1. INTRODUCTION NOISE

2. WHAT IS EXPECTED FROM YOU ? At the end of 1 hours lecture
3.1 Introduction
i. Able to appreciate human response to different noise level.
i. Differentiate type of noise.
ii. Able to calculate noise dose(D).

3. IMPACT OF NOISE & LEGISLATION
3.1 Community response to noise
The community are disturbed by noise
Human is tolerable to certain level of noise but will react to a very loud noise
Public reaction
<40 dB – no reaction
45 dB – isolated complain
50-55 dB – Widespread complaints
60-65 dB – Public starts to take action
> 70 dB – Action by public

4. IMPACT OF NOISE & LEGISLATION
3.2 Types of sounds
Pattern of noise may be qualitatively described by one of the terms
Steady state or continuous
Continuous equivalent sound level
Intermittent
Impulse or impact
Continuous sound uninterrupted sound level that varies less than 5 dB during the period of observation
Continuous equivalent sound level is continuous sound for 8 hours and normally for working environment

5. IMPACT OF NOISE & LEGISLATION
Impulse or impact noise is a noise that becomes peak immediately in short duration of time
Example – noise from gun
Because of the short duration of the impulse, a special sound level meter must be employed to measure impulse noise
Intermittent sound is a continuous sound that persists for more than one second that is interrupted for more than one second
Example – dentist’s drilling

6. IMPACT OF NOISE & LEGISLATION
3.4 Noise Dose and exposure
Noise dose means the amount of noise a human is exposed to.
Human expose to noise is a problem
If exposed too long at a very high sound level, permanent hearing damage may occur
There are a few dose levels and the standard durations of noise exposure
All are related to disturbing risk and the associated health effects
Guidelines
The Planning Guidelines for Environmental Noise Limits and Control
The Guidelines for Noise Labeling and Emission Limits of outdoor Sources
The Planning Guidelines for Vibration Limits and Control

7. IMPACT OF NOISE & LEGISLATION
There is also noise dose standard for workers (D)
there are allowable exposure limits and durations for workers
The greater the sound the shorter the allowable exposure duration

8. IMPACT OF NOISE & LEGISLATION
Daily noise dose, D
Daily noise dose means a unit of measurement of sound level indicated by a sound level meter, when used for A weighted sound level at slow response
D = C1/T1 + C2/T2 + …..+ Cn/Tn
Where,
C1,C2,Cn = actual duration of exposure for an employee at the various noise levels (unit time)
T1,T2,Tn = Respective duration allowed limits obtained from First Schedule (unit time)
D = no units
The standard value of D is not to exceed 1. if D is greater than 1, the workers are not working in safe environment and control measures are necessary

9. P.U.(A) 1/89 FACTORIES AND MACHINERY (NOISE EXPOSURE) REGULATIONS 1989
FIRST SCHEDULE
(Regulation 5 (1)) Permissible Exposure Limits [Am. P.U.(A) 106/89]
Noise Level (dB (A)-slow) Duration of Exposure Permitted per day (hours-minute)

10. IMPACT OF NOISE & LEGISLATION
Example
A worker is working for 1 hour in a noisy environment of 90 dB(A) followed by a 2 hours in 92 dB(A) and 3 hours in 94 dB(A). The next 2 hours he works in a quiet control room. Does the worker comply with the Factories and Machinery (Noise Exposure) Regulations 1989,

11. IMPACT OF NOISE & LEGISLATION
Question
A worker is being exposed to the following noise levels
- 100 dB(A) for 30 minutes
- 85 dB(A) for 6 hour
- 89 dB(A) for 1 hour
Does the worker work in a safe noise level?

12. IMPACT OF NOISE & LEGISLATION
Legislation on noise differ from one country to the other
The basic principle remain the same – to control the noise emission – to safe guide our hearings from being damaged – to have a safe working environment
2 main legislation
- legislation for ambient air
- legislation for safe working environment
Ambient air
Environmental Quality (Motor Vehicle Noise) Regulations 1987 under Environmental Quality act 1974
Guidelines on the Noise Quality for Ambient Air
Working environment
Factories and Machinery (Noise Exposure) Regulations 1989

13. IMPACT OF NOISE & LEGISLATION
Factories and Machinery (Noise Exposure) regulations 1989
Part I – Preliminary
Part II – Permissible Exposure Limit
Part III – Exposure Monitoring
Part IV – Methods of Compliance
Part V – Hearing Protection devices
Part VI – Audiometric Testing Programme
Part VII – Employee Information and Training
Part VIII – Warning Signs
Part IX – Record Keeping
Part X - Miscellaneous