Lai Cheuk Hang

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DEPARTMENT OF REAL ESTATE AND CONSTRUCTION

THE UNIVERSITY OF HONG KONG

Course: BSc(Surv)

Subject: Construction III (RECO2005)

Year/Semester: Year 2/Semester 2

Title: Coursework Part II

Name: Lai Cheuk Hang

UID: 2008263610

Date of Submission: 10thApril, 2010

Submitted to: Dr. F.F. Ng

Topic:

Select an indoor space of your choice and produce an

assessment report evaluating the current states and design of

the indoor environment using annotated sketches and/or

photos as appropriate. Identify any potential problems and

recommend possible solutions to rectify the problems.


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Content

Introduction.........3

Background information......4

Indoor Air Quality........6

Lighting System..........10

Sonic Environment...........12

Conclusion.........13

Reference.......14


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Introduction

Indoo air quality is a major determinant of personal exposure to pollutants in

todays world.(Phillip J. Walsh et al). AGood indoor environment is vitally

important. Users perform a wide range of tasks in an indoor environment.

Examples include breathing, reading and sleeping. Providing a balanced indoor

environment can enhance work efficiency as well as quality.

There are different elements interacting each other from time to time within a

certain indoor space. The three major elements that affect environment are

indoor air quality, lighting and sonic environment. Given the three elements are

well maintained and balanced, users can enjoy a comfortable environment.

In this report, a room in one of the residential halls in the University of Hong

Kong (HKU) will be examined. Potential problems related to the three criteria

will be discussed. Possible solutions will also be suggested to rectify the

problems.


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Background information

In this report, Starr Hall on Pokfulam Road is chosen as a case study to

investigate the indoor environment of its room.

Starr Hall is a 24-storey residential halls located on located on Pokfulam Road. It

is one of the 13 residential halls built by HKU. Locating on Pokfulam Road, i t is

very convenient for students to go to campus. It accommodates 500 students and

it is the biggest hall among all the others. Thus, the indoor environment becomes

crucial because it may directly affect students performance.

A student room on 9/F is chosen for investigation. The layout of the room is

shown in Figure 1. There are two sides, A and B, inside a room accommodating

two students. There is two windows on the right side, allowing air movement for

natural ventilation. Besides, The lighting system consists of daylight and artificial

lighting. There are two sources of artificial lighting. The first one is the

fluorescent tubes installed on ceiling of the room. The second one is the

fluorescent tubes on two desks. Furthermore, there is no special installation or

equipment for sound absorption.


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Figure 1 A room on 9/F

This indoor space is a residential room and the occupants are HKU students.

They carry out daily activities including sleeping, reading and changing. The

design requirements in this space should fit general requirements in a living

place. For example, there is a bed for occupant to sleep, a desk to read and work,

and a chair to sit. Windows should be provided for ventilation. There should also

be sufficient lighting to carry out activities.


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Indoor Air Quality (IAQ)

Havingdifferent significant effects on the surroundings,indoor Air Quality is one

of the most important elements within an internal environment. The essences of

IAQ are to provide comfort and maintain the state of health of occupants. If IAQ

is poor, occupants may suffer from sickness due to air pollution. It may a lso lead

to respiratory diseases because there are air pollutants such as sulphur dioxide

and nitrogen dioxide emitted from vehicles.

IAQ depends heavily on outdoor air quality as air flows from outdoor and

circulates internally. Wind breeze can directly ventilate a room, but it can bring

air pollutants as well. World Trade Organization defines air quality as

The physical and chemical nature of indoor air, as delivered to the breathing zone

of building occupants, which produces a complete state of mental, physical and

social well-being of the occupants, and not merely the absence of disease or

infirmity.

In general, there are three factors affecting IAQ. They include

1. Distribution of adequate ventilation air2. Airborne contaminants3. Temperature and humidity

Distributing adequate ventilation air is vitally important. By letting air flow

through, fresh air is brought into an i ndoor environment. Human activities are

supported by fresh air. If the indoor air is clean, people feel more comfortable

and thus their productivity increases. However, air pollutants may also be


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brought into when outside air is contaminated. Pollution sou rces include

industrial activities and traffic. Equipment such as Heating, ventilation and air

conditioning system (HVAC) may also contribute air pollutants. Thus, it is

important to monitor IAQ with care.

Good ventilation should be supported by natural a nd mechanical ventilation. The

former means air supply and removal by natural means. For example, wind

flowing through doors and windows is natural ventilation. Mechanical

ventilation refers to the use of machines such as HVAC system to displace air.

Airborne contaminants refer to the airborne particles from building materials as

well as outdoor activities by human. Common contaminants include carbon

dioxide, sulphur dioxide and suspended particulates. Even very fresh air

contains airborne contaminants because they are everywhere and cannot be

clear totally. The higher the level of pollutants, the lower is the IAQ. Thus,

minimizing contaminants becomes primary issue for enhancement of IAQ. One

example for tackling this problem is by filtering and purification, using proper

filters and devices in the air exchange system.

Temperature and humidity substantially affect IAQ. These two factors affect the

thermal comfort1experienced by occupants. The rate of evaporation as well as

heat loss from body depends on temperature and humidity. If the environment is

too hot and humid, occupants may feel uncomfortable. As different people have

1Thermal comfort is the condition of mind, which expresses satisfaction with the thermal

environment, but there can be significant individual variation in responses to the thermal

environment.


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different sensation interpretation, it is important to adjust the thermal comfort

to satisfy them. It is suggested that relative humidity of an indoor place should

be around 40% to 70%.

Observation

As shown in figure 2, there are two windows that can be opened for natural

ventilation. From my observation, there is wind breeze flowing through windows

for air displacement. They are successful in providing natural ventilation.

However, the air quality is not very good. It may be due to the fact that the

windows face Pokfulam Road, which has high traffic load at most of the time.

Thus, air contaminants are brought into the room through windows.

Mechanical ventilation is provided by air-conditioning system. The type of air-

conditioner installed is window-mounted type. It supplies cool air from outdoor

and removes hot air from indoor. Temperature and humidity are controlled to

satisfy occupants by turning on air-conditioner. However, it was observed that

when the air-conditioner was turned on for long time, the room became so cold

that it had to be adjusted. But it was hard to find a suitable temperature even

after a number of adjustments. There is no function to maintain constant

temperature, making occupants frustrated.


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Figure 2 Windows in room

Recommendation

The major problem in this room is the inefficient mechanical ventilation. It has

been suggested by environmental experts that25 degree Celsius is the most

suitable indoor temperature. Thus, it is recommended that air-conditioners

which have function for constant temperature adjustment should be installed.


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Lighting system

A good visual environment is essential for occupants to carry out visual tasks

such as writing and reading.Visual environment mainly depends on lighting

system of an indoor space. Light sources provide different amount of light for

illumination. Certain amount of light is needed in order to perform visual tasks. If

the amount is inappropriate, occupants may feel uncomfortable.Lighting system

can be categorized into daylighting and artificial lighting.

Daylighting is sunlight entering the room through window glass. Distribution of

light can be directly from the windows or reflection of daylight onto ceiling and

then back to the working surface.

Lamps are used for artificial lighting. They act as a supplement of light when

there is not enough daylight. At night, it is impossible to carry out visual tasks

without using artificial lighting. Commonly, incandescent lamps and fluorescent

lamps are the major light sources. Selection of lamps depends on size of room,

types of visual tasks, electrical efficiency and other factors.

Observation

There are two windows for daylighting. In daytime, it was observed that there

was enough lighting to carry out different visual tasks. However, occupants

revealed that light source is so strong in early morning that they cannot sleep

easily and the sleeping quality is sometimes poor. The use of window blind does

not help much because the sunlight is too strong.


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Assh w i th followi fi u s th are rows oftwi fluores entli ht

tu esinstalled on ceiling to provide artificial lighting. Besides a fluorescentlight

tu e is also installed on top of a des . Itwas observed thatthe artificial light

source is quite strong atnight. However, the white lightprovided onto the des

produces glare which resultsin visual discomfort.

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Recommendation

To tackle the problem ofstrong daylight, itissuggested thatcolour ofwindow

glass can be changed to pale green or pale blue. Currently, the window s colour is

transparent. Ifthe pale colour is added, itis believed thatthe lightwill notbe too

strong. Sleeping quality of occupants can be enhanced.

Another problem isthe glare produced by white lightonto desk. Itis

recommended thatincandescentlampswith yellow lightcan be used to replace

the fluorescentlamps. This can solve the problem of glare.

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Sonic environment

Sonic environment refers to the acoustic and noise control in a space. There are

different noise sources in a given environment. Examples include human talking

and road traffic. Room acoustics is the behavioror performance of sound in a

room. Reverberation time (RT) serves as an indicator to measure (in second) the

drop of loudness to an inaudible level under quiet environment. The optimum

RT depends on the use of indoor space. For a residential room, the optimum RT

is between 1 and 1.5 seconds.RT can be adjusted by sound absorption and

reflection materials.

Observation

There is no special sonic requirement in the case. Human talking does not

contribute much noise to the environment. However, it was observed that traffic

noise was the major noise source. Occupants revealed that traffic noise could

affect sleeping quality in mornings.Another problem is the noise emitted f rom

air-conditioner. It was observed that the noise level was quite high when air-

conditioner was turned on.

Recommendation

It is recommended that porous absorber such as fiberglass and open cell foam

can be installed to convert sound energy into heat. The use of sound absorbers

can reduce the traffic noise as well as noise from air-conditioner.


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Conclusion

After a deep and thorough investigation, it is found that indoor environment can

seriously affect occupants in different ways. If the quality of environment is poor,

occupants feel uncomfortable and even sick. In the case of a residential room,

they spend most of their time, especially night-time, in the room. They carry out

different activities within an indoor space. The quality of indoor environment, in

terms of air, light and sound, is of paramount importance.

A number of problems are discovered in this report. For example, the fluorescent

lighting on desk may produce glare, which causes discomfort to occupants.

Suggestions are provided to tackle these problems. It is believed that a healthy

and comfortable environment should be provided to occupants. Better design

schemes should be made so that problems can be rectified in early stages. This

can save construction as well as maintenance costs.


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Reference

1. Phillip J. Walsh,Charles S. Dudney,Emily D. Copenhaver (1984), Indoor AirQuality, Florida: CRC Press Inc.

2. Baker, N. & Steemers, K (2002) Daylight design of buildings , London: James &James

3. Mcquiston, F.C., Parker, J.D. & Spitler, J.D. (2005) Heating, ventilating and airconditioning: analysis and design , Hoboken: John Wiley & Sons, Inc.

4. J. Sundell (2004), The history of indoor air quality and health , London:BlackwellMunksgaard

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