An Analysis of Alternative Building Materials in the Coastal Rural Areas of Bangladesh

INOM

EXAMENSARBETE TEKNIK, GRUNDNIVÅ, 15 HP

,

STOCKHOLM SVERIGE 2020

An Analysis of Alternative Building

Materials in the Coastal Rural

Areas of Bangladesh

FUAD ALAM

Bachelor of Science thesis

Titel An Analysis of Alternative Building Materials in the Coastal Rural Areas of Bangladesh Author(s) Fuad Alam, Nabil Hossain

Department Industrial Engineering and Management TRITA number TRITA-ITM-KEX 2020:125

Supervisor Per Lundqvist, Henry Muyingo, Prosun Bhattacharya, Arif Abdullah Khan

Keywords Sustainable Development, Alternative Building Materials, Bangladesh, Coastal Rural Area

Abstract

This study will provide background information about the region of Bangladesh, more specifically the coastal rural area of Bangladesh. This region has due to the global warming become a very disaster-prone region where disaster resilience work has become increasingly relevant. Displacement of the rural coastal population due to disasters is an ongoing issue in Bangladesh which inhibits the large urbanization the capital city, Dhaka faces. This has increased the need of housing which has stimulated the brick industry that has increased its contribution to Bangladesh GDP the last years. Though the brick industry has traditionally been dominated by environmentally unfriendly methods that has caused deforestation and severe air pollution contributing to the cause of its demand creating a negative feedback loop. This study will analyse four different building materials including the tra-ditional one by collecting data, creating analyse models and discussing them to find a more financial, environmental and technical suitable alternative to respond to the current situation to try turn the tide focusing on the rural coastal areas of Bangladesh.

Acknowledgement

This report was co-written together with Nabil Hossain, who studies the Civil Engineering program. Together we have both written and submitted the same report to each respective institutes.

We also want to thank Per Lundqvist, our supervisor at the institute of Indus-trial Management and Engineering for always having and sharing such a positive attitude and view on the project, giving us positive feedback and encouragement but also the assurance that even due to COVID-19 and the obstacles that came with it for this study that everything would be alright.

We want to thank Henry Muyingo, our supervisor at the institute of Real Estate and Construction Management, KTH for always giving us thoughtful, inspring and constructive criticism. We have during the process been sharpened when it comes to viewing information, writing essays and containing the core of something im-portant, thanks to you.

We would also like to extend our deepest gratitude to Prosun Bhattacharya and Tahmidul Islam, our independant supervisors at KTH for helping us whenever we ran into issues or troubles, they consistently allowed this paper to be our own work, but steered us towards the right direction when they thought it was needed. We would also like to express our deepest appreciations to UNDP Bangladesh for allowing us to write our bachelor thesis in collaboration. In this collaboration we want to thank Mr. Arif Abdullah Khan, programme specialist for his humor and intellectual guidance and Ms. Tahmina Tamanna for always having a line of communication open to help us with any complications. Special thanks for the patience and guidance provided by UNDP Bangladesh having faith in us consider-ing the current situation in Bangladesh due to COVID-19 and the complications it has subjected on the collaboration.

Lastly, we would like to recognize the assistance that we have received from Ms. Lisa Anderson from the Embassy of Sweden in Dhaka, Bangladesh who helped us initially establish a contact with the UNDP that began this collaboration.

From the authors,

Examensarbete

Titel En analys av alternativa byggnadsmaterial i de kustliga landsbygdsomr˚adena i Bangladesh F¨orfattare Fuad Alam, Nabil Hossain

Institution Industriell teknik och management TRITA nummer TRITA-ITM-KEX 2020:125

Handledare Per Lundqvist, Henry Muyingo, Prosun Bhattacharya, Arif Abdullah Khan

Nyckelord H˚allbar utveckling, Alternativa Byggnadsmaterial, Bangladesh, Kustliga Landsbygden

Sammanfattning

Denna studie kommer att ge bakgrundsinformation om regionen Bangladesh, mer specifikt landsbygden i Bangladesh. Denna region har p˚a grund av den globala uppv¨armningen blivit en mycket katastrofben¨agen region d¨ar katastrofresiliensar-betet har blivit alltmer relevant. F¨orflyttning av kustbefolkningen p˚a grund av katastrofer ¨ar en p˚ag˚aende fr˚aga i Bangladesh som h¨ammar den stora urbaniserin-gen av huvudstaden Dhaka. Detta har ¨okat behovet av bost¨ader vilket i sin tur har stimulerat tegelindustrin som har ¨okat sitt bidrag till Bangladeshs BNP de senaste ˚aren. Tegelindustrin har traditionellt dominerats av milj¨ofarliga metoder som or-sakar avskogning och sv˚ara luftf¨ororeningar. Denna studie kommer att analysera fyra olika byggmaterial inklusive det traditionella genom att samla in data, skapa analysmodeller och diskutera dem f¨or att hitta ett mer ekonomiskt, milj¨om¨assigt och tekniskt l¨ampligt alternativ f¨or att svara p˚a den aktuella situationen f¨or att f¨ors¨oka v¨anda tidvattnet med fokus p˚a landsbygden p˚a kusten i Bangladesh.

F¨

orord

Denna rapport skrevs tillsammans med Nabil Hossain, som studerar programmet Samh¨allsbyggnad har vi b˚ade skrivit och skickat in samma rapport till respektive institut.

Vi vill tacka Henry Muyingo, v˚ar handledare vid institutionen f¨or fastigheter och byggande p˚a KTH f¨or att han alltid har gett oss tankev¨ackande, inspirerande och konstruktiv kritik. Vi har under processen sk¨arpts n¨ar det g¨aller att titta p˚a in-formation, skriva uppsatser och h˚alla det kort men koncist.

Vi vill ¨aven tacka Per Lundqvist, v˚ar handledare vid institutet f¨or industriell Man-agement and Engineering f¨or sin positiva inst¨allning och syn p˚a projektet, Han gav oss positiv feedback och uppmuntran men ¨aven f¨ors¨akran om att alla hinder som uppstod till f¨oljd av COVID-19 kunde l¨osas.

Vi skulle ¨aven vilja utvidga v˚ar djupaste tacksamhet till Prosun Bhattacharya och Tahmidul Islam, v˚ara oberoende handledare vid KTH f¨or all hj¨alp och tid dem gett oss. De till¨at konsekvent detta papper att vara v˚art eget arbete, men styrde oss mot r¨att riktning n¨ar de tyckte att det var n¨odv¨andigt.

Vi vill ¨aven uttrycka v˚ara djupaste uppskattningar till UNDP Bangladesh f¨or att dem l¨at oss skriva v˚ar kandidatuppsats i samarbete med dem. I detta samarbete vill vi tacka Arif Abdullah Khan, f¨or hans humor och intellektuella v¨agledning och Ms Tahmina Tamanna f¨or att hon alltid har haft en kommunikationslinje ¨oppen f¨or r˚adgivning och hj¨alp.

S¨arskilt tack f¨or t˚alamodet och v¨agledningen som tillhandah˚allits av UNDP Bangladesh, som trott p˚a v˚art sammarbete trots den nuvarande COVID-19 situationen i Bangladesh. Vi vill slutligen erk¨anna den hj¨alp som vi har f˚att fr˚an Lisa Anderson fr˚an Sveriges ambassaden i Dhaka, Bangladesh som hj¨alpte oss inledningsvis att uppr¨atta en kontakt med UNDP som inledde detta samarbete.

Fr˚an f¨orfattarna,

Abbreviations

CCAC - Climate and Clean Air Coalition CSEB - Compressed stabilized earth block FCB - Fired Clay Brick

FCBTK - Fixed Chimney Bull Trench Kiln HCB - Hollow Concrete Blocks

HHK - Hybrid Hoffman Kiln

ISSB - Interlocked Stabilized Soil Blocks UN - United Nations

UNDP - United Nations Development Programme KTH – KTH, Royal Institute of Technology

BUET - Bangladesh University of Engineering and Technology GDP - Gross Domestic Product

CO2 - Carbon Dioxide

CSEB - Compressed Soil Earth Blocks GHG - Green House Gases

Contents

1 Introduction 10

1.1 Background . . . 10

1.2 The Region of Bangladesh . . . 11

1.3 The Coastal Rural Area of Bangladesh . . . 12

1.4 Concepts & Definitions . . . 14

1.5 Aim & Objective . . . 14

1.6 Scope . . . 14

1.6.1 Demarcation . . . 15

1.7 The Sustainable Development Goals . . . 16

2 Methodology 18 2.1 Data Collection . . . 18 2.1.1 Literature Studies . . . 18 2.1.2 Financial Data . . . 19 2.1.3 Financial Analysis . . . 19 2.1.4 Environmental Data . . . 20 2.1.5 Environmental Analysis . . . 22 2.1.6 Technical Data . . . 23 2.1.7 Technical Analysis . . . 23 3 Financial Calculations 24 3.1 Present Value, PV . . . 24

3.2 Net Present Value, NPV . . . 24

3.3 Internal rate of return, IRR . . . 25

3.4 Weighted Average Capital Cost, WACC . . . 25

3.5 Salvage Value, SV . . . 26

4 Environmental Calculations 26 4.1 Number of units needed per meter wall length, nL . . . 26

4.2 Number of units needed per meter wall height, nH . . . 26

4.3 Number of units needed per one square-meter Wall, nW . . . 27

4.4 Total Mortar Joint Volume per one square-meter Wall, Vm . . . 27

4.5 Mass of Mortar, m . . . 27

4.6 CO2 per unit, uCO2 . . . 28

4.7 CO2 per square-meter wall contributed by Units, wu,CO2 . . . 28

4.8 CO2 from mass Mortar, mCO2 . . . 28

4.10 Total CO2 per square-meter wall of units, totCO2 . . . 29

5 The Brick Industry in Bangladesh 30 6 Fixed Chimney Bull’s Trench Kiln, FCBTK 32 6.1 Production Method of FCBTK . . . 32 6.2 Financial Results of FCBTK . . . 36 6.3 Environmental Result of FCBTK . . . 36 6.4 Technical Result of FCBTK . . . 37 7 Hybrid-Hoffman Kiln, HHK 37 7.1 Production Process of HHK . . . 37 7.2 Financial Result of HHK . . . 41 7.3 Environmental Result of HHK . . . 43 7.4 Technical Result of HHK . . . 43

8 Hollow Concrete Block, HCB 43 8.1 Production Method of HCB . . . 43

8.2 Financial Results of HCB . . . 45

8.3 Environmental Result of HCB . . . 46

8.4 Technical Result of HCB . . . 47

9 Interlocking Stabilized Soil Blocks, ISSB 47 9.1 Production Method of ISSB . . . 47

9.2 Financial Results of ISSB . . . 49

9.3 Environmental Result of ISSB . . . 50

9.4 Technical Results of ISSB . . . 51

9.4.1 Wet Compressive Strength . . . 51

10 Results 52 10.1 Crushing Strength . . . 52

10.2 Absorption Capacity . . . 53

11 Discussion 54 11.1 Are the alternative building materials and methods economically sustainable (profitable)? . . . 54

11.2 Are the alternative building materials and methods environmentally sustainable? . . . 55

11.3 Are the alternative building materials and methods appliable in coastal rural area? . . . 56

12 Conclusion 57

13 Appendix 58

13.1 Financial models . . . 58

13.1.1 Sensitivity analysis . . . 61

13.2 Environmental Models . . . 63

13.3 Offer on production equipment . . . 64

13.3.1 HCB offer . . . 64

1

Introduction

1.1

Background

Issues related to an environmental awareness have increased in people’s conscious-ness in past years according to UN1_{. Innovation in the for example the field of}

energy-efficient technology is crucial to increase productivity in the modern indus-try to be able to reduce the carbon footprint to sustain our habits says UN2_.

One of the biggest inhibitors to climate change is the Greenhouse Effect that is fueled by carbon dioxide and other factors. According to the Climate Clean Air Coalition, a partnership of governments working alongside UN Environment, one of the largest origins of carbon dioxide is the brick industry. Every year 1500 billion bricks are produced that together with iron and steel production stands for 20% of the world’s total black carbon emissions3. A fundamental resource for agricultural production in Bangladesh is land and fertile topsoil, yet agricultural lands are progressively decreasing. topsoil degradation is an important threat to sustainable agriculture. In Bangladesh, brick production contributes to soil loss as the country relies on clay-rich soil for brick making. With urbanization and population growth the need of housing, resilient ones, becomes more critical lead-ing to the larger strain on the buildlead-ing industry that we know already is a great contributor to the global warming. So how can the building industry turn this problem into a solution?

One of the top producers of bricks in the world is Bangladesh with a dense, fast growing population4 _{and coastal areas. According to the WORLD AIR}

QUAL-ITY REPORT of 2019 issued by IQAir, Bangladesh has among the worlds worst air quality5_{. The Bangladesh brick sector is a large contributor with its more}

than 7800 kilns as of june 2018, these kilns produced 33 billion bricks, emitting 21 million tonnes of greenhouse gases6. With an increasing sea level due to global

1_{United Nations, #youthstats:environmental and climate change, accessed 11-05-15}

https://www.un.org/youthenvoy/environment-climate-change/

2_{Work Plan of the Group of Experts on Energy Efficiency for 2020-2021 (2019), United Nations}

Economic and Social Council

3_{Climate Clean Air Coalition. Initiatives, Bricks, UN Environment Programme, accessed}

11-05-2020 https://www.ccacoalition.org/en/initiatives/bricks

4_{World Bank. Population growth (annual, %), The World Bank Group, accessed 11-05-2020}

https://data.worldbank.org/indicator/sp.pop.grow?view=map

5_{IQAir (2019) WORLD AIR QUALITY REPORT of 2019}

warming these coastal areas are becoming even more vulnerable to natural hazards such as floods and hurricanes which inhibits the increasing urbanization7_.

As there is an increasing demand for housing there is a need for alternative building materials that are environmentally friendly, affordable but also resilient. Therefore appropriate technology is crucial for the brick industry to be able to satisfy these needs.

The purpose of this study is to look at the alternative building materials and study them in context to Bangladesh with a focus on the coastal areas.

1.2

The Region of Bangladesh

As the title mentions this comparative study will focus on the region of Bangladesh. Bangladesh is considered one of the worlds newer constitutions declaring indepen-dence 1971 after the Liberation War. Prior to this the nation was a part of the State of Pakistan under the name East Pakistan as a result of the demarcation by the Boundary of Partition of India implemented by the British East India Com-pany who conquered the region 1757. Since then the country has recovered having one of the fastest real GDP growth rates in the world8 while also having one of the world’s highest population densities9 _{where the construction sector has}

con-tributed with an average of 7.9% annualy having an average annual growth of 16% compared to the countries total GDP average annual growth of 13.8%10. .

7_{C40 Cities. Staying Afloat: The Urban Response to Sea Level Rise, C40 Cities Climate}

Leadership Group, accessed 11-05-2020 https://www.c40.org/other/the-future-we-don-t-want-staying-afloat-the-urban-response-to-sea-level-rise

8_{World Bank. GDP growth (annual %) – Bangladesh, the World Bank Group, accessed}

12-05-2020 https://data.worldbank.org/indicator/NY.GDP.MKTP.KD.ZG

9_{World Bank, Population density (people per sq. km of land area). The World Bank Group,}

accessed 12-05-2020 https://data.worldbank.org/indicator/EN.POP.DNST

10_{Bangladesh Bureau of Statistics (2019) Gross Domestic Product of Bangladesh at Current}

Figure 1: Map of Bangladesh, showing the borders to India, Nepal, Myanmar and the Bay of Bengal also showing its relation in size in the miniature picture

1.3

The Coastal Rural Area of Bangladesh

The south Asian country shares the coastal border with the Bay of Bengal. This together with the fact that the land is topographically low, as half of the country’s landmass is less than 8 meters above sea level, and the exposure to tropical cyclones makes Bangladesh one of the world’s most disaster-prone countries in the World which directly affects the coastal rural areas11_{. The coastal zone of Bangladesh}

counts for 32% of its area and 26% of its population. Between 1980 and 2011 alone, has Bangladesh suffered over 200 natural disasters claiming 200.000 lives and $17 billion in disaster recover programs 12_{. The coastal rural area is also the home of}

many agriculturalists. This is supported by the fact that the coastal zone has 30%

11_{World Meteorological Organization. Coastal flooding forecasts save lives in Bangladesh,}

pub-lished 7-12-2017, accessed 12-5-2020 https://public.wmo.int/en/media/news/coastal-flooding-forecasts-save-lives-bangladesh

of the countries arable land. This land is threatened by both rising sea levels due to climate change, topsoil digging due to production of raw material for the brick industry that contributes to the climate change but also salinity. Salinity is caused by the tidal flooding during the wet season and upward movement of saline ground water during dry season. According to a study from 2006, approximately 53% of the arable land is affected by salinity which decreases the agricultural productivity as it reduces growth and thus yield depending on the degree of salinity, worst cases the total yield from crops are lost13_{. These are some incentives for the large}

forced urbanization the capital of Bangladesh faces as individuals are displaced due to climate change who now seek to the city for opportunities14_{. This has}

resulted in many slum areas and a high pressure on the building industry to provide housing. According to the World Economic Forum, WEF urban infrastructure and services is considered a fundamental priority in the topic cities and urbanization which includes real estate15_{. These are facts and observations on the present}

stimulated building industry in Bangladesh16 which is highly dependent on the brick industry17_.

13_{S A Haque (2006) Salinity Problems and crop production in coastal regions of Bangladesh} 14_{Tim McDonnell, Climate change creates a new migration crisis for}

Bangladesh, National Geographic published 24-1-2019, accessed 12-05-2020 https://www.nationalgeographic.com/environment/2019/01/climate-change-drives-migration-crisis-in-bangladesh-from-dhaka-sundabans/

15_{Strategic Intelligence, Cities and Urbanization. World Economic Forum, accessed 12-05-2020}

https://intelligence.weforum.org/topics/a1Gb0000000LiPhEAK?tab=publications

16_{Gross Domestic Product of Bangladesh at Current Prices, 2015-16 to 2018-19, Bangladesh}

Bureau of Statistics, accessed 12-5-2020

1.4

Concepts & Definitions

This study will compare four alternative building materials and their methods that are relevant in finding the optimal alternative building material for the coastal ru-ral area of Bangladesh. They will be referred to bricks, building material that have been burned in a kiln in the process and blocks, building material that have been made without the process of firing.

The alternative building material in this study will refer alternative building ma-terials in relation to the most traditional method in Bangladesh today, which is Fixed Chimney Kiln also referred to as Fixed Chimney Bull Trench Kiln, FCBTK. The alternatives are Hybrid-Hoffman Kiln, HHK which also produces bricks but in a more energy efficient manner, Interlocking Stabilized Soil Blocks, ISSB and Hollow Concrete Block which are both block production methods.

1.5

Aim & Objective

The aim of this study is to analyze alternative building materials and how they from a sustainability aspect can contribute to housing building industry in rural coastal areas in Bangladesh.

The purpose is to contribute to the development of more sustainable resources whilst not decreasing economic growth.

The objectives of this study are to answer the following research questions: Are the alternative building materials and methods economically sustainable? Are the alternative building materials and methods environmentally sustainable? Are the alternative building materials and methods applicable in coastal rural area of Bangladesh?

1.6

Scope

The previously mentioned four building materials- FCBTK, HHK, HCB, ISSB- will be analyzed from a sustainable, financial and technical point of view in context to the coastal rural area of Bangladesh. The study will take local conditions to the greatest extent into consideration when analyzing both material and method to depict the most accurate model for the coastal rural area as possible. This includes using local resources to exclude negative environmental effects of transport. The

alternative building materials ought to be as ecofriendly and cost effective without significantly reducing the quality and resilience of the material.

1.6.1 Demarcation

This study was initially planned as a Minor Field Study, with a granted scholar-ship funded by Swedish International Development Cooperation Agency to travel to Bangladesh and complete the following activities:

Studying the social aspects of the four different building materials by surveying and interviewing production workers, production owners, construction workers, con-struction managers and tenants.

Together with the United Nations Development Programme, travelling to differ-ent sites and taking sedimdiffer-ent and soil tests and experimdiffer-enting on them to find optimal raw material for production.

Together with Bangladesh University of Engineering Technology perform experi-ments on all four building materials to collect data on technical properties.

Due to global pandemic caused by the COVID-19 outbreak the minor field study was canceled and substituted with literature studies to the greatest extent and regular feedback from UNDP Bangladesh.

Also due to the time frame of this study and available resources a life-cycle analysis will not be done for the environmental analysis of all the building materials as it is far too expansive. This would have been of great value and is therefore considered as an improvement of this comparative study.

1.7

The Sustainable Development Goals

The 17 Sustainable Development Goals, SDGs is the core of the 2030 Agenda for Sustainable Development as guidelines how to work towards a more sustainable future presented by the UN and adopted by all of UN’s member states 201518_.

The SDGs will be used to define the term sustainability in this study and also in evaluating the alternatives in these areas, the chosen SDGs are the following: Goal 9 - Industry, Innovation and Infrastructure

This goal states among many targets that one of them are reliable, sustainable and resilient infrastructure to support economic development as well as afford-ability and equitable access for all. Another one is the importance of supporting innovation and technology in developing countries, adding value to the industries, even the small-scale ones. The study will explore the topic of the sustainable industrialization of brick production, and how the production can provide for a more resilient infrastructure in the coastal rural area of Bangladesh with the help of innovation and new technology. The financial part will also be evaluated. Goal 11 - Sustainable Cities and Communities

This goal states to begin with the target of ensuring no inadequate housing or informal settlements by 2030 and also supporting the developed countries build-ing sustainable and resilient buildbuild-ings by utilizbuild-ing local materials. The buildbuild-ing materials will be evaluated on how locally sourced the raw materials are for them and how adequate building are able to be built from it, if the material is able to endure natural hazards that have destroyed many communities and creating waves of urbanization due to disaster displacement.

Goal 12 - Responsible consumption and production

The targets of this goal that are emphasized in this study are the encouragement to phase out existing harmful subsidies that may lead to unsustainable market consumption.

The study will compare the building materials on an environmental basis which will identify the harmful subsidies of each option and base the recommendation of the building materials on this.

Goal 15 - Life on Land

This goal focuses on restoring degraded land and soil, including land affected by floods and also halting deforestation as well as investing in reforestation to already damaged land.

The study will analyse the deforestation one building method may cause in form of sourcing raw materials and recommend a option that contributes to this goal by contributing to deforestation the least to ensure the livelihood of the demographic of the coastal rural area.

2

Methodology

This chapter will present how the study intends to answer its research questions. This will be done by collecting data on the building materials. The data will then be used in a financial, environmental and technical analysis for respective building material. The results from the analysis will then be compared to each other to then answer the research questions.

2.1

Data Collection

The core of this comparative study was collecting data by literature where we will collect data by researching various sources of information. This will grant us the fundamental information needed to build an understanding about the subject to then be able to form our analysis based on it. Data has also been collected through offers from the manufacturers of machinery that are presented in the appendix. 2.1.1 Literature Studies

The literature study was first conducted in the first chapter with the purpose of gathering as much background information about Bangladesh, the brick indus-try in Bangladesh and the four building materials, as possible. Previous reports and discoveries within the subject were reviewed and analyzed to develop strate-gies for the project mainly through KTH, Royal Institute of Technology’s library and search function but also occasionally through sites such as ResearchGate and Google Scholar. Since this comparative study was supposed to be a Minor Field Study including a trip to Bangladesh, working together with UNDP on site but was cancelled the methodology for data collection was limited to quantitative methods working from Sweden.

Literature and background information on the Hybrid-Hoffman Kiln was mainly sourced from UNDPs own internal reports whilst the information on Fixed Chim-ney Bull’s Trench Kiln, Hollow Concrete Block and Interlocking Stabilized Soil Blocks was sourced from KTH library, ResearchGate and Google Scholar, this was initially used to produce method processes for the four building materials to gain a fundamental understanding to then be able to create analyzes on key figures. Key figures were gathered quantitatively to produce financial, environmental and technical key figures. The financial key figures to evaluate the building materials on a financial basis through a Cash-Flow chart to be able to count NPV and IRR

to then analyze the result. The environmental key figures were used to evaluate the building materials on an environmental basis using the Environmental Impact Assessment method which then will be analyzed. Lastly the technical key figures were used to create a model wall to compare their strength to be able to analyze it on its technical properties.

2.1.2 Financial Data

Input figures to the cashflow model were gathered quantitatively to produce finan-cial key figures. The capital investment requirement for the brick plants have been estimated with support from a comprehensive study by BUET19 _{and a financial}

report by ADB20. The capital investment requirement for the block plants have been set with support from offers received by the manufacturers of the block ma-chinery as shown in the appendix. The supplier of the ISSB machine was selected because they had worked with the UN in previous projects. The supplier of the HCB machine was selected because of its price and availability. The constituents and amount of raw material needed per building material plant and year have been sourced from previous reports. Cost of raw materials have been collected by look-ing at the local market value of raw material sourced from the Bangladesh bureau of statistics and wholesalers. The sales prices of the different materials have been set to the market value that they hold in the Bengali market. The production capacity of the brick plants has been estimated by looking at what the typical capacity of these methods are in previous reports. The production capacity of the block alternatives has been sourced directly from the producers of these block ma-chines. The conversion rate between the currencies Bangladesh taka and USD was sourced from Morningstar. The Bangladesh corporate tax rate for unlisted com-panies was sourced from KPMG21_{. The risk-free interest rate was set equal to the}

Bangladesh government treasury bond rate which is reported by the Bangladesh Bank.

2.1.3 Financial Analysis

In order to compare the financial status of the different building materials, litera-ture studies have been conducted and data regarding costs and incomes connected to the different materials have been collected from various reports and journals. The financial analysis is based on a cash-flow models with a 10-year perspective

19_{CES & BUET (2016) A Comprehensive Study on the Present status, performance,}

barrier-sand prospects of existing hybrid hoffman kilns (HHKs) operating in Bangladesh.

20_{ADB (2018) Financing Brick Kiln efficiency improvement project} 21_{KPMG (2018) Bangladesh Tax Profile}

for the different building materials. The cash-flow model discovers the key figures NPV and IRR which are used to analyze the profitability of each method.

In order to build the model a few assumptions were made. The yearly output of the different plants is based on a 330 working days assumption for a full year of operation. Workers monthly wage was estimated by looking at what the typical wage was for brick workers. The estimated wage per month was used for all of the workers despite of the building material.

Regarding the products it was assumed with the support of a report by Green-tech Knowledge Solutions that for FCBTK 40%22 of the production becomes waste products and for HHK 10%23 _{becomes waste products. The waste products will}

not be included in the financial analysis thus not have a financial impact on the results.

According to a study by the Asian Development Bank investments in the size of FCBTK plants does not need financing through borrowed capital therefor an as-sumption was made that neither ISSB or HCB plants would require additional financing since they share roughly the same initial capital cost, this leaves only the HHK plant in need of financing24_{. The determination of the equity/debt ratio on}

the investment were based on typical equity/debt ratios of similar investments for HHK plants. The typical equity/debt ratio and interest rate was sourced from a comprehensive report on HHK plants by BUET . In addition, the assumption was made that the bank loan would be paid back after a five-year period. Additionally it was assumed that the time to get the production plant manufacturing would take 6-months. On top of these assumption cost of land was not included into the comparative analysis as it would have been the same for all the alternative thus not contribute to the study.

2.1.4 Environmental Data

The environmental data collected was divided into mortar and building material data. The mortar data consisted of the mortar joint thickness for each building material alternative which describes the mortar required to build with the units. The mortar density and constituents were determined with the use of a study writ-ten at the Vilnius Gediminas Technical25 _{and is considered the same for all the}

building materials. The constituents of mortar were accordingly sand, water and

22_{Greentech Knowledge Solutions Pvt. Ltd. (2014) Fixed Chimney Bull’s Trench Kiln}

(FCBTK)

23_{Greentech Knowledge Solutions Pvt. Ltd. (2014) Hybrid-Hoffman Kiln (HHK)} 24_{ADB (2018) Financing Brick Kiln efficiency improvement project}

25_Seputyt˙e.ˇ _{Jurga and Kiˇcait˙e. Asta (2012) PRIEDO POVEIKIS ˇSVIEˇZIO IR} SUKIET ˙EJUSIO SKIEDINIO SAVYB ˙EMS

cement. Cement was considered the only environmentally impact parameter out of the constituents, hence we complemented carbon dioxide emission data of mortar with data on carbon dioxide emissions from cement production in Asia found in the Journal of Cleaner Production26_.

Assumption was made about the Interlocking Stabilized Block, ISSB not using mortar at all but in fact they do use a grout amount of mortar but it is not able to be calculated upon so we have neglect this data REF. The environmental data on the building material were divided into environmental and geometrical data. The environmental data on the HCB and ISSB was the amount of cement used per unit building material. For HHK and FCBTK the data was gathered from a study from RMIT University, Australia27 in the form of coal consumption which was complemented by data on carbon dioxide emissions from coal fuel type Bitu-minous28_{. Bituminous is the coal type of the locally produced coal in Bangladesh}

also called Barapukuria coal which will be the coal type of choice in this study, to get a perspective as local as possible. The geometrical data were the length, width and height dimensions of each unit building material found by various stud-ies. These data were later used to produce environmental key figures through our environmental analysis.

26_{Kajaste. Raili and Hurme. Markku (2016) Cement Industry Greenhouse Gas Emissions}

-Management Options and Abatement Cost, Journal of Cleaner Production

27_{Tehzeeb. A.H, A. Bhuiyan. Muhammed (2014) Operation of Brick Kilns in Bangladesh - A}

Comparative Study

28_{S. Safiullah, M.R.R Khan and M.A.Sabur (2011) Comparative Study of Bangladesh}

2.1.5 Environmental Analysis

The environmental analysis of the building materials modelled the environmental impact of the carbon dioxide produced when building a one square-meter wall with the building material including the environmental impact of the mortar used in the process.

Figure 2: A depiction of the square-meter wall made up of HCB filled with mortar. The picture is not true to reality in terms of dimensions.

The building material unit dimensions were used to find how many units were required for every row and how many rows on top of each other was needed to build a one square-meter wall, excluding mortar volume. The volume of mortar for the whole wall was then calculated with the help of the surrounding thickness of mortar. The volume multiplied with the density gave us the weight from which we could find the weight cement with the help of the proportion of the mortar mixture. With the data of how much carbon dioxide cement produces we can determine the amount of carbon dioxide emitted by the mortar usage of a one square-meter wall.

With the calculated number of units needed to model a one square-meter wall we calculated the amount of carbon dioxide emitted per unit. For HCB & ISSB we used the amount of cement used per unit multiplied with the amount of units for the wall to calculate the total cement used for a one square-meter wall and then calculate the contributed carbon dioxide from that. For FCBTK & HHK we divided the total yearly consumption of coal in kilograms with the yearly number of units produced which we then multiplied with the amount of carbon dioxide emitted from coal type bituminous.

At last we added the carbon dioxide emissions from the mortar and building ma-terial units used to build a one square-meter wall.

2.1.6 Technical Data

Technical figures regarding the HHK and FCBTK bricks were collected from the comprehensive HHK report by Bangladesh University of Engineering and Tech-nology, BUET29. Technical figures regarding the ISSB block were sourced from an UN report30 _{and a report published in Matec web of conferences}31_{. The technical}

figures regarding the HCB were collected from the book Excellence in concrete construction through innovation published by CRC Press.

2.1.7 Technical Analysis

Technical properties for the different building materials were gathered quantita-tively from various reports and articles. These figures were then compared and used to build graphs in order to showcase the difference in technical properties.

29_{CES & BUET (2016) A Comprehensive Study on the Present status, performance,}

barrier-sand prospects of existing hybrid hoffman kilns (HHKs) operating in Bangladesh.

30_{Urban Energy Technical Note, (UN-HABITAT) (2015) Interlocking Stabilised}

Soil-Blocks (ISSB) https://www.hamk.fi/wp-content/uploads/2018/09/Interlocking-Stabilised-Soil-Blocks-ISSB-UETN-20.pdf) Interlocking Stabilised Soil Blocks Appropriate earth technologies in Uganda

31_{Matec (2017) Comparison of Strength Between Laterite Soil and Clay Compressed Stabilized}

3

Financial Calculations

3.1

Present Value, PV

The present value shows the current value of a future sum of money or cash-flow, given a rate of return.

P V = F V (1 + r)n (1) Where F V = F uture V alue R = rate of return N = number of periods

3.2

Net Present Value, NPV

The net present value is often used in capital budgeting and investment analysis to explore the profitability of a project or investment. The theory behind the net present value formula is by adding discounted future net cashflows, the present value of the investment is identified. The formula uses the present value of cash inflows and the present value of cash outflows over a set period, the net present value is the difference of these cashflows.

N P V = n X t=1 Rt (1 + i)t (2) Where

Rt= N et cash inf low subtracted outf lows during a single period t

i = Discount rate of return that could be earned in alternative investments t = N umber of time periods

N P V = T V ECF − T V IC

T V ECF = T odays value of expected cash f lows T V IC = T odays value of invested cash

3.3

Internal rate of return, IRR

The Internal rate of return is a parameter used in financial analysis to estimate the profitability of potential projects or investments. The internal rate of return is the discount rate that makes the Net Present Value (NPV) of all cash flows from a particular project equal to zero.

0 = N P V = T X t=1 Ct (1 + IRR)t − C0 (3) Where

Rt= N et cash inf low during the period t

C0 = T otal initial investment costs

IRR = internal rate of return t = the number of time periods

3.4

Weighted Average Capital Cost, WACC

The weighted average cost of capital is the firm’s cost of capital in which each category of capital is proportionately weighted. This includes all sources of capital.

W ACC = E V × Re+ D V × (1 − T c) (4) Where Re = Cost of equity Rd = Cost of debt

E = M arket value of the f irm0s equity D = M arket value of the f irm0s debt V = E + D = total market value of the f irm

E

V = percentage of f inancing that is equity D

V = percentage of f inancing that is debt Tc= Corporate tax

3.5

Salvage Value, SV

The Gordon Growth Formula – is used to calculate the salvage value of all future cashflows by dividing the upcoming years cash flow by the WACC-growth rate.

P = D1

r − g (5)

Where

P = Current stock price

g = Constant growth rate expected f or the dividends, in perpetuity r = Constant cost of equity capital f or the company(rate of retur)

D1 = V alue of next year0s dividends

4

Environmental Calculations

4.1

Number of units needed per meter wall length, n

This formula was used to calculate how many building material units were needed to reach a meter in length using the length of a unit in meter.

nL = 1 uL [m] (6) Where uL= Length of unit, m

4.2

Number of units needed per meter wall height, n

This formula was used to calculate how many building material units were needed to reach a meter in height using the height of a unit in meter.

nH = 1 uH [m] (7) Where uH = Height of unit, m

4.3

Number of units needed per one square-meter Wall,

n

This formula was used to calculate how many building material units were needed to reach one square-meter wall surface.

nW = uL× uH[m] (8)

Where

uL= Length of unit, m

uH = Height of unit m

4.4

Total Mortar Joint Volume per one square-meter Wall,

V

This formula was used to calculate the total mortar joint volume per one square-meter wall with the use of number of units per length and number of units per height together with the mortar joint thickness. This formula states that there are no mortar joints on the very top layer of units nor outer perimeters but only between the units.

Vm = (uH-1) × uL× ((H × L × Mjt) + Mjt2 × W
+ (H × W × Mjt)

−H × ( Mjt2 × W
+ H × W × Mjt2
))[m3]

(9) Where

uH = N umber of units needed per meter height, [m]

uL= N umber of units needed per meter length, [m]

H = Height of unit, [m] L = Length of unit, [m] W = W idth of unit, [m] Mjt = M ortar joint thickness, [m]

4.5

Mass of Mortar, m

This formula was used to calculate the mass of mortar, mm based on its volume and density.

mm = ρ × V [kg] (10)

Where

ρ = density, of mortar [kg m3]

4.6

CO

per unit, u

This formula was used to produce the amount of carbon dioxide in kilograms per building material unit using the cement in kilograms per unit and the carbon dioxide in kilograms per kilogram cement.

uCO2 = Cu× CCO2 [kg] (11)

Where

Cu = kg cement per unit [kg]

CCO2 = CO2 per kg cement [kg]

4.7

CO

per square-meter wall contributed by Units, w

This formula was used to produce the amount of carbon dioxide in kilograms per wall of building material units using the number of units to build a wall and the carbon dioxide per unit parameter.

wuCO2 = uCO2 × nw [kg] (12)

Where

uCO2 = CO2 per unit [kg]

nw = N umber of units needed per one square − meter W all

4.8

CO

from mass Mortar, m

This formula was used to produce the amount of carbon dioxide in kilograms from the mass of mortar together with an altered version of carbon dioxide in kilograms per cement ratio in mortar which is 13%.

mm,CO2 = 0, 13 × CCO2 [kg] (13)

Where

CCO2 = CO2 per kg cement [kg]

4.9

CO

per square-meter wall from Mortar, w

This formula calculates the amount of carbon dioxide in kilograms from the total mass of mortar in the wall of units.

wm,CO2 = mm,CO2 × mm [kg] (14)

Where

mm,CO2 = M ass carbon dioxide per mass mortar

4.10

Total CO

per square-meter wall of units, tot

This formula adds the carbon dioxide emissions from the building material units and the mortar used that together builds the wall to get the total environmental impact of a square-meter wall.

totCO2 = wm,CO2 + wu,CO2[kg] (15)

Where

wu,CO2 = CO2 per square − meter wall f rom U nits

5

The Brick Industry in Bangladesh

The traditional way of producing bricks in Bangladesh is by a method called Fixed Chimney Bull Trench Kiln which dates back to 1897 when the British engineer W. Bull introduced the method as the Bull Trench Kiln but faced many regulations during the 1990s and was lastly banned in India 2004-0532 _{because it was far too}

polluting33. Since then Bangladesh have adopted and revised this method to the Fixed Chimney Bull Trench Kiln, FCBTK that has been widely used making up for 92.2% of the kilns in Bangladesh in 201034_{. This method has over the years put}

stress on the arable land as traditional brick manufacturing accounts for roughly 17% of the total loss in agricultural topsoil every year, decreasing carbon sinks and endangering the ecosystem. This is due to the most common practice of producing raw materials comes from digging the topsoil35. The FCBTK being less polluting than its originator is still causing severe air pollution due to its emissions resulting in an AQI score of hazardous level36. This method is seasonal due to not being able to function during rain periods causing a halt in pollution but unfortunately also in employment. The production purpose of the bricks also cause environmental distress as the bricks are often uneven in size, requiring about a three cm thick mortar filling between them. Many times the walls are not assumed aesthetic caus-ing them to be covered with an additional layer of plastercaus-ing which increases the environmental impact even more37.

The Alternative Brick Industry in Bangladesh

With majority of Bangladesh brick production being very harmful in terms of sus-tainability many cleaner alternatives have emerged and are potentially on the rise. One alternative to the FCBTK is the Hybrid-Hoffman Kiln, HHK a Chinese revi-sion of the original method called Hoffman Kiln invented by the German Friedrich

32_{Hoyon Kumar Saha Jahangir Hosain (2016) Impact of brick kilning industry in peri-urban}

Bangladesh

33_{Pallab Kanti Ghoshal (2008) Prospects and Problems of Brick Industry}

34_{Asian Development Bank (2012) Proposed Loans. People’s Republic of Bangladesh:}

Financ-ing Brick Kiln Efficiency Improvement Project

35_{AvS.M. Imamul Huq, Jalal Uddin Md. Shoaib. (2013) The Soils of Bangladesh}

36_{Abu Sadeque, Mohammad PEng (2019), Study on sustainable and affordable appropriate}

building material and/or technology for coastal islands of Bangladesh.United Nations Develop-ment Programme, Bangladesh

37_{United Nations Human Settlements Programme (UN-HABITAT) (2009) Interlocking}

Hoffman 1858. This has been widely used in China and is now steadily entering the Bengali brick industry due to its lower energy consumption and reduction of air pollution38 even though problems with producing raw materials are the same as FCBTK. Both methods produce clay bricks that are fired.

The Hollow Concrete Block, HCB is also an alternative that is being increas-ingly popular in Bangladesh first designed by Harmon S. Palmer in 1890 but first patented 1900 after ten years of experimenting on the constituents for the building material. It began spreading 1905 in the Midwestern region of the United States due to the abundant amount of sand banks and gravel pits as they are a big part of the raw material components to the block. It is considered less environmentally impacting due to the low use of masonry work decreasing construction costs. Also, the hollow form allows facilities for electrical conduits, water and soil pipes inside the brick together with its lightweight makes it a easier material for construction39_.

Another alternative is the Interlocking Stabilized Soil Blocks, ISSB that has gained popularity in especially in East Africa seeing usage in countries such as Uganda. ISSB offers lower construction costs while still providing equal quality and also reduces the environmental impact and has not yet been introduced to Bangladesh but is included in this study to explore the potential of it40.

38_{Kumar, Sonal and Maithel, Sameer (2015) Production of Bricks Through Hybrid Hoffman}

Kiln (HHK), Greentech Knowledge Solutions Pvt. Ltd

39_{China Bangla Engineers and Consultants Ltd. (2019) Techno Economic Feasibility Report}

on Concrete Block in Bangladesh

40_{United Nations Human Settlement Programme (UN-HABITAT) (2009) Interlocking}

6

Fixed Chimney Bull’s Trench Kiln, FCBTK

6.1

Production Method of FCBTK

The method works as following by creating a paste using the mixture of clay, soil and water and processing them through a process machine4142_.

Figure 3: Excavator adding clay and soil mixed with water into the process machine.

Figure 4: Thick paste exiting the pro-cess machine ready to be molded in to the shape of a brick.

The paste then gets moulded into the shape of a brick- a moulded brick which are then sun dried on the outer perimeter of the FCBTK of the to dry out the moisture from water on before being used in the brick making process.

41_{Photo credit to Village Asset (2020), https://www.youtube.com/watch?v=7Fd7blxj3is}

ac-cessed 12-5-2020

42_{Greentech Knowledge Solutions Pvt. Ltd. (2014) Fixed Chimney Bull’s Trench Kiln}

Figure 5: A worker putting the paste produced earlier into a mould pressing it into the shape and then releasing it, covering the sun touched field.

Figure 6: A picture of the brick field where moulded bricks are being dried and fired bricks are being stacked with the fixed chimney in the distant. During the process the bricks are stacked into an oval shaped closed circuit which defines the main area of the FCBTK. In the middle of the circuit there are sev-eral passages for the air to pass through into the chimney and exit. The stacked bricks can be divided into three areas. The first area of the stack consists of un-fired moulded bricks and can be divided into two sections, the first section is the preheated zone where hot air from the second area passes through the unfired moulded bricks heating them and then going into the ducts and out the chimney. The second section is the “beginning” of the set of stacks, where unfired moulded bricks are being unloaded and prepared to be the next preheat zone as depicted below. The two sections are isolated through a seal, often a plastic fold to contain the heat in the second area and also help guide the air into the ducts and to protect the loading workers in the second section of the first area.

Figure 7: Workers are preparing the next set of non-fired moulded bricks to be preheated in the second section of the first area, these bricks have been sun-dried in the fields.

The second area is the temporary kiln, which causes the preheating, this is where the combustion happens by enclosing these stacked bricks with sand, gravel on top to insulate the area, contain the heat and give the workers a platform to work on. The fire and heat hardens the brick which increases its strength and durability, having a steady fire is crucial for optimizing the time bricks need to be burned which is why there are firemen, who feed the fire fuel as depicted below, in this case the fuel is coal which is the most common fuel. The fuel is fed through several holes that are covered by lids to contain the heat; these holes defines the second area as the holes are needed where there is fire to burn the bricks.

Figure 8: Fire masters pouring granulated coal into fuel holes to keep firing going by combustion.

The third area is where the previously fired bricks gets cooled by the fresh air that enters in the “end” of the stack which then goes through into the kiln section and then through the ducts into the fixed chimney and up 20-38 meters above ground level. It is in this area the bricks are then being loaded and transported. The red area is as we have mentioned the third area, the yellow is the second area and the green is the first section of the first area, the preheated zone due to the air. The second section of the first area is where the unloading happens as seen in figure 6.

Figure 9: Depiction of air inlet into the process through third area.

Figure 10: Depiction of air outlet through chimney.

Due to the openness of the FCBTK plant its production is season dependent as it can only function during dry periods so that the unfired moulded bricks can dry before going into the process and also so that the kiln itself stays isolated, pouring rain would not allow combustion not firing to occur as air would be humid and the unfired moulded bricks wet.

When the bricks are done in the middle-area the process repeats but this time by moving one step forward, being that new stacks of moulded bricks gets un-loaded in front of the previously ones who are now being the ones getting fired by creating a new roof with fuel holes and creating a combustion. What was previ-ously the firing area now becoming the cooling zone who cool the recently fired bricks who are then finished and can be removed from the kiln by being loaded and then transported to the place of use.

6.2

Financial Results of FCBTK

The result of the FCBTK cashflow model was an IRR of 44.4% and a NPV of 130951$ over a 10 year period. The profitability reflects the relatively low initial investment cost of roughly 70000$ and small operating cost due to the low labor cost of hiring migrant workers during the 6 month long dry operation season. In addition, the operation cost is further reduced because of there is no financing cost because of the assumption that no financing would be required for investments of this size. The main cost of this building method is the low energy efficiency as the fuel cost in terms of coal is high compared to other brick burning methods. The IRR of 44,4% is higher than the 20,65% weighted average cost of capital.

Table 1: Fixed Chimney Bull’s Trench Kiln Cash Flow-table ($,thousand)

Parameters 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 Capital Investment -70

Revenue 191,58 191,58 191,58 191,58 191,58 191,58 191,58 191,58 191,58 191,58 191,58 Total Operating Cost 131,7 131,7 131,7 131,7 131,7 131,7 131,7 131,7 131,7 131,7 131,7 Operating Profit -10,11 59,89 59,89 59,89 59,89 59,89 59,89 59,89 59,89 59,89 59,89

Financial Cost none

Salvage Value 312,69

Cash Flow -6,57 38,93 38,93 38,93 38,93 38,93 38,93 38,93 38,93 38,93 351,62 Present Value -6,57 32,27 26,74 22,17 18,37 15,23 12,62 10,46 8,67 7,19 53,8

Table 2: Key financial fig-ures for FCBTK Key figures FCBTK NPV* 131 IRR 44,46% WACC 20,65% * _{$, thousand}

6.3

Environmental Result of FCBTK

The environmental result of FCBTK is as shown below in the table. According to the model the total CO2 emitted from producing a square-meter wall of FCBTK

including mortar is 39,7 kg. The full environmental model can be found in the appendix, Table 30.

Table 3: The Environmental Results from the Environmental Analysis

Parameters FCBTK

Number of units needed per one square-meter Wall, nw 56

Total Mortar Joint Volume per one square-meter Wall, Vm* 61

kg CO2 per square-meter wall contributed by Units, Wu,CO2

** _27.8

kg CO2 per square-meter wall from Mortar, Wm,CO2

** _11.9

Total kg CO2 per square-meter wall of units, totCO2

** _39.7

* _l,litre

**_{k g, kilogram}

6.4

Technical Result of FCBTK

The technical results of the data collection are the following findings. The FCBTK brick is made out of 100% clay and have an crushing strength of 173kg/cm2_{. It was}

also discovered that the FCBTK brick has a water absorption capacity of 18.5%.

7

Hybrid-Hoffman Kiln, HHK

7.1

Production Process of HHK

The process begins with extracting clay which is then usually hydraulically exca-vated or by hand from nearby sources such as riverbeds or mining surface clay in pits that then can be transported to the factory. At the factory the clay is processed by crushing it and then adding granulated coal and water to gain fuel containment to ease the combustion in the kiln later and water to add moisture43’44. The clay mixed with coal is then fed into a vacuum extruder which forms the paste into the shape of a beam in a fixed size put onto the conveyor belt. This is then transported to a cutting station where it the shape is cut into brick-sized parts that are then manually loaded from the belt onto carts.

43_{Centre for Energy Studies (CES), Bangladesh University of Engineering and Technology}

(BUET) (2016) A Comprehensive Study on the Present status, Performance, Barriers and Prospects of Existing Hybrid Hoffman Kilns (HHKs) operating in Bangladesh

44_{Photo credit to CLAY BBT, https://www.youtube.com/watch?v=bnu7qZPuuh8, accessed}

Figure 11: Factory worker shovelling coal into clay mixture on conveyor belt.

Figure 12: Conveyor belt content being mixed with water.

Figure 13: Moulded paste exiting the vacuum extrude.

Figure 14: Moulded paste being sliced into moulded bricks.

These carts are then transported into drying vaults that utilize the excess heat from the kiln where the firing and combustion occurs. This through and extended, often underground duct and this is also where the flue gas later is released, acting like a chimney but not nearly as high.

Figure 15: Moulded paste exiting the vacuum extrude.

Figure 16: Moulded paste being sliced into moulded bricks.

The dried bricks are then manually transported into the external kiln sector where they are loaded into annular chambers to be fired. The kiln functions similar to FCBTK process where the fire moves from chamber to chamber resulting in three main areas of the kiln circuit, each chamber has small entries for unloading and loading bricks.

Figure 17: Carts with loaded now dried moulded bricks being attached to a tractor ready for transportation.

Figure 18: Cart with loaded now dried moulded bricks entering an inactive combustion chamber.

Figure 19: Workers stacking dried moulded bricks into an inactive cham-ber a specific manner.

Figure 20: Fire master pouring gran-ulated coal into an active combustion chamber.

The first area is the preheating area where the dried bricks are unloaded and re-ceiving the heat from the chamber before, which is the second area where the combustion occurs and bricks are being fired. This is maintained by fuel holes also. The third area is the zone where fire previously was, which is now being cooled until being loaded.

Demonstration of the clockwise operation process from one chamber to another in a Hybrid-Hoffman Kiln also declaring the three areas and the air passagewaya

a_{Photo credit to Dylan Moore (2011), https://www.cementkilns.co.uk/early kilns.html}

ac-cessed 12-05-2020

7.2

Financial Result of HHK

The result of the HHK cashflow was an IRR of 37% and a NPV of 1474000$ over a 10 year period given that the HHK bricks are sold at the market price of regular FCBTK brick. The sensitivity analysis below reveals that if the price of HHK bricks are increased by 5 and 10% from the base price of the regular brick, the IRR increases to 38 and 40%.

The Hybrid Hoffman kiln is among the more technologically advanced brick kilns. The initial investment cost is substantially higher than those of the other building

materials because of the advanced land development required. The main revenue drivers of an HHK plant is the higher production capacity of roughly 20 million bricks per annum, the higher brick unit price, and the improved energy efficiency reducing the cost of fuel. The operation cost in year 2 to 6 is increased due to the financing cost of the debt for the initial investment. The base-case IRR of 37% is higher than the 18,13% weighted average cost of capital.

Table 4: Hybrid-Hoffman Kiln Cash Flow-table, ($,thousand)

Parameters 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 Capital Investment -3129

Revenue 1292 2584 2584 2584 2584 2584 2584 2584 2584 2584 2584 Total Operating Cost 239 478 478 478 478 478 478 478 478 478 478 Operating Profit -2076 2106 2106 2106 2106 2106 2106 2106 2106 2106 2106 Financial Cost 0 453 415 377 339 301

Salvage Value 864,3

Cash Flow -2076 982 1007 1032 1057 1081 1369 1369 1369 1369 10012 Present Value -2076 832 722 626 543 470 504 426 361 306 1892

Table 5: Key financial figures for HHK Parameter Base NPV* 1474 IRR 37% WACC 18.13% * _{$, thousand}

Table 6: Sensitivity analysis for HHK

Parameter Base 5% Increase 10% Increase

total PV* _{4603 5287 5783}

Capital Investment Cost* -3129 -3129 -3129

NPV* _{1474 2158 2653}

IRR 37% 38% 40%

WACC 18.13% 18.13% 18.13%

7.3

Environmental Result of HHK

The environmental result of HHK is as shown below in the table. According to the model the total CO2emitted from producing a square-meter wall of HHK including

mortar is 29.1 kg. The full environmental model can be found in the appendix, Table 30.

Table 7: The Environmental Results from the Environmental Analysis

Parameters HHK

Number of units needed per one square-meter Wall, nw 56

Total Mortar Joint Volume per one square-meter Wall, Vm* 61

kg CO2 per square-meter wall contributed by Units, Wu,CO2

** _17.2

kg CO2 per square-meter wall from Mortar, Wm,CO2

** _11.9

Total kg CO2 per square-meter wall of units, totCO2

** _29.1

* _l,litre

**_{k g, kilogram}

7.4

Technical Result of HHK

The technical results of the data collection are the following findings. It was found that the HHK brick is made out of 100% clay and have an crushing strength of 351/cm2_{. It was found that The HHK brick has the highest crushing strenght out}

of all the alternative building materials. It was also discovered that the HHK brick has a water absorption capacity of 13.4%.

8

Hollow Concrete Block, HCB

Hollow concrete blocks are produced in a variety of compositions with different finishes and performance characteristics to meet a wide range of needs. For the purpose of this study C15 concrete was selected for comparison to the other build-ing alternatives. C15 is a standard mix which suits Foundation walls, basement walls, structural concrete and walls for example.

8.1

Production Method of HCB

The method begins with assembling the raw material. Firstly, picking the aggre-gates for making the concrete block together with cement is fundamental. Main aggregates used in Bangladesh for making concrete are sand and gravel which can

often be found locally. The cement must be stored isolated from humidity to pre-vent deterioration though premature hydration. Then extracting water free from acids, organic chemicals is mandatory since the water quality can hurt the end-product45_’46_.

The mixing ratios used in this case study will be volume based therefore one-part cement, three one-parts sand and five one-parts gravel. Depending on the quality of the aggregate different ratios can be used. This must be mixed very thoroughly before adding the water. The amount of water added is often produced by trial but after that a fixed amount can be settled for.

Figure 21: Mix of ce-ment, sand and gravel entering sieve creating a mixture.

Figure 22: Container be-ing filled up with mix-ture to transport into processor.

Figure 23: Mixture un-loaded from container into processor as water is added to the mixture. The mix then goes into the mould that is formed including the hollow form which leaves the mix only to be pressed into a compact block.

45_{China Bangla Engineers and Consultants Ltd. (2019) Techno Economic Feasibility Report}

on Concrete Block in Bangladesh

Figure 24: Mixture transported by a conveyor belt into the press machine that forms the mixture into blocks.

Figure 25: The freshly compressed Hollow Concrete Blocks being pushed out of the machine.

After the block is formed it must lay and air dry for up to 8 hours before being cured for several days by sheltering them from direct sunlight and keeping them watered and damp to let the cement to hydrate completely. Before using it in production the block should be dry.

Figure 26: Hollow Concrete Blocks are stacked to dry before being cured.

Figure 27: Hollow Concrete Blocks are cured by watering.

8.2

Financial Results of HCB

The result of the HCB cashflow model with a 10 year perspective was an IRR of 271,40% and a NPV of 2262511$. The profitability reflects the high revenue due to high production capacity and high market value per brick.

Table 8: Hollow Concrete Blocks Cash Flow-table, ($,thousand)

Parameters 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 Capital Investment -72

Revenue 191 382 382 382 382 382 382 382 382 382 382 Total Operating Cost 167 333 333 333 333 333 333 333 333 333 333 Operating Profit -61 28 28 28 28 28 28 28 28 28 28 Financial Cost

Salvage Value 224

Cash Flow -61 18 18 18 18 18 18 18 18 18 242 Present Value -61 15 13 10 9 7 6 5 4 3.4 37

Table 9: Key financial fig-ures for HCB Key figures HCB NPV* ₂₂₆₃ IRR 271,40% WACC 20,65% * _{$, thousand}

8.3

Environmental Result of HCB

The environmental result of HCB is as shown below in the table. According to the model the total CO2 emitted from producing a square-meter wall of HCB including

mortar is 13.7 kg. The full environmental model can be found in the appendix, Table 30.

Table 10: The Environmental Results from the Environmental Analysis

Parameters HCB

Number of units needed per one square-meter Wall, nw 13

Total Mortar Joint Volume per one square-meter Wall, Vm* 9

CO2 per square-meter wall contributed by Units, Wu,CO2

** _12.0

CO2 per square-meter wall from Mortar, Wm,CO2

** _1.74

Total CO2 per square-meter wall of units, totCO2

** _13.7

* _l,litre

8.4

Technical Result of HCB

The technical results of the data collection are the following findings. It was found that the HCB is made out of 33% sand, 11.1% cement and 55.6% gravel and have an crushing strength of 153/cm2_{. It was also discovered that the HCB has a water}

absorption capacity of 6.6%. Which indicates that the building material has a high resistance to wet conditions and the adverse effects of weather.

9

Interlocking Stabilized Soil Blocks, ISSB

9.1

Production Method of ISSB

ISSB are mainly made of laterite, cement and coarse sand. ISSB is a block- not fired which makes it environmentally a very energy efficient and pollution minimizing method to produce building materials. Instead of firing this method utilizes a moulding and compression technique to compactly finalize the block out of its constituents. Therefore, the choice of raw materials is critical to this method to ensure quality. The interlocking comes from the groove design within the block allows the blocks to interlock with one and another to increase strength and reduce use of mortar and plaster. The interlocking technique also speeds up the working process which increases the pace of the labour47.

Figure 28: Different models of Interlocking Stabilized Soil Blocks

The process begins with selecting soils, preferably free of organic material and free of harmful levels of salt. Laterite is often used as soil being highly common in equatorial countries with tropical climate. The soil should then be sieved to re-move materials such as foreign elements and organic matter. This is to be mixed together with relevant ratios of stabilizer in the mixer while water is gradually being introduced into the mix until it is moist enough. It is important that the water does not contain any harmful quantities of alkalis, acids, salts or diverse organic chemicals to risk degrading the quality.

47_{United Nations Human Settlements Programme (UN-HABITAT) (2009) Interlocking}

The mix is then put into a mould where the machine presses the material into a compact block.

Figure 29: The process of mixing sand and stabilizer, pouring the mixture into a hydraulic block machien and then removing the compressed blocks from the mould

After this process the curing of the block begins with carefully stacking them and protecting them from evaporating due to direct sunlight while watering them frequently in at least 7 days depending on the warmth in the operating country. The water curing process takes up to 28 days to complete and is together with the constituents in the beginning of the production what determines the strength of an ISSB48

Figure 30: Stacking of blocks under a plastic sheet.

Figure 31: Curing of blocks with water REF

48_{Urban Energy Technical Note, (UN-HABITAT) (2015) Interlocking Stabilised Soil}

Blocks (ISSB) https://www.hamk.fi/wp-content/uploads/2018/09/Interlocking-Stabilised-Soil-Blocks-ISSB-UETN-20.pdf

9.2

Financial Results of ISSB

The ISSB block is not available in the Bangladesh market. The cashflow model is therefore based on the theoretical incomes and costs. In order to receive a posi-tive NPV each block needs to be sold at 0,191$ per unit. The result of the ISSB Cashflow model was an IRR of 18,84% and a NPV of 2697$, given that the blocks are sold at 0,191$ per unit. The sensitivity analysis below reveals that if the price of the block is increased by 5% and 10% the IRR is increased to 27,17% and 44,47%. The cost of cement drives up the total cost of raw materials. The cement cost is over 60% of the total raw material even though it only stands for 10% of the constituents.

Table 11: Interlocking Stabilized Soil Blocks Flow-table, ($,thousand)

Parameters 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 Capital Investment -72

Revenue 612 1224 1224 1224 1224 1224 1224 1224 1224 1224 1224 Total Operating Cost 24 33 33 33 33 33 33 33 33 33 33 Operating Profit 203 565 565 565 565 565 565 565 565 565 565 Financial Cost

Salvage Value 4542

Cash Flow 132 368 368 368 368 368 368 368 368 368 4909 Present Value 132 305 253 210 173 144 119 99 82 68 751

Table 12: Key financial figures for ISSB

Key figures ISSB

NPV* 3

IRR 18.84%

WACC 20,65%