Chapter 2 environmental strategies for building design in tropical climates

CHAPTER 2: ENVIRONMENTAL STRATEGIES FOR BUILDING
DESIGN IN TROPICAL CLIMATES
2.0 Introduction
The need for energy savings in the building sector is high because buildings are significant
users of energy. Energy efficiency in building is a high priority in many countries especially
a developing country like Malaysia. The use of energy is important since global energy
resources are finite. Furthermore, power generation using fossil fuels such as coal and oil has
adverse environmental effects. The environment and climate have a major effect on
building’s energy consumption and as the result; energy conscious design requires an
understanding of the local climate. Energy efficient building design is usually location
dependent and buildings will normally respond to the natural climatic environment in two
ways; (1) the thermal response of the building structure, fabric heat transfer and thermal
storage; and (2) the response of the building systems such as heating, ventilation, air-
conditioning and lighting systems (Hui, 1997).
All building professionals have a responsibility to reduce emission through better building
energy efficiency at the design stage and right through the operational life of the building
because energy used in buildings is responsible for almost half the CO2 emissions (CIBSE,
2005). The CO2 emission can be reduced through energy conservation in building by various
means and bioclimatic design is one of the strategies.
There are six important aspects of architectural planning which will affect thermal and
energy performance of buildings. These are: site selection, layout, shape, spacing between
building, orientation and common relationship. The elements of the building envelope such
as walls (exterior), windows, roof and underground slab and foundation are significant to
heat transferring into buildings (Cheung et al., 2005).
The fact that environmental design is not new and in most developing countries in regions
such as Malaysia this has a direct impact on the practicality of some modern concepts of
urban and building design from the climatic view point. The vast majority of people cannot
afford thermal stress and its impact on health and productivity. Therefore; it is important to
improve the comfort condition in this region by adapting the urban and building design to the
climate.

2.1 Traditional Architecture
Energy efficient building design is location dependent and energy conscious design requires
an understanding of the climate (Hui, 1997). Traditional or vernacular architecture is well
adapted to the dominant climate of its surroundings. This is the reason that popular
architecture is said to be the origin of bioclimatic architecture (Canas and Martin, 2004).
Bioclimatic design or environmental design approach has received an increasing amount of
attention all over the world in the last few decades and is regarded as crucial to energy
saving in building (Cardinel, 2000; Magliocco, 1999; Coch, 1998; Lucila and Doris, 1998;
Li, 1996; Georgiadou, 1996; Radovic, 1996; Szokolay, 1995; Olgyay, 1959). The bioclimatic
approaches are claimed to be the most practical strategies. Such strategies do not only
depend on the local climate but also on the building type and its function.
Canas and Martin (2004) studied the recovery of Spanish vernacular construction as a model
of bioclimatic architecture. The objective of the study was to set the root of bioclimatic
construction by learning from the traditional construction. The research was mainly focused
on the information obtained from the classical authors of Spanish vernacular architecture.
The aim was to determine the design strategies used in vernacular constructions to adapt
them to the environment.
In the study, all books available from the School of Architecture, Polytechnic University of
Madrid have been studied. Only books with specific examples of buildings have been
selected. The classical authors of vernacular architecture’s references were checked and the
examples of bioclimatic characteristic were studied. A total number of 212 photographs
whose legend refers to the climate conditions have been collected and used to guide the
study of the bioclimatic strategies implemented in Spanish popular architecture.
Ten popular bioclimatic strategies which apply to Spanish constructions were studied: (1)
high thermal mass, (2) protection against solar radiation, (3) use of solar radiation, (4) use of
natural resources, (5) built form, (6) protection against rain, (7) protection against wind, (8)
protection against cold temperatures, (9) town planning and (10) protection of the entrance.
The results of the study have later been used to make a proposal for the recovery of
vernacular constructions with peculiar bioclimatic strategies and to translate some of the
bioclimatic strategies used in vernacular constructions to the present ones (Canas and Martin,
2004).

2.1.1 Bioclimatic Strategies in Traditional Malay Houses
The importance of discovering indigenous design and methods of construction cannot be
over emphasised. The growing interest in vernacular architecture since the exhibition
Architecture without Architects held in the Museum of Modern Art in New York in 1964/65
can be seen from the voluminous amount of work in this area today. Unlike the more
profound studies done on indigenous architecture in some countries, very little work in this
area has been done in Malaysia (Wan Abidin, 1984:28).
In the local context, the traditional Malay House can be a good example to describes good
passive strategies. The traditional Malay house serves the housing needs of the majority of
people living in rural areas of Malaysia. It was evolved by the Malays over the generations,
and adapted to their needs, culture, and environment (Lim, 1997:88).
It is obvious that most traditional Malay House share the same strategies to attain optimal
climatic control. These include; (1) allow adequate ventilation for cooling and reduction of
humidity; (2) use low thermal capacity building materials so that little heat is transmitted
into the building; (3) control of direct solar radiation; (4) control of glare from the open skies
and surroundings; (5) protection against heavy rain; and (6) assurance of adequate natural
vegetation in the surroundings to provide a cooler microclimate (see figure 2.1) (Ahmad et
al., 2002; Lim, 1997).
Figure 2.1: Climatic design of the traditional Malay house (Source: Lim, 1997:80)

Figure 2.2: External environment of the Malay house (Source: Lim, 1997:83)
Site Layout
When faced with unfavourable climatic conditions, optimal stilting and site design may solve
all or part of the problem. In many cases, the house is built without clear geometric order in
the layout. As the owner of the house is the architect himself, the layout has normally been
determined by the owner based on several reasons and mostly the religious rituals. The
layout occasionally, facing the access road leading into the house, nearby river, compounds
and paths surrounds the area. Despite that, the social relationship with the neighbourhood,
lifestyle and local culture have great influence on the house layout and direction. Social
interaction is maximised by the open and non obstructive public private areas.
The houses are far apart from each other and are linked by several open compounds through
small flowing paths. Few obstructive physical barriers are used to separate territories, some
cases defined by the bunds, huge trees and irrigation canals. The compound of the house is
heavily shaded with fruit trees and covered with vegetation, reradiating heat from solar
radiation into the environment (see figure 2.2) and consequently places the house in a cooler
environment (Lim, 1997).

Orientation
The Malay house is also designed to control direct exposure to heat from direct sunlight.
Traditionally, many Malay houses are oriented to face Mecca for religious reasons. The east-
west orientation of the house reduces the exposure of the house to direct solar radiation. The
elongated structure of the traditional Malay house with minimal partitions in the interior,
allows easy passage of air and a cooler micro-climate.
Thermal Resistance
The lightweight construction of the Malay house with minimum mass and many voids, using
low thermal capacity and high-insulation materials, is most appropriate for thermal comfort
in our climate. The wood, bamboo and ‘attap’ used have good insulating properties and they
retain or conduct little heat into the building. Solar radiation is effectively controlled by the
large thatched Malay house roof with large overhangs. The walls of the house are low, thus
effectively reducing the vertical areas of the house exposed to solar radiation. The low walls
also make the task of shading easier. The large overhangs which provide good shading also
provide good protection against driving rain. They also allow the windows to be left open
most of the time for ventilation, even during the rain (Lim, 1997).
Natural Ventilation
There are numerous features in the traditional Malay house that are geared towards providing
effective ventilation. The house is raised on stilts to catch winds of a higher velocity. The
traditional Malay house has an open interior, promoting good cross ventilation and allowing
the space to be used for many purposes depending on the season, occasion, or time of day.
The quality of good natural ventilation is shown by the many voids of the building such as
windows, roof, ventilation grilles and panels. The open stilts at the bottom further increase
the needed natural ventilation.
The windows are installed at the body level and at the most vital area for ventilation. The
windows are mostly at the size of human full height and are open-able for the occupant to
control the amount of ventilation they needed. Winds from the exterior are also encouraged
to flow through the house. It was designed and built taking these points much into account.
This quality of openness reflects the importance given to natural environment in the design
of the Malay house (Lim, 1997: Ahmad et al., 2002).
The carved wooden panels and wooden grilles in the roof are also effective ventilation
devices. The sail like ‘tebar layar’ (gable end) of the roof is used to trap and direct air to

ventilate the roof space (see figure 2.3). Ventilation joints in the roof called the ‘patah’ are
another creative ventilation device used to ventilate the roof space. The random arrangement
of the houses and the careful planting and selection of trees ensure that winds are not
blocked for the houses in the latter path of the wind.
In a natural ventilation design project for houses in Thailand, it was found that, indoor air
quality was significantly improved although the total energy saving was less than 20%. This
health consideration was an important feature justifying the design (Tantasavadsi, et al.,
2001).
(a) Melaka house
(b) Perak house
Figure 2.3: Traditional Malay houses (Source: Sudin, 1980:58-62)
Natural Lighting and Glare
The large roof and low windows tend to be under lighted. This gives a psychological effect
of coolness as strong light is often mentally associated with heat. Indirect sources of light
like internal and external reflected light are used in the traditional Malay house. They are the
best forms of natural lighting for a tropical climate as they minimise heat gain and glare.
Direct sunlight should not be used for day lighting as it is accompanied by thermal radiation.
It can be seen that the traditional Malay house uses mainly ventilation and solar radiation
control devices to provide climatic comfort for the house.
Openings incorporated in the walls
Openings incorporated
at the roof

Figure 2.4: Window or door component for control glare (Source: Wan Abidin, 1984:30)
Windows are kept low and shaded by large roof overhangs to reduce glare from the open
skies. Glare from the surrounding environment is lessened by the less reflective vegetation
ground cover, trees and houses. Glare is also controlled by the use of grilles and carved
wooden panels (see figure 2.4) which break up large bright areas into tiny ones and yet allow
the interiors to be lighted up (Lim, 1997).
2.1.2 Components of the Physical Element in the Malay House
Other than its mystical aspects, which may consist of the rites and rituals of its construction,
the Malay house is made up of three major elements; the physical, the spatial and the
functional (Wan Abidin, 1981). The functional element consists of a list of activities that
may take place within the Malay house ranging from ‘circulation’ to ‘work’. These and other
activities are closely related to one another because of the culture and tradition of the
Malays. The relationship of these activities is translated into rules from which the hierarchy
of spatial importance in the Malay house is derived (Wan Abidin, 1981).

Foundation
Most of the houses were built with stilts underneath with large windows. Early Malay houses
rose on timber stilts and were made of low thermal mass materials which were easily
available from the tropical forests such as timber, bamboo, rattan, tree roots and leaves. In
some places, flooding occurs after heavy rainfalls. To solve this problem, some houses have
used timber stilts to elevate the building above the ground level. The stilts elevate the
building to keep them away from floods and wild animal (see figure 2.1) (Ahmad et al.,
2002; Lim, 1997; Wan Abidin, 1984).
House Form
The spatial element consists of a series of spatial components or spaces from which a Malay
house is made, the minimum two spaces being the ibu rumah (main space in a house) and
dapur (kitchen) which together form what is called the Basic Malay House (the core).
Although these characteristics are particularly common in all Malay houses throughout the
Malaysia Peninsular, their shapes and sizes differ from state to state. All other spaces may be
added to the Basic House (Figure 2.5) based on implicit rules practised by master carpenters
and builders.
Figure 2.5: Spatial components (Source: Wan Abidin, 1984:29)

The addition system is built upon the extension of this core house and this necessarily makes
it the most important and central part of the house. The core house can be huge or small
depending on the needs and affordability of the family. This is made possible by the use of
standard house forms and a variety of construction methods and causes minimal disruption to
the original house (Lim, 1997; Wan Abidin, 1981).
Adequacy of Spaces Use
Interior spaces are defined, not by partitions or walls, but rather by changes in floor level. In
other cases, some of the traditional Malay houses have floors at different levels, indicating
the room functions. For instance, the verandas floor is raised lower than the living room
floor. The split level indicates the room functions and giving a sense of spatial transition in
the building (Ahmad et al., 2002; Lim, 1997). The definition of public and private areas is
unclear and overlaps. The priorities of physical components based on its function are broken
down into their smallest units. These units are also arranged according to rules which are
understood only by master carpenters (Wan Abidin, 1984).
Roof Top
Usually the houses have pitched roofs, verandas or porches in front, high ceilings and lots of
wide openings for ventilation and solar control purposes. The roofs of the Malay vernacular
houses are quite elevated and steep. The use of ventilation grilles and joints allow good
ventilation of the roof. The elevated space cools the house effectively during the hot season
and the steep shape discharges rainwater very quickly during heavy rains in the monsoon.
Generally, low thermal capacity building materials are part of the building heritage. The
most common roofing material used is the ‘attap nipah’ (a thatch made from palm tree
leaves found in the local natural vegetation. This material is mainly used to keep the building
cool (Ahmad et al., 2002).
2.1.3 Physical Changes in the Malay House
The concept of bioclimatic approaches is not new and has been practiced in this region for
many centuries. It was evolved by the natives over the generations, and adapted to their
needs, culture, and environment. The method of building was presumably passed on orally
from generation to generation, and has in some instances taken on a spiritual significance,
becoming an integral part of the relevant culture (Oliver, 1997).

It is understandable that traditional Malay House and the architecture of modern buildings in
most urban areas share the same strategies to attain optimal climatic control. Many of these
strategies are fully applicable to the new building typologies in the urban areas. The
architecture of contemporary buildings (office, retail, residential) in the tropical city deals
with the form of the urban environment, and seeks to improve the quality of human life. The
architectural and structural features of the Traditional Malay House can affect the indoor
climatic conditions and occupants’ comfort. Those features have same strategies that reflect
the following objectives:
 Providing effective natural ventilation.
 Preventing rain penetration during rainstorms.
 Minimizing solar heating of the buildings.
 Maximizing the rate of cooling in the evenings.
 Providing spaces for semi outdoor activities as integral part of the living space.
The general principle derived from an analysis of architectural heritage and cultural
traditions can hopefully be transformed into the new idea of bioclimatic approaches in the
urban environment. The main features which affect the achievement of these objectives are:
 Building layout.
 Organization and subdivision of the indoor space.
 Shading of openings and walls.
 Size and details of windows and doors.
 Orientation of the main rooms and the openings.
 Provision of verandas and balconies.
 Roof type and details.
 Thermal and structural properties of walls and roof.
 Site landscaping.
The high pitch roof with gable ends allows ventilation to the roof space and the large thatch
with large overhangs roof provides good shading against solar glare and protection against
heavy rains. Walls are full of fenestrations with full length fully open-able windows, carved
wood panels and wooden fanlights to allow ventilation. The elongated open floor planning
with minimal partition allows easy passage of air and cross ventilation in the house. The
floor boards have small gaps between to allow air circulation from underneath the house and

the stilts permit the floor to siphon the cross ventilation wind underneath into the house
through the floor gaps. Lightweight and low thermal capacity materials such as wood,
bamboo and atap (roof made from nipah, rumbia or bertam leaves) keep the house cool and
reduce reflective glare to the surrounding. Surrounding vegetation such as ground cover and
fruit trees planted around the house also help in reducing glare, at the same time acting as a
buffer zone that absorbs noise from the surrounding areas. The house orientation is built
elongated east-west direction where most of the openings are facing the north-south façade
(Oliver, 1997).
The Malay architecture was exposed to many new building technologies during colonisation
periods of the Portuguese, Dutch and British. Through many decades, the Malay architecture
has been influenced by Indonesian Bugis, Riau and Java from the south; Siamese, British,
Arab and Indian from the north; Portuguese, Dutch, Acheh, Minangkabau from the west;
and Southern Chinese from the east. For example, some houses in Kelantan a northern state
have a kind of roof which is similar to that of southern Thailand (Ahmad et al., 2002).
The physical changes can be seen in many of the components. Zinc and clay tiles are a
substitute for roofs made of leaves, brick and cement columns are replacements for timber
stilts and ladder. Glass for windows which were formerly open and nails as alternatives for
rattan and tree roots that tie joints together. Each of these had a profound impact on the
Malay vernacular architecture. The process of adopting new technologies to ancient
architecture is not entirely a new idea. Malay architecture has been modified by
technological and cultural changes for centuries. However the changes through different
building typologies have never found a solution for the transformation of the vernacular
architecture.
2.2 Bioclimatic Strategies for High rise Buildings
The hypothetical spectrum of environmental control places the so called passive systems
term (depending on the context) almost synonymous with ‘green’, ‘environmentally
conscious, ‘alternative’ and ‘bioclimatic’ (George Baired, 2001). The terms Bioclimatic was
first invented by Victor and Aldar Olgyay and was aimed at notify a designer the conditions
under which thermal comfort would be possible (Olgyay, 1954; Olgyay, 1963).
When considering high rise building construction, bioclimatic architecture literature
recognizes the following factors as important: (1) Topography, e.g. slope, site orientation,

site views; (2) Movement of the sun and its impact during the year (i.e. solar altitude and
azimuth); (3) Climatic conditions including prevailing wind patterns, incoming solar
radiation, temperature, air moisture; (4) Environmental conditions such as daylight and
shading of the construction site; (5) Mass, volume and size of building; (6) Local
architectural standards; (7) Availability of local building materials (Tzikopolos, Karatza
et.al., 2005).
According to Rahman and Kandar (2005), the following features should be involved in the
paradigm shift of passive design strategies in the tropics: (1) A detail site analysis of the
building site; (2) The principle of the land and sea breezes, (3) A combination of the wind
behaviour at land, sea and valleys for a building site, (4) The choice of trees whether grown
naturally or trees planted later on, (5) Hard landscaping is to be at a minimum, (6) Water
spray on top of roofs or walls to cool the surroundings, (7) Building materials used for the
building envelope, (8) The shape and orientation, (9) Roof shape and roof pitch, (10) Sun-
shadings of all types of roof and wall, (11) Reflective materials and insulation materials, (12)
Air movement inside the building, (13) Wind deflectors, shaping and orientating the building
shell (to maximize exposure to the wind), (14) Building with open plan and air shafts to
encourage stack effect, and (15) Double walls and roofs.
Figure 2.6: Yeang’s bioclimatic approach model
(Source: Nirmal Kishnani, 2002:8; Yeang, 1994)
Figure 2.7: Olgyay’s bioclimatic approach model
(Source: Nirmal Kishnani, 2002:8; Olgyay 1963)
Yeang, (1997) has developed a set of bioclimatic principles for high-rise buildings in a
tropical climate country like Malaysia. From the very first principle “interpretations of

bioclimatic principles” towards the “rethinking the skyscrapers”, the concept of the
bioclimatic skyscraper has become synonymous with his name. This design concept for high
rise building has been developed in Malaysia since the early 80’s and was popular ten years
later. Although most of his basic bioclimatic principles came from the traditional Chinese
shop lot and some from traditional Malay House, it is evident that Yeang has used a series of
high-rise buildings to test various bioclimatic principles. Subsequently, his earlier high-rise
projects appeared only to deal with issues of passive low-energy design, whereas his more
recent ones reflected a more holistic and incorporated bioclimatic approach (John et al.,
2005; Powel Robert, 1999).
The bioclimatic approach by Yeang has dual objectives; delivering occupant comfort and
lowering energy used (see figure 2.6) (Nirmal Kishnani, 2002; Jahnkassim, 2000; Yeang,
1994). The strategies have been translated into a set of design guidelines described as a
bioclimatic model. The model was translated from the philosophy model developed by
Olgyay which defined the primary function of a building as to provide human shelter for the
purpose of creating occupant comfort (see figure 2.7). Olgyay envisaged his exposition on
the Bioclimatic approach some years before the oil crisis in 1973 and altered the criteria by
which buildings were assessed (Oseland & Humphreys, 1994). Yeang invented his approach
in the mid 1980s at a time when the use of fossil fuel was being viewed as a threat (Yeang,
1996). Both were using the same reason (energy issue) to promote their approaches into this
world.
2.2.1 Bioclimatic Categories
Based on the bioclimatic model, Yeang developed a set of pre-design checklists for high rise
building applied mainly in the tropics. The pre-design checklist for bioclimatic approaches
developed by Ken Yeang is presented below.
(1). Plan/ Use patterns/ Ventilation
The building plan’s configuration and depth; the position and
configuration of the entrance and exits; the means of
movement through and between spaces; the orientation and
external views reflect the air movement through the spaces;
and the provision of sun light into the building.

(2). Vertical landscaping
As cooling devices for the buildings since plants absorb heat
they also absorb carbon dioxide and generate oxygen.
(3). Recessed sun-spaces; Balconies & terraces
Balcony can serve as evacuation spaces while terraces for
planting and landscaping. Placing balconies on hot elevations
permits glazing to these areas to be full-height clear panels.
With adjustable glazing at the outer face to collect solar heat
positively, acting likes a greenhouse.
(4). Site/ Building Solar sky-courts
To give sun shading; as large terraces for planting and
landscaping; as a flexible zone for additional facilities, such as
kitchenette, as evacuation spaces in case of emergencies; as
communal spaces or ventilating spaces; permit glazing to
balconies to be full height clear panels; add scale or sense of
humanity to office spaces.
(5). View out from lobby (lift lobby, stairways and toilets); End/ Side core; Awareness of
place
Energy savings (not requiring mechanical ventilation; require
reduced artificial lighting and eliminating the need for
additional mechanical pressurization ducts for fire protection
purposes); Users can orientate themselves more easily; Air
locks to prevent air leakages to outside, thus, lowering heat
loss and thereby conserving energy and reduce noise entering
building.

(6). Site Adjustment (location)
The overall building orientation has an important bearing on
energy conservation but generally not all site geometry is
simply harmonizes with sun path geometry. Corner shading
adjustments or shaping may need to be done for sites further
north or south of the tropics to minimize the impact.
(7). Environmentally interactive wall; Transitional spaces
External walls should be regarded more as permeable
environmentally interactive membranes with adjustable
openings; filter like, have variable parts that provide good
insulation functioning and be open able.
(8). Curtain wall at N & S facades
Tall buildings are exposed to the full impact of external
temperatures and radiant heat. Arranging the building with its
main and broader openings facing north and south gives the
greatest advantages in reducing insulation and air-conditioning
load. Solar shading will control daylight intake, keep away
glare and will reduce energy for artificial lighting.
2.2.2 The Form and Envelope Category
(1). Wind-scoops
Wind scope will capture high velocity wind that flow at upper
level. This will optimize the natural ventilation strategies
where the wind can be directed into ceiling plenums to
ventilate inner recessed spaces and gives a feeling of comfort.
(2). Wind-ducts
In the tropic, wind duct is important for providing cross
ventilation. Sky courts, balconies, and atriums as open spaces
and transitional spaces at the upper parts of the tall building
encourage wind flow into internal spaces. Natural ventilation,
letting fresh air in and exhausting hot room air.

(3). Insulative wall
To reduce heat transfer through skin, the external wall in the
tropics should have moveable parts or adjustable opening that
control and enable good cross-ventilation for internal comfort,
provide solar protection, regulate wind-driven rain, besides
facilitating rapid discharge of heavy rainfall.
(4). Shading devices
Essential to all glazed wall areas facing directly to the sun; to
exclude the great heat load at critical times and reduce
radiation to tolerable limits; allow views; allow solar gain.
(5). Structural mass; Solar-collector wall
Store heat and cool at night time to keep internal spaces cool
in the daytime. To intake solar heat positively.
(6). Water-spray wall
To promote evaporation; water spray periodically with a
sprinkler system to hot facades for evaporative cooling
(7). Service core positions: end core (double core) side core (single sided core) central core
End core and side core provide buffer zone as insulation to
internal floor spaces. Possible for natural ventilation and view
out to lift lobby, stairways and toilets. The double-core
configuration where the window openings run north and south
will result in minimizing air-conditioning loads.
The service core affects the thermal performance of the
building. In the tropics, cores should preferably be located on
the hot east and west sides of the building. Central core is the
least preferred option for the bioclimatic skyscrapers

The theories of the ‘bioclimatic skyscraper’ evolved from the environmental filter ideas in
the 1970s to theories of bioclimatic/ecological design in the late 1990s. According to
(Jahnkassim 2006; Powell, 1999), there are three major phases within the gradual
development of the theories applied in Yeangs’ buildings identified as:
 the ‘climatic’ phase (IBM) - based on intuitive climatic principles and focused on
the idea of the environmental filter;
 the ‘regionalist’ phase (MESINIAGA) - based on a search for a distinctive regional
language within the tropical Asian context;
 the ‘bioclimatic/ecological’ phase (UMNO) - directed towards a more ‘global’
context and focused on the environmental agenda.
2.3 Environmental Performance of High Rise Buildings
Adequate building design can reduce energy consumption while providing a comfortable
environment for the occupants. A bioclimatic building may be so economically efficient that
it may consume even 10 times less energy for heating compared to a conventional building
(Badescu and Sicre, 2003). A construction of a typical bioclimatic structure will incur
additional cost in most cases less than 10%, usually around 3 to 5% (Pimentel et al., 1994)
and this cost is usually returned within a few years (Dimitriadis, 1989).
There is adequate research on the relationship between energy consumption of individual
buildings and natural forces, but very little research into urban scale thermal performance
and energy consumption phenomena (Giridharan et al., 2004). Considering previous research
on high rise buildings around the world, a significant number of research projects have been
carried out with the specific focus on energy consumption (Cetiner and Ertan, 2005),
environmental consideration (Alex, 2005; Jianlei, 2004; Pank et al., 2002) and architectural
design (Wan and Yik, 2004; Till, 2004; Frederik et al., 1985).
In Malaysia, research projects dealing with high rise buildings are rather limited. There are
even more limited studies dealing with the environmental performance of high rise office
buildings and there are no firm guidelines for the creation of an energy efficient design with
sustainable environment within them. Some previous research has been carried out on
residential architecture (Lim and Rao, 2002; Ahmad et al., 2002).

A study into low energy office building (LEO) in Putrajaya Malaysia was carried out by
Roy, et al. (2005). This study however, did not focus on high rise building but more towards
a National Demonstration project aimed at promoting energy efficiency (EE) in buildings.
Five studies have been identified which have a significant connection with environmental
performance of high rise buildings. Most of the studies fall into three major areas such as
environmental consideration, energy consumption and architectural design.
The first study was carried out by Ismail (1996) on wind driven natural ventilation in high-
rise office buildings with special reference to the hot-humid climate of Malaysia. A second
study was carried out by Ismail (2001) with the aim of determining indoor design condition
for air conditioning systems in Malaysia. A third study was carried out by Law (2002)
dealing with the bioclimatic approach to high-rise building design, with specific reference to
the bioclimatic buildings designed by Yeang. A fourth study was carried out by Syed Fadzil
and Sheau (2003) on sunlight control and daylight distribution analysis: the KOMTAR case
study. A fifth study was carried out by Salleh (2005) who studied the potential development
in environmental design and sustainable high rise buildings in Malaysia. This study learnt
from different climates of glazing shading strategies that can be implemented in a tropical
climate.
2.3.1 Environmental Consideration
The study carried out by Ismail (1996) investigated the possibility of incorporating wind-
driven natural ventilation in high-rise office buildings through various conceptual design
alternatives. Six groups of reduced scale-models representing tropical high-rise buildings of
different geometrical configurations were tested in a wind tunnel. The interaction between
the geometry of tall buildings and external winds was investigated. The wind-induced
pressures and flow patterns of representative scale-models were analysed.
The results show that wind-driven ventilation is viable for adoption in some tall office
building sectors. The overall findings confirmed that for the Malaysian hot-humid climatic
conditions, wind-driven ventilation is effective for physiological cooling in some sectors of
high-rise buildings. This is true especially for tall buildings in isolation and those in urban
setting where a building is taller than its surrounding structures. However, wind-driven
ventilation is not feasible for the provision of any effective cooling in a dense urban setting
consisting of equally tall structures, or with taller buildings on the upstream side and in close
proximity (Ismail, 1996).

When high, narrow buildings are placed relatively far apart, they do not reduce the airspeed
near the ground level. In fact such buildings can increase appreciably the ground level
airspeed around them thus improving the ventilation potential for lower buildings between
them, as well as in the streets. The occupants of the high stories enjoy lower temperature, as
well as lower humidity as vapour is generated by evaporation from vegetation and moist soil
at the ground level (Ismail, 1996). This is in addition to the better ventilation potential and
the view offered from the high stories.
2.3.2 Energy Consumption
Malaysia has approximately 16 gigawatts (GW) of electric generation capacity, of which
87% is thermal and 13% is hydroelectric. In 2003, Malaysia generated around 79 billion
kilowatts-hours of electricity. The Malaysian government expects that investment of USD
9.7 billion will be required in the electric utility sector through 2010. Much of that amount
will be for coal fired plants, as the Malaysian government has adopted a policy of attempting
to reduce the country's heavy reliance on natural gas for electric power generation.
The largest thermal project under development in Malaysia is the 2,100 mega watts (MW)
coal-fired project in Tanjung Bin, Johor which began commercial operation in August 2006.
Earlier, in 1994, the Malaysian government granted approval for the massive 2.4 1 gigawatt
(GW) Bakun hydroelectric project in Sarawak, while electricity demand in Sarawak is
modest, currently under 1 gigawatt (GW). The project was supposed to be completed in 2002
but several impediments delayed the project. The Bakun Dam had been slated to send 70%
of its generated power from Sarawak to Kuala Lumpur through the construction of 415 miles
of overhead lines in eastern Malaysia, 400 miles of submarine cables, and 285 miles of
distribution infrastructure in the Malaysia Peninsular. In addition, expansion plans included a
high-voltage line south to Johor Baharu and north to Perlis, near the western Thai border
(Clough, 2007).
Malaysia is reforming its power sector to make it more competitive and lower costs by
divesting some of its power generation units. Malaysia expects to achieve a fully competitive
power market, with generation, transmission, and distribution decoupled, but reform is still
at an early stage and the exact process of the transition to a competitive market has not been
decided. The issue is still under study, and many observers have voiced caution in the light
of the experiences of other deregulated utility systems.

Figure 2.8: Malaysia's electricity generation, 1980-2003. (Source: Clough, 2007).
Table 2.1: Electricity consumption in Malaysia (Source: Kannan, 1997; MEWC)
Year
Electricity Consumption Primary Energy Cost (MR)
Million
(1978 Price)
kWh x 1016
J kWh x 1016
J
1986 13.84 4.982 41.52 14.947 57,859
1988 16.49 5.936 49.47 17.809 66,259
1990 21.02 7.567 63.06 22.702 79,239
1992 27.38 9.857 82.14 29.570 92,866
1994 35.15 12.654 105.45 37.962 109,976
1995 38.05 13.698 114.15 41.094 120,272
1996 43.77 15.757 131.31 47.272 130,621
1997 NA NA NA NA 140,684
MR – Malaysian Ringgit
NA – Not Available
Electricity Consumption
According to Kannan (1997), The Ministry of Energy, Water and Communications (MEWC)
reported that for the period of 1986-96, electricity consumption in Malaysia has grown at a
rate between 12 to 15% per year. Increasing urbanisation is one of the factors contributing to
the growth in electricity demand, for use in residential and commercial buildings (i.e. offices,
shops, hotels). Table 2.1 shows electricity consumption in Malaysia for the 1986-97 periods.

Table 2.2 shows that the office building consume 55 to 65% of its total energy consumption
for air-conditioning, 25 to 35% for lighting, 2 to 6% for lifting and 5 to 15% for others
(Kannan, 1997) and in the most recent energy audit on commercial buildings (offices, hotels
and shopping complexes) showed that the percentage of energy consumption by air-
conditioning systems in the buildings was the highest compared to other systems (Sopian,
2005). A chart in Figure 2.9 shows electricity consumption in Malaysia according to building
type.
Table 2.2: Energy consumption distribution for commercial buildings in Malaysia
(Source: Kannan, 1997)
Building
Types
Air
Conditioning
(%)
Lighting
(%)
Lifts
(%)
Hot water,
Catering,
Laundry
(%)
Miscellaneous
(%)
Hotels 50 – 70 20 - 30 3 - 5 15 - 20 0 - 10
Shops 40 - 55 45 - 55 2 - 4 NA 0 – 10
Offices 55 - 65 25 - 35 2 - 6 NA 5 - 15
NA – Not Available
Figure 2.9: Energy consumption by building type in Malaysia
(Source: Sopian, 2005)
Air Conditioning
57%
Lighting
34%
Lifts
3%
Others
6%
Figure 2.10: Approximate average values of energy consumption in office buildings in
Malaysia

The approximate average values for energy consumption by the systems in office buildings
in Malaysia from both sources can be summarised in a pie chart diagram as shown in figure
2.10. Electricity used for air conditioning system followed by artificial lighting has been
identified as the major contribution to higher energy consumption in Malaysian buildings.
The study found that most Malaysian office building, low and high rise building have an
average measured office temperature of 23.1°C whereas the Malaysia comfort temperature
was found to be 24.6°C. This 1.5K over cooling has significant energy implications (Ismail,
2001). The study shows that the amount of energy consumption can actually be significantly
reduced by at least 20 percent for most existing commercial and public buildings (CIBSE,
2003). For example, a reduction of the office temperature in the new low energy office
building (LEO) from design level of 24°C to 20°C increases the energy consumption by 33%
(Roy, et. al., 2005).
The energy consumption for lighting in Malaysia is about 25-35% of the total energy
supplied to buildings. Studies have shown that the use of daylighting can reduce overall
energy consumption by 20% and also reduce the sensible heat load on air conditioning.
Innovative daylighting systems can also reduce heat gains and glare. Daylight is desirable
over artificial light because of its superior quality and colour rendering. Daylighting can be
achieved, conventionally through window openings and fenestrations or using daylighting
technologies such as light pipes and light tunnels (Sopian, 2005).
Table 2.3: Energy Consumption and energy index for several office buildings in Kuala
Lumpur (Source: Malaysian Energy Centre (MEC), 2006)
Building
Gross Floor
Area
(m2
)
Total Energy
Consumption
(kWhr/yr)
Building Energy
Index
(kWhr/ m2
/yr)
Sapura Holding 70,821 5,413,623 172
Ministry of Energy, Water and Communication 38,606 2,193,166 114
Federal House 14,705 1,653,710 165
Menara AA 28,266 1,808,604 137
Menara SMI 5,763 454,512 243
Menara Telekom 228,406 22,467,339 190
Menara PKNS 57,713 5,874,952 187
Securities Commision Building 94,288 9,645,600 199
In the new Malaysian Standard MS 1525: 2001, "Code of Practice on Energy Efficiency and
use of Renewable Energy for Non-residential Buildings". Following this code, the low
energy office (LEO) building must have energy consumption below 135kWh/m2/year
(MECM, 2004). A recent study shows that not many buildings fall into that category as
shown in table 2.3. According to (MECM, 2004) major energy savings and environmental
benefits can be achieved in the building sector of Malaysia. The energy efficiency measures

are expected to achieve Energy Index of 100kWh/m2
/year. It can be done through a
subsequent energy monitoring follow up program for low energy office building designed
and planned to be LEO building. An ambitious goal was set for energy savings of more than
50% compared to traditional new office buildings. It could be achieved at an extra
construction cost (in Malaysia) of less than 10%, giving a payback period of the extra
investment of less than 10 years. However the achievement is subject to the design and
performance of the LEO building if the following are made:
 Creation of a green environment around and on top of the building.
 Optimisation of building orientation, with preference to south and north facing
windows, where solar heat is less than for other orientations.
 Energy efficient space planning.
 A well insulated building facade and building roof.
 Protection of windows from direct sunshine and protection of the roof by a double
roof.
 Energy efficient cooling system, where the air volume for each building zone is
controlled individually according to demand.
 Maximise use of diffuse daylight and use of high efficiency lighting, controlled
according to daylight availability and occupancy.
 Energy Efficient office equipment (less electricity use and less cooling demand).
 Implementation of an Energy Management System, where the performances of the
climatic systems are continuously optimised to meet optimal comfort criteria at least
energy costs
The cost target of maximum 10% extra costs for the energy efficiency measures have been
predicted to be countered by more than 50% energy savings. The energy monitoring during
use will add vital credibility to the predictions.
Office equipment such as computers, printers and copy machines, are responsible for
increased electricity consumption and thereby also responsible for additional increase in
cooling load. Therefore, special emphasis has to be made to reduce the electricity
consumption for equipment. The personal computer, with its screen has been identified as
the main energy consuming office equipment in a modern office. In contrast, portable laptop
computers are much more energy efficient than stationary computers because they are
optimised for maximum battery life.

2.3.3 Architectural Design
Law (2002) has developed the third category of bioclimatic strategies checklist for high rise
building based on Ken Yeang’s completed buildings. From two categories of bioclimatic
strategies checklist (1) Bioclimatic (2) Form and envelope developed by Ken Yeang. Law
added another category which is (3) Evaluation. Law, tested the checklist in a series of case
studies using post occupancy evaluation techniques which involved the IBM Plaza (Kuala
Lumpur); Menara Mesiniaga (Kuala Lumpur); Menara UMNO (Penang); and the Waterfront
House, Kuala Lumpur (Law, 2002). Unfortunately the third category of bioclimatic
strategies checklist (evaluation) developed by Law and the result of the study have not been
published.
Syed Fadzil and Sheau (2003) studied daylight distribution in high rise office building
(KOMTAR) in Malaysia and compared simulations and measured field work data. This
study highlighted the importance of shading devices in high-rise office buildings design in
tropical climates. The daylight factors were found to range from 6.0% (near the windows) to
2.0% further away from the windows. It was found that without any exterior shading device,
direct light penetration on clear and cloudy days was quite extensive due to the amount of
glass area surrounding the building. On a fine and bright day, day lighting alone is sufficient
for working comfortably in an open office space.
Figure 2.11: Daylight distribution for a typical door in KOMTAR during overcast sky
(Source: Syed Fadzil and Sheau, 2003:716)
Through days of observation, it was also found that only 3 to 4 bays were affected at a time
with different degrees of the extent of sunlight penetration depending on the time, the sun’s
altitude and the orientation of each bay (see figure 2.11). Since sunlight, which is also
common in cloudy to clear days, comes with heat and glare problems, some kind of control
is necessary. This is why designers must make intelligent decisions through research and
thorough analysis. Careful orientation, planning and calculated shading devices are all found
to be importance if the target is energy conscious and environment friendly design.

Salleh (2005) carried out case studies in Europe and Asia to provide guidelines for applying
the design strategies to hot humid climates for high rise high density developments such as
Malaysia. The study addressed the application of different glazing shading strategies
indicating convective and radiant heat exchange for, a) external shading, b) middle sealed
shading, c) middle ventilated shading, and d) internal shading in high rise building (see
figure 2.12). Salleh found that environmental temperatures were reduced by 2°C to 3°C
compared to the more traditional all-air systems, and external blinds reduce the internal
glazing/blind surface temperatures. The reduced ventilation loads have resulted in lower
space requirements for air handling equipment and ductwork, and subsequently produced
capital cost savings.
Figure 2.12: Illustration of different glazing shading strategies indicating convective and
radiant heat exchange for, a) external shading, b) middle sealed shading,
c) middle ventilated shading, and d) internal shading.
(Source: Jones and Salleh, 2005:348)
Events though there are limited studies in this field and the elements of bioclimatic research
are segregated into three different dimensions, the results shown clear direction that better
indoor environment is achieved through appropriate design strategies. Windows are
suggested to be primarily orientated to the North and the South. This orientation receives less
direct sunshine, and only shallow out shading is required to shade off the sun. East and west
orientation receives more sun, and the sun is more difficult to shade off due to the low sun
angles for the radiation in the morning and in the afternoon. Exterior shading must be
efficient to stop the solar heat before it enters the building. The use of punch-hole window
facades and curtain wall windows with exterior shading louvers might be useful. Towards
the east, shading is deeper to protect against the low morning sun. To be realistic the
windows should comprise 25 – 39 % of the façade area, depending on orientation.

2.4 Indoor Comfort Design Condition
The most fundamental approach to building is to provide security and shelter against
uncomfortable outside environmental conditions and this is still today the basis for human
well being in the built environment. The basic measure for operational quality of a building
is the human feeling of comfort which is determined by the sum of the interior and exterior
climatic conditions as well as social expectations (Romhild and Jentsch, 2004). A good
feeling of comfort, the ‘ideal environment’, is achieved when these environmental conditions
are as desired by the majority of occupants. The aspects of human feelings of comfort which
can be influenced most directly by the construction and design of the building envelope are
the aspects of thermal comfort, visual comfort and acoustic comfort. According to Oral et
al., (2004) these three physical components are the core aspects for evaluating the
performance of a building envelope. In the following investigations these core aspects of
human feelings of comfort are considered in conjunction with aspects of reducing energy
consumption and users’ satisfaction.
High performance buildings reflect a concern for the total quality of the interior
environment. By definition, they provide supportive ambient conditions, including thermal
comfort and acceptable indoor air quality, visual comfort, and appropriate acoustical quality.
Air temperature, mean radiant temperature, air speed, and humidity are all factors that affect
thermal comfort. Dissatisfaction with thermal conditions is the most common source of
complaints in office buildings. Small changes in air temperature may significantly affect
thermal comfort.
A comfortable environment has been described as being an environment, in which there is
freedom from annoyance and distraction, so that working or pleasure tasks can be carried out
unobstructed physically or mentally (Croome, 1990). Discomfort can only really be defined
in terms of a lack of comfort. This definition can be said to include the effects of the
environment on health and therefore is the state to be attained in every aspect of the
environment. The concern is with how different meanings of comfort have come to define
indoor environments and the strategies for thermal regulation they represent. Meanings of
comfort have changed dramatically over the last century, with considerable implications for
indoor environmental management and energy demand. This involves providing healthy
surroundings and minimising discomfort. The term ‘comfort’ might be used to describe a
feeling of contentment, a sense of cosiness, or a state of physical and mental well-being
(Heather and Elizabeth, 2004).

Comfort is a personal matter and will vary with individuals. It involves a large number of
variables, some of which are physical with a physiological basis for understanding.
Physically, thermal comfort may include; air temperature and temperature gradients, radiant
temperature, air movement, ambient water vapour pressure, amount of clothing worn by the
occupants and occupants’ level of activity. Other factors influencing general comfort are
light levels, the amount of noise and the presence of odours (Thomas, 1996).
Objective assessment Subjective assessment
Figure 2.13: Assessment of comfort based on the heat-balance model
(Source: Raw and Oseland, 1993:5)
Individuals are also affected by such psychological factors (see figure 2.13) as having a
pleasant view, having some control of their environment and having interesting work. For
some variables it is possible to define acceptable ranges but the optimal value for these will
depend on how they interact with each other, e.g. temperature and air movement, and
personal preference. According to Raw and Oseland (1993), subjective assessment of the
environment must be re thought in terms of thermal comfort, in which context and culture
affect both perception and response. Environment and physiology are believed to interact,
resulting in sensation to which an individual reacts in an objective manner (Nirmal Kishnani,
2002; Raw and Oseland, 1993).
An office environment must provide suitable conditions for the prescribed practice. These
conditions must be provided in association with creating a satisfactory working environment
in every aspect. Therefore, the research on occupant response was, and will continue to be,
solicited by way of surveys and rating scales. With little piece modifications, the method
would be applicable for other comfort assessments, i.e. visual and acoustic comfort.

2.5 Human Comfort and Health
Indoor thermal comfort is the most difficult task to achieve in building compared to visual
and acoustic comfort criteria especially when dealing with a hot humid climate. Even though
they are essential elements (visual and acoustic comfort) to be considered in building design,
the priority is still on gaining high users satisfaction level towards thermal comfort for the
reason that it is quite complicated to achieve. Figure 2.14 shows the interaction between the
human feeling of comfort, building use, building envelope and energy consumption.
Figure 2.14: Interaction between the human feeling of comfort, building use, building
envelope and energy consumption (Source: James et al., 2005:523).
The main causes of climatic stress in Malaysia are high temperatures, solar radiation,
humidity and glare. To achieve climatic comfort in the Malaysian office, these factors must
be controlled besides the control of rain, floods and intermittent strong winds. Generally, in
hot temperature when the external temperature is high, too much heat may enter the space. If
this heat can be absorbed by the building fabric, the peak air temperature during the day will
be lower. If night time ventilation is possible, the heat absorbed by the fabric of the building
can be lost at night when the temperatures are lower but if the building are lightweight and
sealed, they are likely to overheat and will result in a need for air conditioning (Thomas,
1996).
Influencesoftheoutsideclimate
Wellbeing-workefficiency
Surface colouring,
luminance contrast
Air/surface temperature,
air quality (pollutants),
humidity, air movement
Internal noise sources
occupancy, appliances
Building design &
operation aspects
Requirements for
the building
envelope
Acoustic insulationThermal insulation
reduction of heating/
cooling, ventilation
Vision to the
exterior, glare
control
Visual
comfort
Thermal
comfort
Facade Energy consumption
aspects
Acoustic
comfort
Human factors:
age, gender, activity
level, clothing,
expectations,
privacy
HumanComfortaspects

2.5.1 Thermal Comfort
Thermal comfort is defined in ASHRAE Standard 55 (1992) and ISO 7730 (1994) as being
‘The condition of mind that expresses satisfaction with the thermal environment’. The main
sources of heat gain are direct and indirect solar radiation, hot air, together with conduction
and radiation from the building fabric. The other major source of heat gain is the type of
building material used. In most buildings the heat absorbed within the building fabric is
radiated to the interiors of the buildings where high thermal capacity material i.e. bricks,
concrete and zinc is used. This will result in great discomfort.
The American Society of Heating, Refrigerating, and Air Conditioning Engineers
(ASHRAE) in its Standard for Acceptable Comfort 55 (1992), and its addendum, ASHRAE
55a (1995): ‘Thermal environmental conditions for human occupancy describes comfortable
temperature and humidity ranges for most people engaged in largely sedentary activities’.
Acceptable indoor air quality was defined in the draft revision to ASHRAE 62 (1989) as:
‘Air in an occupied space toward which a substantial majority of occupants express no
dissatisfaction and in which there are not likely to be known contaminants at concentrations
leading to exposures that pose a significant health risk’.
Heat is dissipated from the body to the environment by convection, radiation or evaporation,
and, to a lesser extent, by conduction. Heat gain by the body from the environment through
solar radiation or warm air must also be minimised. However, heat loss through conduction,
radiation and convection is negligible in the Malaysian climate because the air temperatures
are continually near the skin temperature. Similarly, because of high humidity, evaporative
cooling and perspiration are greatly reduced and even inhibited. Evaporation of moisture
from the body in the humid climate quickly forms a saturated air envelope around the body.
The saturated air envelope prevents any further evaporation from the body and undermines
the last means of heat dissipation (Lim, 1997).
Thus, to achieve some degree of thermal comfort, the saturated air envelope around the body
must be removed. Air flowing across the body can remove the saturated air envelope and
accelerate evaporation. However, this is insufficient because without ventilation (air
exchange), both the temperature and humidity in a room will build up to very high levels,
leading to very uncomfortable conditions. It is clear that to achieve thermal comfort in the
warm humid Malaysian climate, solar heat gain by the building and human body must be
minimised while heat dissipation from the body must be maximised by ventilation and

evaporative cooling. A deep understanding of such thermal comfort requirements and the
natural environment of the Malaysian climate is reflected in the climatic adaptation of the
traditional Malay house discussed in the previous sections.
2.5.2 Visual Comfort
To provide visual comfort in a building, an appropriate light level is the first factor to be
addressed. This is no easy task but the lighting environment can be split into more areas than
light level alone brings to mind. Nevertheless level is still very important as it must be
appropriate to the task and the user. The level can be maintained using a mixture of day and
artificial lighting and with specific task lighting if required. Daylight may reduce
consumption of artificial lighting from 40 to 80% (Bodart and Herde, 2002). However, it has
been said that ‘Enough light is not enough and that we must satisfy man’s emotional and
intellectual needs and provide it with those qualities’ (Phillips, 1978).
Visual comfort is a function of many variables, including lighting quality (e.g., illuminance
or intensity of light that impinges on a surface, the amount of glare, and the spectrum of the
light), visual contact with the exterior, and availability of natural lighting. Light can affect
the user negatively. The concept of glare where the user is troubled by reflections or
excessive brightness, even to the point of pain, is a common problem in today’s office
buildings. The lighting scheme must be carefully developed to avoid such problems
(Pritchard, 1985). The proportion of day lighting through windows or skylights can affect the
overall effect of the manifestation of the indoor environment and also the emotional response
of the occupant to that environment. Views through the windows of outside are also
important and can affect the feeling of an occupant (Flynn and Spenser, 1977).
The use of colour and contrast is also vital to the human brain in creating an assessment of
the visual environment. Colours are often perceived as affecting the emotions and the choice
and colour rendering of the lighting makes a huge difference to the perception of the overall
lighting scheme (Williams, 1997). The colour of a surface determines how much light is
reflected and how much is absorbed. The ratio of direct to indirect light affects the visual
‘feel’ and comfort of a space. All direct light with no reflected component will show objects
in very high contrasts and sharp shadows. At the other extreme a completely diffuse lighting
scheme (e.g. an evenly illuminated ceiling with white walls and floor) will be shadow-less
and without texture (Thomas, 1996).

2.5.3 Acoustic Comfort
The ear and brain are very good at filtering sound to extract information such as speech from
a background of noise. There are, however, limits and the greater the noise/speech ratio the
less information is received. The brain is capable of filling in the gaps in the information to a
greater or lesser extent depending on one’s prior knowledge of the subject and one’s skills of
interruption (DES, 1975). The pitch of a sound depends on the frequency of the sound wave
and is the equivalent of colour in light; high-pitched sounds are of high frequency. The
human voice produces sound in the range of 200 to 2000 Hz (cycles per second). The human
ear is sensitive to a range of sound frequencies from about 15 Hz, which corresponds to a
very low rumble of a distant bus or the lowest organ note, up to 20000 Hz; door squeaks and
the chirp of some insects have a frequency of about 17 000 Hz. However, the ear is less
sensitive to high and low frequencies than to those in the middle range (Thomas, 1996).
Acoustic quality is obtained through appropriate noise attenuation through the building
envelope, control of equipment noise, and efforts to block flanking sound paths through
fixed walls and floors, and to isolate plumbing noise. In a completely quiet library every
private conversation can be heard some background noise will shield this and make those
talking feel less conspicuous. From the opposite point of view, in quiet, open plan offices
conversations can sometimes be overheard so clearly as to be a distraction to others trying to
work. For example, the maximum background noise level (BNL) for a large lecture room is
given as 30 dBA.
Sound levels (loudness) are commonly measured in decibels (dBA). This is a scale which
takes account of the intensity of all the audible frequencies and weights them in accordance
with the ear’s sensitivity. It gives a single valued number that correlates well with the human
perception of relative loudness.
Sound will normally come either directly from a source or indirectly, having been reflected
from the surroundings, or as a combination of the two. The area and absorption of the
surfaces in a room will affect the amount of indirect sound and therefore the total sound level
within it. One space can be acoustically separated from another by using solid partitions and
by ensuring that no direct air paths connect the two. The heavier the partition, the more
difficult it is for the air pressure waves to vibrate it and the greater the separation.

The sound insulation of an element is basically the difference between the sound level in one
room with a noise source and the sound level in an adjacent room that is separated by that
element. Noise in terms of the communication or privacy factor can either be very annoying
or almost unnoticeable. Expectation can also play a part in the human perception of noise.
This may be particularly noticeable in a building where some occupants are in an open plan
office space and others have single or low occupancy cellular offices. In an under-occupied
building, for example when individuals choose to work outside normal hours, it may become
very noticeable and once heard could be perceived as a distraction or nuisance factor by
occupants (Williams, 1997).
2.6 Ecological, Passive and Bioclimatic Design Strategies
The role of architects, designers, and planners depends upon holistic perception that finds
neither separation among all aspect of design nor any exclusion in the optimization of natural
source of energies, i.e. sun, earth, air, and water. As technologic architectural design might
align with the ecologic forces of natural environment, new architectural and renovation
projects would fit as ecologic design within this pattern (see figure 2.15). Refinements for
control over systems, for comfort, and over wastes can remain largely out of phase with solar
and natural energy systems or be recast within an ecologic concern, action, and realization.
To do less than give honour to the natural environment and her elegant life-giving and
sustaining systems is not to give honour to ourselves as a remarkable expression of natural
environment (Crowther, 1992).
Everything that happens within society goes through an economic sieve. Every project has
its budgetary limitations. But the desires and expectations of clients often tend to exceed the
actualities of cost. This extra dimension with frugality in planning and design can often be
realized relative to the cost of conventional construction. Figure 2.16 shows various
parameters in ecologic design with respect to the economic sieve.
The shift from Passive to Ecological results is in an increasing complexity of the design
process. Whilst the former focuses on specific passive features and systems, the latter looks
at how they come together, often in combination with active systems, to generate desirable
outcomes. It also represents a shift from local concerns, in terms of what happens in and
around the building, to global impact, referring to how it affects the environment beyond its
immediate confines.

Figure 2.15: Ecologic architecture base on design information
(Source: Crowther, 1992)
Figure 2.16: Ecologic design factors (Source: Crowther, 1992)

With ecological design, the passive paradigm acquires a deeper resonance and global
significance. Olgyay implied that bioclimatic design rests between ecological and passive
strategies. The passive approach can be seen as a subset of the bioclimatic, itself a low
energy approach whereas the bioclimatic, falls under the broader ecological (green) design,
which embraces issues affecting the environment at large (Nirmal Kishnani, 2002).
However, the current situation with the intervention of the new concept of sustainable
development has placed bioclimatic, instead of between passive strategies and ecological to
between passive strategies and sustainable development in terms of complexity in design
process and in the context of local and global scale (see figure 2.17).
(a) paradigm shift develop by Olgyay
(Nirmal Kishnani, 2002: 41; Olgyay & Olgyay
1954; 1963)
(b) current paradigm shift (adopted from Olgyay)
Figure 2.17: Relationship of passive, bioclimatic and ecological approaches
Passive design involves a consideration of the building’s shape, form and relationship with
the climate, decisions typically made early in the design process. A passive system may be
little more than envelope insulation or external shading, introduced at any point during the
design process, sometimes even after the building has been completed. A passive mode
refers to a building’s operational reliance on passive systems, such as natural ventilation and
day lighting. A building that utilises these is sometimes described as free running (Hyde,
2000).
As passive strategies are a subset of bioclimatic design, such elements are greatly considered
in the implementation of bioclimatic approaches. In the context of Malaysia, sustainable
building (which is more complex in term of design process) is very new and as far as
building design is concerned, the industry is moving toward that direction. Furthermore,
bioclimatic design is quite established in principle and implementation in this country,
therefore it is realistic to evaluate the performance of such buildings.

Figure 2.18 (based on Vanegas et al., 1996) tries to illustrate how traditional engineering will
be widened, when environmental demands are considered. The economic and socio-cultural
issues are presented in the global context together with the environmental issues of
sustainable development (Bourdeau, 1999).
Figure 2.18: The new approach in a global context of sustainable development
(Source: Bourdeau, 1999:358; Vanegas et al., 1996)
Conventional Building Bioclimatic Building
Figure 2.19: Environmental model developed in this study (bioclimatic vs. conventional)
A bioclimatic building is one that maximises its reliance on passive modes, systems and
principles, utilising configuration and building form to minimise the impact of solar loads,
admit natural light and prevailing winds. It is not, as a rule, an exclusively passive-run
building. The deployment of air conditioning and electrical light, where used, is minimised
and their loads kept down.

This study describes the differences between a bioclimatic and conventional building in an
illustration concept shown in figure 2.19. The diagram is a graphical representation of the
climatic principle, and as such contains no reference to context. It is not intended to be
viewed as a layout of either a conventional or bioclimatic building. The general differences
between these two building designs can be explained as follows:
Conventional Bioclimatic
 Conventional building is likely to have
a hermetically sealed envelope with
less exposed surface area to minimise
fabric heat load
 Bioclimatic building is likely to
incorporate a more permeable skin that
admits light
 Conventional building has greater plan
depth and a central service core.
 Bioclimatic at building is typified by
shallow plan depth (an aspect ratio of
1:3 is deemed dl for hot humid
conditions) and a side placed core.
 Conventional building may not
differentiate façade design according
to orientation, i.e. all façades are likely
to be similar.
 Bioclimatic building acknowledges
orientation in terms of where its
service core and transitional space are
placed, and how its façade are treated.
2.7 Evaluation of Thermal Conditions
Wherever and whatever the conditions, in either indoor or outdoor environment, closed or
open condition, human beings will naturally tend to adjust themselves to the finest comfort
condition. The bioclimatic habitat, benefits from the climate in order to bring its occupants
as close as possible to comfort conditions (Gratia and De Herde, 2002). Auliciems (1983)
found that thermal comfort for groups of people living in diverse climatic regions and
geographic locations is not a constant, but varies with time and place with adaptation to
given environments. His observations have led to the creation of a model of human
thermoregulation that goes beyond one based merely on immediate physiological responses
to ambient warmth as observed in laboratory experiments to the existence of a thermal
expectation feedback parameter. If indoor environments are to be optimized, determination
of human preferences for particular levels of warmth (i.e., the thermopreferendum) becomes
an essential task for microclimatic design (see figure 2.20). Critical to this are the methods
employed in data gathering, data interpretation in the light of known psychophysiological
processes, and the logic of applying these methods and interpretations to the highly adaptive
human organism (Ruck, 1989; Auliciems, 1983).

Figure 2.20: An adaptional model of thermoregulation
(Source: Ruck, 1989; Auliciems, 1983)
Figure 2.21: Relationships between indoor neutralities and outdoor temperatures
(Source: Ruck, 1989; Auliciems, 1983)

The thermal neutrality (TΨ) zone in the maps in figure 2.22 is a pragmatic one. Neglecting
for the moment regions of excessive humidity, the areas enclosed by isotherms T = 24.5 and
T = 26.5 were taken to represent zones of negligible thermal gradients between predicted
temperature (T) and monthly mean temperature (Tm) and were further divided into 5-degree
zones. Between T = 18.5 and T = 28.5, taken conservatively for the present to represent
acceptable extreme values of group neutralities, this yields an additional four zones of
thermal design.
Top: Air cooling requirements in January.
Bottom: Air cooling requirements in July.
*Cooling is required in shaded areas
Figure 2.22: Air cooling requirements in January and July as determined by variable
neutralities and humidity (Source: Ruck, 1989; Auliciems 1983).

Some of these relationships are between outdoor warmth and maximum indoor comfort
levels. The suggested gradient zones and potentials for control options are shown graphically
in figure 2.22. Thus the global patterns for the coldest and warmest months of the year in
figure 2.22 are defined both in terms of indoor thermal comfort as determined by mean
monthly temperatures and by indoor-outdoor gradients. In general, to the warm side of
design zero, i.e., when T, = 25.5°C, the achievement of a sizable negative outdoor-indoor
temperature gradient is difficult with purely passive systems of microclimate control. Such
climates have been described at times by their high measures of relative humidity, such as,
for example, minimum values in excess of 55 percent or those on average 75 to 80 percent
(Szokolay 1980).
2.8 Predicted Mean Vote (PMV) & Predicted Percentage Dissatisfied (PPD)
Thermal comfort for people in a closed place is primarily determined by the radiation and
convective thermal interchange with the environment. Radiation thermal interchange with
the environment depends on the size of radiating surfaces and on surface temperature.
Therefore subjective thermal vote is substantially influenced by the window coverage of
buildings. From the aspect of subjective thermal vote operative, air temperature is more
important than dry air temperature as the former includes radiation temperature of walls and
the neighbouring surfaces. Subjective thermal votes can be assessed in a complex way on the
basis of PMV and PPD values in view of the clothing and activity level of people.
2.8.1 Predicted Mean Vote (PMV)
Predicted Mean Vote (PMV) is an index developed by Fanger from his comfort equation,
which predicts the mean value of the thermal sensation votes of a large group of people in a
given environment (Fanger, 1970). These metrics are based on statistical methods taking into
account the views of large numbers of people tested in a controlled steady, moderate,
internal environment. The metrics are used for predicting the likely response of people to the
thermal environmental conditions, and for specifying what design conditions ‘comfort zones’
will be acceptable: usually 80% satisfaction is deemed acceptable. PMV represents the
'predicted mean vote' (on the thermal sensation scale) of a large population of people
exposed to a certain environment. PMV is an index that predicts the mean value of the votes
on a 7-point thermal sensation scale (ASHRAE Handbook, 1993)
+3
Hot
+2
Warm
+1
Slightly warm
0
Neutral
-1
Slightly cool
-2
Cool
-3
Cold

The PMV index can be determined when the activity (metabolic rate) and clothing (thermal
resistance) are estimated, and the environmental parameters, i.e. air temperature, mean
radiant temperature, air velocity, and relative humidity, are measured. Recommendation on
the use of the PMV index is given in ISO 7730 (ISO 7730, 1994). Since the determination of
the PMV from the equation is a lengthy process, ISO 7730 has provided a computer program
for the PMV determination. The PMV can also be determined directly form tables of PMV
values provided by Fanger and ISO 7730. PMV is derived from the physics of heat transfer
combined with an empirical fit to sensation.
2.8.2 Predicted Percentage Dissatisfied (PPD)
Predicted Percentage Dissatisfied (PPD) index, which has also been established by Fanger,
predicts the number of thermally dissatisfied persons among a large group of people. It is the
percentage of the occupant population who will be dissatisfied in the environment as
predicted by the Fanger thermal comfort equation (Fanger, 1970). Dissatisfied is defined as
‘A vote outside the central three categories of ASHRAE or similar scales. A vote within the
three central categories is referred to as satisfaction with the thermal environment, and this is
called as thermal acceptability’. Thermal acceptability is defined as ‘Any condition in which
80% or more of the people express satisfaction with a given environment’ (ASHRAE
Handbook, 1993). After the PMV value has been determined, the PPD can be determined
from the relationship between PPD and PMV given in Figure 2.23 as well as using the ISO
7730 program mentioned above. PPD is the predicted percentage of dissatisfied people at
each PMV. As PMV changes away from zero in either the positive or negative direction,
PPD increases. Unlike PMV, which gives the average response of a large group of people,
PPD is indicative of the range of individual responses. The PPD is related to PMV by the
following graph.
Figure 2.23: Predicted Percentage of Dissatisfied (PPD) as a function of Predicted Mean
Vote (PMV) (Source: ISO 7730, 1994).

2.9 Office Building Design
There is an increasing demand for higher quality office building. Occupants and developers
of office buildings ask for a healthy and stimulating working environment. The advent of
computer and other office equipment has increased the internal heat gains in most offices.
Highly glazed façade, often with poor shading have become very common. This, together
with the extra heat gains from the electric lighting made necessary by deep floor plans, and
the wider use of false ceilings, has increased the cooling load. These criteria engaged in the
early stages of design can have a large impact on the performance of the finished building.
For example, choice of the overall form of the building, the depth and height of rooms, and
the size of windows can together double the eventual energy consumption of the finished
building. These can also have the day light levels, and temperatures increase to levels which
affect the occupants’ productivity.
A parametric study using climatic weather data to determine directions, which should be
used in practice by the architect to design energy efficient buildings with a good thermal
interior for bioclimatic office building in moderate climate, was carried out by Gratia and De
Herde (2002). The result shows several factors have a significant impact on the energy
consumption in buildings: Insulate the building and have good air tightness, limit and control
internal gains, good choice of the windows area and orientation, adequate ventilation and
thermal inertia.
Giridharan et al., (2004) indicate that energy efficient designs can be achieved by
manipulating surface, sky view factor and total height to floor area ratio (building massing)
while maximizing cross ventilation. High rise high density close structures could dissipate
the trapped solar radiation at least fifty percent if the structure is open at ground level. If, at
upper level, each block is opened for free flow of sea breeze, the thermal comfort would
improve significantly. In addition, increase in altitude significantly reduces the air
temperature. Although the designer has little control over manipulation of altitude, selecting
a site at right altitude and creating substantial level difference during layout design could
probably help. Pfafferott et al., (2004) mentioned that, in moderate climates, an approach to
reduce the energy demand of air conditioned office buildings without reducing comfort is
through passive cooling by night ventilation. Passive cooling by free night ventilation
improves the thermal comfort without increasing electricity demand.

According to Ahmed et al., (1998), formulating passive energy design strategies requires an
understanding of the climatic influence on buildings and the thermal comfort of their
occupants. Their research presents the bioclimatic approach in building designs as well as
techniques that are applied to formulate various strategies in order to achieve indoor comfort
conditions. Four techniques were suggested to be used in the bioclimatic approach to
determine design strategies for buildings in Malaysia; Olgyay’s Bioclimatic Chart, Givoni’s
Building Bioclimatic Chart, Szokolay’s Control Potential Zone (CPZ) and the Mahoney
Tables. Regional climatic data from the Klang Valley area in Malaysia were utilized in
formulating the design strategies. The most preferred strategies found were the use of
ventilation, dehumidification and shading. Consequently, full recommendations for the
integral use of these passive methods were suggested in all buildings in Malaysia.
Earlier than that a study was done to determine the comfort temperature, followed by climate
analysis to determine the annual mean outdoor daily temperature and other parameters such
as minimum and maximum relative air humidity and temperature. The optimum comfort
temperature found was 26.3o
C when the met and clo values were 1.2 and 0.55 respectively.
The annual mean outdoor daily temperature obtained from the climate analyses was 27.7o
C.
Ahmed et al., (1998) added, by using the equation relating the neutral temperature with the
outdoor temperature developed by Humphreys (1978), the mean neutral temperature for
Klang Valley was 26.2°C. Auliciems’ (1981) equation however, produced a lower neutral
temperature. Since Humphreys’ equation produced a neutral temperature closer to their
finding of optimum comfort temperature the equation were later used through out their
investigation. According to them, Olgyay’s method showed the required wind speeds to
alleviate discomfort and Givoni’s building bioclimatic chart helped to determine the overall
percentage of strategies to be applied.
Their study has shown that there is a need for ventilation and dehumidification, and although
air movement can be provided by wide open and shaded windows and there is the possibility
of the intake of unhealthy air. The problem of pollution and air quality in a rapidly
developing region is predictable. In order to achieve indoor comfort, it is impossible to rely
totally on passive systems (architectural or design strategies alone). Due to the increased
uses of computer technology in commercial and educational buildings, artificial air-
conditioned environments are importantly required. Instead of conventional air-conditioning
systems, alternative eco-friendly and renewable energy systems may have to be employed to
achieve the desired results (Ahmed et al., 1998).

2.10 Low Energy Design
The largest energy consumption for an office building in Malaysia is for its cooling and
lighting, which normally accounts for 50% - 60% and 25% - 30% of total energy
consumption respectively. The remaining energy use is for pumps, motors and lifts for
vertical transport and finally energy is used for office equipment (Roy, et. al., 2005).
Microclimatic modifications in today’s world have been dominated by simple engineering
solutions. In contemporary modern building, the technologies of reducing thermal stress are
always together with human growth for the extent of developments, there is a potential for
active air cooling. In certain commercial centres, hotels, and even some office buildings,
cooled areas have been extended beyond the proverbial doorstep. An intentional spillage of
cooled air onto exposed walkways and streets has been carried out in an attempt to add
prestige to particular buildings and to attract people to enter shops and arcades. Air-
conditioning is being used for purposes other than the reduction of thermal stress.
Architects have delegated the responsibility for indoor climate design to HVAC engineers,
whose concern has been more with machines and the mechanics of energy transformation
rather than with human comfort. Heating, Ventilation and Air-Conditioning (HVAC)
systems are installed to provide the occupant with comfort, health and safety (as part of the
microclimate modification). As a result of increasing energy costs, many managers of large,
air conditioned buildings have found it necessary to reduce the intake of relatively warm air
from outdoors in favour of filtering and recirculating air that has already been cooled. This
has necessitated an increased central control of operations to prevent individuals from
tampering with openings to the outdoors. Moreover, within shared spaces, an individual’s
choice and ability to adjust microclimates have been reduced. There also has been a tendency
to neglect thermal insulation and other passive control measures. Consequently, many air-
conditioned spaces are of poor thermal design and create uneven conditions indoors and are
worst during mechanical breakdowns or interruptions in energy supplies.
Energy efficient design is unlikely to be achieved without keeping energy demand to a
minimum through careful design of built form and services. Minimising uncontrolled air
infiltration ‘build tight - ventilate-right’, use of targets and life cycle costing throughout the
project as well as the ventilation design hierarchy (see figure 2.23), beginning with natural
ventilation or mixed-mode approaches, making every effort to avoid the need for air
conditioning, while ensuring that the internal conditions are appropriate. Air conditioning is

not always necessary and adds to capital and maintenance costs, and typically adds around
50% to energy consumption (CIBSE-Briefing 8, 2003).
Figure 2.24: Ventilation hierarchy (Source: CIBSE-Briefing 8, 2003:2)
The most obvious benefit of energy efficiency is lower running costs, amounting to
relatively large savings over the life of the building. However, reduced emissions and less
use of natural resources have now become more important long term benefits. Improving
energy efficiency can also lead to better buildings with greater comfort, a better working
environment, more satisfied occupants and improved productivity as spin-off benefits.
Providing better buildings will enhance the standing of building professionals, resulting in
greater customer satisfaction and a greener image. Energy efficiency is the key route to
reducing emissions from buildings leading to significant benefits for government, building
professionals, clients, owners and occupants. The occupants are usually the key energy users
and to achieve optimum energy efficiency, designers should evaluate occupants’ need beside
the thermal comfort criteria, load calculation, system characteristics, equipment and plant
operation (Joseph et al., 2003). Lighting systems are another key energy consumer and heat
generator. Additional cooling energy and operational cost will be required to remove the heat
generated by luminaries.
Is it feasible to use
NNAATTUURRAALL VVEENNTTIILLAATTIIOONN??
If practicalities prevent this,
is it feasible to use
MMEECCHHAANNIICCAALL VVEENNTTIILLAATTIIOONN??
MMIIXX MMOODDEE VVEENNTTIILLAATTIIOONN??
HHEEAATTIINNGG AANNDD CCOOOOLLIINNGG ((wwiitthhoouutt
hhuummiiddiittyy ccoonnttrrooll))??
FFUULLLL AAIIRR CCOONNDDIITTIIOONNIINNGG ((wwiitthh
hhuummiiddiittyy ccoonnttrrooll))??
IInnccrreeaassiinngg::
•energy consumption
•capital cost
•running cost
•maintenance
•complexity

2.11 Energy and Environmental Evaluation
Ismail and Barber (2000) determined the inside design conditions for Malaysian air
conditioning systems. The study was conducted in eleven Malaysian air conditioned offices
with over 500 workers questioned. The data was analysed on the ASHRAE scale and other
rating scales, and it was compared with the measured air temperature and other indoor
parameters.
The comfort temperature for Malaysian office workers was found at 24.6o
C. It was in general
agreement with other field studies in air-conditioned environments in the tropics and higher
than studies in temperate climates. Ismail and Barber (2001) found that the Malaysian
neutral temperature value in air conditioned buildings is 3.7K lower than the value found in a
laboratory study with Malaysians few years earlier which indicated that the Malaysian
workers adjust and adapt to the lower temperature provided by the typical air conditioned
environment of the modern office.
The comfort temperature range recommended by ASHRAE and other organisations fell
within the comfort temperature range found in the field study (20.3o
C to 28.9o
C). This
indicated that the Malaysian thermal acceptability in air-conditioned environment is wider
than recommended by other standards.
Ismail and Barber (2001) suggested that the previous comfort standards developed for
temperature and other climates are acceptable to the Malaysian workers. This assumes that
Malaysian air conditioned designer and operators use these recommendations which from the
evidence of their field study they did not; where the comfort temperature was found by them
to be 24.6o
C, the average measured office temperature was 23.1o
C. This is 1.5K overcooling
and must have significant energy implications if this is typical of all offices in Malaysia
(Ismail and Barber, 2001). Office air temperatures lower than 22°C to 23°C mean that people
will have to dress up with warmer clothes, and the cooling load of the building increases. A
reduction of the office air temperature from design level of 24°C to 20°C increases the
energy consumption by 33% (Roy, et. al., 2005).
In all cases, the appearance of thermal environmental control, along with climatic necessity,
is natural in the form and detail of the buildings. It is only in recent years that the significant
thermal performance of such buildings has become better appreciated by today’s designers
and systematic investigation of their design undertaken. It is a beneficial reminder that we

are actually only rediscovering principles that were well known in the preceding generations,
though with rather more widespread selection of materials in our era and applied to a larger
scale of building.
Earlier work in environmental design was conceived within a conceptual framework of
mechanics to respond to practical questions such as how to design effective fireplaces and
how to keep bread from rotting in a depot. Researchers opted for extreme reduction in their
models to achieve computability and reliability. They tried to isolate factors, temperature
being the most obvious, that could be measured and focused on establishing objective
standards. The approach goes back to the 18th century and continued until the 1960s with
Victor Olgyay and Aladar Olgyay’s ‘Design with Climate’, ‘Bioclimatic Approach’ to
‘Architectural Regionalism’ (1963). The books proposed physiological standards for human
comfort and became a classic. Environmental designers believed they could achieve optimal
environmental conditions for building schemes as construction engineers did for their
structure. A decade later, it was realized that its use was very limited. The scope of
environmental design had to be enlarged if not even radically revised.
Environmental control and finest comfort for individuals had an obvious impact on world
energy utilization, waste and pollution. According to Alex (2005), in the United State of
America, the scope of environmental studies was extended by taking into account global
concerns about the sustainability of natural resources and a more systemic approach to
modelling environmental design. Environmental conditions, such as hydrothermal or wind
speed conditions are objective and can be measured accurately with the help of instruments.
However, human perception and preferences related to these conditions are highly subjective
and misty. These are inter-reliant with each other and subject to other related factors such as
the activity of the person within the environment. Environmental diversity in architecture
assists us to understand more clearly that outside of environmental boundaries, the goal for
practitioners and researchers should not be an expedition for finding optimal environments
only in theory but should expand the search in the value of practical (Alex, 2005).

2.12 Summary and Conclusion
The creative adaptation for contemporary uses from heritage features has been developed by
Yeang and implemented in most of his high rise residential and offices building design.
However the implementations of these features were not applied as a whole due to several
constrains and mostly pressure from clients.
The lessons gained from traditional architecture are that thermal, ventilation and lighting are
important elements in tropical climates building design. It can be seen in many components
of the traditional Malay house from the roof, walls, windows, doors, floor, stilt and
surrounding vegetation. Design elements that influence indoor environment quality are
summarised as: (1) Geometrical configuration of building envelope, (the shape and profile of
projection, recesses and etc), (2) Location of openings to sun path and wind direction. (3)
Area of opening in pressure and suction regions of the building envelope, (4) Types ands
size of windows opening that allow for air ventilation and daylight penetration. (5) High
ventilated roof, (6) Open plan layout, (7) Minimised the interior obstruction for air flow
areas, (8) Non reflective building materials, (9) Vegetation at surrounding area to cool down
the microclimate, (10) Lightweight and low thermal mass material.
Human comfort depends on a range of climatologically and physiologically related
parameters as discussed earlier. In a tropical climate context, a person will be more
uncomfortable mostly due to the increase in air temperature, humidity and radiant
temperature (temperature of the surfaces surrounding the person) rather than the other two
criteria. As far as thermal comfort is concerned, increased air velocity and reduction of the
clothing level can help in improving thermal comfort level.

Chapter 2 environmental strategies for building design in tropical climates

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