A Health and Safety Guide for Your Workplace

Hearing Conservation
Introduction Personal productivity
• If the job involves a lot of communication,
The risk of noise-induced hearing loss is often hearing impaired workers may quit or transfer
ignored until too late because: to another position rather than risk criticism or
• hearing loss causes no pain suspicion of incompetence.
• workers may feel discomfort and pain from
Corporate productivity
excessive noise, but not from the hearing loss
Compensation premiums, surcharges and penalties
• the loss can occur gradually, so that exposed
can affect the workplace’s productivity and
workers don’t notice until significant damage has
financial health.
occurred
Once damaged, hearing cannot be restored. Damaged Workplaces often contain many sources of noise.
hearing can affect job performance, health and Left unchecked, these sources can cause serious harm
productivity. and easily exceed legal limits. (For more on legal
requirements, see “Legislation”)
Job performance Many options exist for controlling noise exposure.
Hearing impaired workers may pose a hazard to The best way to protect workers from exposure
others and to themselves. They may misunderstand to excessive noise, and ensure workplaces meet
warnings and instructions. their legal obligations, is to set up a hearing
conservation program.
Health
The non-auditory effects of noise may include: Components of a Hearing
• anxiety Conservation Program
• depression
A hearing conservation program is a planned,
• fatigue coordinated course of action implemented to prevent
• withdrawal from social activities hearing loss. However, effective programs do more
• poor digestion than prevent hearing loss. They can:
• stress • improve employee morale
• poor self-image • create a sense of well-being
• higher blood pressure and heart rate
• improve production values, and
(hypertension)
• reduce the incidence of occupational disease

Noise
© Industrial Accident Prevention Association, 2008. All rights reserved. 1
 Contents Identifying Areas with
High Noise Levels
Hearing conservation programs include:
• engineering controls to minimize the amount of Tip: if background noise makes it difficult to carry
sound energy generated on a conversation, then the noise levels in that area
• administrative controls or procedures for probably exceed safe limits.
performing specific jobs or tasks
• personal protective equipment Preliminary ways to identify potentially unsafe areas
include the following:
• training in the following subjects:
• conducting a walk-through survey
• health effects of noise
• tapping into others’ experience by:
• use, care and fit of personal protective equipment
­ – reviewing journals, books and other
• job procedures
publications on noise, especially those specific
• other program components, as required to your industry
• periodic exposure monitoring ­ – seeking employee input
• audiometric testing ­ – asking colleagues in similar workplaces to
share insights
Program Considerations
Common noise sources
Appearing below are five considerations for The main sources of noise in most industries are:
developing and implementing a hearing conservation • grinding operations
program. • machinery powered by compressed air
• (air jet noise)
• Design the program in consultation with joint
health and safety committees • fume extraction and ventilation fans
• gears, especially those driving several pieces
• Develop procedures for workplace monitoring
and employee testing • of equipment
• tools (e.g., oxy-acetylene welding torches,
• Add criteria for minimizing noise output to pneumatic nail drivers)
purchasing policies
• Keep records of training, exposure monitoring Note: every plant may have additional equipment or
and audiometric testing processes that emit noise.
• Review the program with the joint health and
safety committee every year or whenever a new Noise levels by source
process or piece of equipment is introduced A sample list of noise sources and their corresponding
noise levels appears on the next page.
Setting up a program
Setting up a program involves:
• identifying areas in the workplace where high
noise levels exist
• assessing the levels to which workers are exposed
• implementing a control program

Hearing Conservation
© Industrial Accident Prevention Association, 2008. All rights reserved. 2
 Noise Sources and Corresponding Noise Levels Assessing Noise Levels
Processes dBA*
With the location of noise sources in hand, you
air carbon arc cutting 120 can assess the level of noise to which workers are
exposed. CSA Standard Z107.56-06, “Procedures for
hammer mill 102
the Measurement of Occupational Noise Exposure,”
punch press 100 explains how to carry out measurements, what
instruments are needed, and how to interpret results.
arc welding 95
Three types of measurements are commonly
large tire curing press 93 carried out:
• area noise level measurements
plastic grinding machine 89 • personal exposure measurements
• frequency measurement
laundry facilities 74
Area noise level measurements
office equipment 55
• Area measurements indicate the level of noise in
Tools dBA* the area at the time the measurement is taken. It
can only determine exposure if the noise level is
explosive fastening tools 131 constant, and the exposed worker(s) stays in the
area during the entire shift.
table saw 95
Equipment used: a sound level meter.
paint spray gun 91
Personal exposure measurements
*dBA (decibel A scale) is a measurement of sound Personal exposure measurements track exposure
pressure. (See “Glossary” for more on hearing to noise over time (usually eight hours). The
conservation terminology.) measurement is taken by equipment that calculates
the total amount of sound energy received by a
Mapping noise sources microphone.
Once you have identified noise sources, create a floor
plan that shows: Equipment used: a personal dosimeter or an
• equipment and workplace layout integrating sound level meter. Personal dosimeters
are the preferred choice. Since they are worn by the
• areas where noise may be a problem
workers, personal dosimeter measurements better
• number of workers in those areas reflect actual exposure.
• noise control measures already in place (for
examples of control measures, see “Implementing Note: always take more than one personal exposure
a Control Program”) measurement, since noise levels often vary.
Guidelines on the number of samples necessary,
according to the accuracy required, appear in CSA
Standard Z107.56-06.

Hearing Conservation
© Industrial Accident Prevention Association, 2008. All rights reserved. 3
 Frequency measurement • using anti-vibration mounts and flexible drive
Frequency measurement, also known as octave band couplings to prevent transmission of noise from
analysis, helps in the: one part to another
• design of noise absorbing enclosures • mounting motors and pumps on
• selection of personal protective equipment • anti-vibration mounts
• building noise considerations into the design and
This type of measurement is best done by a noise selection of valves
consultant, and is not necessarily for determining
• installing more flexible hosing to reduce hydraulic
exposure.
system noise
Ototoxic effects • installing silencers to reduce noise from
Certain chemicals are toxic to hearing organs pneumatic tools
and the nerves that supply these organs. In work • installing enclosures around noisy machinery
environments where there may be exposure to noise • installing noise absorbing paneling on walls and
as well as certain chemicals (toluene, lead and ceilings
manganese), noise-exposed workers may be at a
higher risk of hearing impairment. (See “Additional Information” for more sources of
information on engineering controls.)
Implementing a Control Program
Administrative controls
Having identified noise sources and calculated
If noise cannot be reduced by engineering controls,
exposure levels, you can now decide what control
then consider administrative controls to modify how
methods best suit your workplace. Three options, in
work is performed. These measures include:
order of preference are:
• reducing exposure by limiting the time employees
• engineering controls stay in a noisy area
• administrative controls, and • performing noisy operations when the least
• personal protective equipment number of workers are present e.g., during lunch
or after shifts end
Other elements of a control program include: • changing the way in which work is performed,
• employee training, and e.g., minimizing the need to strike items or drop
them into bins
• audiometric testing
• routine maintenance of equipment
Engineering controls • rotating workers
These control measures include:
Note: worker rotation is a controversial option since
• modifying equipment to reduce noise output it can be seen as merely distributing the risk among
• absorbing the noise before it spreads workers.
• changing the frequency of the noise
Personal protective equipment
Information on noise control measures for specific If noise cannot be reduced by engineering controls
industries is scarce. However, the following measures or administrative methods, then provide personal
apply to many pieces of equipment and many industry protective equipment (PPE) and related training (see
sectors: “Training”). PPE can reduce the amount of noise
• using helical or other low noise gearing to reaching the ear by 8-15 dB.
reduce noise

Hearing Conservation
© Industrial Accident Prevention Association, 2008. All rights reserved. 4
 Note: the actual reduction in exposure provided by Training
PPE can vary from manufacturers’ claims. Factors Training helps to ensure that workers benefit from
affecting the amount of protection provided include: and support the controls implemented, especially
• how long the protection is worn PPE. Conduct a training needs assessment to
• how well it fits determine what content and level of training are most
• the material of construction suitable for your employees.
• the frequency of the noise. Low frequency noise
causes PPE to vibrate and transmit the sound to Common training topics include:
the ear • health effects of noise
• control measures in place to reduce
Selecting hearing protectors • noise exposure
The table below indicates the class or grade of • reasons for audiometric testing, plus the
hearing protector recommended for specific noise confidentiality of testing results
levels. Ensure that the protector is suitable for the • proper fit, use and care of PPE
noise level and noise frequency.
Note: use examples and situations that apply to
your workplace.
Z94.2-02 Hearing Protection Devices –
Performance, Selection, Care and Use
Audiometric testing
Table 4 Selection of Hearing Protection Devices Ongoing audiometric testing helps to ensure your
Based upon Grade and Noise Exposure in dBA program is effective. Testing and analysis can
identify why hearing loss has occurred, and how to
Recommended
prevent further loss. If the testing is being conducted
Lex,8 (dBA) Grade Class by a consulting firm, provide the firm with exposure
≤ 90 1 C data and information on control measures in place.
≤ 95 2 B
≤ 100 3 A Testing considerations
≤ 105 4 A Timing – Test employees before they start working
≤ 110 Dual* in a noisy area to set a benchmark for later tests.
> 110 Dual+ Ұ Then conduct periodic testing at least annually.
Source: CSA Standard Z94.2-02
Noise Exposure Level (Lex,8) : noise exposure over Accuracy – The following considerations help
an 8-hour period. ensure accurate results:

* Dual hearing protection required. Use a minimum of • the tester must be qualified to conduct
a Grade 2 or Class B earmuff and a Grade 3 or Class audiometric tests
A earplug. • tests must take place in a controlled environment,
Ұ Dual hearing protection required. Also, it is preferably a testing booth
recommended that exposure durations be • the instruments must be calibrated to ensure
limited, octave-band analyses be conducted for accuracy
attenuation predictions, and twice-annual
• the results must be evaluated – either by
audiometry be provided to the affected individuals.
examining individual audiograms, or by
Note: Inclusion of both classification schemes in analyzing the results of a group of audiograms –
this Table is not intended to imply any equivalency. using audiometric data base analytical techniques
The test methods and Grade/Class assignments are • the participating employees must understand the
different and no direct comparison between the two importance of these tests
schemes should be made.
Hearing Conservation
© Industrial Accident Prevention Association, 2008. All rights reserved. 5
Discuss with prospective audiometric testing firms Table of Equivalent Noise Exposures
how they will meet the first four conditions. However,
Steady Sound Level Duration
your workplace is responsible for the fifth.
dBA
Periodic exposure monitoring 82 16 hours
85 8 hours
Periodic monitoring of employee exposure can help 88 4 hours
indicate deficiencies in engineering and administrative 91 2 hours
controls, and reveal problems before they appear in 94 1 hour
audiometric test results. 97 30 minutes
100 15 minutes
Timing – Monitor exposure at least once a year or 103 7.5 minutes
whenever a new process or piece of equipment is 106 3.75 minutes
introduced. 109 1.88 minutes
Source: Ministry of Labour, “Amendments to
Legislation Noise Requirements in the Regulation for Industrial
Establishments & Oil and Gas-Offshore”, May 2007.
Industrial Establishments Regulation
(s.139) The table outlines the maximum permissible daily
Specific requirements regarding noise exposure appear exposure duration for the steady sound levels
in s.139 of Regulation 851 (Industrial Establishments) provided. For example, if a worker is exposed to
under the Occupational Health and Safety Act. Every a steady sound level of 88 dBA, the maximum
employer must ensure that a worker is not exposed to a permissible daily exposure duration is 4 hours. Any
sound level greater than an ‘equivalent sound exposure additional noise exposure that would cause the 85
level’ of 85dBA, Lex,8. Where it is determined that dBA Lex,8 exposure limit to be exceeded would
workers are exposed to a sound level greater than an require control measures to protect the worker’s
equivalent sound pressure level of 85dBA over an 8hr hearing.
period, the regulation also requires that: Note: The regulation requires that every employer
• Protective measures are put in place, which take all measures reasonably necessary in the
includes the provision and use of engineering circumstance to protect workers from exposure to
controls and work practices. hazardous sound levels. Engineering controls should
• Workers wear Personal Protective Equipment be first attempted before implementing a Personal
(PPE) appropriate in the circumstances provided Protective Equipment program. See s.139(9) of the
that all engineering controls are not suitable as per Industrial Regulation, for further specifications on
the limitations listed in s.139(9). when workers are required to wear and use PPE.
Refer to the Industrial Establishments Regulation for
• A clearly visible sign be posted at every approach specific legislative requirements (http://www.e-laws.
to the area where the sound level regularly gov.on.ca)
exceeds 85dBA.
Standards
Canadian Standards International, formerly the
Canadian Standards Association, has developed
many standards related to noise. These standards list
the procedures, required instruments and method of
analyzing measurements. A list of standards appears
in “Additional Information”.

Hearing Conservation
© Industrial Accident Prevention Association, 2008. All rights reserved. 6
 Additional Information increase from 10 to 20 dB does not mean that the
sound pressure has doubled. Instead, it means that the
The following is a list of sources that can provide sound pressure has increased by a factor of 10.
further information.
dBA (decibel A scale) – a measurement of sound
Guideline pressure that has been modified to take into account
• Ministry of Labour Guideline, “Amendments that the ear is not equally sensitive to all frequencies.
to Noise Requirements in the Regulation for
Industrial Establishments & Oil and Gas- Equivalent sound exposure level – the steady sound
Offshore”, May 2007 level in dBA which, if present in a workplace for
eight hours in a day, would contain the same total
Publications energy as that generated by the actual and varying
• Noise Manual, ed. E.H. Berger, W.D. Ward, J.C. sound levels to which a worker is exposed in his or
Morrill, L.H. Royster, 2003 her total work day, determined in accordance with the
• OHS Canada Buyers’ Guide formula set out in subsection (2). O. Reg. 565/06, s. 2.

Standards Impact noise or impulsive noise – a noise of short

duration where the sound pressure level rises very
• CSA Standard Z94.2-02, “Hearing Protection rapidly to a peak and decays to background level (i.e.,
Devices – Performance, Selection, Care and Use” hammering metal plate, nail gun).
• CSA Standard Z107.4-M86 (R2001), “Pure
Tone Air Conduction Audiometers for Hearing Leq (average equivalent noise level) – an average
Conservation and for Screening” level of noise calculated from measurements of noise
• CSA Standard Z107.53-M1982 (R2004), that varies over time.
“Procedure for Performing a Survey of Sound
due to Industrial, Institutional or Commercial NRR (Noise Reduction Rating) – a single number
Activities” representing the attenuation value for a given hearing
protection device (i.e., ear plug, ear muff, etc.).
• CSA Standard Z107.56-06, “Procedures for the
Measurement of Occupational Noise Exposure” These numbers are developed in ideal laboratory
conditions and may not represent the true attenuation
• CSA Standard Z107.6-M90 (R2005), “Pure
of the hearing protection device when worn by a
Tone Air Conduction Threshold Audiometry for
worker, due to variability in exact fit, imperfect seal
Hearing Conservation
due to movement of jaw or perspiration, deterioration
of device over time, and does not account for any
Websites
modification made by the wearer.
• Canadian Centre for Occupational Health and
Safety: www.ccohs.ca
Noise – unwanted sound that causes harm, either
• American Conference of Governmental Industrial by causing hearing loss or stress, or interferes with
Hygienists: www.acgih.org
communication.
• Ontario Ministry of Labour:
www.labour.gov.on.ca
Sound energy – the amount of energy transmitted to
the ear by noise.
Glossary
Sound pressure – the fluctuations in air pressure
dB (decibel) – a measurement of sound pressure caused by noise. The louder the noise, the greater the
where 0 dB is defined as being the faintest sound changes in air pressure. These fluctuations cause the
that a person with normal hearing can hear. This ear drum to vibrate.
measurement scale is not additive. For example, an
Hearing Conservation
© Industrial Accident Prevention Association, 2008. All rights reserved. 7
 How can IAPA help?
Our occupational hygiene specialists provide the following services:
>> Noise level surveys (including basic noise mapping and dose level monitoring)
>> qualitative assessments
>> area and personal noise exposure assessments
>> assistance with meeting legislative requirements
>> workplace program audits and training

Contact IAPA at 1-800-406-IAPA (4272) and ask for an Occupational Hygiene Specialist from our Technical Services Team
or visit the IAPA website at www.iapa.ca and select “Training Schedules” from our Products & Services section to learn
more about our Noise Control and Hearing Conservation (1/2 Day) course.

© Industrial Accident Prevention Association, 2001, 2005, 2006,

2007, 2008.
All rights reserved. As part of IAPA’s mission to inform and educate, IAPA
permits users to reproduce this material for their own internal training
and educational purposes only. For any other purpose, including use in
conjunction with fee for service or other commercial activities, no part
of this material may be used, reproduced, stored in a retrieval system,
or transmitted in any form or by any means, electronic, mechanical,
photocopy, recorded, or otherwise, without the express prior written
permission of the Industrial Accident Prevention Association.
The information contained in this material is provided voluntarily as a
public service. No warranty, guarantee or representation is made by IAPA
as to the correctness, suitability, fitness, or sufficiency of any information
contained in this material. Use of this material means that the user agrees
that IAPA and its employees will not have and are released from any
liability whatsoever, however caused or arising, in connection therewith.
Users also acknowledge that it cannot be assumed that all acceptable
safety measures are contained in this material or that additional measures
may not be required in the conditions or circumstances that are applicable
to the user or his/her organization, and that the user will personally make
his/her own assessment of the information contained in
this material.
While IAPA does not undertake to provide a revision service or guarantee
accuracy, we shall be pleased to respond to your individual requests
for information.

April, 2008
IAPA (Industrial Accident Prevention Association)
Toll free: 1-800-614-IAPA (4272) Fax: 1-800-316-IAPA (4272)
Website: www.iapa.ca

Hearing Conservation 8