Acoustic and Lighting Analysis of Heriott Watt University

Contents

ABSTRACT

1.0 INTRODUCTION

1.1 AIM AND OBJECTIVES

1.2 SITE STUDY 1.2.1 Introduction1.2.2 Reason for Selection1.2.3 Measured Drawing

2.0 METHODOLOGY -

3.0 LIGHTING3.1 LITERATURE REVIEW

3.1.1 Importance of Lights in Architecture3.1.2 Natural Daylighting and Artificial Electrical Lighting3.1.3 Balance between Science and Arts3.1.4 Daylight Factor3.1.5 Lumen Method

3.2 PRECEDENT STUDY

3.3 SITE STUDY3.3.1 Zoning of Spaces3.3.2 Tabulation of Data 3.3.3 Daylight Factor Analysis3.3.4 Types and Specification of Lights Used3.3.5 Artificial Light Analysis3.3.6 Analysis and Evaluation

4.0 ACOUSTICS

4.1 LITERATURE REVIEW4.1.1 Architectural Acoustic 4.1.2 Sound Pressure Level4.1.3 Reverberation Time4.1.4 Sound Reduction Index4.1.5 Issues of Acoustic System Design4.1.6 Acoustic Design for School

4.2 PRECEDENT STUDY

4.3 SITE STUDY4.3.1 Outside Noise Sources a4.3.2 Tabulation of Data (s4.3.3 Indoor Noise Level s4.3.4 Calculation of Sound Pressure Level a4.3.5 Zoning of Spaces s4.3.6 Calculation of Sound Pressure Levels a4.3.7 Tabulation of Sound Pressure Levels a4.3.8 Analysis s4.3.9 Conclusion s4.3.10 Spaces Acoustic Analysis k4.3.11 Analysis or Data Collection SPL and Standard Equipment SPL 4.3.12 Reverberation Time4.3.13 Sound Reduction Index4.3.14 Sound Reduction Index Analysis and Conclusion

5.0 EVALUATION AND CONCLUSION5.1 LIGHTING

5.1.1 Improvements for Lighting5.1.2 Limitation with Lighting

5.2 ACOUSTIC5.2.1 Improvements for Acoustic 5.2.2 Limitation with Acoustic

5.3 CONCLUSION

REFERENCES

APPENDIX

ABSTRACT

This report contains the details of the study conducted on Heriot Watt University with regards to the lighting and acoustical performances. From the research in the site we have broken down into two major segments for the report, which is Lighting followed by Acoustics. Formulas equations and calculations are included as the technical data to estimate both illuminance levels as well as noise levels for both light and acoustics. All orthographic drawings of the plans were given from the university and the diagrams are made with Autodesk Ecotect, which is analysis software. To ease with navigation, a list of figures and tables are used as well as references provided at the end of the report

1.0 INTRODUCTION

Lighting design is one of the major elements when it comes to architecture design, in interior as well as exterior architecture. The texture, colors and solid volumes and enclosed spaces can only be appreciated and enhanced fully when they are fit imaginatively. This project exposes and introduces students to daylighting and artificial lighting requirements in a suggested spaces

Acoustic Design in architecture is an element which the control of sound in spaces is to be concerned especially for enclosed spaces. It is essential to preserve and enhance the desired sound and to eliminate noise and undesired sound. This project exposes and introduce students to acoustic design and acoustical requirements in a suggested space

In a group of 6, we have chosen Heriot Watt University, located in Putrajaya, Selangor as our site of study. We have conducted several visits to our site to ensure the success of our project outcome. Measured drawings, lightings and acoustics measurement as well as photographs have been take while we were on site. We have also done calculations and analysis to the result of our observation and recording

1.1 AIM & OBJECTIVES

• To understand the day-lighting & lighting and acoustic characteristics & acoustic requirement in a suggested space.

• To determine the characteristics and function of day-lighting & artificial lighting and sound & acoustic within the intended space.

• To critically report and analyses the space.

This project also aims to provide a better understanding on the relationship between the type of materials that are employed in terms of building material as well as internal furnishing and finishes as well as the impacts on acoustical and lightings conditions in the building based on the building functions. Understanding the volume and area of each functional space also helps in determining the lighting requirements based on acoustical or lighting inadequacy that is reflected in the data collection. Acknowledging adjacent spaces is also vital to address acoustic concern

In terms of lighting, specification of luminaries, height of each light as well as existence of fernestrations will help to understand the lighting conditions within each space. Backed up with precedent studies, drawing comparisons with our site study, our precedent studies will aid in determining the different types of lighting and acoustic

3.0 SITE STUDY

3.1 INTRODUCTION TO HERIOT-WATT UNIVERSITY

Case Study : Heriot-Watt UniversityArchitect : Hijjas Kasturi Association SDNAddress : No 1 Jalan Venna P5/2, Precinct 5, 62200 Putrajaya, Wilayah Persekutuan Putrajaya, MalaysiaType of Building : University

3.1.2 REASON FOR SELECTION (To be fixed)

Heriot-Watt University is Malaysia’s first purpose-built green campus, setting the stage for more such eco-

friendly education institutions in the country in years to come. Due to its location on the waterfront

commercial district of Precinct 5, the campus offers a diverse and mild intensity mixed commercial

development with an integrated environment.

With its excellent record in GBI rating, the university was designed with an optimising passive outake

whereby the longest façade was facing south and north reducing direct sunlight intake, maximising the

fernestation on this side also promote for natural daylight to come in spaces such as libraries, receptions,

classrooms, common room and cafeterias where lights are needed and automatically reduces the need

for artificial lightings

After we study the basic of this building, we found out it would be a great case study because, this

building was designed to obtain sustainibility and it is an interesting subject to study as it would be a

challenge to figure whether the architect’s take on green design can be succesful for the users of the

building or will it fail and increase the usage of lightings and sound proofing.

3.1.2 MEASURED DRAWINGS

SITE PLAN

Lower Ground Floor Plan

Ground Floor Plan

First Floor Plan

Second Floor Plan

Third Floor Plan

Fourh Floor Plan

Cross-Section

2.0 Methodology

2.1 PRECEDENT STUDIES

Studies of are universities conducted, one for lighting and one for acoustics that are similar to the selected site spaces as precedent studies. After reading through and analyzing the studies, important information and diagrams were extracted for our further analysis and references on site.

2.2 PREPARATIONS

The plans, section and elevation drawings were given from the managements of the university. The data collection points were marked and chosen on the floor plan before going to the site to ease the process. The method of using the Lux Meer and Sound Level Meter were taught to us before heading to the site. To study the basic standard and regulations for the analysis, we have referred to CIBSE, ASHRAE and MS1525 extracted some points for further purposes.

Plans showing data collection points

Lutron digital lux meter LX-101 01dB digital sound meter

2.3 SITE VISIT

We were permitted to analyze and take recordings of the lecture hall, café, 365 room, common room, and staff office of the university. We went to the site twice during the day time (1pm) and nighttime, which is non-peak hours (7pm). Photographs were taken on the site to show the types of lights and materials used as well as the amount of human activities taken place within and around to building to account these evidences.

2.4 RECORDING DATA

For lighting, data collection was conducted using the Lux Meter. Depending on the spaces chosen, readings were taken at 1.5m when standing and 1m for sitting position. For acoustics, data collection was conducted using the Sound Level Meter. The materiality of each component of the spaces was also recorded for further analysis purposes. All the procedures were repeated again to get the accuracy of the readings and then, they were analyzed and compared to the standard comparison tool such as CIBSE, ASHRAE, MS1525 and LEEDS.

2.5 DIAGRAMING

Diagrams are done to show the concentrations of noise and lightings for different parts of our area of study by contouring the diagram for both sound and lighting.

2.6 CALCULATIONS

Calculations are carried out to understand the acoustical and lighting effectiveness of the particular space.

2.7 CONCLUSION

LIGHTINGS

INTRODUCTION

Lighting or illumination is the deliberate application of light to achieve some aesthetic or practical effect. Lighting includes use of both artificial light sources such as lamps and natural illumination of interiors from daylight. Day lighting through windows, skylights, etc is often used as the main source of light during daytime in buildings given its high quality and low cost. Artificial lighting represents a major component of energy consumption, accounting for a significant part of all energy consumed worldwide. Artificial lighting is most commonly provided today by electric lights, but gas lighting, candles, or oil lamps were used in the past, and still are used in certain situations. Proper lighting can enhance task performance or aesthetics, while there can be energy wastage and adverse health effects of poorly designed lighting. Indoor lighting is a form of fixture or furnishing, and a key part of interior design. Lighting can also be an intrinsic component of landscaping.

PRECEDENT STUDY(To be included)

DATA COLLECTION

4.0 ACOUSTIC

4.1 Literature Review

Acoustic is the science of sound. It deals with the study of all mechanical waves in gases, liquids an solids including topics such as vibration, sound, ultrasound and infrasound. There are many kind of sound and many ways that it affects our lives. We use sound to communicate and you might also know that acoustic is important for creating musical instrument ,concert halls, surround sound stereo and hearing aids.

4.1.1 Architectural Acoustic

Architectural acousticians study how to design buildings and other spaces that have pleasing sound quality and safe sound levels. Architecture acoustics includes the design of concert halls, classrooms and even heating systems. Building acoustics is vital in abtaining sound quality that is appropriate for the spaces within a building. From achieving a good buffer from the building’s exterior envelope to the building’s interior spaces, acoustic plays a vital role in realising the mood that is to be created in the spaces that reside the builing

4.1.2 Sound Pressure Level

Acoustic system design can be achieve through the study of sound pressure level (SPL). Sound pressure level is the average sound level at a space caused by a sound wave. Sound pressure in air can be measured with a microphone. SPL is a logarithmic measure in decibels (dB) above a standard level

Sound pressure formula :

SPL = 10 log ( PP° )

Where log is the common logarithmP is the common pressure; andP° is the standard reference Pressure of 20 microPascals

4.1.3 Reverberation Time

Reverberation, in terms of psychoacoustics, is the interpretation o the persistence of sound after a sound is produces. A reverberation, or reverb, is created when a sound or signal is reflected causing a large number of reflections to build up and then decau as the sound is absorbed by the suraces of objects in the space – which could include furniture and people and air. This is most noticeable when the sound source stop but the reflection continue, decreasing in amplitude, until they reach zero amplitude. Reverberation is frequency dependent. The length of the decay or reverberation time, receives special consideration in the architectural design of spaces which need to have specific reverberation times to achieve optimum performance to their intended activity

Reverberation Time formula :

T = 0.161VA

Reverberation time is affected by the size of space and the amount of reflective or absorptive surfaces within the space. A space with highly absorptive surfaces will absorb the sound and stop it from reflecting back into the space. This would yield a space with a short reverberation time. Reflective surfaces will reflect sound and will increase the reverberation time within a space. In general, larger spaces have longer reverberation than smaller spaces. Therefore, a large space will require more absorption to achieve the same reverberation time as a smaller space.

Figure : Reverberation Time Graph

The above diagram illustrates the reverberations time that is attributed to different rooms of different specific volumes with different specific functions

4.1.4 Sound Reduction Index

Where,T is the reverberation time in seconds (s)V is the room volume in m3A is the absorption coefficient

Sound reduction index is used to measure the level of sound insulation provided by a structure such as a wall, window, door or ventilator. The understanding of a sound reduction index is important to incorporate acoustic system design into a given space to decrease the possibility of sound from permeating from a loud space to a quiet space

Sound reduction index :

SRI = 10 log ( WI

W T )

4.15 Issues of Acoustic System Design

WhereSRI = Sound Reduction Index (dB)WI = Sound Power incident on one side of sound barrier (W)WT = Sound power transmitted into the air on the side of the partition (W)

Acoustic Comfort

Acoustic comfort is essential to attain an adequate level of satisfaction and moral health amongst patrons that reside within the building. Indoor noise and outdoor noise are the two main aspects that contribute to acoustical comfort (or discomfort

Main contributors for indoor noise can generally be traced from human activity as well as machine operations. External noise includes noise from traffic or activities that occur outside of the building

Acoustic and Productivity

Spatial acoustics may contribute to productivity in a particular building. Inconducive acoustic enviroments may dampen productivity. Productivity also depends on the building’s functions as well as the type of patrons that occupy the building

“Acoustical comfort” is achieved when the workplace provides appropriate acoustical support for interaction, confidentiality and concentrative work.” (GSA, 2012)

Spatial acoustics is of vital importance especially where workers’ productivity is being emphasized

Impacts of Inappropriate Acoustic

For certain spaces such as in a functional music setting, proper sound insulation helps creat a musical “island” while inadequate sound isolation, imprisons musicians in an inhospitable, Alcatraz like setting. This thus is evident that improper acoustical measures may backfire if design neasures are not implemented properly

Acoustical Discomfort and Health

Noise is an increasing public health problem according to World Health Organizations’s Guidelines for Community Noise. Noise can have the following adverse health efects; hearing loss; sleep disturbances; cardiovascular and psychophysiologic problems; performance refluction, annoyance responses, and adverse social behavior. As such, articulate measures have to be carried out so as to ensure that acoustical discomfort does not exist in spaces where human occupation is kept at prolonged hours

4.1.6 Acoustic Design for University

4.2 Precedent Study

4.2.1 Introduction to the Building

The auditorium of Yildiz Technical University (YTU), located in the central campus of the YTU, is mainly used for congresses, symposium, conferences and various other ceremonies. From time to time, it also hosts events such as concerts. The hall was renovated in order to increase the audience capacity and eliminate some of its disadvantage, which preserving its general architectural characteristics.

The distribution of the acoustic conditions throughout the space and the effects of the renovation on this distribution were determined by performing measurements at several audience locations in the hall. Acoustic measurements were performed in the hall before the renovation, on the unfurnished hall and after renovation. The results obtained from these three distinct situations were evaluated in order to show the impact of interior surface materials on the acoustic characteristics of the space.

4.2.2 Selection of Interior Surface Materials:

The effects of materials with different acoustic absorption characteristics on the acoustical environment are proportional to their surface areas. For this reason, the surface materials chosen to provide the optimum RT for the hall were also assessed with respect to their sizes. Cellular materials for high frequency voices and vibratory panels for low frequency voices were used to obtain a balances frequency distribution.

The reasons for choosing the materials used on the surfaces of the spaces are briefly explained below:

1. Floors The audience platform of the auditorium was furnished with 4mm thickness of felt underlying a carpet of 8mm thickness. Cloth upholstered chairs were preferred for the seating. In order to prevent a sound trap being formed on the stage, and to allow the sound rays to reach the audience in the most appropriate way, it was decided to use more reflective materials for the stage flooring, and so wood parquet on wood joists was preferred for these surfaces.

2. Ceilings

The YTU auditorium before renovation The YTU auditorium after renovation

8mm thick gypsum boards were used, which also covered the air conditioning installation. The coffered ceiling was not wholly covered with wooden material and was partly left as a hard surface, in order to preserve the architectural characteristics of the structure and to prevent the volume, which was already reduced as a result of the increase in the height of the audience platform, being further reduced. In particular the ‘paneled surfaces’, which could have been applied to the stage ceiling, were thought to be useful, but the paint on the concrete ceiling was maintained, since the height of the space excluded this option from consideration. The vertical wooden panels placed around the stage were used to try to meet the need for a reflective surface on and around the stage.

3. Walls A 10mm thick, wooden panel is considered appropriate in terms of the acoustic parameters. Some fiber glass-based absorbing material was places behind these panels in order to maintain the balance between high frequency and low frequency voices. The back wall of the wall was furnished with 10mm wooden panels, which were covered with thick fabrics, to prevent the generation of an echo. Pipes and canals for the air conditioning system were hidden by sloped panels covered with fabrics applied on gypsum, especially at the interface of the back wall and the ceiling.

The surface materials in auditorium, their surface area and absorption coefficient (based on Harris, 1994: Cavanaugh & Wilco, 1999)

4.2.3 Measurements and Analysis

During the renovation project, calculation and assessment were carried out on the RT, sound level and speech intelligibility parameters. Since 2/3 of the audience capacity of the space was assumed to be utilized in the RT calculations, both empty and occupied seat were included in the calculation at different absorption values. As speaking intended to be the main use of the hall, the optimum RT range was determined on the basis of the space volume and speech. The change in RTs calculated by taking the interior surface materials into consideration are shown in table 2. The RTs of the hall, which were measured before renovation, and the RTs obtained from the calculation performed for the empty hall are also included in table 2.

4.2.4 Background Sound Level (BSL)

Sound level measurements were carried out to find the effect of the interior surface cladding of the space on the BSL. As can be seen in Table 3, in the unfurnished condition while the air conditioning was operation, the measurements were above the acceptable noise level at all frequencies. When the air conditioning was turned off under the same conditions, the results were only about 1 dB over the acceptable values at frequencies of 1000 Hz, 2000 Hz and 4000 Hz. On the other hand, the BSLs were always below the acceptable limits in the furnished room, both before and after renovation.

RTs of auditorium, before renovation (measured) and after renovation (calculated)

Measured and acceptable BSLs (air conditioning)

As can be seen in Table 4, by partially covering the ceiling with gypsum board and using wooden panels on the walls, significant decays were obtained for RTs at low frequencies after the renovation.

Measured, calculated and optimum RTs of YTU auditorium for speech activities

4.2.5 Early Decay Time (EDT)

The measured EDT values of the auditorium and optimum EDT values derived from the measured RT values are shown in the Table 5. EDT values measured in furnished conditions (before and after renovation) the spaces were found to be within the optimum range at frequencies except 500 and 1000 Hz. It can be seen that the EDT values are slightly higher than the optimum values, but these small differences are almost certainly not audible. In general, when the EDT values are analyzed, it can be seen that a rather good distribution has been achieved in the auditorium.

Definition (D50)

The D50 parameter, an important factor in speech intelligibility, was also measured and assessed. As the D50 values, generally increased so the intelligibility of speech also improved. As can be seen in Table 6, only one receiver point (R3) was below the limit. When the acceptability limit is raised to 65% it can be seen that, prior to the renovation, none of the receiver points were adequate for intelligibility. On the other hand, after the renovation all the receiver points except R3 were above the 65% limit. It is obviously clear that the speech intelligibility was improved by the renovation.

Measured and optimum EDTs of the YTU auditorium

D50 values of YTU auditorium

Section of the YTU auditorium (after renovation)

Plan of YTU auditorium (after renovation)

4.2.6 Speech Transmission Index (STI)

The STI is also an indicator of the level of speech intelligibility. When the STI values, which were measured at various audience the STI values varied between 0.36 and 0.43 in the unfurnished space. The STI values, which fluctuated in the range 0.52-0.62 in the hall before renovation, were increased to 0.68-0.74 after renovation. This increase was due to shortening the low frequency RT and adequate early reflections.

STI in YTU auditorium

Measured STI values for unfurnished and furnished (before and after renovation) conditions of the YTU auditorium

4.2.7 Total Sound Level (TSL)

Suitability of the TSL was checked in this part. A passage was spoken from the stage and the sound levels at the audience positions were measured at the same time. It was found that the sound levels varied in the range 58.5-64.5 dB before renovation and were in the range 59.0-63.0 dB after renovation. In order to maintain the intelligibility of speech, the sound level in a space with the BSL of 40 dBA must be at least about 60 dB (Cavanaugh & Wilkes, 1999. However, it is clear that these sound levels are dependent on the speaker and can vary according to the conditions. In this study, only an example condition was evaluated.

4.2.8 Evaluation and Conclusion

The comparison of the acoustical parameters measured in the unfurnished and furnished hall (before and after renovation), and the optimum values given for these parameters are shown in Table 8. The change in acoustic environment of the hall due to the use of surface materials can be clearly seen for all the acoustic parameters. Together with the renovation, the RT values were decreased to the optimum values by using suitable indoor surface materials.

Room average measurement results and optimum values for acoustic parameters of the YTU auditorium. (*500-1000 Hz average)

In this study, the change in the acoustic parameters, which was caused by the use of interior surface materials, was shown through measurements and assessments carried out for the unfurnished and furnished hall (before and after renovation). The differences determined between the three distinct conditions of the hall in term of acoustic comfort obviously show the importance the interior surface material preferences in architecture. Within this context, the undeniable need for architects to consult acoustic engineers in order to determine the proper interior surface materials to be used for spaces designed by them (especially spaces for which auditory perception is significant), besides other design characteristics such as dimensions, shape, furnishing, should be emphasized.

4.3 SITE STUDY4.3.1 Outdoor Noise Sources

Due to the fact that our site is isolated from the city, there weren’t much of outdoor noise. Most vehicles that go through this part of Putrahjaya are mostly students and the school staff. Therefore, there weren’t much of vehicular noises eventhough there is a big highway about 1 km away from the school. From our observation, it can be said that the area is quite serene. Moreover, there’s not much human activities as well surrounding the university as the nearest building is Pullman Hotel Putrajaya where it is designed for serenity and calm thus there aren’t much noise coming from the building.

In conclusion, there aren’t much outdoor noises except the occasional vehicular noises during peak hours.

4.3.4 Calculation of Sound Pressure Level

To obtain the sound pressure level measurement of main sources in order to establsh the noise decidel produced by each noise source

4.3.4.1 Calculation for speakers

Using SPL = 10log (l1/10)

Where l1 = Sound Power (watts)

l0 = Reference Power 1.0 x10-12

Number of speakers in Lecture Theater = 6

One speaker produces approximately 80dB

Therefore SPL = 10log(l1/l0)

80 = 10log((l1/l0)

Log-1 (80/10) = l1/(1.0 x 10-10)

L1 = log-1(80/10) x (1.0 x10-12)

L1 = 1.0 x 10-4 W

Total number of speakers = 6

Total intensities = 6 x 1.0 x 10-4

= 6.0 x 10-4 W

Therefore, Combined SPL = 10 log(l1/l0)

= 10 log ( 6.0 x 10-4 / 1.0 x 10-12)

= 87.8 dB

4.3.4.2 Calculation for Air Conditioner

One air conditioner produces approximately 50dB

SPL = 10log(l1/l0)

50 = 10log(l1/l0)

Log-1 (50/10) = l1 (1.0 x 10-12)

L1 = log-1 (50/10) x (1.0 x10-12)

L1 = 1.0 x 10-7 W

Total number of air conditioner in Lecture Theater = 6

Total intensity = 6 x 1.0 x 10-7

= 6.0 x 10-7 W

Therefore, combined SPL = 10 log (l1/l0)

= 10 log (6.0 x 10-7) / (1.0 x 10-7)

4.3.6 Calculation of Sound Pressure LevelZONE 1 : Lecture Theater

Component Material Colour Surface Absorption Surface

FinishCoofficient

(500hz)Area (m2)

Wall

BrickRed-

BrownMatte 0.03 391

Concrete with Plaster Finishing

White Matte 0.06 391

2mm Noise Reduction Foam

Blue Matte 0.96 276.2

FloorConcrete Grey Matte 0.015 286.5

Carpet Black Matte 0.16 286.5

Ceiling Plaster Finishing White Matte 0.02 286.5

Door Timber Brown Matte 0.22 3.6

Furnishing

Fabric Sofa Blue Matte 0.8

Metal Table Black Metallic 0.22

Plastic Table White Glossy 0.15

Upholstered Leather Chair

Black Glossy 0.26

Zone 1 : Lecture Theater 1

6 x Air Conditioner and 6 x Speaker Where, 1.0 x 10-7 is the intensity of 1 Air ConditionerTotal Intensities 1.0 x 10-12 is the intensity of 1 Speaker

6(1.0 x 10-7 W) + 6 (1.0 x 10-4 W) Using SPL = 10log (6.006 x 10-4 / 1.0 x 10-12)= 6.006 x 10-4 W = 167.8 dB

Zone 2 : 365 Room

Component Material ColourSurface Finish

AbsorptionCoofficient

(500hz)

Surface Area (m2)

Wall Brick Red-Brown Matte 0.03 50.4


White Matte 0.06 50.4

Floor Concrete Grey Matte 0.015 282.2Carpet Black Matte 0.16 282.2

Ceiling Plaster Finishing


Door Timber Brown Matte 0.22 5.4Glass Panel Transparent Glossy 0.18

Furnishing Fabric Sofa Blue Matte 0.8MDF Table White Glossy 0.20Upholstered Leather Chair

Black Glossy 0.26

Window Glass Panel Transparent Glossy 0.18 3.0

Aluminium Frame

Silver Metallic 0.25

Zone 2 : 365 Room6 x Air Conditioner Where, 1.0 x 10-7 is the intensity of 1 Air ConditionerTotal Intensities

6(1.0 x 10-7 W) = 6.0 x 10-7 W Using SPL = 10log (6.0 x 10-7 / 1.0 x 10-12) = 57.8 dB

Zone 3 : Common Room

Component Material Colour Surface Finish


Surface Area (m2)

(500hz)Wall Brick Red-Brown Matte 0.03 85.2







Furnishing Fabric Sofa Blue Matte 0.8MDF Table White Glossy 0.20


Aluminium Frame


Zone 3 : Student Common Room4 x Air Conditioner Where, 1.0 x 10-7 is the intensity of 1 Air ConditionerTotal Intensities

4(1.0 x 10-7 W) = 4.0 x 10-7 W Using SPL = 10log (4.0 x 10-7 / 1.0 x 10-12) = 56 dB

Zone 4 : Cafeteria

Zone 4 : Cafeteria



(500hz)

Surface Area (m2)




Floor Concrete Grey Matte 0.015 448.2Timber Plates Brown Glossy 0.16 448.2




Furnishing Plastic Chair White Matte 0.14MDF Table White Glossy 0.20


Aluminium Frame


Zone 4 : Cafeteria6 x Air Conditioner Where, 1.0 x 10-7 is the intensity of 1 Air ConditionerTotal Intensities

6(1.0 x 10-7 W) = 6.0 x 10-7 W Using SPL = 10log (6.0 x 10-7 / 1.0 x 10-12) = 57.8 dB

Zone 5 : Student Reception



(500hz)

Surface Area (m2)








Furnishing Fabric Sofa Blue Matte 0.8MDF Table White Glossy 0.20


Aluminium Frame


Zone 3 : Student Reception 4 x Air Conditioner Where, 1.0 x 10-7 is the intensity of 1 Air ConditionerTotal Intensities

4(1.0 x 10-7 W) = 4.0 x 10-7 W Using SPL = 10log (4.0 x 10-7 / 1.0 x 10-12) = 56 dB

4.3.7 Tabulation of Sound Pressure Levels

Following is the data produced by speakers and air conditioners that are established as main noise sources for different zones of Herriot Watt University, Malaysia.

Zone Sound Pressure Levels (SPL)

Lecture Theater 167.8 dB

365 Room 56.7 dB

Common Room 56 dB

Cafeteria 57.8 dB

Student Administration 56 dB

4.3.10 Spaces Acoustic Analysis

Zone

Non-Peak Hour

Highest Reading: 40dB

40 = 10log(l1/10)

40 = 10logl(l1/1.0X10^-12)

log-1 40/10 = l1/(1.0X10^-12)

1.0 X 10^4 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-8

Lowest Reading: 35dB

35 = 10log(l1/10)

35 = 10logl(l1/1.0X10^-12)

log-1 35/10 = l1/(1.0X10^-12)

3.16 X 10^3 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-9

Total Intensities, l = (1.0 X 10^-8) + (3.16 X 10^-9) = 1.32 X 10^-8

SPL = 10 log(l1/10)= 10 log(1.32 X 10^-8 / 1.0 X 10^-12)= 41.21dB at Zone 1, Lecture Theatre during non-peak hour

Peak Hour


70 = 10log(l1/10)

70 = 10logl(l1/1.0X10^-12)

log-1 70/10 = l1/(1.0X10^-12)

1.0 X 10^7 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-5


50 = 10log(l1/10)

50 = 10logl(l1/1.0X10^-12)

log-1 50/10 = l1/(1.0X10^-12)

1.0 X 10^5 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-7 W


SPL = 10 log(l1/10)= 10 log(1.01 X 10^-5/ 1.0 X 10^-12)= 70.04dB at Zone 1, Lecture Theatre during peak hour

Zone 2: Cafeteria

Non-Peak Hour


68 = 10log(l1/10)

68 = 10logl(l1/1.0X10^-12)

log-1 68/10 = l1/(1.0X10^-12)

6.3 X 10^6 = l1/(1.0X10^-12)

L1 = 6.3 X 10^-6


45 = 10log(l1/10)

45 = 10logl(l1/1.0X10^-12)

log-1 45/10 = l1/(1.0X10^-12)

3.16 X 10^4 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-8


SPL = 10 log(l1/10)= 10 log(6.33 X 10^-6/ 1.0 X 10^-12)= 68.01dB at Zone 2, Cafeteria during non-peak hour

Peak Hour


75 = 10log(l1/10)

75 = 10logl(l1/1.0X10^-12)

log-1 75/10 = l1/(1.0X10^-12)

3.16 X 10^7 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-5


56= 10log(l1/10)

56 = 10logl(l1/1.0X10^-12)

log-1 56/10 = l1/(1.0X10^-12)

3.98 X 10^5 = l1/(1.0X10^-12)

L1 = 3.98 X 10^-7 W


SPL = 10 log(l1/10)= 10 log(3.2 X 10^-5/ 1.0 X 10^-12)= 75.05dB at Zone 2, Cafeteria during peak hour

Zone 3: 365 Room

Non-Peak Hour


60 = 10log(l1/10)

60 = 10logl(l1/1.0X10^-12)

log-1 60/10 = l1/(1.0X10^-12)

1.0 X 10^6 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-6


48 = 10log(l1/10)

48 = 10logl(l1/1.0X10^-12)

log-1 48/10 = l1/(1.0X10^-12)

6.3 X 10^4 = l1/(1.0X10^-12)

L1 = 6.3 X 10^-8


SPL = 10 log(l1/10)= 10 log(1.06 X 10^-6/ 1.0 X 10^-12)= 60.25dB at Zone 3, 365 Room during non-peak hour

Peak Hour


70 = 10log(l1/10)

70 = 10logl(l1/1.0X10^-12)

log-1 70/10 = l1/(1.0X10^-12)

1.0 X 10^7 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-5


55 = 10log(l1/10)

55 = 10logl(l1/1.0X10^-12)

log-1 55/10 = l1/(1.0X10^-12)

3.16 X 10^5 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-7 W


SPL = 10 log(l1/10)= 10 log(1.03 X 10^-5/ 1.0 X 10^-12)= 70.13dB at Zone 3, 365 Room during peak hour

Zone 4: Administration office

Non-Peak Hour


55 = 10log(l1/10)

55 = 10logl(l1/1.0X10^-12)

log-1 55/10 = l1/(1.0X10^-12)

3.16 X 10^5 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-7 W


40 = 10log(l1/10)

40 = 10logl(l1/1.0X10^-12)

log-1 40/10 = l1/(1.0X10^-12)

1.0 X 10^4 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-8


SPL = 10 log(l1/10)= 10 log(3.26 X 10^-7 / 1.0 X 10^-12)= 55.13dB at Zone 4, Administration Office during non-peak hour

Peak Hour


60 = 10log(l1/10)

60 = 10logl(l1/1.0X10^-12)

log-1 60/10 = l1/(1.0X10^-12)

1.0 X 10^6 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-6


41 = 10log(l1/10)

4 = 10logl(l1/1.0X10^-12)

log-1 41/10 = l1/(1.0X10^-12)

1.26 X 10^4 = l1/(1.0X10^-12)

L1 = 1.26 X 10^-8


SPL = 10 log(l1/10)= 10 log(1.01 X 10^-6/ 1.0 X 10^-12)= 60.04dB at Zone 4, Administration Office during peak hour

Zone 5: Student Common Room

Non-Peak Hour


60 = 10log(l1/10)

60 = 10logl(l1/1.0X10^-12)

log-1 60/10 = l1/(1.0X10^-12)

1.0 X 10^6 = l1/(1.0X10^-12)

L1 = 1.0 X 10^6


45 = 10log(l1/10)

45 = 10logl(l1/1.0X10^-12)

log-1 45/10 = l1/(1.0X10^-12)

3.16 X 10^4 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-8


SPL = 10 log(l1/10)= 10 log(1.03 X 10^-6/ 1.0 X 10^-12)= 60.13dB at Zone 5, Student Common Room during non-peak hour

Peak Hour


70 = 10log(l1/10)

70 = 10logl(l1/1.0X10^-12)

log-1 70/10 = l1/(1.0X10^-12)

1.0 X 10^7 = l1/(1.0X10^-12)

L1 = 1.0 X 10^-5


55 = 10log(l1/10)

55 = 10logl(l1/1.0X10^-12)

log-1 55/10 = l1/(1.0X10^-12)

3.16 X 10^5 = l1/(1.0X10^-12)

L1 = 3.16 X 10^-7 W


SPL = 10 log(l1/10)= 10 log(1.03 X 10^-5/ 1.0 X 10^-12)= 70.13dB at Zone 5, Student Common Room during peak hour

4.3.11 Analysis or Data Collection SPL and Standard Equipment SPL

Based on the calculated zoning SPL readings of equipment and calculated SPL readings for the data that is being collected from the decibel meter, the calculated SPL from the data collection are mostly similar to that of the calculated equipment SPL specially for areas with air conditioners and ceiling fans.

However, for areas with speaker readings, calculated SPL is significantly lower (70.04dB for lecture theatre) when compared to the calculated equipment SPL or 167.8dB for the lecture theatre. This probably implies that the speaker was not turned on to its maximum volume when it was being operated thus, indicated an overall lower reading.

4.3.12 Reverberation Time

Reverberation Time:

Reverberation time is calculated to determine the amount of sound energy that is absorbed into the different types of construction materials in the structure as well as the interior elements such as building occupants and furniture that are housed within this closed space.

Calculated Space:

Lecture Theatre

Reverberation times are calculated based on different material absorption coefficient at 500Hz, 2000Hz and 4000Hz for peak and non-peak hours.

- Material Absorption Coefficient at 500Hz for non-peak hours.- Material Absorption Coefficient at 2000Hz for non-peak hours.- Material Absorption Coefficient at 4000Hz for non-peak hours.- Material Absorption Coefficient at 500Hz for peak hours.- Material Absorption Coefficient at 2000Hz for peak hours.- Material Absorption Coefficient at 4000Hz for peak hours.

Volume of Lecture Theatre=1719m3

Material Absorption Coefficient at 500Hz, Non-Peak Hour with 2 persons contained within the space.

Reverberation Time

Component Material Function Area (m2)[A] /

Quantity

Absorption Coefficient

[S]

Sound Absorption

[SA]Ceiling Plaster

FinishCeiling 286.5 0.02 5.712

Wall Reinforced Concrete

Wall 391 0.06 23.46

Brick Wall 391 0.02 7.82Fabric Sound

Absorption Foam

276.2 0.96 265.15

Opening Timber Door 3.6 0.22 0.792Floor Concrete

ScreedFloor 286.5 0.015 4.3

Fabric Carpet 286.5 0.16 45.84People Non-

Peak2 0.42 0.84

Total Absorption

[A]

353.914

Reverberation Time = (0.16 x V) / A= (0.16 x 1719) / 353.914= 0.7s

The reverberation time for the first floor gallery at 500Hz during non-peak hours is 0.7s. This is lower than the comfort reverberation of between 0.8-1.3s. The space is designed in such manner to absorb the noise because of the amount of speaker and activity in the room. Thus at a non-peak hours it is more quiet than needed because of its design to absorb as much noise so the outside won’t be distracted by the activity inside the room


Reverberation Time


Quantity


[S]

Sound Absorption

[SA]Ceiling Plaster



Wall 391 0.06 23.46


Absorption Foam

276.2 0.85 237.55




Peak2 0.42 0.84

Total Absorption

[A]

461.985


The reverberation time for the first floor gallery at 2000Hz during non-peak hours is 0.595 s. This falls below the comfort reverberation of between 0.8-1.3s. Hence, this is deemed to be inappropriate since reverberations are to be kept maximum for a space that requires higher reverberation times.


Reverberation Time


Quantity


[S]

Sound Absorption

[SA]Ceiling Plaster



Wall 391 0.1 39.1


Absorption Foam

276.2 0.91 251.3


ScreedFloor 286.5 0.015 4.29


Peak2 0.42 0.84

Total Absorption

[A]

522.785


The reverberation time for the first floor gallery at 4000Hz during non-peak hours is 0.58s. This falls below the comfort reverberation of between 0.8-1.3s. Hence, there is too much acoustic absorption for a space such as this lecture theater

Material Absorption Coefficient at 500Hz, Peak Hour with 30 people contained within the space.

Reverberation Time


Quantity


[S]

Sound Absorption

[SA]Ceiling Plaster Finish Ceiling 286.5 0.02 5.712Wall Reinforced

ConcreteWall 391 0.06 23.46


Absorption Foam

276.2 0.96 265.15




Peak30 0.42 12.6

Total Absorption

[A]

365.674


The reverberation time for the first floor gallery at 500Hz during peak hours is 0.75s. This falls below the comfort reverberation of between 0.8-1.3s. Hence, there is too much acoustic absorption for a space such as this lecture theater.


Reverberation Time


Quantity


[S]

Sound Absorption

[SA]Ceiling Plaster



Wall 391 0.06 23.46


Absorption Foam

276.2 0.85 237.55




Peak30 0.42 12.6

Total Absorption

[A]

473.745


The reverberation time for the first floor gallery at 2000Hz during non-peak hours is 0.58s. This falls below the comfort reverberation of between 0.8-1.3s. Hence, there is too much acoustic absorption for a space such as this lecture theater


Reverberation Time


Quantity


[S]

Sound Absorption

[SA]Ceiling Plaster



Wall 391 0.1 39.1


Absorption Foam

276.2 0.91 251.3


ScreedFloor 286.5 0.015 4.29


Peak30 0.42 12.6

Total Absorption

[A]

534.545


The reverberation time for the first floor gallery at 4000Hz during peak hours is 0.51s. This falls below the comfort reverberation of between 0.8-1.3s. Hence, there is too much acoustic absorption for a space such as this gallery.

Reverberation Time Analysis and Conclusion

By obtaining the reverberation timings for the main first floor gallery for 500Hz, 2000Hz and 4000Hz, we are able to understand the acoustic reverberation patterns for sounds of different frequencies.

During non-peak hours, reverberation timings indicate timings of 0.7s, 0.6s and 0.5s for sounds of 500Hz, 2000Hz and 4000Hz respectively. However, during peak hours reverberation timings hover below the 0.8s – 1.3s. This thus suggests that the influx of visitors or occupants into the area during peak hours help in enhanced sound absorption.

Most of the higher reverberation timings during non-peak hours are also attributed to the double volume space that is present within the lecture theater. The bouncing of acoustic rays onto the gallery’s glass facades as well as the sloping roofline indicates how sound bounces off these materials and onto the gallery space. When sound form the speaker’s tweeters bounce off glass which bears a lower acoustic absorption rating, sound gets reflected more than it gets absorber thus, translating to higher reverberation timing.

4.3.13 Sound Reduction Index

Identifying the lecture theater as a main space to analyze the acoustic transmission into and from the area, this space require a lot of sound absorption due to the extreme noise source needed in this space as it is where 200 people maximum gather to listen to one source of voice.

Lecture TheaterMaterial Surface Area (m2) Transmission

Coefficient of Material

Sn x TCN

Concrete Brick Wall 391 6.31 x 10-5 0.025Timber Door 3.6 2.51 x 10-4 9.06 x 10-4

2mm Sound Absorption Foam

276.2 5.41 x 10-6 1.49 x 10-3

Total Surface Area 670.8

TAv = [0.025 + (9.06 x 10-4) + (1.49 x 10-3) / Total Surface Area = [0.025 + (9.06 x 10-4) + (1.49 x 10-3) / 670.8

= 4.08 x 10-5

SRIoverall = 10log (1 / 4.08 x 10-5) = 43.9 dB

4.3.14 Sound Reduction Index Analysis and Conclusion

Based on the calculated values of 43.9 dB respectively for Lecture Theater, this implies that the acoustic buffer in the area as well as the sound buffer from outdoor noise is adequate enough to isolate each space from external as well as adjacent noise sources.

Both areas incorporate the use of a variety of materials such as bricks, concrete and glass. The balance of the use of effective materials that help provide better acoustic absorption with materials of poor acoustic ratings help in the overall reduction in sound transmission between spaces.

Also, the walkway that leads the entrance into the lecture hall acts as a buffer space where noise levels will be reduced before entering the lecture theater. Likewise happens when sound transmits through the lecture theater before entering the door. Voids within the seating area also enable noise to be transmitted to the ground floor and not be wholly contained on the first floor.

Documents

Acoustic and Lighting Analysis of Heriott Watt University