occupational noise exposure and hearing conservation

Download Occupational Noise Exposure and Hearing Conservation

Post on 27-Jan-2017

2.695 views

Category:

Business

3 download

Embed Size (px)

TRANSCRIPT

Occupational Noise Measurement

Occupational and Environmental Noise Risk Identification and Assessment to Validate Controls and Hearing Conservation ProgramPresented by: Bernard L Fontaine, Jr., CIH, CSP, Managing Partner, The Windsor Consulting Group, Inc. 2013 by The Windsor Consulting Group, Inc. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of The Windsor Consulting Group, Inc.

Occupational Noise Exposure Course Learning Objectives

Participants will be able to:Describe the consequences to health and well being of excessive noise exposureUnderstand the measurement (including dosimetry) of noise in relation to current standardsConduct surveys in the workplace to assess risks from noiseCopyright 2013 The Windsor Consulting Group, Inc.

Occupational Noise Exposure Course Learning Objectives

Awareness of noise hazards in the workplace, at sporting events, and during recreational activity Direct and indirect effect of noise on peopleIdentification and assessment of noise risk Understanding of hearing and hearing lossInterpret data based on exposure standardsSelect possible noise control measures including hearing protectionCopyright 2013 The Windsor Consulting Group, Inc.

Occupational Noise ExposureTopics to be Discussed

Physical properties of sound and human effectRisk assessment and noise surveysAnalysis and interpretation of noise dataNoise controls engineering and administrativeEducation and training requirementsAudiometry and hearing disordersEnvironmental noise sources and effectCopyright 2013 The Windsor Consulting Group, Inc.

4

Occupational Noise ExposureWHAT THIS COURSE WILL NOT PROVIDE:

The course is not intended to provide the skills to become an acoustics expertSelect the proper engineering controls based on octave band analysisSpecific instruction on how to operate noise measurement equipment or perform audiometryComprehensive discussion on hearing protectors or audiometric determination

Copyright 2013 The Windsor Consulting Group, Inc.

5

Occupational Noise ExposureWHAT THIS COURSE WILL NOT PROVIDE:

Exposure information on super low, extremely low, and tremendously low frequency used in submarine and mine transmission or man-made noise

Exposure information on high, very high , super high, extremely high, and tremendously high frequency noise from radio and television broadcast, microwave or wave scanners, satellite communications, radio astronomy, ultrafast molecular dynamics, condensed matter physics or amateur radio noise

Copyright 2013 The Windsor Consulting Group, Inc.

6

What is Noise?Noise is an unpleasant / unwanted soundTypes of noiseContinuousImpulseImpact

Side effects of noiseLoss of hearingPhysiological/psychological stressAccidentsBehavioural effectsNegative impact on health

Copyright 2013 The Windsor Consulting Group, Inc.

7Noise means different things to different people (e.g. rock music and elderly parents). Noise can get in the way of sounds we would rather hear. We are exposed to noise at work, home and in traffic. If it gets loud enough it can cause problems.

Hearing is one of life's important gifts (babies crying, etc.) How it effects us depends on age, health, frequency of sound, length of exposure.

(i) Continuous - music, grinders, engineers running(ii) Impulse - pneumatic tools, punch press, gun shots - more damaging.

Difference - length of time over which the sound occurs, both can create noise at damaging levels.

Side effect of noise:(i) Behavioural effects - annoyance and agitation(ii) Stress induced problems - high blood pressure and stomach ulcers(iii) Fatigue and impaired concentration causes an increase in errors(iv) Speech interference - poor communication and safety risks causing accidents(v) Reduction in productivity level - distracting(vi) Loss of hearing

Loud noises can cause hearing lossProlonged exposure to a harmless noise can cause hearing lossDamage from hearing loss is irreversibleNoise induced hearing loss is preventablePrevention involves:Noise controlsSafe work practicesEducation

Occupational Noise ExposureCopyright 2013 The Windsor Consulting Group, Inc.

8Experts have identified that prolonged exposure to too much noise causes deafness.

One of the important facts to grasp is that hearing loss resulting from industrial noise develops slowly and becomes progressively worse through continued exposure. This phenomenon prevents the exposed person from being aware of the danger until it is too late.

In most cases, loss of hearing takes place over a number of years. Gradual changes in hearing could be blamed on the persons age.

Once deafness occurs it cannot be rectified by surgery or medication.

This program will discuss methods of noise control (e.g. barriers and exposure reduction, safe work practices - PPE)

Occupational hearing loss is the most common work-related illness in the United States. Approximately 22 million U.S. workers exposed to hazardous noise levels at work, and an additional 9 million exposed to ototoxic chemicals. An estimated $242 million is spent annually on workers compensation for hearing loss disability.

Occupational Noise ExposureCopyright 2013 The Windsor Consulting Group, Inc.

9

Sound Versus NoiseSound is a pressure change detectable by the human ear.Pitch (frequency) ranges between 20 to 20,000 HzVolume ranges between 0 to 140 dB (decibels)

Noise is a type of sound.Carries no informationRandomGenerally described as undesirable or unwanted sound

Copyright 2013 The Windsor Consulting Group, Inc.

10

(Illustration: OSHA.gov)

Effects cardiovascular system

Effects the nervous system

Interferes with speech and concentration

Causes annoyance, stress, and fatigue

Reduces work efficiency

Lowers morale

Masks warning sounds

Non-Auditory Effects of NoiseCopyright 2013 The Windsor Consulting Group, Inc.

11

Illustration: Microsoft Clip Art

Non-Auditory Effects of NoisePsychological can startle, annoy, and disrupt concentration, sleep, or relaxation.

Interference with communication, resulting in interference with job performance and safety.

Physiological noise induced hearing loss, aural pain, or even nausea.

Copyright 2013 The Windsor Consulting Group, Inc.

12

Illustration: Microsoft Clip Art

The Physics of Sound

Copyright 2013 The Windsor Consulting Group, Inc.

The Physics of Sound

Copyright 2013 The Windsor Consulting Group, Inc.

The Physics of Sound

Copyright 2013 The Windsor Consulting Group, Inc.

Properties of Sound

Copyright 2013 The Windsor Consulting Group, Inc.

Sound is a fluctuation in pressure above and below the ambient pressure of a medium that has elasticity and viscosity.

The medium may be a solid, liquid, or gas.

Sound is also defined as the auditory sensation evoked by these oscillations in pressure

Sound PropagationCopyright 2013 The Windsor Consulting Group, Inc.

Properties of Sound

Period (T) is the time it takes to complete one full cycle

Frequency (f) is the number of times per second a complete wave passes a point. The number of cycles per second is termed Hertz (Hz).

The period and the frequency are simply related by the following equation:

T = 1/f (seconds)Copyright 2013 The Windsor Consulting Group, Inc.

Properties of SoundSpeed (c) of sound in air is governed by air density and air pressure which in turn relates to the ambient temperature and elevation at or above sea level

At sea level, the speed of sound in air is about 343 m/s

Sound travels about 1 kilometres in 3 seconds (much slower than the speed of light)Copyright 2013 The Windsor Consulting Group, Inc.

Properties of Sound

Wavelength () is the length of one complete cycle, and is measured in meters (m).

It is related to the frequency (f) and speed of sound (c) by:

Wavelength () = c/f metersCopyright 2013 The Windsor Consulting Group, Inc.

Properties of SoundFrequencyWavelength100 Hz3 x 107 m1000 Hz3 x 106 m10,000 Hz3 x 104 m1 x 106 Hz/1 MHz300 m10 MHz3 m100 MHZ0.3 m1,000 MHz0.3 m

Wavelength in air at standard atmospheric conditionsCopyright 2013 The Windsor Consulting Group, Inc.

Properties of Sound

Copyright 2013 The Windsor Consulting Group, Inc.

Properties of Sound

Copyright 2013 The Windsor Consulting Group, Inc.

Properties of SoundSLMs have electronic circuits which convert the microphone signal to an RMS sound pressure level

The RMS pressure is used because it can be related to the average intensity of the sound or the loudness of the sound

For a pure (simple sine wave) tone it can be shown that the peak pressure and the RMS pressure are related:

Prsm = Ppeak = 0.707 x Ppeak 2For more complex signals, there is no simple relationship between the two

Copyright 2013 The Windsor Consulting Group, Inc.

Properties of Sound

Peak sound is imp

Recommended

View more >