INTRODUCTION NOISE

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).

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

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

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

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

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

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

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) 85 16-0 86 13-56 87 12-8 88 10-34 89 9-11 90 8-0 91 6-58 92 6-4 93 5-17 94 4-36 95 4-0 96 3-29 97 3-2 98 2-50 99 2-15 100 2-0 101 1-44 102 1-31 103 1-19 104 1-9 105 1-0 106 0-52 107 0-46 108 0-40 109 0-34 110 0-30 111 0-26 112 0-23 113 0-20 114 0-17 115 0-15

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,

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?

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

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