Comparing Green Building Rating And Sustainable Building Rating Construction Essay

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We currently rely on 'green' building rating tools to assess building performances. In the case of residential building assessments, there are the Code for Sustainable Homes, LEED for Homes and CASBEE for Home (Detached House) which are the most prominent. Environmental potential is the key green building performance indicator for these tools, with much less emphasis for indicators that focus on social and economic aspects of sustainability.

The assessment frameworks are also incapable of explicitly expressing the relationships and influences between all three roots of the 'triple bottom line' that is fundamental in achieving sustainability.

This paper analyzes the aforementioned building rating tools, including the newly released GBI for Residential New Construction in Malaysia in terms of their scoring coverage that will expose their inherent assessment inclinations. Understanding the scoring characteristics of these tools would assist the development of a sustainable residential building assessment scheme for Malaysia rather than just adapting existing 'green' building rating framework.

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introduction

Sustainability requires a broad understanding of the socio-economic and environmental implication of a residential development. As guidance to involved stakeholders, many building assessment tools were developed all over the world. Three prominent broad-based building rating tools are currently in use. The Code for Sustainable Homes or the Code has been in use since April 2007 in the UK, Leadership in Energy and Environmental Design environmental rating system or LEED for Homes in the United States and Comprehensive Assessment System for Building Environmental Efficiency or CASBEE for Detached Homes is in use in Japan.

This paper presents an analysis made by the authors based on the distribution of allocated scores with regard to the three roots of sustainability, which are, environment, economy, and social. All assessment criteria or indicators were reclassified into these three categories based on their direct influence on any of the three categories gathered from guidelines produced for all analyzed building rating tools. This effectively prevented any double counting of scores for any indicator that could affect more than one category. The sums of allocated scores were then analyzed to find out whether the three categories are assessed adequately or not.

Although the selected building rating tools were not designed for use in climatic or socio-economic surroundings other than their origin, they were still used as case studies to reflect on the accordance with the principles of sustainability. The findings from the analyses would prove that whether these building rating tools were really about assessing the sustainability of homes as claimed to be or not. The findings were then compared to the newly released Green Building Index or GBI for Residential New Construction in Malaysia.

Building Sustainability Index or BASIX was not selected as a case study because it was only intended to assess the energy and water efficiencies of homes (NSW Department of Planning, 2006). Meanwhile, Green Star Multi Unit Residential (Pilot) tool was also not selected because it only assesses residential buildings with a minimum of six units (Green Building Council Australia, 2009). Both of these tools originated in Australia.

Context of study

Sustainability in architectural terms

In an architectural context, the environment takes centre stage in the concept of sustainability. This is despite the fact that there are other underlying concerns with regard to social and economic sustainability, which are implicitly linked to the sustainability of the environment (Hagan, 2001). Even in Malaysia, building the greenest homes would require the best green technologies available to attract purchasers. Expensive eco-gadgetry has taken precedence over good passive solar design that would otherwise require minimal financial cost implication. Yeang (2006) reminded that even though 'eco-gadgetry and technological systems are relevant experiments towards an eventual ecologically responsive built environment, their assembly into one single building do not make it automatically ecological.' Such a building should only be labelled 'green', not sustainable. Adequate eco-gadgetry alone should not be the prerequisite of sustainability, and this is much in line with Williamson's et al (2003) believe.

Developers of green residential properties seemed to forget that the main agenda for housing is rooted in the social and economic realm, whereby the provision of socially adequate and affordable housing is the focus, especially for a developing country such as Malaysia, not just the conservation and protection of the environment.

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Despite the very high and steady demand for socially responsible and affordable housing even in this current economic glut, recent reports highlighted the very large volume of housing that remained unsold due to an over-supply in the high-end housing market (Utusan Melayu (M) Berhad, 2009b, Bernama, 2009). By not considering the socio-economic condition of the population, too much luxury housing was built, resulting in exploitation of ecologically sensitive land and unmitigated environmental degradation around major Malaysian cities.

On another level, it all seemed to be the course of development of a growing nation like Malaysia where the per-capita income has been rising even though the earning gap between the rich and the less fortunate has grown. According to Brandon and Lombardi (2005), 'sustainability is more about maintaining the status quo and qualitative improvements' rather than sustained growth. However, in Malaysia sustained growth is needed to equitably spread the socio-economic wealth. Unlike previous Western development models, the environment must still be considered in Malaysia due to the limited carrying capacity within its borders. As an exporter of energy and a large importer of goods and food, Malaysia's ecological footprint is many times larger than its physical size (Venetoulis and Talberth, 2005), and this is alarming as the population and rate of consumption of resources have been steadily growing each year.

Without very rapid adaptation to new environmental technologies and socio-economic strategies, Malaysia could well emulate other developed nations such as Japan or the Netherlands and other European countries that have very large ecological deficits (Rees, 1997, 1996). Thus, leapfrogging to adopt a much more sustainably oriented housing is urgently needed to aid the nation's progress.

Building rating tool has been listed as one way to achieve sustainability while mitigating climate change which is also felt in Malaysia in the form of prolonged droughts, more and bigger flooding, more sporadic typhoons and others (Mahmood, 2009, Samaile, 2009, Utusan Melayu (M) Berhad, 2009a, c, Zulkafli, 2009).

The Code for Sustainable Homes

Assessment in the Code is based on good and best-practice targets that are technically feasible and deliverable by the local UK building industry. The performance targets are claimed to be more demanding than the minimum standard needed to satisfy the UK Building Regulations and other relevant legislations (Department for Communities and Local Government, 2008).

According to the Department for Communities and Local Government (2008), the primary objectives of the Code are to:

'identify issues which are known to impact on the environment;

establish performance measures which are known to reduce environmental impacts, exceed the requirements of legislation and regulation, and can be objectively assessed, evaluated and delivered in a practical and cost effective way by the construction industry;

identify environmental issues for which mandatory minimum performance must be achieved in order to gain a Code rating;

assess environmental performance in a two stage process (Design stage and Post construction) using objective criteria and verification;

record results of the Code assessment on a certificate assigned to the dwelling'.

There are nine assessment indicators in the Code that include energy and CO2 emissions (Ene), water (Wat), materials (Mat), surface water run-off (Sur), waste (Was), pollution (Pol), health and wellbeing (Hea), management (Man), and ecology (Eco). Since early 2008, all new residential properties in the UK require environmental certification before selling (Department for Communities and Local Government, 2008). The Code is being made a compulsory criterion for all homes in the UK in stages.

LEED for Homes

Similar to the Code, LEED for Homes is geared to certify and brand green homes. However, it is only targeted to assess the top 25% of homes with best practice environmental features (US Green Building Council, 2008). There are eight assessment categories in LEED for Homes that include innovation and design process (ID), location and linkages (LL), sustainable sites (SS), water efficiency (WE), energy and atmosphere (EA), materials and resources (MR), indoor environmental quality (EQ), and awareness and education (AE). Although gaining a foothold in the US building market, LEED for Homes remains a voluntary building rating tool.

CASBEE for Detached Homes

The main objective of CASBEE is to increase the stock of superior housing that provide good living environment, usable for a long time, and designed to save energy and resources to reduce the environmental load and improve the quality of living in the whole of Japan (Institute for Building Environment and Energy Conservation, 2007). According to IBEC (2007), 'CASBEE evaluates the general environmental performance of detached houses from two viewpoints:

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1) Environmental quality (Q)

Q1 = Comfortable, healthy and safe indoor environment

Q2 = Ensuring a long service life

Q3 = Creating a richer townscape and ecosystem

2) Environmental load (L) by load reduction (LR)

LR1 = Conserving energy and water

LR2 = Using resources sparingly and reducing waste

LR3 = Consideration of the global, local, and surrounding environment'.

CASBEE gives higher scores to detached houses with balanced qualities in all relevant environmental fields (Institute for Building Environment and Energy Conservation, 2007).

GBI for Residential New Construction

It is claimed that the GBI is specifically designed to assess homes in Malaysia's tropical weather and that this building rating tool is developed to suit the local environmental and developmental condition, cultural and social needs (Pertubuhan Arkitek Malaysia and The Association of Consulting Engineers Malaysia, 2009).

According to PAM and ACEM (2009), there are six assessment criteria in GBI, that include energy efficiency (EE), indoor environment quality (EQ), sustainable site planning and management (SM), materials and resources (MR), water efficiency (WE), and innovation (IN). For a start, GBI is only intended as a voluntary assessment system. To add weight to its implementation, the federal government, national housing associations, building and housing developers associations, and other non-government organisations support GBI. It is hailed as one of the main drivers to push the local building industry towards creating sustainable buildings and homes. Due to its very recent release in July 2009, there has not been any published post GBI implementation report.

Analyses of score distribution

The authors have analyzed in detail each building rating tool, indentified their coverage, and compared them in the following sections. The reclassification of each indicator in all four building rating tool is based on the concept of the 'Triple Bottom Line'.

TBL was initially a concept used in the business world. However, now it is more widely accepted as a trait of sustainability as a whole due to its concurrence to the equal distribution and balance between the environment, economic, and social sustainability (Blair et al., 2004).

In order to achieve sustainable homes, the three roots of TBL have to be balanced with 33% fair share coverage in each analysed building rating tool. The total scores for each TBL root have been calculated and are presented in the following sections.

Score distribution analysis of the Code for Sustainable Homes

The scoring structure and score allocation contained within the Code was critically reviewed and the results showed that nearly 70% of scores are given to the assessment of environmental criteria of assessed homes. Meanwhile, just over 25% of total points are allocated for the assessment of social criteria, well short of its fair share in a TBL scenario.

The assessment of economic criteria only gets just over 5% from the overall scores. This clearly showed that the Code is more inclined towards the assessment of the environmental qualities of homes. This is certainly contrary to Building Research Establishment's claim that the Code assesses the sustainability of homes. Changing the imbalanced (refer to figure 1) TBL make-up of the Code would be too disruptive and perhaps more social and economical indicators could be added to balance the whole assessment structure. Another suggestion would be to alter the weight provisions to each assessment category, indicators covering health and management could have more weights but this would certainly be against the consensus gathered by BRE regarding the importance of each indicator.

Figure 1 Overall allocation of points for the Code for Sustainable Homes

The above pie chart was derived from calculating the allocated scores, using the following mathematical formula:

S = ∑((Sc / Sm) x Wc); whereby,

S = Total appropriated score (%)

Sc = Category score

Wc = Category weight

Sm = Maximum score from every category

Tables 1 and 2 below present the detailed scoring distribution of social and economical scores in the Code.

Table 1

Detailed 'Social' scores in the Code

 

Sc

Sm

Wc

S

Ene

3

29

36.40

3.77

Wat

0

6

9.00

0.00

Mat

0

24

7.20

0.00

Sur

0

4

2.20

0.00

Was

0

7

6.40

0.00

Pol

0

4

2.80

0.00

Hea

12

12

14.00

14.00

Man

7

9

10.00

7.78

Eco

0

9

12.00

0.00

Total

22

104

100.00

25.54

S Social (%)

=

25.54

Much of the social scores are concentrated in the 'Health and Wellbeing' assessment criteria with 12 points. This is because this indicator covers assessment areas such as day lighting, sound insulation, private space, and lifetime homes that are all geared towards encouraging the construction of homes, which are more comfortable and liveable throughout the lifetime of the occupants (Department for Communities and Local Government, 2008).

Table 2

Detailed 'Economy' scores in the Code

 

Sc

Sm

Wc

S

Ene

2

29

36.40

2.51

Wat

0

6

9.00

0.00

Mat

0

24

7.20

0.00

Sur

0

4

2.20

0.00

Was

0

7

6.40

0.00

Pol

0

4

2.80

0.00

Hea

0

12

14.00

0.00

Man

0

9

10.00

0.00

Eco

2

9

12.00

2.67

Total

4

104

100.00

5.18

S Econ. (%)

=

5.18

S Env. (%)

=

69.28

One of the indicator which is dedicated towards financial gain, is 'Energy labelled white goods', whereby it is to encourage the purchase of energy efficient electrical appliances. An indirect implication of this is the possibility of reduced COâ‚‚ emissions due to reduced energy consumption by using such appliances. The other indicator is 'building footprint' that is to ensure that the house's footprint is efficient to reduce building material consumption and building costs. From close observation of all indicators, economic gains are only indirectly achieved by fulfilling other environmental or social assessment criteria.

Score distribution analysis of LEED for Homes

The scoring structure and score allocation contained within LEED for Homes was also critically reviewed and the results showed that just more than 62% of scores are given to the assessment of environmental criteria of assessed homes.

Meanwhile, just over 32% are allocated for the assessment of social criteria, almost equivalent to its fair share of 33% in a TBL scenario. However, the assessment of economic criteria only gets just over 5% from the overall scores.

Compared to the Code, LEED for Homes has more score allocation for social indicators in the form of 'Innovation and design process', and 'Awareness and education', which are not covered in the Code. This building rating tool also has indicators pertaining to occupant health and wellbeing, and an indicator to encourage the purchase of energy efficient electrical appliances.

Figure 2 Overall allocation of points for LEED for Homes

However, in all, this building rating tool is also more inclined towards the assessment of environmental attributes of homes. The above pie chart in figure 2 was derived from calculating the allocated scores, using the following mathematical formula:

S = ((∑Sc + ∑Pc) / (∑Sm + ∑Pm)) x 100; whereby,

S = Total appropriated score (%)

Sc = Category score

Pc = Prerequisite score from every category

Sm = Maximum score from every category

Pm = Maximum prerequisite score from every category

Table 3

Detailed 'Social' scores in LEED for Homes

S

Sc

Sm

Pc

Pm

ID

7

11

1

3

LL

1

10

0

0

SS

2

22

0

2

WE

0

15

0

0

EA

0

38

0

2

MR

8

16

0

3

EQ

21

21

7

7

AE

2

3

1

1

Total

41

136

9

18

S Social (%)

=

32.47

Table 4

Detailed 'Economy' scores in LEED for Homes

S

Sc

Sm

Pc

Pm

ID

3

11

2

3

LL

0

10

0

0

SS

0

22

0

2

WE

0

15

0

0

EA

3

38

0

2

MR

0

16

0

3

EQ

0

21

0

7

AE

0

3

0

1

Total

6

136

2

18

S Econ. (%)

=

5.19

S Env. (%)

=

62.34

Similar to the Code, economic gains by satisfying the assessment criteria in LEED for Homes are indirect and caused by more important environmental or social gains that are underlined in LEED's guidelines.

Score distribution analysis of CASBEE for Detached Homes

Figure 3 Overall allocation of points for CASBEE for Detached Homes

The scoring structure and score allocation contained within CASBEE for Detached Homes was also critically reviewed and the results showed that over 50% of scores are allocated to the assessment of environmental criteria. This figure is much lower than the two building rating tools analysed previously. In the mean time, just over 38% is allocated for the assessment of social criteria, which is more than its fair share of 33% if the TBL is to be balanced.

CASBEE has more social indicators. Firstly, the consideration of the local townscape and landscape that involves careful architectural consideration when locating and integrating a house in an established neighbourhood, and secondly, utilizing regional resources and inheriting regional housing culture that would ensure the survival of local construction methods, housing style and living environment. Much of the reason for a higher allocation of social score is because of the high category weight of 0.45 that is allocated for Q1, 'Comfortable, healthy and safe indoor environment'.

The total for weights for all building quality, Q is one (Institute for Building Environment and Energy Conservation, 2007). This showed that in Japan, occupant comfort and health is the most important, in the pursuit of greener housing. One good indirect implication of this is the possibility of reduced pressure on their healthcare system.

The assessment of economic criteria however, only gets over 11% from the overall scores. Much of it came from Q2 indicator, 'Ensuring a long service life', directly presage financial benefits from reduced maintenance, replacement of building parts or refurbishment due to wear-and-tear as well as water and fire damages. The pie chart in figure 3 was derived from calculating the allocated scores, using the following mathematical formula:

S = (∑Sc / ∑Wc) x 100

S = Total appropriated score (%)

Sc = (Ssc / Sm) x Wc

Sc = Category score

Wc = Category weight

Ssc = (Sd x Wsc) x Sm; whereby,

Ssc = Sub-category score

Sd = Detailed score

Sm = Maximum Score (5)

Wsc = Sub-category weight

Table 5

Detailed 'Social' scores in CASBEE for Detached Homes

S

Ssc

Sm

Wc

Sc

Q1

5.00

5

0.45

0.45

Q2

1.25

5

0.30

0.08

Q3

3.50

5

0.25

0.18

LR1

0.25

5

0.35

0.02

LR2

0.00

5

0.35

0.00

LR3

0.83

5

0.30

0.05

 

Total

 

2

0.77

S Social (%)

=

38.35

Table 6

Detailed 'Economy' scores in CASBEE for Detached Homes

S

Ssc

Sm

Wc

Sc

Q1

0.00

5

0.45

0.00

Q2

3.75

5

0.30

0.23

Q3

0.00

5

0.25

0.00

LR1

0.00

5

0.35

0.00

LR2

0.00

5

0.35

0.00

LR3

0.00

5

0.30

0.00

 

Total

 

2

0.23

S Econ. (%)

=

11.25

S Env. (%)

=

50.40

Score distribution analysis of GBI for Residential New Construction

With regard to earlier analyses, GBI's distribution of scores is more severely inclined towards the assessment of environmental attributes of housing. This is because overwhelmingly, 81% of points are allocated for environmental assessment.

Only 18% from the total scores are allocated to the assessment of social aspect of housing with indicators concerning occupant's health and wellbeing, building and design management, and home office provision and internet connectivity. The remaining 1% of scores is allocated for economic assessment.

Ten social points came from 'Indoor environmental quality' indicator that promotes better health through good indoor ventilation rate, good day lighting, reduced noise transmission and reduced usage of indoor finishes containing hazardous chemicals. However, the award of only one point for using indoor finishes with low volatile organic compound (VOC) content is too small. This is inadequate, since the purchase and application of such products would require more financial investment compared to conventional finishes. Other social scores came from the encouragement to provide high-speed internet access of more than 1MB per second, good building management provisions and building user education.

The sole economy point came from 'Good quality construction' indicator that encouraged the use of the Malaysian Construction Industry Development Board's (CIDB) Quality Assessment System for Building Construction Work (QLASSIC). The award of three points for this would improve the quality of construction of houses from the current endemic poor construction quality and poor overall construction management. As a result, homebuyers would get better value from their purchase.

Further analyses of GBI for Residential New Construction

Overwhelmingly, the tool awards 81 points for good environmental criteria. According to PAM and ACEM (2009), three points are allocated for achieving minimum overall thermal transfer value (OTTV) and roof thermal transfer value (RTTV) levels. However, it is more useful if these were added to the 'Advanced energy efficiency performance', whereby higher levels of OTTV and RTTV are required. More points are needed to encourage either the installation of renewable energy generators such as photovoltaic panels due to their high costs or to encourage reduced electrical consumption through change in lifestyle. As it is, a maximum of five points is achievable for managing to produce only 5kWp of total home energy consumption or 100%, whichever is lower, not higher! (Pertubuhan Arkitek Malaysia and The Association of Consulting Engineers Malaysia, 2009).

Most of the points (39) in GBI are centred on the reduction of use of private motor vehicles through indicators such as, public transport access, and community services and connectivity. Both indicators with 12 and 8 points each out of 100 are too high considering the inadequate amount of public transport available nationwide. Only a few of the biggest cities around the Klang Valley would have adequate public transport, and much of it would still be within city limits.

Suburbs where most city inhabitants live would not be served well by public transport of any form. As much as eight out of 12 points allocated for public transport provision are achievable if the intended house is constructed within 250 meters of a bus stand. This would definitely favour inner city infill housing projects over suburban housing developments. Although positive, in reality, inner city housing land is valued too highly for any socially responsible and affordable housing. Even low-cost housing tower blocks are built on peripheral land far away from city centres to the disadvantage of lower income groups. This trend has pushed the majority of city population into the surrounding suburbs involuntarily, while more facilities and infrastructure have to be built in haste to service the physically growing city limits. On the contrary, urban infill housing projects only require continual upgrades to existing infrastructure and community facilities rather than very large investments for new ones.

Figure 4 Overall allocation of points for GBI for Residential New Construction

It is good that CIDB's industrial building system (IBS) is acknowledged in GBI. The adoption of IBS would increase building contractor efficiency and professional work ethics, with less construction waste leaving construction sites.

It is also good that achieving both good storm water management and re-development of existing and brown field sites, are well awarded with three and four points each. Flash floods are very common in urban areas and it is partly due to the poor storm water drainage systems and planning. In GBI, rainwater recycling is encouraged through this indicator but other means of reducing flood risks such as having permeable surface around the house, reduced reliance of concrete drainage and opting for permeable bio-swales should have been included as well. Such measures would not cost more than any conventional external surface and drainage materials and construction.

If accentuating development of houses on existing and brown fields within existing urban fabric with sufficient public transportation, community services and infrastructure are the main criteria of sustainable houses, then the award of only two points for not building on or near environmentally sensitive sites would certainly not help. More points should be added to this indicator to deter explorations of virgin sites that could be ecologically valuable in sustaining natural services. Too many luxury landed housing developments are being built on steep slopes (steeper than 30Ëš) while other types of dwellings encroach into ecologically sensitive riverbanks and forest reserves. Due to Malaysia's heavy rainfall (Department of Statistics Malaysia, 2007) much larger waterways setback than the 15 metres that is prescribed by GBI or other alternative solutions are needed to ensure that no properties are damaged during floods and very heavy downpours that causes fast river water flows that could erode riverbanks. Encouraging the rehabilitation of nearby riverbanks and other ecologically sensitive areas could also be very useful rather than just the discouragement of building near or on them.

Table 7

Detailed 'Social' scores in GBI for Residential New Construction

S

Sc

Sm

EE

5

23

EQ

10

11

SM

2

39

MR

0

9

WE

0

12

IN

1

6

Total

18

100

S Social (%) = 18.00

The pie chart in figure 4 was derived from calculating the allocated scores, using the following mathematical formula:

S = (∑Sc / ∑Sm) x 100

S = Total appropriated score (%)

Sc = Category score

Sm = Maximum score from every category

Table 8

Detailed 'Economy' scores in GBI for Residential New Construction

S

Sc

Sm

EE

0

23

EQ

1

11

SM

0

39

MR

0

9

WE

0

12

IN

0

6

Total

1

100

S Econ. (%) = 1.00

S Env. (%) = 81.00

As is, the use of recycled building materials would only be done by non-conventional and non-regulated builders that build squatter housing or rural houses. Well-organised builders in urban areas however, would not even contemplate the use of recycled building materials to reduce material consumption and, thus reduce embodied energy and energy spent to extract, produce and transport the building materials to the construction site.

It is still a good step in the right direction however, but more support from the building material manufacturing community and supplier is needed to jump-start this new industry of supplying building materials made with recycled contents. As it stands, earning the two points for this indicator would only translate to the recycling of used shuttering and framing. Plywood and timber shuttering and framing are extensively used for construction. GBI only encourages the recycling of these items not more than 15 times. Otherwise building quality would deteriorate. To be fair, the recycling of these items should be separated from this indicator and awarded specific points. If not, the positive contribution of using building materials with recycled contents would be dissolved and ignored.

conclusion

From the analyses, it is obvious that the building rating tools do not assess homes adequately between the three roots of TBL, but more inclined towards the environmental impacts and sensitivities of assessed homes. This is probably because many environmental indicators are readily quantifiable and easily affected through the use and installation of relevant technologies and devices, while the assessment of social criteria of homes is more subjective and require personal views and difficult to quantify.

Most of the social indicators within all four building rating tools are concerned with the health and wellbeing of home occupants in the form of indoor air quality, thermal comfort and mobility. Other socially viable indicators are not included except for the successful integration of homes architecturally in their context in CASBEE for Detached Homes.

Indicators that are directly linked to economic sustainability are very few in all building rating tools in study. All four building rating tools at the outset, reminded that in pursuit of environmentally friendly homes, the costs and economic concerns are to be disregarded. Although it seems that this declaration is quite logical and legitimate as most certified green homes around the world cost a fraction more than conventional homes, their running costs are much lower due to higher inherent operational efficiencies afforded by the incorporated environmental technologies.

AcknowledgEment

The first author is delighted to thank the Ministry of Higher Education, Malaysia and University of Malaya for financially supporting the study.