ENVIRONMENTAL CONTROL

ACOUSTICS AND NOISE CONTROL (ARC 507)

AN ANALYSIS

ON

OUTDOOR ACOUSTIC STANDARDS

BY

GBADE PRAISE OLUWATOSIN (ARC/09/7382)

FALODUN SEYI LOVE (ARC/09/7380)

COURSE LECTURER:

PROFESSOR OLU OLA OGUNSOTE

THE DEPARTMENT OF ARCHITECTURE

SCHOOL OF ENVIRONMENTAL TECHNOLOGY

FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE,

ONDO STATE, NIGERIA

JULY, 2014

P a g e | 2

TABLE OF CONTENTS

ABSTRACT……………………………………………………….………………………………3

1.0 INTRODUCTION ………………………………………..………………………………3

2.0 OUTDOOR ACOUSTICS STANDARDS ………………………………………...……...4

2.1 INTRODUCTION…………………………………………………………………....4

2.2 HISTORY………………………………………….………………………………....4

2.3 OUTDOOR ACOUSTIC CODE …………………………………………………… 5

2.4 TYPES OF OUTDOOR ACOUSTICS …………………………………………..… 6

3.0. UNDERSTANDING OUTDOOR NOISE SOURCES ………...…………………………...6

4.0. INSTRUMENT USED IN MEASURING SOUND LEVEL …………...………………..…7

5.0 HEALTH EFFECTS OF OUTDOOR ACOUSTIC …………..……………………………..8

6.0 CASE STUDIES CONDUCTED …………………………………………….………..9

6.1 CHICKEN REPUBLIC ……………………………………………………………9

BRIEF DESCRIPTION

OUTDOOR SOURCES OF NOISE

EXISTING OUTDOOR ACOUSTICS SITUATION

6.2 POST GRADUATE STUDENT HOSTEL ………………….…………………..10

BRIEF DESCRIPTION

OUTDOOR SOURCES OF NOISE

EXISTING OUTDOOR ACOUSTICS SITUATION

7.0 EXTERNAL NOISE CONTROL (HOW TO CONTROL OUTDOOR NOISE)………11

8.0 CONCLUSION …………………………………………………………………………14

9.0 REFERENCES ………………………………………………………………………...14

P a g e | 3

ABSTRACT

Whether it’s a passing train, a rumbling air-handling unit, or a coworker’s takeout order,

unwanted sounds can disrupt work and learning; persistent noise can even affect our health. In

schools and conference rooms, poor acoustics prevent people from hearing teachers and

presenters. Space comfort is really a combination of factors that includes day

lighting and electric lighting, indoor environmental quality, temperature, and acoustics. The

assault on ears in the space can come from traffic noise outside, mechanical equipment in

adjacent spaces, and copiers, phones, and voices within the workspace.

The acoustical environment is a very typically given little or no attention during project planning

and design. The functionality and aesthetics are usually the primary focus of the designer. Too

often overlooked, are the factors contributing to the productivity of human activities occupying

the a particular space. Providing a comfortable environment for humans contributes significantly

to their optimum performance and reduced absenteeism. Design strategies can optimize acoustic

performance, and acoustical materials can provide further enhancements which are indoors and

outdoors

P a g e | 4

1.0 INTRODUCTION

Acoustics is known to be the science of sound. Noise is the unwanted sound of any

environment. Acoustics deals with, the indoor acoustics and outdoor acoustics control of noise.

This is an interdisciplinary science that deals with the study of all mechanical waves in gases,

liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works

in the field of acoustics is an acoustician while someone who works in the field of acoustic

technology may be called an acoustical engineer. The application of acoustics is present in

almost all aspects of modern society with the most obvious being the audio and noise control

industries.

Architectural acoustics (also known as acoustics and building acoustics) is the science and

engineering of achieving a good sound within a building and is a branch of acoustical

engineering. Acoustical architectural design incorporates noise reducing concepts in the details

of individual buildings. The areas of architectural concern include building height, room

arrangement, window placement, and balcony and courtyard design.

Hearing is vital for the location of sounds it may be warn of danger, the enjoyment of pleasant

sounds such as music and the natural environment. It also plays and important part for most

importantly for humans, the development of speech and language for communication.is one of

the most important of the human senses.

Acoustic generally has no bounds it spreads throughout field helps in the identification of

different noise levels in different environment it is considered to determine the need for essential

precaution of how it affects human and the environment on a wide scale of just fairness.

Sound and noise analysis are for both indoors and outdoors likewise for proposed architectural

designs and urban designs like the Simulated for concert hall acoustics.

2.0 OUTDOOR ACOUSTIC STANDARDS

2.1 Introduction

Outdoor acoustic standards are the many forms to which they may be opportunities to

meet project sustainability goals in conjunction with good acoustical design if they are

considered early in the project development phase. For example, a reinforced concrete wall may

be recommended as a passive solar design strategy. If the building is located next to a busy

highway or railway, that wall could provide the necessary sound transmission reduction to

achieve an acceptable indoor acoustical environment. For projects having security requirements,

that same wall could serve to mitigate blast. The key is getting the acoustical, security and

sustainability consultants involved at project conception and use the integrated design

process throughout the project.

P a g e | 5

Outdoor acoustics can be tested but tests for transmission loss at lower frequencies typical of

traffic noise recommended for l roofs and walls may range from 30 to 56, depending on outdoor

noise levels. Most of the effect of outdoor acoustics standards which are not been put in place

before the construction of a building.

Acoustical products like ceiling tiles, insulation, and carpeting, among others can help

meet the project's sustainability goals since many of them are recyclable or are manufactured

from recycled content. Ceiling tile and carpet tile manufacturers 'take back' their products that

are damaged or at end-of-life. These programs are helping to eliminate the huge amounts of

carpet and ceiling tile that used to end up in landfills.

2.2 HISTORY OF OUTDOOR ACOUSTIC STANDARDS

The first application of modern scientific methods to architectural acoustics was carried out

by Wallace sabine in the fogg museum lecture room who then applied his new found knowledge

to the design of symphony hall, Boston. Architectural acoustic can be about achieving good

speech intelligibility in a theatre, restaurant or railway station, enhancing the quality of music in

a concert hall or recording studio, or suppressing noise to make offices and homes more

productive and pleasant places to work and live in. Architectural Acoustic design is usually done

by acoustic consultants.

2.3 OUTDOOR ACOUSTICS BUILDING CODES

This federal agency mandates that each state is responsible for enforcing this standard or a

similar standard. The standard can vary from state to state, depending upon the individual

circumstances and various interpretations of the terminology. Most outdoor acoustic standard

have been laid by each country so as to Regulations were

health, safety, welfare of people within and around buildings

conservation of fuel and power

Achievement of sustainable development.

In July 2003, the regulation authorities tightened the standards of sound insulation for both

separating walls and floors, and internal walls and floors for all residential buildings. The aim of

the standards is to improve the acoustic environment by reducing noise transmission between

and within all residential dwellings. In July 2003, Approved Document E introduced five key

differences to the previous legislation: if any inspection agencies actually check the quality of

construction from a sound isolation perspective and too few building contractors are really

conversant with good noise control construction techniques. The lack of a few pennies worth of

caulking compound can reduce the sound performance of a 60dB (A) rated wall to less than the

minimum of 45 dB (A) required by the building code. No matter what the cause, they can all be

sealed to insure an airtight barrier thereby maximizing the acoustical performance of the wall.

P a g e | 6

2.4 TYPE OF OUTDOOR NOISE

The level of unwanted noise has to been determined. The different levels of noise are being

accepted into different area, situation and buildings.

Also the type of areas and their acceptable noise levels in outdoor acoustics standard

Types of area Acceptable Noise level dB (A)

Rural residential 35-45

Sub-urban residential 45-55

Urban residential 45-55

Urban residential with work- shop, business or

main roads

50-60

City centre (business trade, administration) 55-65

Heavy industry 60-70

The different types of noise producing sources are;

Road traffic

Railways

Aircraft

Industry

Office machines

People

3.0 UNDERSTANDING OUTDOOR NOISE SOURCES

Noise is an unwanted sound and for it to be properly addressed there has to be an understanding

of the types of indoor and outdoor noise sources. SOURCE, PATH AND RECEIVER are the

three components that must be present for noise to exist, in which the outdoor sources of noise

will be discussed here.

A sound here has to be created by a means in which the sounds then travel along a path as to

reach the receiver on the other end. In outdoor acoustics, sound are the known by the levels in

which they affect the area possible so as to help in the finding a solution. The path moves in

different angle. It basically comes from the sources of the sound created. That is, without the

sound, the path will not be created.

P a g e | 7

Common External sources of noise and their respective Noise levels are given in the table below

Common outdoor activities Noise level dB(A)

Jett fly at 10.00 ft 110

Gas lawn mower at 3 ft 100

Diesel truck at 5 ft at 50mph 80

Noisy urban area, daytime Gas lawn mower at

100ft commercial area

70

Heavy traffic at 300ft 60

Quiet urban day time 50

Quiet urban night time 40

4.0 INSTRUMENT USED TO OUTDOOR ACOUSTIC STANDARDS

Sound level meters come in various shapes and forms, but they have common points.

They tend to have a pointy bit at the top to stop the sound reflecting back at the microphone.

Some lower cost sound level meters, do not have a pointed top but instead have the microphone

on an extension to get it away from the case, again to reduce reflection. This method is used to

keep the case design cost down.

HOW A SOUND LEVEL METER WORKS

SOUND LEVEL METER

P a g e | 8

5.0 HEALTH EFFECTS OF OUTDOOR ACOUSTIC NOISE

Outdoor acoustic has an effect on health due to the different levels of sound from different

angles. There are different types of ways outdoor acoustics noise affects us.

Hearing loss- Exposure to high levels of noise have differing effects within a given

population, and the involvement of reactive oxygen species suggests possible avenues to treat or

prevent damage to hearing and related cellular structures. The elevated sound levels cause

trauma to cochlear structure in the inner ear, which gives rise to irreversible hearing loss. A very

loud sound in a particular frequency range can damage the cochlea’s hair cells that respond to

that range, thereby reducing the ear’s ability to hear those frequencies in the future. However,

loud noise in any frequency range has deleterious effects across the entire range of human

hearing.

Cardiovascular effects- Noise has been associated with important cardiovascular health

problems. In 1999, the World Health Organization concluded that the available evidence

suggested a weak correlation between long-term noise exposure above 67-70 dB(A) and

hypertension. More recent studies have suggested that noise levels of 50 dB(A) at night may also

increase the risk of myocardial infarction by chronically elevating cortisol production. Fairly

typical roadway noise levels are sufficient to constrict arterial blood flow and lead to elevated

blood pressure; in this case, it appears that a certain fraction of the population is more susceptible

to vasoconstriction. This may result because annoyance from the sound causes elevated

adrenaline levels trigger a narrowing of the blood vessels (vasoconstriction), or independently

through medical stress reactions. Other effects of high noise levels are increased frequency of

headaches, fatigue, stomach ulcers, and vertigo.

Annoyance-is defined as the subjective impression of the unwanted sound. Because some

stressful effects depend on qualities of the sound other than its absolute decibel value, the

annoyance associated with sound may need to be considered in regard to health effects. Even

sound levels as low as 40 dB(A)- about as loud as a refrigerator or library can generate noise

complaints and the lower threshold for noise producing sleep disturbance is 45 dB(A) or lower.

Child physical development- There is ample evidence that environment has a role in shaping

the physique, behavior, and function of animals including man, from conception and not merely

from birth. The fetus is capable of perceiving sounds and responding to them by motor activity

and cardiac rate change”. The effects of noise are highest when it occurs between 15-60 days

after conception, a period in which major internal organs and the central nervous system are

formed.

Cognitive development- When young children are regularly exposed to levels of noise that

interfere with speech, they may develop speech or reading difficulties, because auditory

processing functions are compromised

P a g e | 9

6.0 CASE STUDY CONDUCTED ON OUTDOOR ACOUSTICS SOUND

A case study was conducted on the difference between a residential and a commercial outdoor

acoustic standard of different area. Case studies conducted on outdoor acoustic standard where

chicken republic (commercial building) and post graduate student hostel (residential building)

CHICKEN REPUBLIC (COMMERCIAL BUILDING)

Brief description- This is an eatery located along the major road beside FUTA Road. This is

located close to a Highway road to facilitate easy access by people (customers) travelling,

living around or passing by and their vehicles so that this will generate revenue to the owner

due to its good location for business.

Outdoor Sources of Noise- These are Road traffic noise, noise from pedestrians as the

building is centered between roads and the noise from the generator. Although attempt was

made to reduce the noise from Road Traffics received by the building through the use of

shrubs and metal barriers, but these were made inefficient as the road and the top part of the

shrubs are almost at the same level, meaning the road and the lintel level are almost at the

same level. Ceramic tiles were used as wall covering material but there are large openings on

the wall reducing the effects of these acoustic wall material

Existing Outdoor acoustic situation- A study of the environment reveals that many features

were put in place to control acoustic problems of the environment as well as the building, but

these are not sufficient to reduce considerably the problems of acoustics. These features are:

the use of shrubs to absolve noise, the use of barrier (fence) and the use of ceramic tiles to

reflect and deflect sound rays. The level of the road is higher than the normal ground level of

the building. This commercial building is located closed to these major roads so as to achieve

its purpose for which it was found. Due to this setbacks have to be created so as to help in

controlling noise from road traffic and pedestrians.

Front view of the building

P a g e | 10

The use of shrubs to reduce outdoor noise. The T-junction of the roadway

POST GRADUATE STUDENTS HOSTEL (RESIDENTIAL BUILDING)

Brief description- This is a residential building (hostel) for post graduate students located

within Federal University of Technology, Akure at Obakekere, opposite Great hall. This

building was meant to enhance better living and reading environment for students.

Outdoor Sources of Noise- These are Road traffic noise and noise from pedestrians which

have been reduced to the minimum. Other sources of noise are: conversation at the

immediate Outdoor environment and wind noise- as this causes the surrounding trees to

generate noise.

Existing Outdoor acoustic situation- A study of the area reveals that proper plans were put

in place by considering features that could help in controlling acoustic problems of the

environment and the building. These features are: proper setbacks from the road to reduce

noise levels reaching the building, the normal ground level of the building is at higher level

compare to the road, the use of block wall as barrier (fence) and buffer zone created by the

forest trees beside the building.

The road leading to the post graduate

building

P a g e | 11

The front view of the building . The use

of fences has been use to deflect the noise

from the road

7.0 EXTERNAL NOISE CONTROL (HOW TO CONTROL OUTDOOR NOISE)

Many of the problems could have been prevented in the first place had a little more

attention been paid to noise control during the design and construction process. After the fact,

when the noise problems are discovered, solutions can be very difficult and expensive to resolve

and in most cases there is no easy solution.

The primary purpose is to present easy way of estimating the minimum required sound

transmission loss (TL) from the outdoor noise to the most common sources of exterior

environmental noise: aircraft, highway traffic and rail transportation. These are devised to

enable the architect to explore glazing options early in project development. The need for this

planning tool is great and ever-increasing due to more extensive use of land areas close to

airports, highways and rail transportation lines. This, coupled with greater building owner/user

expectations for noise control and wider use of lightweight, lower-cost building materials, has

heightened the importance of exterior environmental noise considerations.

Before you commence this type of remediation it might be advisable to employ the services of an

acoustical engineer who can take sound measurements with specialized sound equipment, which

by probing can detect weak links or pathways of the noise. But the Methods in which it can be

controlled are

Screening -This is most commonly used in controlling traffic noise, as in the case of a highway

passing near a housing estate. The screen can be made from wall, hedges or other barriers.

Landscaping plays an important role in the choice of screens. This is most efficient when the

screen is placed nearest to the source.

P a g e | 12

.

Wall barriers may reflect sound from one side of

the highway to the other

Cross section of a

berm

Planning- Increasing the distance between noise sources (especially Road Traffic noise) and

buildings will reduce noise level received to a considerable level. To protect the spaces in a

building from noise from a nearby highway or railway, lay out the building so that restrooms,

mechanical and electrical equipment rooms, and other less noise-sensitive spaces are adjacent to

the roadway. When designing a campus near high noise activity, locate gymnasiums and other

less noise-sensitive facilities closer to the noise source and place buildings needing quiet

surroundings in the shadow of those facilities.

As always, while siting for noise control, incorporate sustainable site planning into the decision-

making process.

It is more likely for a project to remain within budget if opportunities are sought to apply a single

design approach to achieve multiple design objectives.

Before a building is being constructed, proper planning on how to control external noise should

be taken into consideration. Site planning plays an important role in noise control. Increasing the

distance between noise sources (especially Road Traffic noise) and buildings will reduce noise

level received to a considerable level. Noise-sensitive buildings such as garages, workshops and

stores should be placed nearer the noise source.

P a g e | 13

Open space can be placed near

the highway to reduce noise

impacts on residences

Building design-This is another means of controlling External noise which requires that the

functional layout of buildings should place noisy zones such as living rooms, bathrooms and

kitchens nearer the noise source. While quiet areas such as Bedrooms be protected.

Insulation -The use of sound insulating materials in external walls and openings can reduce

outdoor noise received by a building. Increasing the thickness of wall, using Acoustic panels,

acoustic Glass or double glass and reducing the size of openings, where possible, improves

sound insulation. In recent years recycling old industrial buildings has become a very popular

means of providing high-rise loft type dwellings. Frequently the existing finishes of existing

concrete, brick or wood are left as the interior finish, supposedly to provide the “loft” type of

décor. Such designs require even more design attention if sound privacy is to be achieved.

Potential noise problems can be quite challenging so the buyer should insist that actual on-site

testing will validate the sound design performance criteria.

Finally, describe the nature of the sounds, when and where you can hear it. Is it impact noise or

airborne noise or a combination of both? When was the unit built and if possible what the nature

of the construction is. If the unit is of recent construction vintage, you may need to procure a set

of architectural drawings. The more information you can provide the closer you will come to

determining the nature of the problem and finding a solution. Beyond the lack of caulking

compound to seal obvious leaks, do not be deluded into thinking there are any easy fixes for

noise problems and anyone who tells you otherwise should be able to provide conclusive data

that their simple solutions will work satisfactorily.

P a g e | 14

8.0 CONCLUSION

Due to the complexity of acoustical and noise problems in buildings along with an

overwhelming variety of material designs and combinations, it is impossible to cover all

problems in a short article such as this. The most important, or controlling, sound paths must be

identified in order to know how to construct or modify a dwelling to meet a specified noise

criteria. The ideal sound insulation design would achieve a condition where all the important

sound paths transmit the same amount of acoustical energy. This eliminates any weak links in the

building’s insulation envelope and is commonly referred to as a “balanced acoustical design”.

9.0 Reference

En.m.wikipedia.or/wiki/Architectural_acoustics

Maekawa, Z., Rindel, J. H. and Lord, P. (1997). Environmental and Architectural

Acoustics. Spon Press, New York.

http://en.wikipedia.org/wiki/Category:Acoustics

Passchier-Vermeer W, Passchier WF (2000), “Noise exposure and public health”

Environ. Health perspect. 108 suppl 1:123-31

Callendar, J. H (1974). Time-Saver Standards for Architectural Design Data. McGraw-

Hill Book Company

http://www.industrialnoisecontrol.com/outdoor-noise-barriers.htm

http://www.acousticalsurfaces.com/soundproofing_tips/html/multi_familybuild.htm

Sabine, Wallace Clement (1922), collected papers on acoustics, Harvard University

Press.

Kryter, Karl D. (1994). The Handbook of hearing and the effects of noise: physiology,

psychology, and public health. Boston: Academic press

\