Design Report Housing and Facilities 2011

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Housing Development in Westonaria

A Design Report submitted to the Faculty of Engineering and the

Built Environment as partial fulfilment of the requirements of the degree

by

Housing and Facilities Group C

BACCALAUREUS INGENERIAE

In

CIVIL ENGINEERING SCIENCE

At

UNIVERSITY OF JOHANNESBURG

STUDY LEADER: Dr Dundu

20 October 2011


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OWS 4B

Housing Development in

WestonariaDesign Report for Housing and Facilities

10/20/2011

Brenden Jordaan 200612481

Edrie Du Toit 200602828

Kelly Hall 200723064

Larushkan Soobiah 200833658

Mikhail Bramdaw 200823954

Neil Pienar 200709097

Sunette Verster 200602699


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i

ANTI-PLAGIARISM DECLARATION

Title: Scoping Report for Housing and Facilities Development

Full name: Edrie Du Toit

Student number: 200602828

Course: Civil Design 4B (OWS 4B)

Lecturer: Prof. Legge

Due date: 20 October 2011

Plagiarism is to present someone elses ideas as my own. Where material written by other

people has been used (either from a printed source or from the internet), this has been

carefully acknowledged and referenced. I have used the Harvard Convention for citation and

referencing. Every contribution to and quotation from the work of other people in this essay

has been acknowledged through citation and reference. I know that plagiarism is wrong.

I understand what plagiarism is and am aware of the Universitys policy in this regard. I know that I would plagiarise if I do not give credit to my sources, or if I copy sentences

or paragraphs from a book, article or Internet source without proper citation.

I know that even if I only change the wording slightly, I still plagiarise when usingsomeone elses words without proper citation.

I declare that I have written my own sentences and paragraphs throughout my essay and Ihave credited all ideas I have gained from other peoples work.

I declare that this assignment is my own original work. I have not allowed, and will not allow, anyone to copy my work with the intention of

passing it off as his or her own work.

SIGNATURE .DATE...


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Abstract

The Housing and Facilities Design Group are responsible for decisions regarding the sizing

and basic layout of each housing and facility structure on the Syferfontein Farm, as well as

the materials to be used with structural analysis, logic and innovative thinking as a guiding

tool. These structures are designed with population growth as well as possible future

development in mind.

Green technology has been incorporated into the design where applicable to aid in lower

carbon emissions and a more environmentally friendly construction practice. Keeping in

mind that it is not always economically possible to use entirely green practise, a balanced

approach is needed.

Given the geological surroundings of the Syferfontein Farm, good foundation design is

imperative to keep the housing and facilities structurally sound for short and long term.

The completed project would accommodate a population of 257 500 on a 2000 ha site, whilst

accounting for a population growth rate of 0.25% per annum. It was found that the total cost

for the project would be approximately R 63.8 bn. and would require a construction time of

approximately 15 years.


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Acknowledgements

The Group of Housing and Facilities would like to thank the following people for their help

and guidance which aided in the completion of this report:

Dr M Dundu (University of Johannesburg, Civil Engineering)

Dr F Okonta (University of Johannesburg, Civil Engineering)

Mr P van Tonder (University of Johannesburg, Civil Engineering)

Ms S Potgieter (University of Johannesburg, Librarian)

Martha de Jager (CNCI, Librarian)

Susan Battison (CNCI, Librarian)


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Table of Contents

ANTI-PLAGIARISM DECLARATION .................................................................................... i

Abstract ......................................................................................................................................ii

Acknowledgements .................................................................................................................. iii

Table of Contents ...................................................................................................................... iv

List of Figures ............................................................................................................................ x

List of Tables .......................................................................................................................... xiv

1. Introduction ............................................................................................................................ 1

2. Project Scope ......................................................................................................................... 2

3. Site Description ...................................................................................................................... 6

3.1 Climate ............................................................................................................................. 6

3.2 Geological Setting ............................................................................................................ 7

3.3 Topography ...................................................................................................................... 7

3.4 Vegetation and Fauna ...................................................................................................... 8

3.5 Water Resources .............................................................................................................. 8

3.6 Archaeological, cultural and heritage interest. .............................................................. 10

4. GREEN ALTERNATIVES ................................................................................................. 11

4.1. Passive Heating and Cooling ........................................................................................ 11

4.1.1 Passive Solar Heating ............................................................................................. 11

4.1.2 Passive cooling........................................................................................................ 13

4.2 Solar Geysers ................................................................................................................. 13

4.2.1 Introduction ............................................................................................................. 13

4.2.2 Benefits ................................................................................................................... 14

4.2.3 Types of Solar Water Heating Systems .................................................................. 15

4.2.4 Types of Collector Plates ........................................................................................ 16

4.2.5 Eskom Rebate ......................................................................................................... 17


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4.3 Lighting .......................................................................................................................... 17

4.3.1 LED globes ............................................................................................................. 17

4.3.2 Sunlighting .............................................................................................................. 18

4.3.3 Solar LED Garden and Landscaping Lights ........................................................... 18

4.3.4 Day/Night Sensor .................................................................................................... 19

4.3.5 Motion Sensors ....................................................................................................... 19

4.4 Insulation........................................................................................................................ 19

4.4.1 Roofs ....................................................................................................................... 19

4.4.2 Walls ....................................................................................................................... 20

4.4.3 Floors ...................................................................................................................... 20

4.4.4 Windows and sliding doors ..................................................................................... 21

4.5 Green Building Materials ............................................................................................... 21

4.6 Green roofs..................................................................................................................... 26

4.7 Rain water harvesting .................................................................................................... 28

4.7.1. Introduction ............................................................................................................ 28

4.7.2 Uses of harvested rain water ................................................................................... 29

4.7.2 Proposed water harvesting systems ........................................................................ 30

4.7.3 Advantages and Disadvantages............................................................................... 32

4.8 Heat Pumps .................................................................................................................... 33

5. Design Results ..................................................................................................................... 35

5.1. Spatial Design ............................................................................................................... 35

5.1.1. Housing .................................................................................................................. 35

5.1.2. Facilities ................................................................................................................. 37

5.1.3. Summary of Facilities ............................................................................................ 38

5.2. Structural Design .......................................................................................................... 71

5.2.1. Steel Truss .............................................................................................................. 71

5.2.1.a. Specifications ...................................................................................................... 71


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5.2.1.a.i. Overall Dimensions........................................................................................... 71

5.2.1.a.ii. Loading Conditions .......................................................................................... 71

5.2.1.a.iii. Bending Moment and Axial Force .................................................................. 72

5.2.1.b. Sections ............................................................................................................... 73

5.2.1.c. Connections ......................................................................................................... 74

5.2.1.d. Base Plate ............................................................................................................ 76

5.2.2. Masonry Structure .................................................................................................. 77

5.2.2.a. Layout ................................................................................................................. 77

5.2.2.b. Analysis and Design Methodology ..................................................................... 78

5.2.2.c Design .................................................................................................................. 78

5.2.2.c.i. Roof ................................................................................................................... 78

5.2.2.c.ii. Slabs ................................................................................................................. 79

5.2.2.d. Masonry Design .................................................................................................. 82

5.2.2.e. Stairs .................................................................................................................... 84

5.2.2.f. Foundation ........................................................................................................... 85

5.2.3. Concrete Multi-Storey Structure ............................................................................ 86

5.2.3.a. Specifications ...................................................................................................... 86

5.2.3.a.i. Overall Dimensions........................................................................................... 86

5.2.3.a.ii. Roof and Floors................................................................................................ 86

5.2.3.a.iii. Stability ........................................................................................................... 86

5.2.3.a.iv. Fire Resistance ................................................................................................ 88

5.2.3.a.v. Loading Conditions .......................................................................................... 88

5.2.3.a.vi. Exposure Conditions ....................................................................................... 89

5.2.3.a.vii. Materials ........................................................................................................ 89

5.2.3.a.viii. Foundations ................................................................................................... 89

5.2.3.a.ix. Scope of design ............................................................................................... 89

5.2.3.a.x. Design Process Followed ................................................................................. 90


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5.2.3.b. Sizes of Members ................................................................................................ 91

5.2.3.b.i. Slab ................................................................................................................... 91

5.2.3.b.ii. Beam ................................................................................................................ 91

5.2.3.b.iii. Column (EDGE & INTERNAL) .................................................................... 91

5.2.3.c. Vertical Design Loads ......................................................................................... 92

5.2.3.d. Design Moments ................................................................................................. 95

5.2.3.d.i. Beam Moments ................................................................................................. 95

5.2.3.d.ii. Column Moments .......................................................................................... 100

5.2.3.e Lateral Loading .................................................................................................. 104

5.2.3.f. Reinforcement ................................................................................................... 105

5.2.3.f.i. Slab .................................................................................................................. 105

5.2.3.f.ii. Beam ............................................................................................................... 106

5.2.3.f.iii. Column (EDGE & INTERNAL)................................................................... 107

5.2.3.g. Foundation Design ............................................................................................ 108

5.2.3.g.i. Multi Story Basement ..................................................................................... 108

5.2.3.g.ii. Methodology .................................................................................................. 109

5.2.3.g.iii. Raft foundation ............................................................................................. 109

5.2.3.g.iv. Reinforcement for Raft foundation ............................................................... 110

5.2.3.g.v. Cantilever retaining wall ................................................................................ 111

5.2.3.g.vi. Reinforcement for Cantilever wall ............................................................... 112

5.2.3.g.vii Piles (Option) ................................................................................................ 112

5.2.3.h. Isolation Joint Sizing......................................................................................... 112

5.2.3.i. Green Design Considerations ............................................................................ 112

5.2.3.j Roof Drainage ............................................................................................................. 114

6. Costing ............................................................................................................................... 115

7. Environmental Impact Assessment .................................................................................... 117

7.1. Legal Framework ........................................................................................................ 117


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7.1.1. The constitution of South Africa.......................................................................... 118

7.1.2. The National Environmental Management Act ................................................... 118

7.1.3. Legal Requirements in terms of Other Acts ........................................................ 119

7.1.3.a. National Water Act (Act No. 36 of 1998) ......................................................... 119

7.1.3.b. Conservation of Agriculture Resources Act (Act No. 57of 1983).................... 119

7.1.3.c. White Paper on Integrated Pollution and Waste Management for South Africa

........................................................................................................................................ 120

7.1.3.d. National Environmental Biodiversity Act (Act No. 10 of 2004) ...................... 120

7.1.4. National Environmental Management Biodiversity Act (Act No.10 of 2004) .... 121

7.1.5. National Environmental Management: Protected Areas Act (Act No.57 of 2003)

........................................................................................................................................ 121

7.1.6. National Veld and Forest Fire Act (Act No.101 of 1998) ................................... 121

7.1.7. National Heritages Resources Act (Act No.25 of 1999)...................................... 122

7.1.8. National Environmental Management: Air Quality Act (Act No.39 0f 2003) .... 122

7.1.9. Sustainable Development..................................................................................... 122

7.1.10. National Building Regulations and Buildings Standards Act (Act No.103 of

1997) .............................................................................................................................. 123

7.2 Impact Assessment Methodology ................................................................................ 123

7.3. Impacts and Mitigation ............................................................................................... 125

7.3.1. Impacts during Construction Phase ..................................................................... 125

7.3.2. Impacts during Operational Phase ....................................................................... 135

7.4. Conclusion .................................................................................................................. 143

8. Green Alternative Recommendations ................................................................................ 144

8.1. Housing ....................................................................................................................... 144

8.2. Community Related Facilities..................................................................................... 146

8.3. Educational Facilities .................................................................................................. 148

8.4. Public Service Facilities .............................................................................................. 150

9. Conclusion ......................................................................................................................... 152


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References .............................................................................................................................. 153


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List of Figures

Figure 2.1: Steel Frame....................................................................................................... 3

Figure 3.1: Map of Site Area ............................................................................................. 6

Figure 3.2: Contour Map of the Site ................................................................................. 7

Figure 3.3: South facing view of the property .................................................................. 8

Figure 3.4: Quarry ............................................................................................................ 9

Figure 3.5: Marsh just east of the dirt road on the property ............................................. 9

Figure 4.1: Evacuated tube collectors on a roof ............................................................. 14

Figure 4.2: Passive solar water heating system .............................................................. 15

Figure 4.3: Illustration of how Sunlighting works .......................................................... 18

Figure 4.4: Solar LED Garden and Landscaping Lights .................................................. 19

Figure 4.5: Thermguard sprayed on the ceiling ............................................................... 20

Figure 4.6: Cellulose fibre used for floor insulation ........................................................ 20

Figure 4.7: Sublayers for a green roof ............................................................................ 27

Figure 4.8: Rain water harvesting alternatives ................................................................ 30

Figure 4.9: Rainwater Harvest system ............................................................................ 31

Figure 4.10: Watree design............................................................................................. 32

Figure 4.11: Heat pump outside a house ....................................................................... 34

Figure 5.1.1: Market share of fresh produce markets in South Africa ........................... 39

Figure 5.1.2: Roof Top farming ..................................................................................... 39

Figure 5.1.3: Top view of market ................................................................................... 40

Figure 5.1.4: Newtown Precinct Public Toilets ............................................................. 40

Figure 5.1.5: Example of efficient layout for fire station ................................................ 61


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Figure 5.1.6: 1st Floor ...................................................................................................... 64

Figure 5.1.7: 2nd Floor ..................................................................................................... 64

Figure 5.1.8: 3rd Floor ...................................................................................................... 65

Figure 5.1.9: 4th Floor ..................................................................................................... 65

Figure 5.1.10: Fifth Floor ................................................................................................. 66

Figure 5.1.11: Roof .......................................................................................................... 66

Figure 5.1.12: Green roof ................................................................................................. 67

Figure 5.1.13: One double lane separated by foot paths ................................................. 70

Figure 5.2.1: Steel truss ................................................................................................... 71

Figure 5.2.2: Loading on the truss .................................................................................... 72

Figure 5.2.3: The axial force diagram............................................................................... 72

Figure 5.2.4: The bending moment diagram .................................................................... 73

Figure 5.2.5: Front view of the eaves connection ........................................................... 74

Figure 5.2.6: Angled view of the eaves connection ........................................................ 74

Figure 5.2.7: Front view of apex connection ................................................................... 75

Figure 5.2.8: Angled view of apex connection ................................................................ 75

Figure 5.2.9: Dimensions of base plate ............................................................................. 76

Figure 5.2.10: Illustration of RDP conceptual design ...................................................... 77

Figure 5.2.11 : Layout of RDP Units ................................................................................ 77

Figure 5.2.12: Roof truss dimensions ............................................................................... 79

Figure 5.2.13: Imposed axial loads from roof truss .......................................................... 79

Figure 5.2.14: 120 mm prestressed 1st floor slab ............................................................ 80

Figure 5.2.15: Tendon Profile ......................................................................................... 80


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Figure 5.2.16: Floor Slab Profile ................................................................................... 81

Figure 5.2.17: 200 mm pre-stressed ground floor slab ................................................... 81

Figure 5.2.18: Typical Masonry block to be used ........................................................... 82

Figure 5.2.19: Outer block wall ........................................................................................ 82

Figure 5.2.20: Centre wall block and grouting pattern ................................................... 83

Figure 5.2.21: First floor slab minimum width ............................................................... 83

Figure 5.2.22: Stair slabs ................................................................................................. 84

Figure 5.2.23: Ground Floor Slab ................................................................................... 85

Figure 5.2.24: Two-way spanning slab and monolithically cast T beam ..................... 86

Figure 5.2.25: (a) Overall plan dimensions; (b) Half building design plan;

(c) End elevation ............................................................................................................. 87

Figure 5.2.26: Design algorithm ..................................................................................... 90

Figure 5.2.27: Cross-section of beams ............................................................................ 91

Figure 5.2.28: Load cases - critical columns for axial loading ....................................... 92

Figure 5.2.29: Axial loading for internal columns .......................................................... 92

Figure 5.2.30: Axial loading for edge columns ............................................................... 93

Figure 5.2.31: Floor loading and critical frames for bending .......................................... 93

Figure 5.2.32: Point load simplification for slab to beam load distribution .................... 94

Figure 5.2.33: Load case factors for moment determination .......................................... 94

Figure 5.2.34: Load Case 1 Bending Moment Diagram (Y-direction) .......................... 96

Figure 5.2.35: Load case 2 Bending Moment Diagram (Y-direction) ............................. 96

Figure 5.2.36: Load case 3 Bending Moment Diagram (Y-direction) ............................ 97

Figure 5.2.37: Load Case 1 Bending Moment Diagram ........ ..........................................98


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Figure 5.2.38: Load Case 2 Bending Moment Diagram ................................................ 98

Figure 5.2.39: Load Case 3 Bending Moment Diagram ................................................. 99

Figure 5.2.40: Wind load and induced lateral floor loads .............................................. 104

Figure 5.2.41: Slab reinforcement ................................................................................. 105

Figure 5.2.42: Bending reinforcement in Y-Direction ................................................. 106

Figure 5.2.43: Bending reinforcement in X-Direction ................................................ 106

Figure 5.2.44: Internal column reinforcement ............................................................ 107

Figure 5.2.45: Edge column reinforcement ................................................................. 108

Figure 5.2.46: Basement Raft ..................................................................................... 110

Figure 5.2.47: 8m span middle strip ........................................................................... 110

Figure 5.2.48: 8m span column strip .......................................................................... 110

Figure 5.2.49: 5m span middle strip ............................................................................. 111

Figure 5.2.50: 5m span column strip ............................................................................. 111

Figure 5.2.51: Retaining wall ......................................................................................... 111

Figure 5.2.52: Sun-lighting system for building assuming maximum channelling

distance of 20m ............................................................................................................. 113

Figure 5.2.53: Low income High-rise 2ha plot ............................................................. 113

Figure 5.2.54: Water Volumes prediction for green roof sections................................ 114


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List of Tables

Table 2.1: Proposed Housing............................................................................................ 2

Table 4.2: Green roof characteristics............................................................................ 28

Table 4.3: Advantages and disadvantages of rainwater harvesting.............................. 32

Table 5.1.1: Summary of Housing................................................................................... 35

Table 5.1.2: Summary of Facilities................................................................................... 37

Table 5.1.3: Religion in SA............................................................................................. 44

Table 5.1.4 : Religious institution distribution.................................................................. 44

Table 5.1.5: Summary of values..................................................................................... 45

Table 5.1.6: Number of users........................................................................................... 46

Table 5.1.7: Cars per income bracket and number of petrol stations required.................. 47

Table 5.1.8: Division of pupils within economic groups................................................. 50

Table 5.1.9: Division of areas for high income schools................................................. 51

Table 5.1.10: Division of areas for medium income schools.............................................52

Table 5.1.11: Division of areas for low income schools....................................................54

Table 5.1.12: Division of areas for RDP schools.............................................................. 56

Table 5.1.13: Number of disabled children by gender...................................................... 57

Table 5.1.14: Hospital Beds ............................................................................................ 59

Table 5.1.15: Number of floors for each clinic.............................................................. 59

Table 5.1.16: Officer to citizen ratio................................................................................. 63

Table 5.2.1: Truss sections............................................................................................... 73

Table 5.2.2: Shear and Moment capacity checks............................................................ 84


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Table 5.2.3: Imposed Loads............................................................................................ 88

Table 5.2.4: Dead Loads.................................................................................................. 88

Table 5.2.5: Beam Moments for Y-direction; bending about X-axis.............................. 95

Table 5.2.6: Beam Moments for X-direction; bending about Y-axis.............................. 97

Table 5.2.7: Cantilever Reinforcement........................................................................... 112

Table 6.1: Costing for Complete Town.......................................................................... 115

Table 7.1: Impact assessment ....................................................................................... 123

Table 7.2: SP Value Definitions.................................................................................... 124

Table 7.3: Anticipated Biophysical Impacts during Construction Phase...................... 125

Table 7.4: Anticipated Socio-Economic Impacts during Construction Phase.............. 132

Table 7.5: Anticipated Biophysical Impacts during Operational Phase....................... 135

Table 7.6: Anticipated Socio-Economic Impacts during Operational Phase............... 135


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1. Introduction

The demand for land is a growing problem around the world. Most of the land that is best

suited for construction has already been used. This leaves engineers with the issue of finding

new innovative ways of making use of lesser suited pieces of land. Areas which were

previously avoided for terms of major construction will now have to be used to accommodate

the population growth. Therefore these pieces of land will have to now be used for the

development of new housing projects and towns.

This responsibility lies predominantly on the shoulders of civil engineers. Areas such as

Syferfontein with large amounts of dolomitic soil, as well as other problem soils will be

increasingly dealt with in the future. Not only does this space need to be used as effectively

and efficiently as possible, but new technologies and innovative approaches are a necessity

for sustainability and lasting infrastructure that can benefit the community and society as a

whole.

One of the most crucial challenges relevant to current Engineers, is the growing amount of

greenhouse gases. Incorporating solar heating, green roofing and recyclable materials in

construction are some of the newer approaches that can vastly reduce carbon footprint, as

well as ensure sustainability of precious resources.

The Housing and Facilities Design group of 2011, have taken on various classical as well as

innovative approaches to produce designs that are balanced between being green and

economically viable, while adhering to a high standard of quality.


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2. Project Scope

There is a need to promote growth and development of the area west of Johannesburg as well

as address the current housing shortage in the country. The University of Johannesburg

Group C, of the 4th

year Civil Design class, was requested by LTE consulting to assist them

with the feasibility study of a proposed high density development with regard to housing and

facilities. The proposed 2000 hectare site was inspected and a desktop feasibility study was

carried out in accordance with the general specifications and information gathered from the

visit. The site is to house approximately 257 500 people, as well be self sustaining with

regard to services such as water supply and power generation. The proposed development

will comprise of:

Table 2.2: Proposed Housing

Income Group Number of Units People per Unit

Total Population

at Completion

Date

Population

Increase 30

years after

completion

RDP 22 500 6 135 000 10 501

Low Income 12 500 5 62 500 4 862Medium Income 10 000 4 40 000 3 112

High Income 5 000 4 20 000 1 556

The study was done assuming that the project will be completed within a period of 15 years

with a design life of 30 years thereafter. The growth of the population from the time of the

projects completion to the end of the design life was accounted for in the design and

therefore all buildings were designed with the capacity for upgrades. The population is

estimated to grow at a rate of 0.25% per annum, therefore the design of housing and facilities

need to accommodate for the impact of this growth. The residential buildings are therefore

designed to allow for another floor at the top of the structure. At the end of the design life the

population will have increased by approximately 20 031 people taking the total population

that will require housing and facilities to 277 531.

The project required a spatial design to be done for all facilities and residential buildings.

This information was relayed to the Town Planning group so that a map of the town layout


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could be produced. The spatial design was done by using the guidelines set out by the CSIR

Red Book, however due to the large population that will be designed for on a relatively small

area of land; engineering judgements had to be made by the group to facilitate this demand.

The structural design was done by analysing three different types of buildings, a steel truss

structure, a masonry structure and a multi-storey concrete structure. The results from the

structural analysis from these structures were then used in order to make a judgement on the

feasibility of all the buildings in the town.

Steel Truss

The truss dimensions and general layout and purlin placement were initially determined.

These dimensions were used to calculate the wind loading on the structure. The wind load

that was used for further analysis was the worst case scenario.

The worst case general load was calculated by calculating all 6load cases and selecting the

worst loading case. The loading case that was used was 1.2DL + 1.6LL.

The truss was analysed in Prokon to select initial sections and obtain the member forces and

moments. These member forces and moments were used to check whether the selected

sections were adequate. Once the final sections were selected the baseplate, connections andfoundations were calculated.

Figure 2.1: Steel Frame


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Masonry Structure

The RDP units were designed with maximum space, minimum materials and cost in mind,

while incorporating environmentally friendly materials and practice as far as economically

viable. For example making use of compressed earth blocks is considered to be

environmentally friendly.

Traditional structural analysis methods such as moment distribution method and other

fundamental structural analysis methods were adopted. Software such as Microsoft Excel and

Prokon were then used as checking tools.

Basic research into masonry and timber design had to be undertaken, while making use of the

SABS 0164 code for masonry design. Various design books were followed as are listed in the

reference list. Concrete Manufacturer Association manuals were consulted for prestressed

hollow core slab use.

Multi-storey Concrete Structure

The multi-storey concrete structure was analysed by considering a low income multi-storey

building and analysing the structural requirements needed for that building. The analysis

included determining the loads acting on the building, the sizing and reinforcement design ofcritical columns, beams and slabs, as well as the design of the foundation for the building.

The analysis of the building was done by doing first principle hand calculations. These

calculations were then checked using Prokon software.

Once all the calculations were completed the feasibility study could be done. The preliminary

sizes of all members in the building, obtained from the hand calculations, were then evaluated

according to cost. The feasibility study also contained information of the time it would take to

construct a project of this nature as well as the practicality of the project.


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Deliverables and Persons Responsible

Scoping

Site description [K]

Project description and possible alternatives [L ,M]

Legal framework [E , B]

Overview of possible green building alternatives [ K, E, N ,S]

Anticipated environmental impacts [S]

QuantitativeAnalysis

Estimation of housing types and facilities required [L,M,K,S,E,N]

Estimation of erf area per building [L,M]

Estimation of building dimensions [ALL]

CAD drawings of buildings and/or [B,L ,M]

floor layout s [ALL]

This forms the basis of entire design project as all groups are dependant

EstimationsBased on CSIR guidlines, population statistics and logistics

Design

Detailed structural design of a multistorey concrete building[L,B,M]

Detailed Masonary Design of an RDP block [N,K] Detailed Structural design of a steel structure [E,S,N]

Foundation designs and recommendations [K.N]

All designs were done according to the relevant SANS codes and based

on fundemantal structural design and analysis methods covered in thedegree (i.e from first principles)

All designs have bene checked

Feasability

Overview of green aspects (materials, technology etc.) [ALL]

Cost estimates [E,N,L,M]

EIA (possible mitigation of impacts) [N,S,B]

L Larushkan, N Neil, M Mikhail, E Edrie, K Kelly, B Brenden, S - Sunette

COMPLETE

COMPLETE

COMPLETE

COMPLETE


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3. Site Description

The site that the proposed housing development will take place on is located south west of the

Lenasia area at the co-ordinates of 262048S 274725E. It is located on the Syferfontein

Farm in Westonaria and the farm can be accessed via dirt roads just off the N12 highway.

The site is just under 2000ha in area and there is currently an airfield located on it as well as

an old mine dump.

Figure 3.1: Map of Site Area.

The Syferfontein Farm lies just east of the South Deep Gold mine one of the deepest mines

in the world, and south west of Lenasia. . The Baragwaneth Airport, which is still in

operation, lies within the boundaries of the farm and is of heritage importance. African Bricks

has used the property to mine clay for brick manufacturing.

3.1 Climate

Warm summers and mild winters characterise this region with a subtropical highland

climate (Ward, 2002). The temperature occasionally drops below freezing point in winter but

generally a moderate temperature. Afternoon thundershowers can be expected in the summer

months and cold fronts in winter bring cold southerly winds.


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3.2 Geological Setting

In the past, development of this region has been avoided due to unstable dolomites, flood

plains, marshes, unstable alluvium and chert deposits, active clays and collapsible soils. The

surrounding area of Lenasia consists of dolomite chert from the Malmani Subgroup. Just westof Lenasia the ground consists of shale and coal of the Ecca Group of the Karoo Super group

which overlie dolomite. (Greater Johannesburg Metropolitan Council, 2000).

There is dolomite present on the site and it will be accounted for in the geotechnical

evaluation of the project.

African Brick manufactures a large amount of bricks from the Syferfontein clay deposit it

has a very high quality which is relatively rare in South Africa and is estimated to last until

2018. (African Brick Centre, 2007)

3.3 Topography

The property has a fairly uniform flat terrain with a gentle South to North Slope of less than

5 with a sharp incline to a ridge on the south end.

Figure 3.2: Contour Map of the Site

1590

1750


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3.4 Vegetation and Fauna

Fauna and flora for this area are fairly typical for the region with flat Highveld grasslands. A

herd of goats were spotted near the low-lying wetland which could signify that the water is

not poisonous. Very little to no large bushes or trees were observed except for large shrubsoverlying an old farm structure adjacent north of the wetland area.

Figure 3.3: South facing view of the property. (Hall, 2011)

3.5 Water Resources

The farm does appear to have shallow ground water levels identified by some wetland just

west of the centre of the property, and two dammed up areas; one in the quarry and one in a

marsh where animal droppings appeared around the waters edge (possibly signifying that the

water is not highly contaminated).

According to locals, mining nearby the site has contaminated water resources in the area with

uranium. It would thus not be suitable to use water on site for potable water, however further

investigation will be needed to accurately assess contamination levels.

There are no large water sources in the immediate vicinity of the site and the annual average

rainfall usually just exceeds 700 mm.


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Figure 3.4: Quarry (Hall, 2011)

Figure 3.5: Marsh just east of the dirt road on the property. (Hall, 2011)


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3.6 Archaeological, cultural and heritage interest.

As yet, no archaeological or cultural points of interest on the farm have been identified. The

Baragwaneth Airport, which is currently situated on the proposed site will be demolished,

however the demolition will be required to be cleared with the municipal authority. Therequirement for building around an air field is a radius of at least 3km. Therefore if the

demolition of the airport is not authorised an alternative site will have to be found.


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4. GREEN ALTERNATIVES

4.1. Passive Heating and Cooling

4.1.1 Passive Solar Heating

Introduction

During winter months, space heating in homes consumes major quantities of electricity.

Using solar power decreases this usage and consequently has favourable effects on the

environment.

Process

Sunlight enters the building through glass windows and objects inside the house either

absorbs or reflects the sunlight. If it is reflected, the heat will travel through the room but

wont be able to exit through the glass window and so it is contained within the building.

At night when the sun has set heat cant be obtained any more. Thus it is necessary to

regulate heat gathered during the day so that the house doesnt overheat during the day and so

that there is still available heat at night. The heat can be managed by using materials in the

house that have a high thermal mass. Materials that have high thermal masses take longer to

heat up, thus preventing overheating of the room, but they also hold on to heat for longer.This is beneficial for night time as heat is always transferred from warm to cold areas. As the

temperature of the room decreases at night time the objects with high thermal masses will

start releasing gathered heat to the cold areas of the room. This ensures that the house stays

warm no matter what time of day it is.

Methods of Optimising the Process

OrientationIn the southern hemisphere, building should be orientated with their glazing facing north.

This must be true north and not magnetic north and efficiency is reported within 30of true

north. However, the closer to true north, the more efficient.

(http://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htm)
http://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htm


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GlazingThe building should be designed and situated in such a way that as many of the windows as

possible face north. This is called glazing. There should be enough glazing in a building to

ensure sufficient heat in winter but not too much as this could cause overheating in summer.

Tilted glass is very efficient for heat in winter but is more prone to overheating in summer.


Sun temperingSun tempering involves adding more windows to the north side of a house so that more

thermal mass can be exposed to heat from the sun.


Thermal massMaterials with high thermal mass are very important in order to have a system with high

functionality. These materials can absorb and retain heat making it very useful in ensuring

that a house stays warm during the night. Examples include concrete, brick, tile, water etc.

The abilities of these materials are because of their high density and specific heat and thermal

conductivity properties. These materials are used in the interior of homes as walls, floors,

fireplaces, etc. and dont necessarily need to have sunlight directly on them to absorb and

store heat. (http://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htm)

Trombe wallPart of the north wall is built out of a material with high thermal mass and glass is placed a

couple of centimetres from the wall. Heat enters through the glass and cant escape, giving

the material in the wall time to absorb it. These walls then radiate the heat into the house at

night. (http://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htm)
http://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htm


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4.1.2 Passive cooling

Landscaping

Placing trees in strategic places can help with cooling of a house. If a tree is planted in front

of a north facing window this will block the sunlight during the summer months. The tree

wont interfere with winter warming techniques as the leaves will fal l off during winter

allowing the sunlight through.


Overhangs

Overhangs for north facing windows are designed in such a way so as to prevent sunlight

entering the house during summer months. However, they must also allow sun in during the

winter months. This is possible since the suns rays are at a lower angle during winter

months.

Many variables dictate the sizing of the overhang such as climate, roof geometry, latitude,

etc. But in South Africa the length should be about 0.5 meters.

(http://www.hedon.info/EnergyEfficientHousingtoBenefitSouthAfricanHouseholds?bl=y)

4.2 Solar Geysers

4.2.1 Introduction

More solar energy reaches the earth every day than can be used by the earths inhabitants in

25 years. The power generated by the sun is equivalent to 1 kW/m of area exposed;

therefore, utilising this energy can have significant benefits economically as well as

environmentally. Both of these benefits are due to a decrease in electricity requirements.

Environmentally, this results in a decrease in the consumption of fossil fuels and

economically, a household saves on their electricity bill. On a domestic level, the largest

portion of electricity usage goes toward water heating by the geyser. Thus using solar power

to complete this task ensures benefits to the home owner and the environment. (Solar Heat

Exchangers, 2011)
http://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htmhttp://www.hedon.info/EnergyEfficientHousingtoBenefitSouthAfricanHouseholds?bl=yhttp://www.hedon.info/EnergyEfficientHousingtoBenefitSouthAfricanHouseholds?bl=yhttp://www.hedon.info/EnergyEfficientHousingtoBenefitSouthAfricanHouseholds?bl=yhttp://www.hedon.info/EnergyEfficientHousingtoBenefitSouthAfricanHouseholds?bl=yhttp://www.nmsea.org/Passive_Solar/Passive_Solar_Design.htm


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Figure 4.1: Evacuated tube collectors on a roof.

(http://www.sourcerenewable.com/en/pages/services-technologies.aspx)

4.2.2 Benefits

Although the initial installation of a water heater can be expensive, the pros far outweigh the

cons. Some of the benefits are:

Solar energy is free and unlimited and cannot be taxed. Reduction in electricity usage and also electricity bill. Reduces dependence on the electricity grid. Reduces dependence on fossil fuels. Contributes to the protection of the climate Solar water heaters have a service life of 20 years Between 50-90% of hot water can be supplied by solar power. The energy used to produce a solar water heater is 13 times less than the energy it

produces.

Energy is always available (the sun comes up every day), and little maintenance isrequired. (Solar Heat Exchangers, 2011)


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4.2.3 Types of Solar Water Heating Systems

Active and passive systems

Passive systems: This system is the most energy efficient since it solely relies on the

thermosyphon properties of water. That is, when water heats up it expands and becomes more

buoyant. This causes hot water to rise in the solar water heating system and any colder,

denser water sinks. This requires the storage tank to be placed above the collector panel at an

angle in order for the water to be able to rise to the tank. One problem is that at night time

this system reverses due to cold temperatures. The water in the pipes on the collector plate

cools and sinks. This pushes the hot water from the storage tank down to the plate where it

also cools down. The flow is reversed and the water cools down. This can be avoided through

correct placement of the storage tank or using a one way valve.

(http://www.solarwaterheating.co.za/)

Figure 4.2: Passive solar water heating system.

(http://www.solarwaterheating.co.za/)


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Active systems: These systems use pumps to drive the hot water from the solar collector to

the geyser. This means that the geyser doesnt have to be situated above the collector and can

be hidden. This system thus has aesthetic benefits and is more efficient; however, it is less

energy efficient since the pump uses electricity. (http://www.solarwaterheating.co.za/)

Direct and Indirect Systems

Direct systems:These systems allow water to run directly through the pipes situated on the

collector plate and then into the storage tank. Thus the water that runs through the copper

pipes is the hot water that is eventually used. This system holds certain problems for extreme

temperatures; for example, when temperatures reach freeze point the water will freeze and

possibly crack the pipes. Similarly these systems are problematic in high temperatures as they

dont provide protection against overheating. (Solar Heat Exchangers, 2011)

Indirect systems: In indirect systems, the pipes consist of a closed off system containing

propylene glycol (antifreeze). Branches of small diameter pipes containing antifreeze run

through the storage tank. The heated antifreeze from the collector plate rises and the copperpipes conduct the heat from the antifreeze to the water after which the cooled antifreeze

moves back down the system. (Solar Heat Exchangers, 2011)

4.2.4 Types of Collector Plates

Flat plate collectors: This is considered the most durable collector and also the most suitable

for domestic use as the temperatures reached are adequate for bathing or showering. The

collector consists of an oven like glass covered box. The glass is of high quality and can

withstand hail. It contains a black plate which absorbs heat from the sun and this heat is then

transferred to the fluid containing copper pipes welded to the plate. There are two horizontal

pipes (headers) at the top and the bottom of the pipe and many vertical pipes (risers) in

between. The top horizontal pipe leads the fluid which has heated up into the storage tank and

the cold fluid that leaves the storage tank sinks into the bottom horizontal pipe. Thus the

process is repeated. (Solar Heat Exchangers, 2011)


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Evacuated tube collectors: This collector consists of many vertical tubes instead of risers

that connect to the horizontal pipes. There are two tubes, one placed within the other with a

vacuum between the two. The inner tube is covered with a black paint which attracts sunlight

and the water is contained within this tube. The outer tube is clear glass allowing sunlight to

reach the inner tube while the vacuum prohibits heat from exiting the system. These

collectors are less durable due to the decreased quality of the rounded glass but they reach

higher temperatures since heat cannot leave the system. (Solar Heat Exchangers, 2011)

4.2.5 Eskom Rebate

In response to recently announced electricity increases Eskom has created a rebate system for

solar water heaters. The initiative is aimed at decreasing electricity usage by encouraging

home owners to implement green alternatives. Buyers are required to purchase their solar

water heater at an Eskom accredited supplier. The full amount must be paid and the rebate

forms must all be completed and sent to the facilitating auditors. The rebate will be paid

within 8 weeks from the date of the auditors receiving the forms. This initiative makes solar

water heaters more affordable for high and middle income homes since prices are greatly

reduced. For instance when purchasing a R33 000 (300 litre) solar water heater, the price can

be reduced by as much as R12 000.

(http://www.iolproperty.co.za/roller/news/entry/eskom_raises_solar_geyser_subsidy)

4.3 Lighting

4.3.1 LED globes

Instead of the conventional 70W globes 9W LEDs will be used. A 9W LED emits the same

light strength as a 70W globe. An LED globe is considerably more expensive but lasts for

60 000 hours where the conventional incandescent bulb only provides 1 500 hours. Not only

does it last longer but will save an immense amount of electricity in the long run.


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4.3.2 Sunlighting

Sunlighting is a method that is used to collect the sunlight from outside and channelling it

through buildings to provide a natural light source. For Sunlighting to be used, a

concentration panel that collects the sunlight is required. This concentration panel is placedon the outside of a buildings walls. The system is made up of a series of reflective guides

that sends the sunlight inside the building. (www.cfmd.com)

Throughout the day, the suns movement is tracked by the optics, and the concentration of

sunlight is factored by ten. The light is then transmitted through glazed windows. The light

guides are thin narrow reflective film coated corridors. Despite the fact that electricity is

greatly saved windows can now be treated to minimise glare and only function for the view

which they provide. (www.cfmd.com)

Figure 4.3: Illustration of how Sunlighting works(www.cfmd.com)

4.3.3 Solar LED Garden and Landscaping Lights

Green roofs and gardens can use the Solar LED Garden and Landscaping Lights to provide

light during the evening. It works on the same concept as the Sun Jar. The LED lights are

wrapped around objects or plants as shown in the figure below. The solar cell must however


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receive a maximum amount of sunlight during the day hence it should be placed in manner

that prevents it from falling in the shade of any plants or walls.

Figure 4.4: Solar LED Garden and Landscaping Lights (www.mantality.co.za)

4.3.4 Day/Night Sensor

Day/Night sensor globes are placed outside and switch on at night automatically. They are

used to save electricity and act as a security measure.

4.3.5 Motion Sensors

Motion sensors are sensors that are attached to light globes. The light bulbs will only be on

when the sensors detect motion. This technology is advantageous for corporate buildings and

apartment corridors. It reduces the electricity usage.

4.4 Insulation

4.4.1 Roofs

Roofs should be treated with a layer of cellulose fibres. It consists of recycled newspapers

with non toxic chemicals added in order to make it rodent and fire resistant. In summer it

prevents heat from entering the building through the roof. In winter it prevents heat from

leaving the building through the roof. Using this form of insulation is easy to apply and

relatively cheap, it is therefore recommended for use in all income brackets.(www.thermguard.co.za)
http://www.mantality.co.za/http://www.mantality.co.za/http://www.mantality.co.za/http://www.mantality.co.za/


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Figure 4.5: Thermguard sprayed on the ceiling. (www.thermguard.co.za)

4.4.2 Walls

A layer of Rigifoam in a cavity wall will provide insulation and soundproof qualities to any

building. The Rigifoam is able to insulate the cavity due to its closed cell nature. Rigifoam

is the same as polystyrene except that it is environmentally friendly and contains no CFCs or

HCFCs.

4.4.3 FloorsThermguard is sprayed below the floor covering to prevent heat from escaping through the

floors, and cold from entering your home in winter. During winter the cold tends to enter a

building mainly through the floors. It is therefore vital for any building to have proper floor

insulation.

Figure 4.6: Cellulose fibre used for floor insulation (www.thermguard.co.za)


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4.4.4 Windows and sliding doors

Double glazed glass will be used for its insulating properties. These are window panes that

are separated by a spacer, usually air or gas. Air or a gas occupies the area between the

window panes. The spacer seals the space and prevents the gas from leaking out. Thismethod is used to reduce the transfer of heat across the building. The areas temperature does

not drop below zero in winter therefore a glass thickness of 3mm will be adequate. In

addition, double glazed panes can prevent outside noise from entering the building.

4.5 Green Building Materials

Embodied energy

The embodied energy of a building material can be understood as the total primary energy

consumed (or carbon released over its life cycle). This would include extraction,

manufacturing and transportation. (Inventory of Carbon & Energy (ICE) v1.6a, 2008).

Recycled Aluminium

Although the embodied energy of aluminium is one of the highest, it would be incorrect to

assume that there are no green aspects related to its use. Aluminium is inherently durable

and corrosion resistant which reduces life cycle costs as well as easy to mould reducing

product manufacturing costs. Transport costs are also reduced due to its lightweight and

modular assembly capability. Aluminium has a high thermal conductivity which for

insulation purposes is not ideal, but it does however provide reflective insulation which

retains energy (Paterson, 2010).

One of the most important aspects of aluminium use is that it is easily recyclable, and

facilities for this have been established for over 100 years (ibid). Re-melting aluminium

requires less than 5% of the energy to produce primary aluminium and it can be recycled

indefinitely without loss of properties with up to 95% of building material being recoverable

(75% of all aluminium ever smelted is still in use today) (AFSA 2010)


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Advantages Disadvantages

Durable / Corrosion resistant Expensive

Lightweight High thermal conductivity

Easy to work with Very high virgin embodied energyReadily recyclable Not generally used for structural purposes

Reflective insulation

Aluminium Embodied Energy (MJ/Kg)

Virgin 218

Recycled 28.8

(Inventory of Carbon & Energy (ICE) v1.6a, 2008)

Uses for aluminium:

Finishes Window frames Roof sheeting Fenestration systems Drainage systems

Life expectancy: 60+ Years

Recycled Steel

Steel has significantly lower embodied energies than aluminium. Steel is 100% recyclable

and can be recycled indefinitely without loss of properties. Steel is easily available, can be

relatively lightweight and corrosion resistant if galvanised.


Durable / Corrosion resistant High thermal conductivity

Cheaper than aluminium low embodied energy for metal

Easy to work with

Easily recyclable


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Steel Embodied Energy (MJ/Kg)

Virgin 35.3

Recycled 9.5

Virgin Galvanised Sheet 39Engineering Steel (recycled) 13.1


Uses for aluminium:

Finishes Window frames Roof sheeting Fenestration systems Drainage systems Doors Structural

Life expectancy: 60+ Years

Green Concrete

Concrete is the most commonly used construction material in the world and, because of its

extensive use, generates a relatively large carbon footprint. The major contributing factor

towards concretes large carbon footprint is the production of cement; it is a rule of thumb that

for every ton of cement clinker produced a ton of carbon is released into the atmosphere.

The embodied energy of concrete is very low as concrete is a composite material, of which

the bulk is aggregate with embodied minimal embodied energies as low as 0.01 (Inventory of

Carbon & Energy (ICE) v1.6a, 2008).

In a push towards sustainable development and reducing environmental degradation, the

minimisation of the carbon emissions generated from concrete is of great importance. Hence

greener concrete designs are becoming favourable. With the use cement replacement

extenders formed as by-products from industrial processes the embodied energy of

concrete can be further reduced. The appropriate use of admixtures, for example, to reduce

water and thus cement content can also contribute to a more environmentally friendly greenconcrete.


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Can be designed for Durability Cement has a large carbon footprint

Cheap Rubble very hard to recycle

Easy to work with UnpredictableLow thermal conductivity Susceptible to climate i.e. corrosion of

reinforcement

Very low embodied energy Susceptible to climate i.e. corrosion of

reinforcement

Can be designed green Steel Reinforcement has high embodied energy

Readily available

Concrete Embodied Energy (MJ/Kg)

General 0.95

Prefabricated 2.00

Blocks (13Mpa) 0.81

50% Blast furnace slag (30Mpa) 0.82


Uses for concrete:

Flooring, paving etc. Drainage systems Structural

Life expectancy: Design based: usually 50 years +

Timber

Wood is environmentally friendly as long as it is forested for future sustainability. Wood has

great versatility, excellent insulation properties and is aesthetically pleasing. The embodied

energy is due to harvesting and preparation.


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Low cost Window frames are high maintenance

Sustainable Wood expands and contracts depending on the temperature

Versatile Becomes brittle once weatheredLight Weight Wood floors needs to be cleaned with special chemicals

Recyclable Window frames shows larger air leakage than aluminium

Reusable

Durable

Timber Embodied Energy (MJ/Kg)

General 8.5

Plywood 15


Uses of wood:

Finishes Window frames Doors low load bearing Structures e.g. roof trusses

Compressed Stabilised Earth Blocks (CSEB)

CSEBs are a relatively new technology and are manufactured using the available natural soil

in the area and a CSEB press. The soil is moistened and then poured into a press to form

blocks. Stabilisation is achieved using small amounts of cement or lime, if necessary.

Advantages include:

Giving employment to locals and uplifting the community with the high labourintensity required.

Minimisation of transportation and COemissions. Minimal time and money used by utilising local materials.


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Energy savings, with an energy consumption of 110 MJ (compare to kiln fired blocksusing 539 MJ), 16 kg/m2 CO2 emissions compared to concrete blocks at 26 kg/m2.

Depending on the quantity of cement, CSEB blocks are almost always cheaper thankiln fired blocks.

Deforestation is minimised as wood is not needed to burn the blocks as is requiredwith kiln fired. Another important aspect of CSEB blocks is that they are bio-

degradable, unlike many other construction materials.

(Auroville Earth Institute, Circa)

Limitations include:

Proper soil identification is required Low technical performances compared to concrete. Untrained teams can produce low quality products. Over-stabilization through fear or ignorance causes increased costs Under-stabilization results in low quality products.

Uses for CESB:

Masonry

4.6 Green roofs

A green roof involves growing vegetation on top of a roof with a waterproofing layer (and

other optional layers). They not only provide good insulation for buildings, but also keep

them cool during hot summer months. The roofs plants shade the building from solarradiation and reduce net heat gain in summer, while in winter the soil decreases the amount

of energy required to heat the building. They are aesthetically pleasing and have good storm

water retention properties.


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Figure 4.7: Sublayers for a green roof. (http://www.toronto.ca/greenroofs/what.htm)

Extensive Green Roofs

Thin layer of soil Low plant diversity Little or no irrigation required

Intensive Green Roofs

Deep Soil Irrigation system required High plant diversity

Challenges

Motivation and education to sustain green roofs. Intensive roofs impose a greater weight loading on roofs, have high capital cost, and

expertise required.


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Selling the concept to the client.(Kuhn M. & Peck S. Circa.)

Table 4.2: Green roof characteristics (www.igra-world.com)

Extensive

Semi-

intensive Intensive

Maintenance Low Periodically High

Irrigation No Periodically Regularly

Plant Communities Moss, grass Grass, Shrubs Shrubs, trees

System Build up height60 - 200 mm 120 - 250 mm

150 - 400

mm

Weight 60 - 150 kg/m120 - 200

kg/m

180 - 500

kg/m

Costs Low Middle High

UseEcological

protection layer

Designed

Green roof

Park like

garden

4.7 Rain water harvesting

4.7.1. Introduction

Rain water harvesting would be a very effective green alternative for the proposed project.

Considering that the MAR (mean annual rainfall) of the area is 0.5m and roof area for the

proposed town is roughly 3 000 000 m2(20 000 000 m2* 25% of area for buildings * 60% of

this is roof area), approximately 1.5 million cubic metres of rain water can be harvested per

year.

Rain water harvesting collects the water from a catchment area and then diverts the water to

wherever needed.


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4.7.2 Uses of harvested rain water

Storing the rain water

The rain water is collected from a catchment area, and then stored in a surface or

underground water tank for later use. The untreated water could then be used for irrigation,

cleaning, flushing toilets, etc.

Discharging rain water underground

Due to the dense population in urban areas, rain has difficulty reaching the ground and thus,

infiltration is reduced. As a result, plants without water irrigation die from inadequate water

supply. In addition to this, urban areas are becoming more prone to flooding due to the

decreased infiltration of storm water. Removing storm water through rain water harvesting

eases the demands placed on storm water management systems and so, reduces the likelihood

of flooding. This would have significant positive effects as the storm water level over urban

areas can be four times as high as that over natural areas. (Wypych & Bokwa, 2003)

Rain is typically relatively clean, good quality water, and requires little filtration for it to be a

good source of drinking water. Due to pollution of groundwater and surface water and the

increased demand for water, rainwater harvesting could be considered as an additional water

source. (Worm & van Hattum, 2006)


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Figure 4.8: Rain water harvesting alternatives

The figure above shows the possible alternatives that rain water harvesting could be used for.

It moves from low cost on left to high cost rain water harvesting on right. One of the largest

costs for rain water harvesting is storage of the water. What has to be determined is if storage

should be on the surface or underground. Surface storage is cheaper than underground storage

because necessary soil removal is reduced. It is also easier to repair if something goes wrong

but lack of space means underground storage is a more realistic option.

4.7.2 Proposed water harvesting systems

Low Cost Housing

The figure below shows how rain water harvesting could be done for low cost housing.

Rain catchmentarea

Light filtration(e.g. Leaves)

Tank

Used for simpletasks such as

washing andirrigation

Light filtration

Surface storage(With greywater)

Can be used forwashing,

irrigation, toiletdischarges e.t.c

Sub-surfacestorage (With

greywater)

Can be used forwashing,

irrigation, toiletdischarges e.t.c

Discharged intoground (e.g.

soakaway pit)

Required cleaningto make water

drinkable

Surface storage

Used as regular

clean water

Sub-surfacestorage

Used as regular

clean water


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Figure 4.9: Rainwater Harvest system

(http://savingh20.blogspot.com/2010/12/we-are-still-here.html

High rise buildings

For the high rise buildings, water can be collected on the roof and then transported to the

ground floor by gravity. There was a study done in Singapore were it was determined an

effective saving of 4% of water used. This water then didnt have to be pumped from the

ground floor. This saved the amount of water to be used, as well as electricity and capital.

(Srinivas, 2007)

Rain catchment area

Typically what is used as a rain catchment area is an impervious surface such as a roof. But

there have been attempts at deviations from this such as a concept by an Australian designer

called Chris Buerckner, called The Watree. Watree is something like an upside down

umbrella that is designed to be placed in parks and playgrounds as a rain shelter for people, as

well as to collect rain water to be stored in tanks. An example of one of the designs is shown

in the figure below.


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Figure 4.10: Watree design. (Jolly, 2008)

4.7.3 Advantages and Disadvantages

Table 4.3: Advantages and disadvantages of rainwater harvesting

Advantages DisadvantagesSimple construction: Construction of RWH

systems is simple and local people can easily be

trained to build these themselves. This reduces

costs and encourages more participation,

ownership and sustainability at community level.

High investment costs: The cost of rainwater

catchment systems is almost fully incurred during

initial construction. Costs can be reduced by

simple construction and use of local materials.

Good maintenance: Operation and maintenance

of a household catchment system is controlled

solely by the tank owners family. As such, this is

a good alternative to poor maintenance and

monitoring of a centralised pipe water supply.

Usage and maintenance: Proper operation and

regular maintenance is a very important factor

that is often neglected. Regular inspection,

cleaning and occasional repairs are essential for

success of the system.

Relatively good water quality: Rainwater is of

better quality than other available or traditional

sources (groundwater may be unusable due to

fluoride, salinity or arsenic).

Water quality is vulnerable: Rainwater quality

may be affected by air pollution, animal or bird

droppings, insects, dirt and organic matter.

(Worm & van Hattum, 2006)


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4.8 Heat Pumps

Introduction

Heat pumps work on the simple principle of transferring heat from one space to another.

Electricity is used to do this however, since heat is only being transferred and not generated,

electricity usage is minimal. This makes heat pumps energy efficient and in addition to space

heating, they can also be used to heat water making them a viable alternative to solar geysers.

Their setup costs are less than that of solar geysers however, their energy efficiency is not as

good. (www.heatpumps.org.uk)

How it works

Heat pumps work in a similar manner to refrigerators. There are two heat exchangers, one

that absorbs heat and the other that rejects it. This system is sealed so that no heat is lost and

is connected to a piping system which is filled with refrigerant. A refrigerant is a fluid with a

low boiling point and it is circulated by the compressor. The compressor exploits the fluids

ability to evaporate when heated and then condensate, returning to liquid form. This ensures a

continuous system of heat transfer. (www.heatpumps.org.uk)

At a domestic level, heat pumps use the air outside as a heat source. Even during winter, heat

is present in the air and can be used for space heating. During the summer months the process

reverses and air inside of a house is used as the heat source. Thus, heat inside the house is

expelled and the space is cooled. Geothermal heat pumps are also possible with the ground

used as the heat source. (www.heatpumps.org.uk)
http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/


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Figure 4.11: Heat pump outside a house.

(http://www.sourcerenewable.com/en/pages/services-technologies.aspx)

Pros and Cons

Pros

Savings on electricity Dehumidifies the air in humid areas Low capital cost

Cons

Ineffective in areas where temperatures reach below 0C Heat produced isnt as intense as that of a heater Backup heating and cooling means are required Dehumidifies the air in dry areas

(www.heatpumps.org.uk)
http://www.sourcerenewable.com/en/pages/services-http://www.sourcerenewable.com/en/pages/services-http://www.sourcerenewable.com/en/pages/services-http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.heatpumps.org.uk/http://www.sourcerenewable.com/en/pages/services-


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5. Design Results

5.1. Spatial Design

These values were based on data from the latest CSIR Summary Guidelines and standards for the Planning of Social Facilities and Recreational

Spaces in Metropolitan Areas 2010, population statistics and engineering judgements.

The allocated land use for housing and facilities by town planning was a maximum of 40%. Therefore this requirement governed the spatial

design considerations.

5.1.1. Housing

Table 5.1.1: Summary of Housing

SINGLE-

STAND Housing type DescriptionStoreys

(floors)Units/

floor Units / stand Number of Stands Stand size (ha)Total required Area

(ha)

RDP 4 block 1 4 4 5625 0.0315 178

Low incomesingle 300

sqm 1 1 1 500 0.03 15

Mediumincome

single 700sqm 1 1 1 1120 0.07 78.4

High Incomesingle 1100

sqm 1 1 1 1250 0.11 137.5

Total 409


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MULTI-

STOREY Housing typefloor area/

UnitStoreys

(floors)Units/

floorUnits /

BuildingNumber of

BuildingsStand size /

building(ha)Total required Area

(ha)

Low income80 sqm

10 20 200 602 per 5 building

grouping 24Medium

income150 sqm

8 60 480 18 4.5 81

High Income 300 sqm 13 18 234 15 4.5 67.5

Total 173

COMPLEX Housing typefloor areas/

UnitStoreys

(floors)Units/

floorUnits /

ComplexNumber of

co

Design Report Housing and Facilities 2011

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