Summary of Noise Breakout Session Presentations and Discussion
Submitted by: Lee Hager
One of the issues addressed at the Workplace Controls Workshop, co-sponsored
on March 10-12, 1998 by NIOSH, AIHA, and ASSE, was the unfinished business of
noise control. The breakout session on noise issues was divided into three
primary areas, with invited speakers and discussion on the State of the Art and
Unfinished Business; Emerging Technologies; and Protective Equipment. This
document begins with the summary presentation provided at the closing Plenary
Session on Thursday, March 12; presentation summaries and pursuant discussion
notes from each of the breakout sessions follows:
Plenary Presentation Summary
Discussion points were summarized after the
breakout sessions by John Franks and Lee Hager. Hager presented the summary to
the assembled workshop group at the closing Plenary Session.
Hager indicated that the group felt it important to integrate the discussion
on a larger scale. It was impossible to discuss noise without addressing hearing
and hearing health, and the discussion of hearing health was impossible to limit
to the workplace without consideration of non-occupational exposure.
The consensus of the group was that existing, proven technology exists and is
readily available to control worker exposure to hazardous noise. Participants
then focused on the underlying reasons for lack of implementation, the barriers
to effective hearing loss prevention, and the research agenda necessary to
promote the widespread application of these existing control and protective
The invited presentations provided a meaningful basis for discussion. Our
Noise Control: State of the Art and Unfinished Business
Richard R. James
Noise Control: Emerging Technologies
Richard R. James
Hearing Protectors: State of the Art and Emerging Technologies
State of the Art in Noise Control
Significant technological progress has been made in noise control
engineering, but real progress has been severely limited. The current regulatory
regieme has resulted in limitation of effective control implementation to some
industries, primarily larger facilities with top-down support of health and
safety issues. Implementation has been limited in application and impact, with
limited awareness of the availability of controls, especially in small and
medium sized businesses. Consensus was that sufficient proven technology exists
to control worker exposure to noise, both through noise control technology and
techniques and through the use of hearing protection devices (HPD). Much of the
discussion, then, centered on identifying the barriers to effective
implementation of current technology.
The group found it hard to present valid arguments on many salient issues due
to lack of appropriate definitions.
|What is enforcement effectiveness?|
We found that there is no feeling for the implications resulting from the
unnecessary hearing loss that is accruing, both in economic terms as well as in
social impact. We found no evidence that an infrastructure exists to support a
noise control agenda were one to be created. There is no feeling for the
essential training agenda. Who needs training – who are the target audiences?
What do they need to be trained on – what are the important topics and what
should be the emphasis of training? How do we assess the effectiveness of
In summary, the existing hearing conservation paradigm has failed. Data to
date show hearing loss is progressing at a higher rate than we would expect if
existing programs were effective. We propose breaking the essential research
agenda into a surveillance aspect, a new technology aspect, a personal
protective equipment aspect, and a social marketing aspect.
Technical surveillance is required. We must revisit assumptions on scope of
exposure. New information is required on the distribution of exposures. We must
assess the current state of exposure monitoring. We propose a research agenda
that will collect, collate and distribute data on noise exposure
|Existing MSHA data|
|Other existing data sets|
|New data for the 95% of small and medium sized workplaces for which
there is no evidence of monitoring having been conducted in any form|
We must assess the impact of changing workplace demographics on noise
exposure distribution. The manufacturing base has changed significantly since
previous studies were conducted. The fundamental responsibility and loyalty
relationship between employer and employee has changed due in part to the effect
of downsizing and outsourcing. We need to determine the effect of this dynamic
on management of worker exposure to noise.
Part of the technical surveillance effort should be the development and
maintenance of a hazardous task inventory, or a compendium of industry specific
noise hazards and noise sources. NIOSH has started this effort in the
construction trades, but it should be expanded to cover all of industry.
The other critical aspect of the surveillance agenda is economic
surveillance. We have no feel at this time for the implications of current trend
in hearing loss continuing. We must relate real costs to maintaining hearing
health for the worker, for industry and for society in general. Hard costs
include Worker’s Compensation; health care and the implications for hearing
health maintenance under managed health care; and costs for hearing aids and
Indirect costs related to hearing health merit scrutiny as well. Research
into increased risk of accidents due to impaired hearing, high noise levels, or
compromised hearing due to use of HPD; productivity analysis; research on
communication ability and related implications; and costs of under realization
of career potential (example: US Army hearing requirements for promotion and
retention) are important. In addition, analysis of worker expectation of
retention and maintenance of full functionality needs analysis. Where our
fathers expected to retire after 40 years in industry with compromised hearing,
the current generation of workers with their focus on health and wellness will
likely not be so accommodating.
We need a national inventory of hearing critical jobs, both in the public and
the private sectors. Part of this research should focus on methods for assessing
auditory functionality; methods for determining the hearing-criticality of
specific jobs, tasks, and occupations; and methods of accommodation to address
workplace accessibility for the hearing impaired.
Distribution of information, specifically on controls, was one of the
greatest needs identified by the group. We identified the need for a best
practice compendium and an acoustical materials compendium to collect and
distribute existing, proven control technology. Broad distribution of "buy
quiet" specifications to aid the purchase of inherently quiet machines and
equipment is another aspect of best practice information distribution. These
steps can help integrate noise control with the business process.
A national exposure database linked to noisy activities, hearing loss
prevention outcomes, and hearing protection should be developed to provide a
Research into the development of low cost personal noise dosimeters or
personal exposure monitors with a retail cost of less than $100 (less than $20
is likely feasible) can make information about hazard levels and total noise
burden available to large groups of exposed people, both on the job and off.
Using the model of the musical greeting card, consideration should be given
to developing an inexpensive hearing screening tool. While not clinical in
precision, this kind of gross self screening could be a great asset in raising
public awareness of noise as a hazard and in motivating the individual to
maintain hearing health and function. Similar technology could be applied to
personal hearing protector fitting.
Analysis should be conducted on the effect of the redistribution of
responsibilities for hearing health. Based on current business trends, we expect
a shift from sole management responsibility under the hearing conservation
paradigm. The new paradigm will entail greater worker involvement, as the worker
bears more responsibility for their healthcare, and supplier involvement as they
bear more partnership responsibility for ensuring that their industrial consumer
maintains a safe and health workplace.
Part of the supplier link involves consumer products as well. A labeling
requirement like an MSDS for noise that would communicate to end-users the level
of hazard, consequences of use, and appropriate self protective behaviors (like
using hearing protection or limiting time of use) can close the gap between the
linked exposures in the workplace and elsewhere.
Personal Protective Equipment
Important aspects of the HPD utilization issue merit research. We have no
current definition of HPD comfort and no real definition of effectiveness. HPD
fitting, or an assessment of the protection provided by given device under given
conditions to a given individual, should be addressed with improved methods and
technologies for field fit testing and user training. Simple but reliable
methods for self-assessment of fit should be developed, with annual training and
verification of appropriateness of HPD selection part of the hearing loss
Further study is needed on the effects of HPD on functionality in the
workplace. Analysis of the effect of HPD use on warning signal detection;
localization of noise sources; and speech and communication in the workplace are
important. In addition, each of these research aspects should be considered for
both the normal-hearing and for the hearing-impaired.
New technologies integrating speech communication systems and other
technologies with HPD should be pursued, with special focus on tailoring systems
for hearing impaired. Integration of multiple technologies including chemical
exposure monitoring and other health surveillance should be considered to
increase value and raise the credibility of the use of these devices.
One of the fundamental failures determined by the group was the sole reliance
on regulation and on management for responsibility for hearing health in
society. Lack of a broad based social marketing effort to raise the awareness of
the public on hearing health as a wellness issue speaks to under-valuation of
hearing health in society.
The large-scale awareness campaign which will be required to raise awareness
of society in general should be based on wellness models. This effort could be
started by a consortium of professional associations to promote hearing health
as wellness as a new paradigm. Worker groups, including organized labor;
employers, both large and small; and the general population should be mobilized.
A focus on youth, using anti-smoking or other public health awareness models,
could be a great preventive measure to improve the hearing health of those
entering the workforce. Noise awareness media should be developed using tools
like the tinnitus demonstration tape employed by the Carpenters Union and
hearing loss demonstration media.
Breakout Session I: State of the Art and Unfinished Business
Jim Banach chaired this session with 21 in attendance.
Richard R. James, James, Anderson & Associates, Inc.
Mr. James has been a consultant to industry on hearing loss prevention
issues since the early 1970’s. His broad experience in HLP development and
administration enalbe him to provide a broad perspective on the current state
of noise control. He opened the breakout session with an overview of the
current state of noise control in industry contrasted with the expectations
which formed the basis for existing regulation.
Current State of the Art
The Bolt, Beranek, and Newman study of 1976 developed as background for the
Hearing Conservation Amendment reflected expectations that, after "best
effort" engineering controls, by 1985 less than 1% of the workforce would
be exposed to noise greater than 90 dB(A) TWA, and that 3.6% would be exposed
greater than 85 dB(A) TWA. One reason for the failure to achieve these goals is
the current enforcement paradigm, under which employers were permitted to
substitute hearing conservation efforts for noise control where TWA exposures
did not exceed 100 dB(A) TWA, predicated on the assumption that both efforts
would achieve equal effectiveness in worker protection.
Evidence that this served as an excuse to abandon efforts to protect workers
against the effects of noise is found in the cost analysis of effective HCP
efforts and current market studies.
1976 cost analysis = $32 per worker to provide effective hearing
1983 Hearing Conservation Amendment cost analysis = $62.73 per worker
1992 DOL analysis = $86.60 per worker
Thus, the market estimate for hearing conservation services in industry,
using the NIOSH estimate of 30 million workers exposed to noise levels above 85
dB(A) TWA, is $1.9 billion even using the 1983 HCA analysis. We see no evidence
of expenditures approaching this level in industry. A recent market analysis
reflects projected market for hearing conservation services and products as
Hearing Protectors = $180 million
Audiometric Exam = $120 million
Market estimates for monitoring and noise control are so small as to be
unmeasureable. Per the NOES study, little activity in protecting worker hearing
is evident in industry.
||Percentage of Industrial
Workplaces Participating in:
We can only conclude that the noise control market is currently in suspended
animation, and noise is a non-issue for most employers.
Problems with current system
There has been a failure in the exposure monitoring regime. There is no
requirement for any systematic or documented procedure; no requirement for
frequency of monitoring; and a failure to provide useful results for decision
makers/management. Useful information for program management such as Hearing
Conservation Program trends and Noise Control effectiveness measures has been
No correlation is made between hearing conservation effort and noise control
effectiveness. Key interrelated data has been managed separately, under the
charge of different functional group both locally at the plant level and
globally at the corporate level. Exposure data, audiograms, worker demographics,
Hearing Protection selection and use, and training records are collected, stored
and managed separately with little or no correlation.
Currently, equipment suppliers consider noise control optional. "Buy
quiet" purchase specifications must be considered a "feasible
engineering control" measure, and lack of a concerted and documented effort
to obtain new equipment which will not add exposure risk to the workforce should
be a citeable offense. This is increasingly important given the amount of
non-occupational exposure in the workforce.
"Buy quiet" purchase specifications share a number of common
|75 or 80 dB Lavg emissions as the specified limit|
|A specified procedure for collecting and reporting noise emission data,
typically requiring measurements on a 1 meter envelope around the machine;
measurement at the operator work station; and testing under full
load/typical operating conditions.|
At present, there are significant gaps in the both research data and program
implementation. We have no handle on:
|Whether we have the right workers in the program|
|Whether we are preventing hearing loss|
|How many people are at risk|
|Whether or how well noise control is working to reduce exposure|
|Whether we are in compliance|
|What are the current program strengths|
|What are the current program weaknesses|
|What are the barriers to implementation|
Thomas Thunder, Acoustic Associates
Mr. Thunder offered observations based on his 25
years experience in noise control and hearing conservation. His background as
both a noise control engineer and an audiologist in hearing conservation
practice gives him a unique perspective on the current state of the art. His
comments reflect fundamental misunderstandings at the industrial consumer level
of many basic precepts included in the current regulation.
Top Ten Beliefs Impacting Hearing Conservation:
- OSHA requires a soundbooth for audiometric testing.
- A technician who operates a microprocessor audiometer does not need to be
False – CAOHC certification is not required; training is still
fundamental and very important
- Dosimetry is the only OSHA approved method of noise exposure assessment.
False – other methods are workable; just because OSHA uses dosimetry
does not make other methods invalid.
- We don’t need to report an STS until it’s a 25 dB change.
False – STS and recordability are different issues, and the law still
has important follow-up action required at a 10 dB shift.
- The NRR is a reliable and accurate indicator of protection.
- I’m already doing audiometric testing; why do I need a noise survey too?
There us no current psychological or procedural link between noise
exposure and hearing loss. The requirement to "remonitor as
necessary" from the 1983 HCA is bogus.
- Protected sound level = unprotected level – NRR
There is great confusion as to the basis for NRR calculations,
specifically the dB(A) vs dB(C) criteria for development. It is likely that
in many industrial environments the arbitrary 7 dB correction factor faulty,
and we are functioning with unknown real world protection and the NRR as an
unreliable estimate of protection.
- If I can’t get below 90 why bother with engineering controls?
There is a great misunderstanding of benefit from controls which may not
achieve OSHA’s PEL or design goal, but which could provide significant
benefit to the worker.
- If noise levels are excessive, just hand out HPD
This common practice reflects a lack of understanding of comprehensive
nature of HCP, and skips important steps in effective HCP administration,
including hearing testing, exposure assessment and a control strategy and
- Engineering noise control is not required until 100 dB TWA.
The common understanding or interpretation is that "OSHA raised PEL
to 100" or that OSHA raised the de facto HCP standard. This reflects a
gross misunderstanding of the paradigm.
Factors that have diminished the control of workplace noise
Industry has, in large part, defaulted to reliance on hearing protection
devices (HPD) in lieu of noise control. HPD was never intended as replacement
for noise control.
Where control technology has been applied, sound absorption has in many cases
been viewed as a panacea. It is assumed that absorption is effective, when in
many cases, this is simply not true.
OSHA’s enforcement stance has been a barrier to effective control
implementation. In most cases, fines have been too small to raise awareness. I
suggest that we consider making fines commensurate with amount of overexposure,
such that the greater the overexposure, the greater the penalty to the employer.
Hearing loss formulas and Worker’s Compensation formulas undervalue
hearing. For example, the average hearing loss claim in Illinois is $16,000
before expert witness and attorney fees. More than 12 formulas exist with great
variability, resulting in confusion and lack of consistency. In addition, the
political basis of worker’s compensation results in claim amounts and
procedural hurdles to realistic compensation for hearing loss. We are seeing an
interesting trend in litigation, however, where workers are pursuing
compensation outside the exclusive remedy of worker’s comp by suing the
manufacturers of noisy/hazardous equipment.
The multiple criteria (85 dB(A) TWA action level vs 90 dB(A) TWA criterion
level) are confusing to industry and should be revisited.
The fundamental unfinished business in noise control, however, comes down to
a lack of knowledge. Little is communicated in higher education or in industrial
practice about the importance of source controls. There is a severe lack of
academic training programs on noise control, and in fact, engineers are
graduating with absolutely no noise knowledge or training. There is no
infrastructure to support acoustic engineers.
Robert D. Bruce, CSTI – Progress on Noise Control in the Workplace
Mr. Bruce was instrumental in developing the
research which served as the basis for the current Hearing Conservation
Amendment. He provided an extensive historical perspective on noise and
hearing issues, and provided some insight as to the development and net
effect of current standards, regulations, and implementation directives.
History of Noise and Hearing Issues
Issues of noise exposure and hearing loss have a long history, starting with
Pliny the Elder and his observation that people living near waterfalls with the
attendant noise exposure developed hearing loss. Ramazini and the coppersmiths
through observations related to boilermakers in the late 19th
century and Holt in 1882 in the blacksmith, weaver, railroad worker trades
indicate convincingly that we’ve known the effects of noise for over 100
What constitutes hazardous noise is another issue. The generally accepted
criteria is that of 90 dB(A) TWA; upper limits vary significantly based on
factors such as exchange rate. For example, the ACGIH criteria permits 28
seconds at 115 dB using a 3 dB exchange rate, while OSHA permits 15 minutes at
115 dB with a 5 dB exchange rate.
Hearing protectors have a long history as well. HPD history reflects the
effect of regulation in stimulating innovation. From 1880’s to 1920’s, for
example, less than 20 patents per year were issued related to HPD. In the 1970’s
and 1980’s, after the promulgation of regulation more than 70 patents per year
Noise measurement history traces back through Lockheed measurements from the
1940’s (with resulting sound levels of 92 to 130 dB) and the WADC Technical
Report. One of the first published analyses was in a 1953 AIHA Quarterly, titled Noise Surveys
in Manufacturing Industries. Octave band measurements were taken in 600
locations and results compiled.
Current state of noise control
Who learns of noise controls/hearing loss issues? First, engineers, doctors,
and scientists. Second, management; and third, workers. Due to this default
system of information dissemination, the issue has historically not been treated
The fundamentals of noise control are well understood, dating from the Noise in
Industry publication in 1944. This document even included a seminal noise
Several terms were employed in the past to describe the activity we are
discussing. Everything from noise conditioning to noise reduction to noise
control have found a place in the lexicon. Perhaps we should have called it
Noise Prevention to give this issue he credibility it deserves.
Technical feasibility as used today is based in large measure on the BBN
Controls/OSHA report prepared in the context of the Hearing Conservation
Amendment. It included a list of sources and controls found throughout
One of the charges of the new defunct Office of Noise Abatement and Control
involved product labels and information regarding hazardous noise. Labels were
intended to provide worker warnings of hazard and consequences of use.
Progress has been made
In 1998, we have better materials for acoustical treatment and engineering
controls and a better understanding of their use. We are seeing, however, a
transfer in responsibility for noise control as a function of the current
business trend toward downsizing, resulting in more subcontractors. Employers
have outsourced health & safety responsibility to these subcontractors at
the same time they are putting pressure on subcontractors to reduce costs. The
net result is that the subcontractors use HPD as substitute for noise control.
What do we need to do?
Several research projects should be considered to address these needs.
|Update a national noise abatement feasibility study.|
|Consider a "Quiet City Contest" to raise awareness of noise as a
|Revisit use of recording hearing loss on the OSHA 300 log as a lever on
employers. ALCOA for one has integrated this report as part of a plant
summary status report, raising the stakes for plant management on all
recordable issues, including hearing loss.|
|National Save Your Hearing Day could be another avenue for raising public
|Define the term "serene" acoustically to make it an objective
goal for community planning.|
Engineering is the most trusted profession in America. This trust entails
responsibility and a certain standard of excellence. As professional noise
control engineers, we have the obligation to inform people about the potential
hazards of excessive, unprotected exposure to noise.
Jon Weinstein, Industrial Acoustics Corporation
Mr. Weinstein’s position as a leading
manufacturer and supplier of noise control equipment and installations
gave the group a view from the supplier side of the issue. He opened with
a statement regarding the White Paper prepared to stimulate discussion in
the group. He found it unbelievable that so little is spent on noise
monitoring and noise control that it is untrackable. He stated that
feasibility is proven for many noise control processes.
Source enclosure is a proven and feasible noise control measure. Proper
design is key to success, with appropriate access designed into the enclosures.
Enclosures are low tech, but effective with 20 to 30 dB reductions common.
Basically, this is a mechanical engineering solution to the noise problem. Lots
of things are feasible with good basic mechanical engineering and design. These
examples (Mr. Weinstein showed a number of photographs of enclosure
installations) are Primarily from mid-1970’s through early 1980’s, since the
most recent emphasis has been on environmental issues rather than workplace
Receiver/personnel enclosures are another proven approach (examples
provided). I can’t understand why expenditures are off the radar screen when
these kinds of feasible controls are available. Absorption is a consideration
where reduction of reverberant field will provide benefit. Gas flow silencers
have also been proven effective in many situations.
The discussion that followed these
presentations was wide-ranging, with many more questions than firm
answers. The following summary tracks the discussion in more or less
chronological order, with speakers identified where possible.
Banach: Two summary points: we’ve come a long way and what’s really
changed? We are where we were 25 years ago, with some pockets of exception. We
are twenty-five years in and the marketplace doesn’t have a clue.
Anderson: How do we encourage engineering? What are the incentives?
James: We’re missing a role model for effectiveness. We must establish
benchmarks and take corporate staffs "out of comfort zone" on this
Anderson: Can we use expenditures on HCP/HLP as a measure of commitment?
Bruce: No, but what then motivates action? Bad press or publicity, but there
is no danger of that in HC/occupational area.
Daniel: How can we use that to our advantage?
Thunder: We must find a way to use cost. Economic feasibility was driving
factor for current status. We’re digging the same hole if we use reliance on
James: Could inspectors start to look at funds allocation/budgets for
HCP/HLP? The CPL intended to balance engineering cost with HCP/HLP. If hearing
loss exceeds presbycusis, inspectors should look at budget to see if program has
minimal or sufficient financial support.
Anderson: Use buy quiet to encourage engineering controls
Brandys: NIOSH needs to get global perspective. There is success evident in
the noise area in other areas and with our foreign competitors – Europe is an
example. The reality of conditions in the US is that if it’s not in the
regulation with significant enforcement penalties ($) it won’t happen.
Bruce: Could we consider attaching fine to each recordable hearing loss? Use
the OSHA 300 log as an enforcement tool.
Brandys: That would encourage falsification of reports, underreporting of
hearing loss, and fabricating data. I realize that this bears criminal penalty,
but would industry consider the risk worth the reward?
Daniel: We need small business focus. In many facilities, there is no current
awareness of hazard. We’re dealing with language barriers (Spanish and
Vietnamese at least) in the workforce, compounded by a lack of community/general
public understanding of the issue of hazardous noise. Many of these small
employers are marginal operations, and their number is increasing due to
outsourcing. We must find a way to impact the community. Insurance carriers have
been ineffective in pursuing this issue.
Johnson: Look to Europe/EC as model to eliminate unfair competition
Franks: ISO 9000 certification ostensibly carries over to suppliers, but is
not enforced in H&S areas.
Resnowski: Perhaps we need a multi pronged approach, including a best
Practices compendium, involvement of manufacturers and designers, community and
public relations efforts and training and education to make this work.
Franks: Who could pay for this effort? OSHA? NIOSH? SBA?
Hayden: NIOSH has recent history (asphalt machinery) of success with
equipment manufacturers with just the threat of regulation.
Bruce: No one understands the impact of hearing loss.
Schneider: One of the fundamental issues is that, as a society, we undervalue
hearing. My firm recently offered fully paid for hearing aids to 69 candidates,
based on their audiograms; ten took advantage of the offer.
Thunder: Hearing aids carry stigma. I see a similar stigma with requiring
people to use HPD @ 85 w/STS.
Hayden: Worker’s Compensation is a non-issue nationally.
Daniel: What about kids entering the workforce?
Franks: NIOSH has had real difficulty recruiting "normal hearing"
young test subjects for HPD research in Cincinnati – we’re having trouble
finding 20 year old kids with normal hearing. Based on NIOSH estimates of
hearing loss, Worker’s Compensation should be $10B annually; in 1986, the
actual amount was $600M.
Meyers: This is in part a generational issue. To our parents’ generation,
hearing loss was considered part of the job. We need to move to or develop a
model of "you take hearing, you pay".
Weinstein: Noise control was a much easier sell in 1975-1980. The technology
is there; interest is not. We’re finding more success in environmental
applications than occupational.
Thunder: Is this, or should it be, a lifestyle issue with retirees?
Fechter: There are fundamental problems and perceptions when dealing with
this issue. Hearing loss is insidious; it has a long onset; it’s non-life
threatening; and there is a real perception that hearing loss is inevitable with
age. Hearing aids are not well accepted. We are seeing, though, some good
activity from organized labor.
James: We need to turn the paradigm from hearing loss to hearing health. We
must establish the cost to society if this trend is unabated.
Banach summarized discussion for the group.
- Need incentives for real change
- Need good examples/models
- Need to frame as not exclusively an occupational issue
- Need to define real costs of HL/lost asset
- Need global perspective
- Need useful information for real workers
- Need help/get word out with small companies and general population
- Best practices distribution
- Focus on quiet designs
- Need passion/emotion
- Need evaluation measures for Hearing Conservation/Hearing Loss Prevention
efforts, Noise Control efforts, and regulatory enforcement
Breakout Session II: Emerging Technologies
Alton Burks chaired this session with 21 in
Dan Johnson – Instrumentation for the 21st Century
Mr. Johnson has worked for many years as a
research scientist in noise instrumentation and the effect of noise on hearing.
He provided an overview of instrumentation and measurement issues.
The current state of the art in noise instrumentation is quite encouraging.
Dosimeters with statistical output, smart sound level meters (SLM), real time
analyzer (RTA) technology, and computer interfaces have made the job of noise
measurement and exposure assessment easier.
There are, however, deficiencies in the currently available instrumentation.
For example, infra- and ultra-sound are not effectively managed currently.
Impulses greater than 140 dB are difficult to manage. The wearer’s voice
continues to be an issue when using dosimeters. While greatly streamlined from
previous generations, the measurement equipment is still too bulky. Long term
measurement remains difficult. Current instrumentation does not integrate
automatic quality control, and perhaps most importantly, the instruments provide
insufficient feedback to wearer.
There are several issues that can and should be addressed in the near future.
We should address the issue of feedback to wearer. We need to get the data
into the hands of the worker.
We need a database of typical noises – a national compendium of exposure
sources and their parameters.
It is technologically feasible to develop an inexpensive overdose
indicator, probably for less than $50, maybe for less than $20, that should
be made available to the general public.
In the slightly more distant future, other technological advances should
provide even better tools for exposure assessment.
Micro-mini instrumentation, perhaps as small as a wristwatch, could make
Noise data could be piggybacked with general health monitoring in a single
instrument that could assess blood pressure, etc.
Instrumentation should be able to assess a combination of noise and
Large exposure and hearing databases should exist for research.
In the most distant future, noise analysis could be related to individual
susceptibility. As we find ways to look at individuals and how they react to
noise exposure from different types of sources, variable analysis could
personalize noise exposure risk with an expert computer system built into the
Improvement is happening now, with the promise of great things to come in the
Richard James: Changing Paradigm, Re-engineer the Process
Mr. James laid out a new vision for hearing loss
prevention and described how some emerging technologies in business
management and exposure assessment could lead to effectiveness in
preventing hearing loss.
The elements of an effective hearing loss prevention process as laid out in
Practical Guide for Preventing Occupational Hearing Loss are a good
starting point for the discussion about re-engineering the hearing health
Audit the program
Adopt Engineering and Administrative controls to minimize risk
Audiometric evaluation to assess the effect of the hazard
HPD as an interim protective measure
Education and motivation to involve the worker in their own hearing health
Recordkeeping as an audit and compliance assessment tool
To effectively change the paradigm, hearing health must be viewed as an
asset, both by the individual and by the business community. To help this
process and give it credibility, we need to develop an economic analysis of
hearing health and implications, tying dollar values to both the direct and
indirect costs of unnecessary hearing loss.
There are safety issues involved with hearing health; no real measure has
ever been taken of the accident related implications of hearing health, hearing
loss, or use of hearing protection. The most compelling arguments, though, may
be societal in nature. Who will bear the eventual long-term cost of hearing
health for our generation? Most likely, this burden will fall on the federal
government through the Medicare program. Thus, bad actors or poor hearing health
managers will outsource their responsibility to taxpayers.
To be effective, we must change the equation such that our perception is not
that hearing loss prevention equates with compliance, but that instead hearing
loss prevention equate with wellness. Hearing health is a wellness issue.
Task-based exposure assessment modeling (T-BEAM) is an emerging technology
that could help in this effort. The systematic collection of task related sound
levels can be a powerful tool in communicating risk to those who can take the
"on the ground" action to protect against the effect of noise – the
Effective campaigns, like the one necessary for this paradigm shift, require
a champion to carry the issue forward. Who are our constituencies, and who are
the potential champions for hearing loss prevention?
- Workers at risk. If we can find a way to make workers aware of the value
of their hearing health and the importance in maintaining their
functionality, they could be the most powerful constituency of all.
- Employers. It is clearly in the best interest of the business community to
maintain a fully functional workforce; to minimize risk of accidents; to
maximize productivity; and to reduce long-term costs through effective
hearing loss prevention and hearing health management. We must learn to
speak to employers and the business community in their language to
effectively promote hearing health as a business asset management issue.
What do employers need to see to make them effective champions for hearing
|Issue scope. Reporting not only STS cases, but the number of workers
showing impairment as well, can give managers incentive.|
|Protective equipment. Managers need to be able to rely on HPD use as an
effective protective measure, at least in the short term. They need HPD that
will adequately protect their workforce without compromising communication
ability, and they need help in selecting the HPDs most appropriate for their
|Audiometric testing progress. Are we testing the appropriate people? Are
we effectively identifying who is at risk? Is hearing test analysis
sufficient to provide useful information for program management?|
|Training initiatives. Training must be oriented to the specific needs of
individuals and specific workplaces. "One size fits all"
compliance oriented training videos are simply not effective.|
|Engineering Benchmarks. Employers must have reasonable noise control
engineering guidelines and benchmarks. Communicate what’s already been
done to encourage broad application.|
We need methods to put the pieces together. At the core, we must develop ways
to identify, protect, and motivate the "at-risk" worker. We must
direct and manage both hearing loss prevention efforts and noise control as
business processes by communicating with the business world in the language they
understand – money. Incorporating the fundamental noise control elements of
buy it quiet (firm commitment to low noise purchase specifications for new
equipment), make it quiet (retrofit noise control where appropriate) and keep it
quiet (motivating workers and training maintenance staffs to ensure that noise
controls are maintained), combined with the development of hard costs for both
effective and ineffective hearing health asset management will enable real
Alton Burks lead the discussion in this area.
Daniel: No good methods are in use for noise studies meeting these criteria.
Brandys: How do we deal with exposure dominated by single frequency, but
where A-weighted exposures are below OSHA standard? This relates to hearing loss
at specific frequencies. The EPA regulations cover this in the community arena
and as nuisance noises, but is not well covered under OSHA. In addition, we need
to clarify the effect of longer workdays – there is confusion under current
Bruce: Can we find an industrial or business perspective on these issues?
Daniel: I’ve heard of some good work from ALCOA in this area. Is that a
Franks: We need a universal database – the Pan European effort may be a
model. They looked at 10 noise areas and include consequences of hearing loss.
Part of this effort was a session on measurement issues. One important aspect is
to harmonize NoiseScan (the European effort) and Hearsaf 2000. We are changing
the function of audiometry away from a recordkeeping effort to a worker
functionality assessment and intervention tool.
Brandys: We must publicize successes.
Franks: The cheap dosimeter is a great concept. How can we convince
instrument manufacturers, the business world, and the public of the utility of
devices like this?
Banach: Public awareness could be a key. Have we addressed hunters, fishermen
with the message "what are you missing?" with hearing loss?
Fechter: Risk communication is the underlying concept.
Rosnowski: Can we use a web page?
Bruce: The current OHSA CPL with100 dB default criteria for engineering must
Palmer: Hearing aid rehabilitation and acclimation could be very effective.
In my personal experience, the military paid for a full week at Walter Reed to
ensure that I understood how to use my hearing aids and could use them
effectively. They included my spouse; that support was critical in my acceptance
of my aids. I believe they have done a study about hearing aid acceptance with
and without acclimation and rehabilitation.
Thunder: Insurers are asking for quantitative quality of life improvement
analysis for insurance payment or hearing aids.
Burks: Should we engage in dialog with "other side"?
Franks: It appears that we’re all on the same side. If we’re going to
"preach to the choir", our goal should be to increase the "size
of the choir". We must learn to express hearing health in corporate
language, and speak in and distill our issues to dollars.
Schneider: In my company, a worker nearly fired due to hearing loss. He
misunderstood verbal instructions, which led to errors in job performance, and
nearly cost him his job and the company an experienced worker.
James: Safety issues could have some significance in communication with the
business community. The recent study in the Journal of the American Medical
Association which correlated "disabilities" which, in this case,
included self-diagnosed hearing loss, and industrial accidents was quite
compelling. In addition, the Dutch Shipyard study in the mid-1980’s showed a
stringer correlation between accidents and hearing loss/high noise that between
accidents and drug or alcohol use on the job. I suggest a research proposal that
would report non-occupational accident correlation to lost workdays, perhaps
using emergency room data, that would measure increased likelihood of accidents
due to compromised hearing health. Could we look at the correlation between high
noise and compromised respirator use? Workers often remove respirators and
hearing protection short-term removal to aid verbal communication.
Bohl: John Casali has done some analysis on the FWHA truck driver criteria in
a similar area.
Bruce: In the 70’s, there was a study done at the Rayethon plant in
Massachusetts correlating noise and accidents. One of the interesting findings
was that noise control resulted in a reduction in absenteeism.
Daniel: How do we disseminate this data?
Franks: We need research in information dissemination.
Rosnowski: Use common TTS measures like the radio test – if the radio seems
too loud when you get in your car the next morning, you were likely overexposed
the previous day.
Thunder: Can we develop improved self-screening technologies, like the
Audio-D Card with test tones or the Beltone piece with words? There have been
speech intelligibility studies done in SCBA for firefighters if that could help.
Breakout Session III: Personal Protective Equipment/Hearing Protectors
John Franks chaired this session with 26 in attendance.
Fredrick Lindgren, Peltor/Aearo Company: HPD Issues for the 21st
Mr. Lindgren and his company are leading
suppliers of hearing protection to industry. His global experience with
alternate methods (used in Europe and elsewhere) for assessing hearing protector
performance provided an analysis of the current state of hearing protection
technology and barriers to effective use.
Noise-induced hearing loss (NIHL) is the most common occupational injury.
With the proliferation of hearing protection, how can this be?
Selection habits could be a mitigating factor. While the Noise Reduction
Rating (NRR) factors on current protectors range from 6 to 33 dB, most
protectors exceed 25 dB, making them suitable for population at risk of exposure
100-115 dB. Evidence indicates that 95% of exposures are 95 dB or less,
requiring less than 15 dB protection. At this level, nearly any HPD will provide
sufficient protection, so why is HPD not preventing NIHL? Several issues come
- Real world performance of HPD is suspect. Laboratory protection values
have not been proven in field performance tests.
- Hazardous levels are not perceived as dangerous by the user.
- Comfort and utilization are key aspects of user acceptance, but are not
- Overprotection. HPD with more than 20 dB NRR results in perception of
isolation by the worker and compromised communication ability.
The HPD rating system may be a contributing factor as well. The NIOSH long
method is a good measure, but relating that to the NRR, which is A-scale based,
is subject to problems with low frequency dominance. The HML method is frequency
specific and uses a dBA – dBC calculation to better estimate effectiveness in
Buying patterns complicate the issue. End users have no control over HPD
purchasing decisions in most cases, and buyers don’t consider comfort when
making selections. NRR and cost are only factors typically considered when
making these decisions.
I offer these recommendations for selection. Where the TWA is less than 100,
any HPD will do. Selection should be based on comfort and utilization. Where the
TWA exposures approach 95, select carefully since with high exposures,
appropriate selection is increasingly critical.
Roadmap for 21st Century
We need to develop realistic attenuation values. We should retire single
number methods of assessing attenuation, and use the HML method where selection
is critical. In place of the NRR, we need to develop single number method for
rating HPD comfort. This will force comfort as R&D issue for HPD
We need standards for non-linear HPD, like active noise reduction (ANR)
hearing protectors and those offering sound restoration. We should evaluate the
impact on of HPD on speech communication, and provide guidelines on using
communication equipment in noisy environments.
Dan Gauger, Bose Corporation: Hearing Protectors and Active Noise Reduction
Mr. Gauger’s firm is active in the field of
active noise reduction (ANR) hearing protection, and developed one of the
first commercially available units. He provided an overview of this
leading edge technology in hearing protection.
Overview of Active Technology
While the application of active noise reduction (ANR) technology may have
been oversold in some situations, especially in industry, the concept dates to
1930’s. It became practical in 1970’s with technological development in
op-amps and miniaturized computers. The first commercial product was developed
for general aviation application in 1989.
The current uses of ANR technology in hearing protection include general
aviation, military communication headsets (primarily in heavy armored vehicles),
consumer products like those offered by NCT, Koss, and Sony, and some limited
We must address some hard realities when discussing ANR in hearing protection
applications. The cost, of course, far exceeds foam earplugs. ANR requires
power, and there are technical issues (the "big woofer" problem and
difficulty in pushing ANR frequency range) which are barriers to widespread
application. ANR is not a panacea, and at worst is a placebo.
Attenuation Measurement Issues
How much attenuation is offered by ANR hearing protectors? The real-ear at
threshold test (REAT) can’t be applied due to the electronic noise floor
inherent in ANR devices. The microphone in real ear (MIRE) test is typically
used, but these methods provide different values for passive devices at low
frequencies. For example, the REAT exceeds MIRE test results by 7 dB at 125 Hz,
and by 2 dB @ 250 Hz. What is the maximum SPL at which ANR works or provides
sufficient protection? ANSI working group S12/WG39 is working on standard to
address these issues.
Attenuation, however, is not the only issue. It is critical to motivate the
worker to use HPD; can ANR improve acceptance? ANR adds a degree of freedom to
HPD design, and permits a reduction in band pressure, increasing comfort in some
situations. This has been very important in the general aviation market.
Could ANR increase situational awareness in areas such as conversation,
machine noises, warnings, and alarms? HPD use is a safety issue, and ANR
technology has the potential to be a benefit in this area. ANR sounds different
to the user as well due to flatter response. Different earcanal occlusion
effects could be a factor.
ANR is a proven technology, but is a tough sell to industry. There are
important questions yet to be resolved, including the benefit of increased
worker acceptance; improved situational awareness; improved safety, and improved
user comfort all speak to the underlying issue - what’s the added value in ANR
Kevin Michael, Michael & Associates, Inc.: Comprehensive Use of Hearing
Protectors: Integration of Training, Field Monitoring, Communication, and
Dr. Michael is a professor and researcher,
and is the developer of a new technology to assess the fit of hearing
protectors in a field environment. He discussed the importance of
individual HPD fit and new technology related to field fit-testing of
Where do hearing protectors fit in the world of currently available HC
services? The noise control programs have no consideration of HPD use; the
hearing testing program has no consideration of HPD use; and the HPD
manufacturers have concern only for highest NRR. There is little emphasis on HPD
management, little support for OHCs on HPD selection, and scattered support for
training & motivation on HPD application.
ANSI working groups are looking at some aspects of HPD management to address
some of these issues. Working Group S12/WG35 is trying to standardize a method
for HPD selection to maximize communication ability in specific noise
environments, and Working Group S12/WG11 is developing lab methods to estimate
HPD field effectiveness; standardizing rating systems; and standardizing field
monitoring systems to assess individual HPD fit.
There are some field monitoring systems currently available and in use.
FitCheck is used for insert HPD like earplugs. It replicates the lab procedure
under headphones and provides objective measurement of HPD attenuation on
individual user. It has been field tested at ALCOA Cleveland and Lebanon, PA;
Latrobe Steel; Alyeska Pipeline; and with the US Army.
Spectrum is a important factor in HPD effectiveness. An earmuff with an NRR
of 24 was tested under varying spectral conditions. It showed a field test NRR
of 24 dB protection in a flat spectrum; 35 dB in a rising spectrum (High
frequency intensive); and 8 dB in a falling spectrum (Low frequency intensive).
A dual microphone system is available for testing earmuffs.
The European Union has developed guidelines for sound levels under hearing
protectors to maximize communication ability (EN 458). Using octave band
analysis, calculate A-weighted sound level under protector. These are the EN458
|L(ear), the A-weighted sound level at the ear under the hearing protector
>85 dB(A) is insufficient protection|
|L(ear) 80 dB(A) to 85 dB(A) is acceptable|
|L(ear) 75 dB(A) to 80 dB(A) is good|
|L(ear) 70dB(A) to 75 dB(A) is acceptable|
|L(ear) less than 70 dB(A) is overprotection|
Maximizing communication while using HPD encourages full shift use and
discourages the "more is better" assumptions underlying HPD purchasing
in industry. In addition, it provides a basis and incentive for manufacturers to
develop wide range of comfortable, moderate attenuation HPD.
John Franks, NIOSH: Carpenter Training Video
Dr. Franks is Chief Scientist in NIOSH’s BOVS
office in Cincinnati, and leads their effort in hearing loss prevention.
Franks provided a copy of a NIOSH training video developed in conjunction
with the Carpenters union intended for new apprentices. It had strong focus
on personal responsibility and HPD, and was set in a real context. His brief
comments preceding the viewing of the tape centered on the difficulty
managing the noise exposure of temporary or itinerant workers, specifically
in the construction trades where machismo tends to make the workers resist
using PPE. The video was produced with a shift in focus from
train-the-trainer to train-the-worker, to make each worker more
knowledgeable and accountable for their own hearing health. A specific
reference was made of the use if tinnitus in the video, with the thought
that since it is a more immediate result of overexposure to noise than is
hearing loss, it may be a superior motivator for trainees.
Discussion of this portion of the breakout was
facilitated by John Franks.
Thunder: Is the 7dB C to A correction used in NRR calculations based on NIOSH
studies of typical industrial spectra?
Franks: We find it to be more inclusive than using C alone.
Lindgren: A 5 dB correction may be better, but any single correction factor
will be wrong.
Meyers: We’ve received many calls on OSHA’s 50% derating scheme; we feel
it leads to overprotection with proper HPD use.
Johnson: Where did "95% exposures <95 dB" come from?
Franks: From the BBN study in the 1970’s.
Daniel: How can we assess the effect of a video like this without audiometric
Franks: We use worker observation and questionnaire techniques, which have
proven quite effective.
Unknown: I have questions about the intermittency correction factor; should
we use a 5 dB exchange to 100 dB and 3dB above that?
Lindgren: Yes, we should vary exchange rate by level
Anderson: For Kevin Michael – Was the ALCOA fit test used for research or
for training/motivation of the workers?
Michael: It was actually used for both. We tested from 250 to 2k; the test
took 5 to 7 minutes. Currently, the test equipment costs about $3k, but that’s
building single units. It’s possible to build this kind of test into the
audiometer as well.
Daniel: How much of the world does NONE of this?
Bruce: For Dan Johnson – I see great potential in your technology ideas.
Could we tie the HPD in with hard hat and throat mic for communication? Build
two-way radios, other biological monitoring, and, "man down" warning
systems into the unit to add value.
Gauger: Similar ideas are under consideration now.
Meyers: For Michael – Did you test repeatability and consistency in fit
testing day to day?