى استدمتها. النظام يحتوي على مجموعة من التقنيات والاجراءات ومستويات استهلاك الطاقة التي تتوقع LGBC   رؤيتها في المباني الخضراء

يقوم مقيم معتمد من قبل LGBC بأخذ جرد لاستهلاك الطاقة والمياه، التقنيات والاجراءات المستخدمة في المبنى، ثم تقوم LGBC بعطاء درجة للمبنى بناءا على مدى جودة استهلاكه وموافقته للتقنيات والاجراءات الخاصة بنظام تقييم الأرز.

ترجمة: طه واكد – مهندس مدني مهتم بشؤون البيئة – مصر

شريك مؤسس في مشروع دقيقة خضراء  –  معد وكاتب حلقات دقيقة خضراء عاليوتيوب

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