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The effects of noise and excessive sound pressure levels

(SPLs) on office occupants and the strategy to improve

acoustic comfort in office buildings

Thesis: Facilities Management

Trimester 1 2015

Submission date: 1 June 2015

Author: Joel Nyoni

Student number: 213062013

Supervisor: Dr Adam Krezel

Faculty of Science, Engineering and Built environment

(School of Architecture and Built Environment)

Deakin University, Australia

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Table of Contents Abstract……………………………………..4 Table of Contents…………………………..2 List of figures…………………………………3 List of tables……………………………3

1. Chapter 1 Introduction………………………………..5

2. Chapter 2

2.0 Objectives of the study and Research relevance………6 2.1 Limitations of the research……………………………6

3. Chapter 3

Problem analysis and Research Methodology 3.1 The problem of noise in buildings…………………7 3.2 Consequences of persistent noise………………..8 3.3 Research methodology…………………………….8 3.4 Research site and case study buildings…………….10 3.5 Discussion of research findings………………………13 3.6 Analysis of the results…………………………………..14

4. Chapter 4

Literature review 4.1 Introduction…………………15 4.2 Noise and sound pressure levels terms……………………..15 4.3 Early conception of noise…………………………………..16 4.4 Sources of noise……………………………………………..16 4.4.1 Noise from outside sources………………………………..17 4.4.2 Noise from inside sources…………………………………….18 4.5 Sound reduction capabilities of materials……………………….19 4.6 Building envelope and construction techniques………………..19 4.7 Physiological and psychological effects of noise on occupants………19 4.7.1 Non auditory effects………………………………………………..20 4.7.2 Auditory effects……………………………………………………..20

5. Chapter 5

Recommendations and solutions 5.1 Introduction………………………………………………….21 5.2 Problem identification methodology………………………21 5.3 Strategies for noise attenuation…………………………..22 5.4 Glazing………………………………………………………24 5.5 Insulation……………………………………………………..24 5.6 Walls………………………………………………………….24 5.7 Case study buildings recommendations……………………..26 5.7.1Corporate office block A………………………………….27 5.7.2 Office block B………………………………………………28 5.7.3 Office bloc C…………………………………………………28 5.7.4 Corporate office block D…………………………………..28 5.8 Conclusions……………………………………………..28

6. Chapter 5

Conclusion……………………………….29

7. References…………………………………….31

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List of figures Figure 1.The Research process……………………………………………….8 Figure 2.Location of the case study buildings………………………………..9 Figure 3.Corporate business park office block A near Monash Freeway…….10 Figure 4.Ofice building B near Monash Freeway……………………………11 Figure 5.Office block C near Eastern Freeway…………………………….11 Figure 6.Office block D near Eastern Freeway………………………………..12 Figure 7.Noise Levels and their sources………………………………………..15 Figure 8.Common sound pressure levels…………………………………………16 Figure 9.The Fishbone method…………………………………………………….20 Figure 10.Traffic noise levels and weighted range………………………………20 Figure 11.Noise transmission system……………………………………………..21 Figure 12.Typical wall insulation cross-section……………………………………23 Figure 13.The AMMR plan………………………………………………………….25 List of tables Table 1.Noise exposure levels in Europe and Australia………………………..6 Table 2.Standard acceptable noise levels by WorkSafe Australia…………….6 Table 3.Sound Insulation capabilities of glazing types…………………………24 Table 4.Sound pressure levels and their effect on office workers performance……24

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ABSTRACT

Noise is one of the major causes of lowered productivity and health concerns in office workers. Noise causes physiological and psychological problems among office workers. Investigations into literature showed noise lowered productivity, stress, absenteeism, hypertension and even permanent loss of hearing and financial loss due work related compensation. The aim of this research effort was to find out methods and strategies to mitigate or eliminate completely the traffic noise transmission into office buildings. This research sought to identify other elements within the buildings itself in order to create noise free environment which would increase acoustic comfort and productivity at the same time. In the effort to investigate and establish noise filtration and their sources, the research used survey data derived from occupants living near the Eastern and Monash Freeway in Melbourne, Victoria in a project called 2Loud? Additional information on traffic noise levels and patterns was acquired from VicRoads. The methodology also included investigation of the building material used on the walls and the type of insulation material used on four selected buildings situated near the Freeways. The building envelope’s key elements which are the ceiling, roofs and floors and their coverings were also investigated on their soundproofing and sound reflection capacity. Indoor noise sources were discovered from office machinery, people, air conditioning plant and vertical transportation systems. The research investigation showed that there was evidence of higher noise levels of 35-45dBA experienced inside the selected case study buildings. This is actually higher than that stipulated by WHO, AS/ NZS 2107/2000 and also BSI 8233/2014. The investigation found out that there was low sound attenuation by the building envelope due to ineffective insulation of the wall of the two buildings that had brick veneer walls. The other two buildings with glazed walls also suffered high noise ingress due to unrated single pane glazing and poorly rated seals. In order to reduce noise transmission it was recommended that, first the root cause be identified and also the amount of sound pressure be established in order to use the best material for corrective purposes. A problem solving plan devised for solving noise issues in existing buildings called the Active Modify Maintain and Retrofit was introduced. It premised on the principle of continuous improvement until noise is reduced to standard levels at an economic cost. The researcher recommended retrofitting the walls with high soundproof material in the roof and floors and ceiling. Indoor noise mitigation was to be implemented through sound masking, dampening of HVAC and lift noises and partitioning offices with low sound transmittance materials. The issue of construction material, sound insulation and sealing and maintenance has been identified by this researcher as most critical in abating noise and SPLs at low overall cost. Existing buildings were targeted in the context of Facilities and building management in this research prompting the issue of retrofitting and modifications to reduce sound pressure levels.

Related topic areas: Environmental performance and consideration; Materials and construction

Keywords:

Noise reduction coefficient, Sound pressure levels, weighted sound reduction index, Traffic noise, Insulation

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Chapter 1

Introduction

The issue of noise has been with human beings from early start of civilization of the ancient empires, Roman and Greek Kingdoms (Moela 2010). Noise has been an unwanted source of complaints up until today, and still people are finding ways to mitigate or eliminate it while. At the same time people are still developing machinery, aircraft and complex buildings that increase environmental noise. It is the occupants of the building in offices who bear much of this noise that prompted this research. This research seeks to find ways to reduce the effects of noise in the short to long term. Chapter 1 introduces the framework of this thesis and Chapter 2 discusses the objectives and the research relevance of the thesis on noise, office occupants and the community environment. Chapter 3 includes the problem analysis and the methodology used in this thesis. This chapter also discusses what really are the problems and their consequences on office occupants. In the same chapter the research methodology was discussed detailing data collection methods, analysis and also what the results meant. Chapter 4 discussed the literature review on the subject of traffic noise and the effect on office workers in buildings. Research on studies conducted on noise sources, sound reduction and material identification were discussed. The effects on health on office workers were also examined to determine the depth of the impact earlier on and predictions in the future. Chapter 5 explored the methods that can be used to solve the noise issue in the building as a result of poor insulation, poorly rated facades and choice of building envelope material. In this chapter the AMMR plan was introduced. Furthermore solutions to each of the selected case study buildings along the two Freeways were given. The overall view is that noise is commonly accelerating into a “disease” and is quite passively fatal and the mechanism for reducing sound depends on where the sound comes from. If it is generated from within the room then sound needs to be absorbed. Any airborne sound from outside then insulation of the space may be the best. Sound transmitted through the structure, means the structure needs to be isolated from sources of vibration.

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Chapter 2

Objectives of study and Research relevance

Sound and vibration constitute the “twin evils” in the list of indoor environmental parameters that

contribute to perceived comfort besides, lighting, indoor air quality, and thermal comfort (Bluysen et al,

2010). Acoustic comfort is an important goal in the design of office buildings and its tenancy. Simplified as

excessive “noise”, acoustic levels have different effects on office occupants’ health on the short to long

term with loss of hearing and pulmonary diseases and stress levels rising. The effects of excessive noise

at above the legal sound pressure levels have known effects on the productivity and concentration of

office workers. To the office occupants, health has become a major source of concern, litigation and

compensation claims and according to AAAC (2011) claims have risen year by year. The reason for

researching on the effects of noise and how it may be reduced in office buildings are explained in the

following points below:

To determine the extent of impact of excessive sound pressure levels and noise in office building

environment and effect on long term and short term on the health and productivity of workers.

Noise and sound pressure levels analysis are two relevant factors in the design and

consequently in the use of buildings. These two factors are used in the determination of

architectural design of buildings as evidenced in the construction of halls, music auditorium,

amphitheaters and studios, office and residential buildings. Noise and sound pressure levels

have also been used to determine construction and materials choices and construction

techniques in an endeavor increase building value and acoustic comfort.

The use of noise and sound pressure levels has been very important in the operations and

environmental performance of buildings in that, building managers and facility managers have

the responsibility of ensuring abatement of noise during tenancy and operation of a facility to

guarantee optimum occupant productivity and health at the same time.

To determine the physiological and psychological effects of noise on office workers. Through

literature review the effect of noise will be uncovered from the occupational health and

psychological point of views. This helps the steps needed to mitigate the impact of noise on

workers.

What type of intervention can be applied to mitigate effects of noise on occupants? The solution

will differ according to current outer and indoor sound pressure levels of the buildings.

The final objective is to determine whether cost effective maintenance, modification and

retrofitting in existing buildings is feasible in the reduction of noise and individual risk of hearing

loss.

The need to maintain and restore the commercial value of the building and for a remunerable

Return on investment (ROI) for the building owner.

2.1 Limitations of the research

This research explored the sources of noise from within and outside the building in a specified suburban

area of Melbourne in the City of Boroondara. The physical area under research was between the two

freeways, the Monash and Eastern Freeways. The research relied on data collated by the Deakin

Research team (Leao, 2013) and also from VicRoads. The other limitations of this research are that noise

levels cannot be reduced at certain instances. It would be difficult to control what is not within your reach

For example; traffic and aviation noise or noise caused by natural weather like thunder and wind cannot

be controlled by building owners or facility managers. However it is possible to control the transmission of

noise and vibration to the receiver or into the inside of the buildings. The other limitation of the research

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is material choice of walls is limited also by specification of Building codes Australia, Environmental

Protection Authority including WorkSafe Victoria. This means noise abatement will be implemented to

certain levels as long as they meet the required threshold of 35-45dB as specified by the AS/ANZ

2107/2000. Considerations in noise abatement costs must be taken aboard in each exercise as it can be

uneconomic and impractical to implement certain noise reduction solutions.

Chapter 3

Problem analysis and Methodology

3.1 The problem of Noise in buildings

This study mainly concentrates on the exposure of noise in office buildings and thus will explore the effects of noise related to buildings from within and outside the office buildings. The problem that ignited the research on noise levels is the potential of far reaching health hazards noise can cause to employees working in the offices. Most of workers will not recognize the effects of the noise on their health and neither will their managers notice the lowered productivity and other psychological effects on their employees until after some time. In further authenticating the noise problem the Environmental Protection Authority, EPA has a policy for the control of noise called Control of Noise from Commerce, Industry and Trade No N-1 which deals with noise exposure and its control in the commercial sector. Noise levels in Australia are higher than those in Europe as stated in Table 1.This explains the gravity of the problem. According to EPA, noise in the City of Melbourne has to be limited and people have the right to complain or take legal action if noise is not abated. Table 1 Noise exposure levels in Europe and Australia (Source: Fritschi, 2011)

Region Noise exposure levels

European Union 55-65 dBA

Australia 85-140dBA

Table 2 shows the noise levels accepted by the regulator EPA (2014). Noise higher than the stipulated can result in complaints or legal action. In addition, the Owner Corporation Network (OCN n.d.), an organisation that represents owners of property in the strata community in New South Wales in both residential and commercial property stated that noise is one of the most frequently stated dispute in buildings complaints in Australia (OCN.org).

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Table 2 Standard acceptable noise levels regulated by WorkSafe Australia (Source: OHS Act, 2007)

The World Health Organisation (WHO) found that there were high exposures of noise in the European Union with about 40% of the population experiencing traffic noise exceeding 55dBA. The report also stated that 20% of the population was exposed to 65dBA during daytime and 30% exposed to 55dBA during night time. Guide lines for noise levels according to WHO is 35dBA in residential buildings and 60dBA in office buildings. WorkSafe Victoria reported that in Victoria the noise exposure standard level was 85dBA over an average of an 8 hour working period and at 140dBA at peak levels. Table 1 shows the comparison of noise exposure levels (Fritschi, 2011). The report shows that Australia has higher levels of noise than Europe. Table 2 shows the different levels of regulated noise levels according to WorkSafe Victoria. It shows the acceptable levels in the offices that it should be 50- 60 dBA. This level would have already surpassed the World Health Organisation benchmark. 3.2 Consequences of continued noise

It was a critical step to analyse the consequences of excessive noise and sound pressure levels in the office buildings. Noise has been found to cause the following in individuals on the short to long term basis;

1. Noise Induced Hearing impairment can be caused by noise at the frequency range of 3000-6000Hz. This can cause speech comprehension problems and can also transform into a social handicap (Fritschi, 2011)

2. Noise can cause speech masking thus making it difficult for fruitful conversation and general communication. Sound pressure level of speech is about 50dB(A) thus any levels of 35dB(A) and anything above will mask the audibility of the speech.

3. Physiological conditions such as hypertension and Ischaemic heart conditions can be induced by exposure to noise over 5-30 years (Maxwell, n.d.)

4. Mental illness caused by noise is common with people taking tranquilizers and painkillers and even drugs to cure the effect of noised induced stress.

Area or equipment

Typical noise

levels dB(A)

Library 38 - 48

Typical office 50 - 60

Typical lab 55 - 65

Photocopier 59 - 71

Vacuum cleaner 68 - 74

Typical factory 76 - 82

Noisy lawn mower 87 - 94

Belt sander 90 - 97

Hand drill 95 - 101

High pressure spray painting 98 - 103

Angle grinder 95 - 107

Chainsaw 106 - 115

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5. Performance levels and productivity are also reduced in the office as noise levels rise with reading and problem solving ability being reduced drastically.

The consequences of exposure to noise and their overall effects prompted this research with the aim of finding ways to abate, mitigate causes of noises transmission from their sources to the receiver in office environments. The question is what is it that needs to be done on existing buildings in the eyes of the Owner, property manager, Facilities manager or building manager to arrest this problem. Berglund and his colleagues researched on the noise in the community and found out that 120million people had been affected by workplace induced hearing loss (Berglund, 1999). The financial loss due to noise effects was also estimated to be running high as a result of low productivity, litigations and medical insurance and costs. Noise will need to be abated, reduced or when circumstances allow to be totally eliminated. The principle “if you can make it you can modify it or eliminate it”, is a virtue by this author. In Australia Noise Induced Hearing Loss compensation claims mounted to $30 Million in 2001/2, meaning by now it has increased unabated (Sparnon and Machotka, 2007)

3.3 Methodology

This sub-section explains the research methodology. The first stage of the process was to identify the existing buildings and define their envelope and facades. Both qualitative and quantitative information would be used to ascertain exposure levels in the study area. The investigation of the noise level nuisance and corresponding pressure levels in this study dwelt on authenticated studies and reports from VicRoads (2013), the Environmental Protection Authority (2014) and also through results from a previous study called 2Loud? by a Deakin research team, Leao (2013). The Deakin team of researchers investigated the Sound pressure levels that were emitted by traffic along the Monash Freeway and the Eastern Freeway in Melbourne. The research concentrated on the investigation in the City of Boroondara, a council area in the City of Melbourne. The 2Loud? Project was focused on the development of a mobile phone app to monitor and report indoor noise cause by traffic. This research tied up the findings of the noise levels and used the values to determine the indoor noise in suburban dwellings along the 2 major freeways, namely Monash and Eastern Freeways. This also meant the same sound pressure levels were likely to affect commercial office buildings in the same proximity of the freeways.

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Figure 1 Research process (Source: Adapted from James McMillan and Sally Schumacher's (2006))

Figure 1 show the research method used in this investigation. Data analysis of the noise levels would

lead to a problem solving stage which would show ways to abate the noise problem. The use of a

problem solving technique to noise control is to be used by this researcher and resonates with Root

Cause Analysis method advocated by Mindtools (2015). The five stages of the Root Cause Analysis will

be named here. The stages are as follows;

1. Problem definition

2. Data collection

3. Identification of casual factors

4. Identification of root causes

The above four stages constitute the research process and all results and analysis will lead to step 5

stated below

5. Recommend and implement solutions

All stages of this framework are important as they are reliant on each other. It would be difficulty to find

the solution and implement strategies without first knowing the root cause of the problem.

3.4 Research site and case study buildings In this research, four low rise buildings of between 2-4 storeys were selected in the vicinity of these two major freeways as in Figure 2. The buildings are described below, each with its façade, as follows

materials used on walls,

Research Method

Data collection methods

Results and Conclusion

Final Analysis

Qualitative Methods

Boroondara residents feedback

Buildings analysis

Quantitative methods

Noise levels data

VicRoads data 2 Loud? results

EPA noise levels

Qualitative

deductions

and

analysis

Statistical

analysis

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the approximate percentage of glazing and

the estimated the noise attenuation capacity of the facades

Figure 2 shows location of case study buildings along major freeways (Adapted from GoogleMaps) The selected buildings were the following:

A. Corporate office block A, on Monash Freeway

B. Office Block B, along Monash Freeway

C. Office block C,near Eastern freeway

D. Corporate Business park office block D, Eastern Freeway

A

B

C D

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Figure 3, Corporate Business park office block A, near Monash Freeway

This office building named A was constructed on concrete foundation and steel reinforced columns with underneath car park. The wall consists of 100% single glazing on the North side which faces the Monash Freeway and also the Southern side as shown in Figure 3. The Glazing is made up of single glazing 10mm thick tinted glass and the rest of the walls are constructed from pre-cast concrete walls. The outdoor noise level according to VicRoads was 55-63dB.

Figure 4 Office building B, near Monash Freeway

A

B

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The building in Figure 4 has a concrete floor and double Vernier brick walls. An approximate calculation was that a wall to window ratio was 60:40. The windows are double glazed with dark tint. The outdoor noise range is from 55-63 dB

Figure 5 Office blocks C, near Eastern freeway

The office block in Figure 5 is a double storey building consisting of brick veneer walls. The wall to window percentage is approximately 40: 60%. The windows are single glazing, tinted and framed. The SPL (out) of this building as recorded by VicRoads was 55-63dB

C

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Figure 6 Office block D, near Eastern freeway

The corporate office block on Springvale near the Monash Freeway is a 3 floor office with concrete floors

also on built with double glazing as shown in Figure 6. The walling is 70% glass on the front façade while

the remainder consists of aluminum cladding. The back wall is made up of pre-cast concrete walls and

20% glazing. The Outdoor noise exposure level ranged from 55-63dB.

3.5 Discussion of research findings

The study of noise along the two Freeways indicate that there was significant higher than prescribed

Sound Pressure levels of noise that was emitted by traffic to the neighborhoods and corporate business

premises. According to AS/NZS 2107:2000, the recommended design sound levels in buildings near

roads is between 35-45dB. There was also identified that on the Monash Freeway that 78% of study cells

with more than 900 residents were exposed to sound pressure levels above those recommended by

WHO. The Eastern Freeway also had 87% exposed to levels higher than the recommended by WHO

which is 55dB for outdoor noise. The indoor noise for the Monash Freeway as stated by results from

2Loud? showed that were between 32.5db -44 dB with an average of 40.0dB. The highest SPL recorded

was 49.6dB in one study area near Richmond. On the Eastern Freeway, the indoor SPL recorded was

higher than that stipulated by the AS/ ANS standards of between 35-45 dB(A). The data showed noise

levels were from 41.3- 51.8 dB with an average of 47.8dB. In an isolated study area the highest recorded

was 63.2dB. The study showed an outcome of indoor SPL as 40dB and outdoor SPL of 57.1.The sound

attenuation elements of the facades of the offices ranged from single glass glazing and brick veneer to

aluminum.

3.6 Analysis of the results

The results showed that in the selected offices along Monash Freeway the occupants were being

exposed to higher than the recommended threshold of the noise indoor and outdoor pressure levels.

D

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Although the readings were from 10pm to 7am this does not affect the noise levels emitted during the day

from 7am to 10pm. The sound pressure levels recorded by the VicRoads and participants of the City of

Boroondara or COB, the recorded noise levels were between 53-63 dB. This means the day time SPLs

could be higher also for both Freeways and residents and office workers are being affected. The study

buildings in this research were based on 4 buildings chosen along the 2 Freeways.

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Chapter 4

Literature Review

4.1 Introduction

This Literature review explores the various concepts of noise, its causes and the effects according to

different researchers and acoustic professionals. Terms defining the nomenclature related to noise will be

explained so that a full understanding is achieved in the context of traffic noise and abatement in

buildings. The early view of noise as an annoyance is also discussed leading to a review of the view and

findings of other authors. In subsection 1, the noise sources from outside the building as viewed by

researchers and specialists in construction and building technology are discussed. Subsection 2 will delve

into noise from the inside as studied by practitioners and its effects on occupants. The effect of building

envelope design and material will also be investigated to find how it affects sound filtration, absorption or

transfer to occupants. Subsection 3 will deal with effects of noise from the perspective of other

researchers and specialists in acoustic control and also medical evidence. The last subsection will

explore some measures that have been used to solve noise issues in office buildings.

4.2 Noise and Sound pressure levels terms Noise is simply defined as unwanted sound. As stated before noise is measured in decibels or dBA (Lin Fritschi et al, 2011). Sound is what people hear. Noise has properties and measuring instruments to quantify it mainly by its amplitude and frequency. Amplitude is defined as the loudness measured in decibels (dB) Frequency is the pitch of the noise measured in hertz (Hz) The higher the pressure fluctuation of the noise, the louder it gets. That means there are more noise and the higher the frequency of pressure fluctuation, the higher the pitch. Sound Pressure level (Lp) is the sound pressure that has been converted on the decibel scale or Logarithmic scale. Sound Pressure level is measured in Pascal’s (Pa) and 0 decibels is regarded as the quietest to the human ear. The human being range of hearing is from 20 micro PA (2x10-5Pa) to 20Pa. Frischi and his colleagues then concluded that the human ear is designed to hear sound pressures and

frequencies up to certain levels since when any increase of 1dB will translate to higher sound pressure

levels and the ear cannot take anymore. Every increase of 3dB doubles the Sound pressure levels. It is

this explanation that brings the question what is then the effect and sources of such noises in buildings

and on humans. In support of this view, Stansfield (2003) indicated that there was much evidence of non-

auditory effects due to noise at levels of 85-90dBA if one is exposed over long periods. It seems the

human ear is vulnerable such that utmost care is a necessary requirement.

4.3 Early conception of noise

Noise is not a new phenomenon. Noise has been an annoying issue and a centre of complaints since the

early Roman times, states the Wakefield Acoustics in the Noise Control manual for Vancouver (Wakefield

Acoustics). This manual revealed that restrictions on movement in some parts of historical cities like

Rome were ordered in a bid to lower the effect of noise caused by passing wagons during the night. In

the USA, the arrival of motorized vehicles and machinery in New York in 1899 and the advent jet airlines

in Vancouver between 1960-70 all led to the influx of high noise levels, thus noise has had a negative

historical impact from time immemorial. CertainTeed, an organisation in acoustics confirmed that

historically the early Greek builders constructed amphitheaters with acoustical properties as early as 5BC.

Thus noise has been under scrutiny and a cause for concern and the above history shows humankind

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has been trying to quieten the environment while at the same time pushing mechanization and

technological advances. It is important to discuss its sources in the next subsection.

4.4 Sources of Noise This subsection will summarize the sources of noise in buildings. It is worthwhile to mention some instruments used to measure sound transmitted and sound received in buildings. A measuring instrument for the sound level is called the Sound level meter and in addition the following instruments can be used

Sound level meter

Sound data loggers

Noise monitors

Dosimeters

Octave analyzers Noise in the buildings emanate from external and internal sources Internal sources:

1. Building services that includes air conditioning systems (HVAC) and duct system, 2. photocopiers, 3. lifts, walking steps 4. Inter-tenancy noise 5. Speech 6. Boiler plant and pipes and valves

External noise sources

1. Traffic and pedestrians 2. Construction works 3. Trains 4. Aeroplanes 5. Wind and seismic loads

.

Figure 7 Noise levels and sources (Source: WorkSafe Victoria)

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4.4.1 Noise from outside sources

Noise that comes from outside the buildings has been identified as from man -made and also from the

natural. Several noise sources that impact on office environment include the following, aviation, traffic,

construction noise, wind, rain, seismic movements and also pedestrians. Fritschi and his colleagues

(1999) studied the sources of noise and stated that construction sites, traffic, pedestrians and airplanes

were major sources of noise in the city and overall across the landscape. Figure 3 Shows that the office

building require a threshold of 60dBA, whereby external noise from traffic near the buildings emit sound

pressure levels of 80-90dB and city construction works emits 90-100dB. In a grave matter in1998, the

noise issue along the two major freeways, that is the Monash and Eastern Freeways a group of residents

formed the Eastern Freeway Noise Abatement pressure group to force VicRoads to install noise barriers.

Their evidence was the high level of noise that was being caused by traffic especially by the application of

air brakes. (Leao, 2013)

Figure 8 Common sound pressure levels in dB (A) (Source: Dept. of Environment and Heritage

protection, Queensland).

As noise is emitted, its characteristics need to be studied (Queensland Government, 2013). The noise

characteristics include tone, sound pressure levels, sound pressure, time, frequency and duration. While

the Queensland government state the characteristics of the noise needs to be measured, Nassiri, et

al.(2013) in addition to the characteristics included meteorological conditions during measurement such

as wind pressure, precipitation, relative humidity, temperature and distance from noise sources. It is the

correct measurement of sound levels that determines the reality and thereby assists in deriving the best

corrective action for noise abatement.

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4.4.2 Noise sources from inside the building

Noise also is emitted from within the building. The Association of Australian Acoustics Consultants

(AAAC, 2011), VicRoads (2011), EPA (2014) all produced their own significant reports stating the sources

of noise in a building. These sources were primarily identified as follows, noise from inter-tenancy,

building services. In addition to that noise sources may also come from photocopiers, floor tapping and

from doors and windows. InspectAdia (2015), Maxwell and Xu et al (2014) listed HVAC as the main

source of internal noise source. The view seemed to emanate from the fact that HVAC systems were the

one of the biggest plants in the buildings. Structural and air-borne noise due vibration did not receive

much mention except by Zhou and Zhao (2014) who extended their stud to include vibration from

construction equipment and trains. In further information review, it was found that structural related noise

included, footsteps, noise from lifts, appliances, water hammer and interpersonal speech. The latter two,

interpersonal speech and footsteps would pose a problem to eliminate since they depended on personal

characters and etiquette. Internal and external noise transmission is also determined by the building

internal structures and the contents of the building. It is therefore necessary to discuss the Sound

Transmission index (Rw) or ability of materials to reduce noise in the following sub-section.

4.5 Sound Reduction index of construction material or walls

Sound enters buildings through different methods. Walls, windows, doors and roofs all constitute medium of noise passages. The Australian Building Codes Board identified ways to increase the sound insulation performance of the building elements. The Board cited the increase of surface material, additional skins of material and the use of deeper cavities in walls. In addition to increasing the material thickness, Sound absorption, Noise reduction coefficient (NRC) can also be used in upgrading material density and the absorption performance. Material such as glass wool, rock wool, polyester, and sheep wool and cellulose fibre have high sound absorption capacity and thus can be useful in reducing noise. Straube and Van Straaten (2002) found out that the use of double glazing or triple glazing offered more sound insulation of buildings. These double facades as they called them not only reduced sound ingress but also improved daylighting, thermal comfort and also natural ventilation. Structure borne sound reduction As stated earlier on noise enters the building through the structure. Trucks, buses and even trains will not only cause noise in buildings but will add vibration too. The primary solution for vibration as stated by Humphrey (2007) was isolation of the vibration in the system. The BCA Guidelines state the procedure and standards for vibration control. Some measures include the use air gaps between panels and floors, use of materials such as rubber, springs and shock dampers. 4.6 Building envelope and construction techniques

Walls in buildings are critical in the control of sound transmission. The British Standards Institution (BSI,

2014) on building sound insulation recommended the use heavy insulation by mass to reduce noise

ingress. The institution however discouraged foam insulation and recommended that when foams are

used brick layers would need to be added. In view of this it can be argued that sound transmission

control can be two fold that is by insulation the walls, roofs and floors and secondly by deflecting the

sound away from walls rather than targeting one element only. The Building Code of Australia Board

(2004) concurs with this approach in collaboration with the AAAC pointing out that sound transmission is

a factor of material insulation capabilities and can be reduced by absorption and material modifications of

building elements (ABCA, 2004,Chapt. 3.14)

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4.7 Physiological and psychological Effects of noise to occupants

Noise has harmful long-lasting effects on workers in an environment. Cheremisnoff (1977) described

noise in two types that included the type of sounds and the exposure time. He stated that there were two

types of noises, the intermittent and continuous noise. The most dangerous noise was the continuous

noise which for example would be harmful at 6hrs continuous exposure at 100Decibels. Cheremisinoff

further added that noise caused no auditory and auditory effects on workers. The two groups of effects

will be discussed below in the context of the office environment

4.7.1 Psychological and non-auditory effects

There has been substantive evidence of the effects of noise in office buildings recorded. Maxwell (n.d.)

cited lowered work morale, job satisfaction and stress as common indicators of effects of noise in office

workplaces without mentioning the age of the building and location including sound pressure levels. This

sub-section will examine the negative impacts of noise. Jansen and Gros (1986) made a finding on the

literature that suggested that accepted noise levels differed from task to task and with respective work

environment. I n German the stipulated noise ranking according to (Guideline No 205S Part 3 1981)

55 decibels for office work that requires planning and intelligent decision making

70 decibels for uncomplicated and mechanized office work or factory work

85 decibels for all other work activities

Stress

Job satisfaction and morale

Attitude ( negative emotion) and anxiety

Annoyance and nuisance

Prolonged reaction time and lack of concentration

Distraction and slowness of mental processing

Increase in risk taking

Increase of errors

Decrease in volume, speed and quantity

It can be concluded that the physical effects can be subjective to individuals depending on their personal

and physical bearing. According Jansen and Klosterkotter (1980) some people are less sensitive to noise,

and may not be disturbed by noise while others are motivated by sense of achievement. However the

research by Cheremisinoff (1977), ACCC, (2013), Jansen and Gros, (1986) showed that noise had a

knock-out effect on health and psychological bearing leading decreased productivity.

4.7.2 Physiological and auditory effects

The responses to sound in a human being takes place at lower than 20dBA according to ACCC (2011).

This means any little increment in sound pressure levels will cause a reaction in a person as Jansen and

Gros (1986) stated in their study of noise pollution. In detail the trio stated that an uncharacteristic noise

tended to cause eye pupils to dilate as a basic reaction. Further indicators by the same researchers found

out that there was reaction to salivary glands, blood circulation rate, respiratory glands, gastro- intestinal

movements in response to noise. These are only the responses to noise without considering the ensuring

21

outcome or end resulting disease. The resultant effect is therefore development of conditions that link low

blood supply due to vasco- constriction and ultimately to high palpitation and high blood pressure.

Tinnitus or ringing of the ears has been pointed out as a disease caused by noise in the widespread

working community (WHO, 2013: Jansen and Gros, 1986). With the ringing of noise in a working

environment one is sure to lose the apprehension speech intelligence and lead to poor communication

altogether. One cannot carry orders properly thus resulting loss of productivity, effectiveness and even

self-esteem.

The most critical of the effects of noise was its impact called Noise Induced Hearing loss (NIHL).

According to Nelson et al (2005) and Moela (2010). NIHL is responsible for 16% 0f hearing loss in adults

which translate to 4Million people on the Disability adjusted life years since the people got affected by

hearing impairment. THE Study further stated the percentage varied from World Health Organisation

(WHO) regions at the rate of 7-21%. NIHL is a permanent disability stated the Australian Safety and

Compensation council (Sparnon & Machotka, 2007) stated that in Australia NIHL comprised of 19% of

total claims in compensation but only 3.2% of injuries and diseases claims in 2006.

These results suggest that noise is a passive killer often showing up later when the damage is no longer

reversible. Other noted effects of noise have been stated as loss of symmetry in those affected. The

monetary loss/compensation for hearing loss in 200/01 period was $30 million and as the population

increased the figure is now higher (Sparnon & Machokta). There has to be means to arrest this situation

as more workers in offices are being affected.

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Chapter 5

Recommendations and Solutions

5.1 Introduction

The desire to reduce noise ingress and its effects in office buildings require systematic approach in

eliminating the real and not perceived causes. This chapter focuses on the methodological way of

problem solving in the first subsection and will explain the application the Actively Maintain, Modify and

Retrofit plan or AMMR strategy this author devised to attenuate noise in existing buildings. The next

subsection will concentrate on the recommended customized solutions to each of the four study buildings.

The solutions offered cannot be regarded as exhaustive but can be improved especially using the method

of continuous improvement.

5.2 Problem identification method: The Fishikawa method

The abatement of noise in office buildings can be tackled using the problem solving methods such as

Root cause analysis, Fault Tree analysis and the Fishbone or Fishikawa method. The first step was to

establishing the fact that there is noise, and higher than normal sound pressure levels. The Fishikawa can

be used to show the fault cause effect system of the noise and sound pressure with aid of measuring

instruments such as sound meters.

Figure 9 shows the Fishbone problem finding method of noise sources

Noise & High SPLs

Office equipment Building services,

printers

Traffic, Aviation

noise,

Construction

machinery

Wind,

thunder, rain

Outdoor noise

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Figure 5 shows the building elements which are also sources of noise and other outside sources such as traffic and machinery at construction sites. Maxwell (n.d.) and Cheremisinoff (1977) indicated that noise control could be controlled by the three interactive systems that is the receiver of the noise, the noise source and the transmission media as shown in Figure 6. In this study the concern was concentrated on managing the effect of traffic noise into office buildings without taking into consideration the noise generated indoors by building services, office equipment and other accessories. Outdoor noise enter the building through the following unrated elements, walls, ceilings, doors, floors, windows and even the roofs

Figure 10 Traffic noise levels and the indoor weighted range

Figure 10 shows the systematic lay out of the noise generated by traffic from the freeway. From the Literature review the results of excessive Sound pressure levels were found to be above those recommended by the World Health Organisation and AS/NZS 2107/2000 on the working areas. This means the noise levels are a violation of standards and legal laws thus corrective actions would need to be implemented to align the acoustic character of the building to the acceptable standards. According to Fishbone method it can be seen that noise sources range from traffic, aviation, construction noise, building services and even some office equipment. Through analysis of traffic noise as a single source of noise, it can be deduced that there is some passages that allows noise to enter the buildings. Figure 6 explains the noise transmission system where the source has been identified as the traffic. Before the noise gets to the receiver it has to pass through the transmitter or media. In the case of office buildings or dwellings the media is the building envelope, i.e. façade, glazing, walls, insulation and roofing. Thus the media or building envelope plays a critical role in noise absorption, reflection or transmission.

Traffic Noise

53- 63db Indoor noise

32.5-44.3 dB

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Application of the Active Maintain, Modify and Retrofit Plan (AMMR)

Figure 11 shows the noise transmittance system

Thus from Figure 6 it is advisable that building managers, architects and space planners identify the noise sources and use methods to eliminate, isolate or muffle the noise. Noise levels in the offices should be at a stipulated 35-45dBA according to AAAC and WorkSafe Victoria. The Building Codes Australia supports the design of offices with their agreed engineering standards according to AS/ NZS Standards. Building managers (BM) or Facility managers (FM) control what they can. Since it is not the responsibility of building owners managers to control traffic noise, their focus should be diverted to controlling weighted noise through the building envelope and leave traffic noise to VicRoads and EPA The managers and owners also cannot control noise from outside sources like aviation, seismic or wind noise but can control the transmitted noise and noise at the receiving end i.e. human ears. The only noise sources that can be controlled are that of building services equipment and office equipment which under their direct responsibility. 5.3 Strategies for noise attenuation

This subsection discusses the remedies that may be applicable to office buildings in an effort to reduce or eliminate noise. Several researchers, regulatory bodies and construction councils have come up with solutions that have managed to attenuate noise to improve productivity and health targeted at specific buildings. After implementing some solutions the problem often surfaces again in a different form and still torments building owners, occupants and even building managers. The strategy involves managing the noise in the three dimensional system, that is Source, Transmitting medium and the Receiver. As cited by Zhou and Zhao (2014) suitable building material plays a major role for sound pressure level management and design. The trio recommended that removal of noise sources was better than preventing noise ingress to receptors. The following analysis of the building elements below discusses possible solutions to noise attenuation 5.4 Glazing

Glazing present aesthetic image of a building but it is important to maintain the effectiveness of keeping away noise and other building environmental problems such as lack of natural sunlight structural strength of the building. In all classes of windows and glazing whether double or single glazing it is recommended that seals be used in conjunction with wooden window frame as these decrease the ingress of noise into the building.

Receiver

Transmitter

Source

Apply the

Actively

Maintain, Modify

and Retrofit rule

(AMMR)

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5.5 Insulation

Sound absorbing materials can significantly reduce noise in office buildings. The use of plasterboard and mineral wool has a combined Sound Reduction Index of 30-40 dBA. Insulation also plays a role in thermal comfort and damping of vibrations in buildings. 5.6 Walls Brick walls can deflect and also absorb noise. Clay bricks have a sound reduction index 45 dB if used as single lines. The brick wall increases their effectiveness if a cavity of 50mm to an Rw of 46dB. Wooden walls also have sound insulation capabilities. Other materials used for walls are fibreglass, concrete blocks and gypsum wall boards. It is also recommended that acoustic seals be fitted on the outside walls as well as in the inside joints where the floor and ceiling meets the wall. It should be remembered that heavy or thicker walls are good for acoustic insulation but cost effectiveness will need to be given consideration.

Figure 12 Typical acoustic wall insulation (Source: Kolářová, Zuzana; Kalousek, Lubor.2014)

The Actively Maintain Modify and Retrofit (AMMR) Model This model works on the premise that an existing building has had problems with noise levels that continue have productivity and health effects on the occupants

26

Figure 13 the AMMR plan 5.7 The recommendations for noise level reduction strategy for the case study buildings

These recommendations have been given in the context of the model of the AMMR Model and as the acronym suggests they are subject to continuous improvement and modification. In order to reduce the ingress of noise, it is required to inspect the buildings and check its compliance with the Building Codes of Australia reference on Sound Insulation on Class 5 buildings and also the Part J2 External Glazing. The economic factors have not been included due to the limitation of the scope of this research.

Noise

External & internal Sources

Walls, windows, doors, enclosures, floors, ceilings

HVAC/ Boilers, Fans, Lifts, seals, cooling towers, vibration,

motors, printers, plumbing, ducting

Inter-office

noise, speech

privacy

If ok

If failed

Retrofit Modify Maintain

If failed If noise continues

Yes continue to

maintain

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Table 3 Sound insulation capabilities of glazing (Source: Adelaide City Council, n.d.)

Noise reduction

Single pane non sealed window 6mm thick Rw (15-20) Not very good

Single glazing with acoustic seal 6-10mm thick Rw (30-33) good

Single laminated with acoustic seal 7-11mm thick Rw (33-36) Better

Double glazed 6mm with 50-100mm air gap Rw (40-45) Best for traffic noise

Secondary glazing 6.38-13mm with 50-100mm air gap

Rw (40-47) Best for low frequency and truck noise

Table 4 Sound pressure levels and their effects on performance

Sound level in dBA Effects

More than 100 Substantial decrease in performance

85-100 Increased probability of decreased performance: Compensation more difficulty

70-85 Increased decrease of performance with strong need for achievement: turnaround possible

70- below Substantial and lasting decrease in performance infrequent

5.7.1 Corporate office block A, near the Monash Freeway

In this building, the first point of action is to check the glazing since the façade is almost 100% glazing on the side facing the Freeway. It is recommended to use double glazing windows or laminated panes with tint to avoid cracking brought about by possible metrological conditions and vibration. The next issue is to check the window or glazing seals. Broken seals allow noise ingress. To reduce inter-room noise it is also recommended to use plaster board walling and soundproofing material such as glass wool or Rockwool. It is recommended to continue to test the noise ingress level after fitting double glazing panes and new sealing for the purposes of maintenance and continuous improvement. In this way the sound pressure levels can be brought to WHO levels and AS/ ANZ standards. 5.7.2 Office block B, along Monash Freeway

This building can have the impact of noise reduced through retrofitting of new windows with double 6mm glazing. The windows may be fitted with wooden frames to insulate against noise. The inside of the external walls require noise barrier boards or plasterboard with Glass wool or Rock wool insulation. Continuous inspection and maintenance is also a requirement to make sure sound pressure levels remain in the recommended range. 5.7.3 Office block C, near Eastern freeway

This building is another structure with outer walls made of clay brick. To reduce the impact of noise it is required that windows be fitted with double glazing with or without air pockets. Seals may need to be

28

fitted or if they are not, then sound rated seals can work in shutting out noise. Floors can be fitted with cellulose or natural wall insulation to dampen indoor sound pressure. 5.7.4 Corporate Business park office block D, Eastern Freeway

This building requires double glazing with acoustic seals. Since the building is glazed on the 3 sides and has concrete walls on the remainder side there is a high possibility of noise entering it from the glazed sides. Thus to control noise ingress internal partitioning using insulated timber frames with Rockwool and natural wool would reduce sound pressure levels from the inside and increase speech clarity altogether. It is also critical to seal other noise paths like the revolving doors frames to reduce noise. 5.8 Conclusion of recommendations

Noise attenuation n building is possible with first identifying the real cause, building defects and other areas of the building elements that might be the source of noise. Through the use of the Active Maintain, Modify and Retrofit plan (AMMR), a building has its acoustic performance regenerated to high performance to meet National Australian Built Environment Rating Scheme (NABERS). The Green star (Green Building Council of Australia) rating, as design tool can be used to manage retrofits that will increase acoustic comfort in the buildings. In analysis of the solutions, it was recommended that buildings office blocks B and C which have brick veneer envelopes should undergo retrofits on glazing and internal wall insulation to attenuate noise. An addition of plastering or rendering would also increase the sound reduction index of the walls. Blocks A and D which have higher percentage of window glazing walls would benefit noise reduction through double glazing and fitting rated seals to the windows and doors. It was also recommended that regular preventive maintenance and continuous improvement strategies be implemented in order that the buildings indoor environmental performance to be maintained.

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6. Conclusion

This research investigated the effects of noise on the productivity and health of office workers. Noise is still rated as one of the most significant environmental problems and a continuing threat to the comfort and health of people. The effect of noise in office workers was found to be evident in the negative change to their physiological and psychological well-being. A literature review was carried out identifying current and past trends of noise and effect on health productivity in the office setting. The World Health Organisation (2011) and Australian Safety and Compensation Council or ASCC (Sparnon and Machotka, 2006) reported major findings in the permanent loss of hearing. Also recorded by the ASCC was that office workers also suffered from hypertension, tinnitus, low morale, absenteeism high stress levels among other physiological conditions The methodology for acquiring the information was based on a Deakin project that had researched on the development of smart phone app to record indoor noise in residencies along the Monash and the Eastern Freeways. The survey results indicated that outdoor noise was between 53-63 dB and indoor noise was 32.5- 44dB on both freeways. The indoor sound pressure levels were found to be way higher than those recommended by the World Health Organisation (WHO) and AS/ANZS 2107/2000 and also British Standards 8233/2014 stipulates that executive office rooms should have a noise level of between 35-40dBA. In this research four office buildings named A, B, C and D each along was selected for a case study. The results showed that the office occupants were likely to be affected by traffic noise from the freeways according to VicRoads noise data and the Deakin project, 2 Loud? (2013) Solutions to abate the effects of noise centred on establishment of the root cause of the noise. This would be followed by determining the necessity of the following strategies of modification, maintenance and retrofit of the façades and the building envelope, hence the introduction of the AMMR plan by this author. Noise attenuation tasks ranged from increasing insulation on the walls, fitting double glazed windows, seals on doors and windows and using good sound insulating partitioning material. It was also recommended to use cost effective methods in sound level attenuation in the quest to improve acoustic comfort. Noise, if it is well organized, it is music to the ears but it can also be an annoyance and a health problem as the threshold gets higher, disorganized and unintended to the listener.

30

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