Adaptive reuse of buildings and its life cycle sustainability benefits

Harn Wei Kua (Dr.), Abhimanyu Goel

Mark Lam

Smart Materials Laboratory

Department of Building

School of Design & Environment

National University of Singapore

Primary Schools in SingaporeSource: https://www.moe.gov.sg/media/speeches/files/2011/map-of-primary-schools-phase-1-3.JPG

INTRODUCTION

• Schools regularly undergo renovations to enhance learning experience for our children.

• To increase the sustainability of these works, adaptive reuse of old school buildings is important in integrating education with mitigation of climate change.

• Patterns of renovation for 12 primary school buildings were studied, to determine how adaptive reuse technique can be applied.

• Life cycle sustainability assessment applied to quantify the environmental, economic and social benefits of adaptive reuse.

Profile of Possible Land Use Allocation in Singapore Beyond 2030Source: https://alfa-img.com/show/urban-planning-areas-in-singapore.html

RESEARCH PHILOSOPHY

How the “old” leads to the

present

ALTERNATE DESIGNS …

Could the present be designed

differently

Apply what we learn to future

design of schools

Evaluate original designs of 12 school buildings according to 4 adaptability factors

Internal : Ability of existing internal layout of building to adapt to future change of space.

Extension: Ability to have additional physical elements. Example: an added extra floor to the existing structure to perform additional functions .

Use: Ability of modified space to be used for alternate uses without being renovated in future.

Planning: Enhancement of existing structure for future use by means of transformable materials. This requires a design which is future-ready in case of any additional space required.

Create adaptive reuse design concept from patterns in these

cases

New adaptive reusable designs for

these buildings

Evaluations of life cycle sustainability

benefits of adaptive reuse.

Resources of re-construction

Cost

Effort

Time

How they affect …

RESEARCH METHODOLOGY

SYSTEM BOUNDARIES OF CONCRETE AND STEEL

Iron Ore extraction

Local transportation

Pelletization SinteringBasic

Oxygen Furnace

Continuous casting

Transportation to Singapore

Transportation to storage

Transportation to construction

site

Electric arc

furnace

Continuous casting

Scrap collection (in Singapore)

Local transportation

Primary steel

Secondary steel

Construction Demolition

Water Sand Gravel

Raw material acquisition

Local transportation

Manufacturing of Ordinary Portland

Cement

Transportation to Singapore

Transportation to storage

Transportation to construction

site

Reinforced concrete Preparation on

siteConstruction

1 kg of reinforced concrete contains:• 0.04 kg of secondary steel• 0.29 kg of OPC• 0.09 kg water, 0.2 kg sand• 0.36 kg of gravel

Source: Kua, H. W. and Maghimai, M. (2017), Steel-versus-Concrete Debate Revisited: Global Warming Potential and Embodied Energy Analyses based on Attributional and Consequential Life Cycle Perspectives. Journal of Industrial Ecology, 21: 82–100. doi:10.1111/jiec.12409

Internal Extention Use Planning

School 1 ×

School 2 × × ×

School 3

School 4 × × × ×

School 5 ×

School 6 ×

School 7 ×

School 8

School 9 ×

School 10 ×

School 11 ×

School 12 ×

Future Scope of Adaptability in

existing designSchool Name

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

School 1 School 3 School 4

Cost

Time

Effort

Qualitative evaluation of 4 factors of adaptability of 12 schools

RESULTS• Cost/time/effort evaluated as “resource score”. • E.g. any work that requires installation of

structural elements, including demolition of existing blocks, is rated as “high” in cost, effort and time; each of these are given a score of “5” on a scale of 1-5.

• Any cosmetic modification, including paint work, is rated as “low” and scored “1”.

RESULTS

LOW

LOW

HIGH

COSTTIMEEFFORT

School 3

HIGH

HIGH

HIGH

COSTTIMEEFFORT

School 4

% of original GFA demolished: 17.6%% of original GFA reconstructed: 85%

% of original GFA demolished: 1%% of original GFA reconstructed: 56%

Gross floor area (GFA) change analysis

New Block to fulfill additional floor area required (retaining

the old block)

Original Design

Retaining the “E” Block

Configuring the grid according to constant vertical circulation

New Designed Floor Plateadding space around the

old Block

Basic Floor Plate

Area of demolition and reconstruction avoided: 5,120 Sq. M + 5,120 Sq. M= 10240 Sq. M

Adaptive Reuse Design:Total Area expanded 23520 Sq. M (almost the same as previous case 24860 Sq. M)

5120 Sq. M area retained and 18400 Sq. M area new constructed(previous case 24860 Sq. M was newly constructed)

Constant space for Services

Staircase

Functional Spaces

Overall reuse strategy: retain the “E” block and build around this block to fulfil the new floor area required.

• Total area of demolition avoided: • 5,120 m2

• Total amount of reinforced concrete saved:• Area: 1,554.3 m2 (around 1.55 m3)• Mass: 3.75 tonnes

• Total demolition energy avoided: • 41.3 MJ (11.1 MJ per tonne of reinforced concrete (Kua & Maghimai, 2017))

• Total area of re-construction avoided: • 5,120 m2

• Total construction energy avoided: • 614,400 – 870,400 MJ (at 120-170 MJ per m2 constructed (Heravi et al., 2016))

• Total embodied energy of reinforced concrete avoided:• 4,500 – 6,750 MJ (at 1.2-1.8 MJ per kg of reinforced concrete (Kua & Maghimai,

2017))

• TOTAL ENERGY SAVED = 618,941.3 to 877,191.3 MJ

• TOTAL CO2 REDUCTION = 40,137 to 56,192 tonnes

POTENTIAL LIFE CYCLE ENVIRONMENTAL BENEFITS (SCHOOL 4)

Cost Estimates

Construction

US$1,715 - 1,930 / m2

Demolition

US$73 - 111 / m2

US$1 = S$1.40

• Total area of demolition avoided:

• 5,120 m2

• Total amount of reinforced concrete saved:

• Area: 1,554.3 m2 (around 1.55 m3)

• Mass: 3.75 tonnes

• TOTAL MAXIMUM POSSIBLE SAVINGS

= (USD 8.78 million to 9.88 million) + (USD 373,760 to 568,320)

= USD 9.15 to 10.45 million

POTENTIAL LIFE CYCLE COST SAVINGS (SCHOOL 4)

SOCIAL LCA

1) Sustainability = as little modification as possible.

2) Adopt a “story-based”, instead of indicator-based, approach.

3) Social “story” is a consequence of changing from the present school design to an alternate school design. Study the social benefits of heritage conservation.

4) Lessons learnt to provide incentives and impetus for future adaptive building design.

SOCIAL VALUE OF HERITAGE CONSERVATION

Building as a connection through

time.

Heritage artifacts salvaged and displayed throughout the schools.

Discarded wood from deconstruction of old buildings.

SOCIAL VALUE OF HERITAGE CONSERVATION

Old National Stadium of Singapore

Wood salvaged from old National Stadium used to make stage in new school building

• The assessment of sustainability benefits is based on life cycle sustainability analysis (LCSA).

• A unified model of LCSA that:• Addresses the inter-

dependence of life cycle stages;

• Describes direct/indirect rebound effect;

• Describes life cycle resilience;

• Defines social LCA as social consequences of changes in indicators; and

• Integrates stakeholder engagement.

Source: Kua H W, 2017. On Life Cycle Sustainability Unified Analysis, J. of Industrial Ecology, forthcoming

ON-GOING WORK

1. Reducing the need for demolition and construction of new structures will yield substantial environmental and economic benefits.

2. New paradigm in design (e.g. one based on “diversifying” spaces in floor plate) can inject flexibility and adaptability into current school designs to achieve the point (1).

3. From social LCA angle, there is a need to tie adaptive design strategy with the educational goals of schools.

4. There is a need to apply LCSA models (e.g. unified model) to fully understand the sustainability impacts of implementing these adaptive design concepts.

CONCLUSIONS

ACKNOWLEDGEMENT

We would like to thank the Ministry of Education, Singapore, for providing the Academic Research Fund to support this 3-year research project.

REFERENCES

• Kua, H. W. and Maghimai, M., 2017. Steel-versus-Concrete Debate Revisited: Global Warming Potential and Embodied Energy Analyses based on Attributional and Consequential Life Cycle Perspectives. Journal of Industrial Ecology, 21: 82–100. doi:10.1111/jiec.12409

• Kua, H. W., 2017. On Life Cycle Sustainability Unified Analysis, J. of Industrial Ecology, forthcoming