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Building and Environment 42 (2007) 2114–2123

www.elsevier.com/locate/buildenv

Environmental assessment of brick production in Greece

Christopher Koroneos�, Aris Dompros

Laboratory of Heat Transfer and Environmental Engineering, Aristotle University of Thessaloniki, P.O. Box 483, 54124 Thessaloniki, Greece

Received 29 September 2005; received in revised form 28 February 2006; accepted 17 March 2006

Abstract

Brick constitutes one of the major materials used for the construction of buildings. The present study analyses the different stages

followed during brick production and the materials and energy used in each stage. The purpose is to identify ‘hot-spots’, i.e. parts of the

life cycle that are important to the total environmental impact. The analysis is performed using life cycle assessment (LCA) methodology,

which is a method used to identify and quantify the environmental performance of a process or a product from ‘‘cradle to grave’’. LCA

methodology provides a quantitative basis for assessing potential improvements in environmental performance of a system throughout

the life cycle. The system investigated includes raw material acquisition, industrial production, packaging and transportation. Energy use

and emissions are quantified and the potential environmental effects are assessed. The main energy inputs to the production system are

electricity, diesel and solid fuel (Pet-Coke). The environmental burdens that arise from the operation of a brick industry are mainly due

to air emissions derived from fossil fuel utilization.

r 2006 Elsevier Ltd. All rights reserved.

Keywords: Brick production; Environmental impacts; Greece; Life cycle assessment; Sustainable construction

1. Introduction

The construction industry can play a vital role towardssustainable development. Sustainable construction can beachieved with the application of tools that deal with theassessment of the whole life cycle, site planning andorganization, material selection, re-use and recycling ofmaterials, waste and energy minimization. The construc-tion industry is one of the most important industrial sectorsin Europe, accounting for 9.7% of the GDP and 47.6% ofthe gross fixed capital formation in 1999 [1]. The life cyclestages made up of the construction, use and disposal ofbuilt facilities, present major environmental impacts.

Construction activities consume more raw materials byweight than any other industrial sector. As much as 50% ofall materials extracted from the Earth’s crust are trans-formed into construction materials and products. Thesesame materials when they enter the waste stream, accountfor some 50% of all waste generated prior to recovery.Construction and demolition waste constitutes the largest

e front matter r 2006 Elsevier Ltd. All rights reserved.

ildenv.2006.03.006

ing author. Tel.: +30231 0995968; fax: +30 231 0996012.

ess: koroneos@aix.meng.auth.gr (C. Koroneos).

waste stream by weight in the European Union, most ofwhich though, is recyclable. Disposing of these wastematerials is presenting increased difficulties [1].Material production industries have been attributed to

be one of the largest fuel consuming sectors of theeconomy. This indicates that savings in fuel consumptionin these industries could have a substantial impact on totalfuel demand [2]. Moreover, environmental assessments thatinclude energy use for materials production are veryimportant for the implementation of improvement optionsto the life cycle of the product. Environmental assessmentsof material production can provide criteria for designdecisions when choosing materials offering similar perfor-mance for a given application [3,4].Brick belongs to the wide family of construction

materials and is mainly used for the construction of outerand inner walls in buildings. Brick production industryrequires large inputs of resources and causes severalnegative environmental effects. Studies indicate that brickmanufacture has a large impact relating to energy use andcarbon emissions [5–7]. The systems in brick productionare oriented and optimized to satisfy economic and qualitydemands. Environmental issues have become of major

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Table 2

Plant operation data

Annual production of the plant 7,387,200 kg

Number of bricks produced per day 13,080

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–2123 2115

importance due to the rise of concern for the protection ofthe environment.

A life-cycle approach is essential for the evaluation andimprovement of the environmental performance of theconstruction products [8]. Construction products need tobe viewed in terms of functional units, how they performthroughout the life-time of a built facility and whathappens to them at their end of life. In the present study,the life cycle assessment (LCA) methodology is implemen-ted in the brick manufacturing industry.

There are many difficulties in conducting life cyclestudies. Ideally, a complete study should include rawmaterial acquisition, industrial refining, storage anddistribution, packaging, consumption and waste manage-ment, all of which together comprise a large and complexsystem [9,10]. The results of the LCA methodology can beimplemented in order to optimize the environmentalperformance of the production system.

2. Life cycle assessment

2.1. Goal definition

The main goal of the environmental assessment is toidentify key issues associated with the life cycle of brick

Fig. 1. Schematic presentation

Table 1

Characteristics of the brick under consideration

Brick dimensions Weight after baking process

17� 14� 28 cm 5.945 kg

produced and used in Greece. The plant from which thenecessary data are taken is located in the industrial area ofSindos, in the outskirts of the city of Thessaloniki.The brick production plant produces more than one type

of a brick. These types differ in weight and dimensions. Forthe purposes of the present study one ton of a specific typeof brick has been chosen as a functional unit. Thecharacteristics of this brick are summarized in Table 1. Awall of approximately 6.6m2 uses one ton of these brick(168 units).The data that are used in the present LCA study

constitute of:

�

of t

Da

An

An

Die

ma

Die

An

raw data that were given by the brick production plantin Greece;

� measured data on site; � calculated data based on bibliographical information.

he system investigated.

ys of plant operation per year 95

nual electricity consumption 105,050 kWh

nual pet-coke consumption 397,014.5 kg

sel consumed for transportation of raw

terials and distribution of end product

37,365 lt

sel consumed for raw material acquisition 10,592.5 lt

nual production of scrap bricks 16,910 kg

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Fig. 2. (a)–(e) Input and outputs in the brick production subsystem.

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–21232116

2.2. The brick life cycle

The complete system investigated is shown in Fig. 1. Thebrick life cycle is divided into subsystems for detailed

analysis in order to produce a clear and detailed picture ofthe individual processes. For each subsystem the mass flowrate, energy consumption, air emissions, liquid and solidwastes are presented.

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Fig. 2. (Continued)

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–2123 2117

The life cycle is divided into the following subsystems:

1.

Raw material acquisition: The raw material used for theproduction of bricks is clay, which is transported to the

factory by trucks with capacity of 15.1m3. The basicingredient of clay is kaolin (Al2O3 � 2 SiO2 � 2H2O). Thepercentage of kaolin affects the plasticity of clay. Clayswith high content in kaolin are called greasy clays while

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Fig. 2. (Continued)

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–21232118

the ones with low content are called non-greasy clays.Greasy clays have high water absorbency and whenmixed with water have high plasticity, which makesthem easier to process. Bricks constructed with greasy

clay tent to fracture and shrink during the baking anddrying processes. Non-greasy clay is harder to processbut the bricks do not shrink or fracture during thebaking and drying processes.

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Fig. 2. (Continued)

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–2123 2119

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Fig. 2. (Continued)

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–21232120

2.

Manufacturing process: The plant operation datashown in Table 2, indicate high usage of energy inthe form of electricity, pet coke and diesel. Themanufacturing process consists of the following sub-systems.(a) Mixing and feeding: The clay arrives in the factory

located in Sindos and it is stored in piles where itremains for 20 days before use. During this period oftime the oxygen of atmospheric air destroys theanaerobic bacteria that exist in natural clays. It hasbeen proven empirically that the existence ofmicroorganisms in the clay causes problems in thedrying and baking processes. In order to takeadvantage of the properties of greasy and non-greasy clays a mixture of the two is used. The mixingand feeding processes are made using diggingmachines.

(b) Shaping: During this sub-process the clay is firstsmashed in order to reduce the size of its particles(up to 25mm) and is cleaned from unwantedmaterials. Then the clay is mixed with water througha kneading process. The plasticity of the mixturedepends on the amount of water added and theoriginal mixture of greasy and non-greasy clay. Thisproportion varies from 1.5:1 to 2.5:1. After thekneading process the clay passes between tworotating cylinders with very small gap (�2mm) inorder to smash all large particles that exist in theclay. The processed clay passes through a screw-likecompressor where it is shaped and cut to form thebricks. The non-baked bricks are finally placed inwooden palettes.

(c) Drying: The non-baked bricks are placed in a filedfor 4–5 days in order to dry.

(d) Baking process: The dried bricks are placed incoaches and then through rail trucks are transportedinside a furnace that operates at 980–1030 1C. Thecoaches are moving slowly inside the furnace and theresidence time inside the furnace is about100–130min. The fuel used in the furnace is Pet-coke. The transportation of Pet-coke is made by 38-ton trucks from the harbor of Thessaloniki.

(e) Packaging and storage of bricks.

3. Distribution of bricks for use in building construction:

Bricks are transported by heavy vehicles to distributionand construction sites.

4.

Recycling/reuse of scrap bricks: Scrap bricks consist of0.23% of the production capacity of the plant. They arecollected and used as raw material for the production oftiles although a mixture up to 30% fine waste brickcould be reused onsite as additives for brick productioncontributing economically and environmentally to theproduction plant [11].

5.

Disposal: Final disposal of bricks is realized either by theend of the life cycle of a building or during reconstruc-tion processes. The lifetime of a building is considered tobe 80 years. Demolition waste in Greece is usedfor landfilling purposes since there is no suitableplant for reduction and sorting of the waste materialand reutilization of the demolition waste. Recyclingof construction and demolition waste is stronglypromoted by the European Union in the framework ofenvironmental protection and waste managementpolicy [12,13] so it is expected in the next years, the

ARTICLE IN PRESSC. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–2123 2121

volume of waste that is reused in Greece will becomemuch bigger.

2.3. Life cycle inventory

Detailed analysis of the energy inputs and emission out-puts of the production system is presented in Figs. 2(a)–(e).Figs. 3 and 4 present the overall results for the productionof 1 ton of bricks and one brick, respectively. Raw materialacquisition is a large energy consuming process of the life

Fig. 3. Inputs and outputs for the production of 1 ton of bricks (6.6m2).

Fig. 4. Inputs and outputs for the production of one brick.

cycle. The use of energy derived from diesel is 1458.6 kWh.During the shaping processing of bricks, 351.56 kWh areconsumed for the shaping of clay. Moreover, 182.99 kWhare consumed for clay kneading, 95.88, 98.62 and93.13 kWh for smashing, sheeting of kneaded clay andcleaning of clay, respectively. The dying process uses102.66 kWh produced from diesel.The baking process is the most energy consuming

process of the brick life cycle. Due to the pet cokeconsumption, 39,121.02 kWh are consumed. There is also119.05 kWh electricity used during the process.Finally, 2841.3 kWh of diesel fuel are consumed for

product distribution to the product merchants and finalconsumers. It should be noticed that the emissionsproduced by the trucks used for the transportation of theraw materials and of the products of the different stages arecalculated using the COPERT methodology [14]. The dataused for the calculation of emissions during the transporta-tion processes are shown in Table 3.Pet-Coke is the main energy source (86.1%) in brick

production (Fig. 5). Baking of the bricks is the most energyintensive process. The contribution of each energy sourceto emissions is shown in Fig. 6. Pet-coke has the greatestcontribution in CO2, SO2 and NOx emissions. The use ofdiesel contributes mostly to CO, VOC, PM and NOx

production.

Table 3

Transportation data used

Distance between raw material extraction site

and manufacturing plant

24 km

Distance between manufacturing plant and

distribution site

32.5 km

Distance between manufacturing plant and tile

production plant

5 km

Number of bricks transported by the 16 ton

truck

1270

Number of bricks transported by the 26 ton

truck

1420

Mean speed of loaded truck 50 km/h

Mean speed of unloaded truck 65 km/h

Pet-Coke86.1%

Diesel11.5% Electricity

2.4%

Fig. 5. Energy consumption in the brick production process.

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0% 20% 40% 60% 80% 100%

CO2

CO

SO2

NOx

PM

VOC

Liquid waste

Solid waste

Electricity Diesel Pet-Coke

Fig. 6. Distribution of emissions per energy source in the brick production

process.

Table 4

Categorization of the impacts

Impact category Equivalent mass Unit

Greenhouse emissions 220.679 kg CO2-eq

Acidification 2.229 kg SO4-eq

Eutrophication 0.043 kg PO4-eq

Winter-smog 2.012 kg SPM-eq

Summer-smog 0.0092 kg C2H4-eq

Solid waste 2.788 kg

Table 5

Normalization and weighting factors

Impact category Normalization factor Weighting factor

Greenhouse effect 0.0000742 2.5

Acidification 0.00888 10

Eutrophication 0.0262 5

Winter smog 0.0106 5

Summer smog 0.0507 2.5

Solid waste 0 0

0

0.005

0.01

0.015

0.02

0.025

Nor

mal

isat

ion

Gre

enho

use

Em

issi

ons

Aci

difi

catio

n

Eut

roph

icat

ion

w-s

mog

s-sm

og

Fig. 7. Normalization scores.

00.020.040.060.08

0.10.120.140.160.18

0.2

Env

iron

men

tal S

core

Gre

enho

use

Em

issi

ons

Aci

difi

catio

n

Eut

roph

icat

ion

w-s

mog

s-sm

og

Fig. 8. Valuation scores.

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–21232122

2.4. Impact assessment

The emissions of the system have been grouped intoimpacts (characterization step) based on the EcoIndicator95 method [15]. The Eco-Indicator is one method ofaggregation (or, as described in ISO draft 14042, ‘‘weight-ing through categories’’) that leads to a single score. Siximpact categories were considered: global warming, acid-ification, eutrophication, winter smog formation, summersmog formation and solid wastes. Table 4 summarizes theresults from the categorization of the impacts, for thechosen functional unit. From the life cycle of brickproduction, 220.68 kg CO2 equivalent contribute to thegreenhouse impact category. Equivalent acidification emis-sions add up to 2.23 kg SO4-eq and winter smog emissionsto 2.012 kg SPM-eq.

The environmental score of each effect is calculatedbased on the simple formula:

Environmental score ¼ characterized value

� normalization factor

� valuation factor:

Weighting factors are applied in order to scale theseriousness of the results, measured in indicator points. Thenormalization and valuation weighting factors used for thepurpose of this study are shown in Table 5 [15]. Figs. 7 and 8illustrate the results extracted during the previous stages.

At the final step, the valuation scores are added up togive a total impact. The total impact indicator of the bricklife cycle is calculated to be 0.35. The standard Eco-indicators can be regarded as dimensionless figures. Thescale is chosen in such a way that the value of 1 point isrepresentative for one thousandth of the yearly environ-mental load of one average European inhabitant. Theabsolute value of the points is not very relevant as the mainpurpose is to compare relative differences between produc-tion processes. The brick life cycle can be compared withalternative solutions for the construction of walls, for

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0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

indicator

Summer-smog

Winter-smog

Eutrophication

Acidification

Greenhouse Effect

Fig. 9. Indicator graph.

Greenhouse Effect11.62%

Summer-smog0.33%

Acidification56.19%

Winter-smog30.26%

Eutrophication1.60%

Fig. 10. Contribution of the effects to the indicator.

C. Koroneos, A. Dompros / Building and Environment 42 (2007) 2114–2123 2123

example gypsum boards, in order to improve the environ-mental performance of buildings [16]. The ‘‘indicator’’graph (Fig. 9) shows that acidification is by far the categoryaffected mostly by the brick production. This can also beseen on Fig. 10 where the acidification effect accounts for56.19% of the total environmental impact. Winter smogcontributes by 30.26% to the total impact, followed by thegreenhouse effect that contributes by 11.62%.

3. Conclusions

The LCA conducted on the process of brick productionindicated that this process is very energy intensive. Most ofthe emissions to the environment are attributed to theenergy use, directly at the site with the combustion of pet-

coke and diesel and indirectly with the use of large amountsof electricity. The emissions of CO2 make up the biggestpercentage of all releases to the atmosphere. When it comesto the effect of the environmental impacts, acidification hasthe highest value. This is mainly due to the fact that at themanufacturing stage low-grade fuel with high sulfurcontent has been used. The combustion of this fuelproduces large amounts of SO2 and NOx. The use of acleaner fuel would reduce very much the environmentalimpact of the production process.

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