Scholarly article on topic 'Environmental Life Cycle Assessment of a Residential Building in Egypt: A Case Study'

Environmental Life Cycle Assessment of a Residential Building in Egypt: A Case Study Academic research paper on "Civil engineering"

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Abstract of research paper on Civil engineering, author of scientific article — Ahmed Abdel Monteleb M. Ali, Abdelazim M. Negm, Mahmoud F. Bady, Mona G.E. Ibrahim

Abstract Residential buildings play prominent role in sustainable development and environmental impacts. Therefore, the aim of this paper is using the life cycle assessment (LCA) tool to assess the environmental impacts of the Egyptian typical residential building. SimaPro V8.1 was used in the analysis under ISO 14040 standards. Results show that the main contributor to all other environmental impacts are mainly those related to energy use in the operational/use stage contributing by (71.9%). On the other hand, the disposal scenarios provide positive environmental impacts by (-12.1%). Further possible measures to enhance the environmental impacts are mentioned in the paper conclusions.

Academic research paper on topic "Environmental Life Cycle Assessment of a Residential Building in Egypt: A Case Study"

Available online at www.sciencedirect.com

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Procedia Technology 19 (2015) 349 - 356

8th International Conference Interdisciplinarity in Engineering, INTER-ENG 2014,9-10 October

2014, Tirgu Mures, Romania

Environmental life cycle assessment of a residential building in

Egypt: A case study

Ahmed AbdelMonteleb M. Alia'*, Abdelazim M. Negm\ Mahmoud F. Badya,

Mona G.E. Ibrahimb

a Environmental Engineering Department, Egypt-Japan University of Science and Technology, (E-JUST), P.O.Box 179, New BorgAl-Arab City,

Postal Code 21934, Alexandria, Egypt bSchool of Energy, Environment and Chemical & Petrochemical Engineering, Egypt-Japan University of Science and Technology

Abstract

Residential buildings play prominent role in sustainable development and environmental impacts. Therefore, the aim of this paper is using the life cycle assessment (LCA) tool to assess the environmental impacts of the Egyptian typical residential building. SimaPro V8.1 was used in the analysis under ISO 14040 standards. Results show that the main contributor to all other environmental impacts are mainly those related to energy use in the operational/use stage contributing by (71.9%). On the other hand, the disposal scenarios provide positive environmental impacts by (-12.1%). Further possible measures to enhance the environmental impacts are mentioned in the paper conclusions.

© 2015 TheAuthors.Publishedby ElsevierLtd.This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of "Petru Maior" University of Tirgu Mures, Faculty of Engineering

Keywords: Environmental Impact Assessment; Life Cycle Assessment; Residential Building; Egypt.

1. Introduction:

Every product or process goes through various phases or stages in its life. Each stage is composed of a number of activities. For industrial products, these stages can be broadly defined as material acquisition, manufacturing, use and maintenance and end-of-life. In case of buildings, these stages are more fully delineated as: materials manufacturing, construction, use and maintenance, and end of life [1].

* Corresponding author. Tel.: +020-100-5490811; fax: +02-03-4599520. E-mail address: ahmed.abdelmonteleb@ejust.edu.eg

2212-0173 © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of "Petru Maior" University of Tirgu Mures, Faculty of Engineering doi: 10. 1016/j .protcy.2015.02.050

1.1. Material Manufacturing

This stage includes removal of raw material from the earth, transportation of these materials to the manufacturing location, manufacture of finished or intermediate materials, building product fabrication, and packaging and distribution of building products [2].

1.2. Construction

This phase accounts for activities relating to actual construction of a building project. Typically, the following activities are included in this stage: transportation of materials and products to the project site, use of power tools and equipment during construction of the building, on-site fabrication, and energy used for site work. Permanent impacts to the building site also fall into this stage [3].

1.3. Use and Maintenance

This stage refers to building operation, which includes energy consumption, water use, and environmental waste generation. It also takes into account the repair and replacement of building assemblies and systems. The transport and equipment use for repair and replacement is also considered in this stage.

1.4. End of Life

This includes energy consumed and environmental waste produced due to building demolition and disposal of materials to landfills. The transport of waste building material is also included in this stage. Recycling, reuse and incineration activities related to demolition waste can also be included in this stage, depending on the availability of data. (The return of significant high-value materials to the inventory through the recycling and the reusing process can even be considered as a "negative impact") [3].

Each LCA stage may have a hidden element which is individual worker transportation. Scheuer et al. [4] mentioned that LCAs have typically not included individual worker transportation. Cole et al. [5] however, did include worker transportation in construction of structural assemblies; hypothesizing a significant impact, based on the number of workers on a building project, their mode of transportation, and the duration of the construction process. Cole found that worker transportation could account for 10-80% of total construction energy. This study, however, did not account for worker transportation, because no detailed actual information are available for this particular case study , and worker transportation was not included for other processes used in this study, such as material production.

2. LCA application to Egyptian residential building case study

The study choses existing buildings, typical of current Egyptian construction techniques and building typologies in New Assiut City (NAC), from cradle to grave LCA analysis. To study a residential pattern and analyze its models, the area of each pattern had to be calculated, along with its percentage in the housing of NAC. Analysis for housing patterns in NAC shows that Ibn Baytak (means build your house project) ranks first in the city with a 33.15% of the total patterns area [6]. Ibn Bytak consists of five phases. The first and third phase are located in the second district. Whereas the fifth stage in the first district, and the second and fourth phases are located in the future extension of the NAC [7].

The case study is chosen in the first phase for studying the Environmental Impact Assessment (EIA) of the model using the LCA tool. The selected model comprises three building types X, Y and Z. Model X is attached from one side and with three free facades. For Models Y and Z both two are attached from two directions and free from the other two, i.e. only two facades. Table 1 illustrates the numbers and percentages of the three models. In this paper, the analysis is done only on type Z because it is the most common (56.45% of the total Ibn Baytak models).

Table 1. Numbers and percentages of the three Ibn Baytak models [6]

Model Number Percentage

Model X 206 plots 40,95 %

Model Y 13 plots 2,60%

Model Z 234 plots 56,45 %

3. Steps of the LCA Process

SimaPro V8.1 was used in the analysis of environmental life cycle assessment of the selected residential building in NAC. SimaPro is a dedicated LCA software tool for undertaking LCA studies according to EN ISO 14040 [8] and EN ISO 14044 [9]. Figure 1 shows the four main phases of LCA according to the ISO standards [11].

Fig. 1. LCA phases according to ISO 14040 [10].

3.1. Goal and scope definition

Setting on the goal is an important step in applying LCA in building construction industry. A possible goal is to evaluate/assess the environmental impact of Egyptian typical residential buildings throughout their entire life cycle. The lifetime of the buildings is assumed to be 50 years, which is consistent with most of the published case studies, it can be seen in L.F. Cabeza, etal. [11] where he compiled more 70 literature case studies in Table 6 in his paper.

• System boundaries

The system boundaries determine which unit processes are included in LCA study. The system-building is broken down into process units, encompassing all the elements, materials, and components that constitute the building and are affected by flows of matter and energy during their life phases. For classifying the building' elements, the research choose typical residential building in NAC which is Ibn Baytak model Z. The study suggests three phases of the LCA which are; construction material (which include; material production and building construction), operational/use phase and End-of-Life phase (including the disposal, recycle and reuse stages). This closed loop is from cradle to cradle stage as shown in Fig. 1. Each item has many other elements which will be studied by using Life Cycle Impact Assessment (LCIA).

• Functional unit:

The functional unit of the study is the usable floor space (m2) of the building under study. The reference flow is the amount of material required to produce a building designed according to the given goal and scope.

3.2. Life cycle inventory (LCI) database:

The analysis accounts for the full cradle-to-cradle life cycle of the building studied, including material manufacturing, and end-of-life (disposal, incineration, and/or recycling), including the materials and energy used across all life cycle stages. Architectural materials and assemblies include primary materials and all additional materials required for the product's manufacturing and use (including hardware, sealants, adhesives, coatings, and finishing, etc.) up to a 1% cut-off factor by mass with the exception of known chemicals that have high

environmental impacts at low levels. To the best of the authors knowledge and from previous authors literature which published in [12], Egypt suffered from shortage of life cycle inventory database, thus, the authors collected all required quantities and specifications of the residential building in Table 2 and any missing data will be taken from literature review and international papers which summarized in in L.F. Cabeza, et al. [11], assumptions and Ecoinvent V.3 Database in the SimaPro software.

Table 2. Collected quantities and specifications of the selected residential building in Egypt.

Rough Estimate • Steel = 1368 Kg

of building . Cement = 8186Kg

Materials

• Red Brick = 17.7 m3, the density = 1920 kg/m3

• Sand = 85.7 m3, the density = 1600 kg/m3

• Gravel = 14.50 m3, thedensity = 1520 kg/m3

• Water for constructing the building = 1338 Liter, the density = 1000 kg/m3

• Wooden = 0.7 m3, the density = 640 kg/m3

• Glass = 4 m2 and the thickness = 0.004 cm, the density = 2580 kg/m3

• Ceramic = 30 m2 and the thickness = 0.006 cm, the density = 3250 kg/m3

• Plaster Paints = 170 m2 and the thickness = 0.002 cm, the density = 2100 kg/m3 Transportation • From Cement and brick distributors to building site = 5 KM.

• From other materials distributors to building site = 5 KM.

• Type of Truck transportations:

o For transport the cement = 8.186/10 (ton for one truck) = 0.8186 Trucks Unit for 20 KM. o For transport the sand = 85.7/10 (m3 for one truck) = 8.57 Trucks Unit for 5 KM. o For transport the brick = 11200 brick need only one truck for 5 KM. o For transport the steel = 1368 Kg needs only one truck for 5 KM.

o For transport output of drilling = 90 /10 (m3 for one truck) = 9 Trucks Unit for 30 KM to disposal site, o SO,it needs 24 truck unit from truck tonnage of 24 tons from EUR03 type.

o Only one car to transfer Traditional Cement Mixer and the workers in the building site for 5 KM to the disposal site, back and forth.

Construction of Buildings • For drilling stage; two types of machines: o Working hours =10 o Solar gas consumption = 30 Liter

• For Traditional Cement Mixer: o Working hours = 5 o Solar gas consumption =15 Liter

Operational Use • Electricity Consumption Monthly = 492 KW

• Water Consumption Monthly = 100 m3

• Natural Gas Consumption Monthly =16 m3

Demolition / End-of-Life • A high-reach excavator is used to demolish the building after 60 years life span, o Working hours = 3 o Solargasconsumption = 10Liter

• For transport output of building demolition 30 KM to disposal site.

• Disposal scenario:

o Landfill = 20%, Disposal = 20% and Reuse = 60%.

o 80% from building materials will be recycled and the remainder (20%) will be burned (Incineration).

Manufacturing includes cradle-to-gate manufacturing wherever possible. This includes raw material extraction and processing, intermediate transportation, and final manufacturing and assembly. Due to data limitations, however, some manufacturing steps have been excluded such as the material and energy requirements for assembling doors and windows. The manufacturing scope is listed for each entry, detailing any specific inclusions or exclusions that fall outside of the cradle-to-cradle scope. Transportation of upstream raw materials or intermediate products to final manufacturing is generally included in the SimaPro datasets utilized within this tool. Transportation requirements between the manufacturer and installation or use of the product, and at the end-of-life of the product, are included from this study. Infrastructure (buildings and machinery) required for the manufacturing and assembly of building materials, as well as packaging materials, are included and are considered inside the scope of assessment.

End-of-life treatment is based on hypothetical scenario because Ibn Baytak project in Egypt does not have waste treatment system and rates according to building demolition and all components goes to the landfill without any benefit. This includes the relevant material collection rates for recycling, processing requirements for recycled materials, incineration rates, and landfilling rates. Along with processing requirements, the recycling of materials is modeled using an avoided burden approach, where the burden of primary material production is allocated to the subsequent life cycle based on the quantity of recovered secondary material. The impacts associated with landfilling are based on average material properties, such as plastic waste, biodegradable waste, or inert material. Specific end-of-life scenarios are detailed for each entry in the next table.

3.3. Life cycle impact assessment (LCIA):

The use of impact categories gives the ability to compare the environmental impacts of the different options. Characterization factors, or equivalency factors, describe the relative impact of the different environmental flows[13] A larger characterization factor means a larger impact for that flow. Characterization factors are multiplied by each of the environmental flows to convert all them into an equivalent amount of the category indicator. The category indicator is the flow that is usually associated with that particular impact category (for instance, CO2 for global warming category[14]. Table 3 describes the environmental impact categories which are required for LCI inventory involved in SimaPro V.8.1. This study used the IMPACT 2002+ (version Q2.2) category to assess the environmental impacts of the Egyptian typical residential building.

Table 3. Sources for characterization factors and damage units of IMPACT 2002+(version Q2.2) [15]

[source]

Midpoint category

Midpoint reference substance Damage category

Damage unit

Normalized damage unit

[b] [b] [b]

Human toxicity (carcinogens + non-carcinogens)

Respiratory (inorganics)

Ionizing radiations

Ozone layer depletion

Photochemical oxidation (= Respiratory (organics) for human health)

Aquatic ecotoxicity

kg Chloroethylene into air-eq Human health

kg PM2.5 into air-eq Bq Carbon-14 into air-eq kg CFC-11 into air-eq

kg Ethylene into air-eq

kg Triethylene glycol into water-eq

Human health Human health Human health Human health Ecosystem quality

Ecosystem quality

Terrestrial ecotoxicity

kg Triethylene glycol into soil-eq

Ecosystem quality

PDF m-y

Terrestrial

acidification/nutrification

kg SO2 into air-eq

Ecosystem quality

[source] Midpoint category Midpoint reference substance Damage category Damage unit Normalized damage unit

[c] Aquatic acidification kg S02 into air-eq Ecosystem quality

[c] Aquatic eutrophication kg P043- into water -eq Ecosystem quality

[b] Land occupation Water turbined m2 Organic arable land-eq • y inventory in m3 Ecosystem quality Ecosystem quality

[IPCC] Global warming kg C02 into air-eq Climate change (life support system) kg C02 into air-eq Point

[d] Non-renewable energy MJ or kg Crude oil-eq (860 kg/m3) Resources

[b] Mineral extraction MJ or kg Iron-eq (in ore) Resources MJ Point

Damage unit

Normalized damage unit

[b] Land occupation

Water turbined

[IPCC] Global warming [d] Non-renewable energy

[b] Mineral extraction

m2 Organic arable land-eq • y inventory in m3

kg C02 into air-eq

MJ or kg Crude oil-eq (860 kg/m3)

MJ or kg Iron-eq (in ore)

Ecosystem quality

Ecosystem quality

Ecosystem quality

Ecosystem quality

Climate change (life support system)

Resources Resources

kg C02 into air-eq

• [a] IMPACT 2002, [b]Eco-indicator 99, [cJCML 2002, [d] Ecoinvent, [IPCC] (IPCC AR5 Report), and [USEPA] (EPA). DALY- Disability-Adjusted Life Years; PDF= Potentially Disappeared Fraction of species; eq= equivalents; y= year.

In LCA-type models, two main methods in describing impacts can be distinguished: [16], At the level of midpoint impacts, e.g., covering issues such as climate change, ozone layer depletion, human toxicity, acidification, and abiotic resource depletion. Furthermore the study uses the endpoint impacts of Egyptian residential building, covering issues, such as; [17]

• Human health, expressed as the number of years of human life lost or suffering from disease.

• Quality of ecosystems, expressed as the loss of living species in a certain area over a time.

• Natural resources, expressed as the surplus of energy necessary for further extracting minerals and fossil fuels.

3.4. Results, Interpretation andDiscussions:

The inflows involved in building LCA stages are presented in Fig. 2. The most significant inflows correspond to the operational/use stage (about 71.9%), because of the huge amount of energy required for the household appliances, maintenance and daily living through the lifetime of the buildings. The following significant inflow corresponds to the preparation of all building material (24%), which is used in the construction phase. However, there is a big difference between the contribution of this stage and the operational/use stage. The inflows for construction building stage are in smaller magnitude (16.2%). Finally, there is a green line which pertains to the demolition phase (-12.1%). This is attributed to the benefits from the disposal stage including recycling which is suggested by the authors to be included in the life cycle of Ibn Baytak project (Table 2).

BukJrg Disposal ■10.4%

—»—r

Operational ^J se I Phase

0.6p Reuse Bulking Components

Assembly-Buking Model

Operational AJse Phase

Building Disposal Buking construction Assembly • BuJdng Model

•12.1 16.2 24

1. SES kg Bride, at pl»itjRKU

3.61E4kg Portland cement, strength dass Z

8.19E3 kg Steel, low-afcyed, at

3. HE3kg Akyd paint, white, 60% in

Z57E3kg Ceramic tiles, at regional

6.04E5 kg Sdica sand, at plant/OEU

□ Assembly

□ Life cyde

□ Disposal scenario

□ Disassembly

□ Reuse

□ Material

□ Energy

□ Transport

□ Processng

□ Use

□ Waste scenario

□ Waste treatment

Fig. 2. The network flow of Building LCA stages; the top process only and with cut off 3%.

As shown in Fig. 3, the comparison between the building LCA stages from the environmental impacts point of view. There are three impacts which influence negatively on the environment, namely, the respiratory inorganics, global warming and non-renewable energy. In details, the operational/use stage has the biggest share in these categories then the building metrical preparation, building construction and finally by negative figures, the building disposal (Demolition stage). This is caused due to the particulate per matter 2.5, carbon dioxide and the Megajoule -which consumed as the energy - have the biggest adverse impact on the environmental in the building industry. Another main sources of these impacts is the air emissions which released from the process of the building LCA and the consumption/depletion of the raw materials. Furthermore, the carcinogens, non-carcinogens, terrestrial ecotoxicity and the land occupation have smaller magnitude in the environmental impacts.

Carcinogens Non-carcino Respiratory Ionizing Ozone layer Respiratory Aquatic eco Terrestrial Terrestrial Land occup Aquatic acid Aquatic eutr Global Non-renewa Mineral extr gens inorganics radiation depletion organics toxicity ecotoxicity add/nutri abon ification ophication warming ble energy action

I Assembly -Building Model I

3 Operational/Use Phase

I Building construction

Analyzing 1 p "Residential Building ModeT;

Method: IMPACT 2002+ V2.05 / IMPACT 2002+ / Normalization

Fig. 3. Environmental impact outflows for the usable floor space (m2) of the building under Midpoint impact.

Moving to the endpoint method as can be depicted from Fig. 4. It is observed that the operational/use phase is the major contributor to the damage of human health, degradation of ecosystem quality, climate change and resources depletion. The minimum effect is on the ecosystem quality degradation. The figure shows a saving from the building disposal scenario by 3 (Pt.) Eco point for the environment.

Assembly - Building Model Building Disposal Operational/Use Phase Building construction

H Human health Oi Ecosystem quality O Climate change ■ Resources

Analyzing 1 p -Residential Building ModeT;

Method: IMPACT 2002+ V2.05 / IMPACT 2002+ / Single score

Fig. 4. Environmental impact outflows for the usable floor space (m2) of the building under Endpoint impact.

4. Conclusion

According to the analysis above, the results indicate that the use stage is also the main contributor to all other environmental impacts, which are mainly related to energy use in the operational/use stage, which contribute 71.9% from the total effects. The main impact categories that have the biggest share are the respiratory inorganics, global warming and no-renewable energy. Therefore, on a life cycle basis, the main improvement opportunities in the housing sector lie in the reduction of the impacts in the use stage of the house. Whilst people behavior plays a big role, the greatest improvement opportunities are in the design stage of the house. In addition, the large interest from this study is the role of the disposal scenarios that can provide a positive impact environmentally, numerically, by -12.1% through the human health and the maintaining sources (raw materials). Therefore, it must set conditions and laws of how people can benefit from the remains of the building after demolition and to recycle and reuse each component of the building. That is what the authors strongly recommend to be considered by the Egyptian authorities and people due to its positive impact on the environment.

It is noteworthy that our research presents a useful analysis for helping understand the characteristics of adverse environmental effects of Egyptian building LCA, and how to find the environmental solutions to minimize the adverse environmental impacts such as; reducing operating energy consumption, selecting sustainable materials and/or construction assemblies with longer service lives, such that they are replaced less over the building life cycle and using sustainable fuels and raw materials in the building material preparation stage.

Acknowledgements

The first author would like to thank Egyptian Ministry of Higher Education (MoHE) for providing him the financial support (PhD scholarship) for this research as well as the Egypt Japan University of Science and Technology (E-JUST) for offering the facility and tools needed to conduct this work.

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