Transcript PART62

30 CFR Part 62:
MSHA Standards for
Occupational Noise Exposure
Noise Induced Hearing Loss
• Among the top ten work-related
illnesses according to National
Institute of Occupational Safety &
Health (NIOSH)
• 24,000 M/NM miners at risk under old
rule (30 CFR 56/57.5050)
Mining - “High Risk” Occupations
Task Area:
Jobs:
Drilling/Cutting
Wagon/Rotary Drill, Jachammer, &
Stone Saw Operators
Haulage
Truck, Bulldozer, Front-End-Loader,
Shovel, Dragline, & Dredge Operators
Plant/Mill
Plant Workers: Crushing, Sizing,
Washing, Grinding, & Bagging
Maintenance
Laborer, Cleanup, Mechanic,
& Welder
What is Noise?

Unwanted or
undesired sound
Sound is Vibrational Energy
Travels in Waves
from a Source
FREQUENCY
INTENSITY
Cycles per Second
Decibels (dB)
Hertz (Hz)
Characteristics that Determine the
Degree of the Noise Hazard:
1. Intensity (volume, loudness)
2. Frequency (pitch)
3. Duration of exposure
Common Frequencies
Hertz (CPS)
63 125 250 500 1000
2000
4000
-trombone-- ----------piccolo----------------
----truck----
8000
-------compressed air noise----------------
-------------speech---------------
Decibel (dB)
• A unit of measure of sound
pressure levels
• 20 times the common log of the
ratio of the measured sound
pressure level to the threshold
of hearing @ 1000 Hz
• NOT SIMPLE MATH!!
Relationship between intensity and
decibels for measuring hearing
dB
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
Intensity
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
100,000,000
1,000,000,000
10,000,000,000
100,000,000,000
1,000,000,000,000
10,000,000,000,000
100,000,000,000,000
(1 thousand times)
(1 million times)
(1 billion times)
(1 trillion times)
Common Sound Levels
Pain Threshold
Channel Burner
Chain Saw
Air-Track Drills
Large Haul Trucks
Bulldozers
Scrapers
Front-end Loaders
Rock crusher
Street Traffic
Normal conversation
Inside house
Soft Whisper
Threshold of hearing
140 dB
125 dB
120 dB
115 dB
109 dB
107 dB
104 dB
101 dB
94 dB
83 dB
60 dB
45 dB
10 dB
0 dB
What Difference Does 5 Decibels Make?
• MSHA uses a 5-dB doubling factor
as the basis of its regulations
• With every increase in exposure of
5 dB, the worker’s allowable time in
an area is cut in half.
• 3 dB is the mathematically correct value
& is used for noise control engineering
Permissible Noise Exposures
Duration per day
Sound level
(hours of exposure)
(dBA, slow response)
8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
1-1/2 . . . . . . . . . . . . . . . . . . . . . . . . . 102
1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
1/2 . . . . . . . . . . . . . . . . . . . . . . . . . . 110
1/4 or less . . . . . . . . . . . . . . . . . . . . 115
Noise Measurement
• Expressed as a “dose,” or percentage of
allowable limit, where 90 dB is the
criterion & 5 dB is the exchange rate
• TWA of 90 dB for 8 hours = 100%
• Measured on “A” scale & slow response
• Either by dosimeter or sound level meter
• Personal sampling
“A” Weighting (dBA)
50 HZ
at
95 dB
5000 HZ
at
76 dB
PERCEIVED AS EQUALLY LOUD BY THE HUMAN EAR
Adjust the dB Scale to Account for
the Ear’s Sensitivity to Different
Frequencies
The Human Ear
• The ear of an average,
healthy, young adult
can respond to
frequencies in the range
of 20 Hz to 20,000 Hz
• The human ear is most
sensitive to sounds of
1000 Hz to 4000 Hz
Anatomy of the Human Ear
Transmission of Vibrations through Inner Ear
Oval Window
Long Waves (Low Frequency
and Low Pitch) act at top of
the Cochlea
Ossicles
Round Window
Short Waves (High Pitch and High
Frequency) act at the base of the
Cochlea
Early Signs of Hearing Loss
• Ringing in the ears after a noisy activity
• Difficulty understanding what people say
• Turning up the volume of the TV or radio
when others hear fine
• Not hearing background noises such as
the telephone or doorbell
Cross-section Normal Cochlea
with Hair Cells
Cross-section Damaged Cochlea
& Loss of Hair Cells
Temporary Threshold Shift
• Hearing loss may initially be
temporary
• Ear becomes fatigued by noise
• Recovers after a period of rest
• Pattern repeated for months &
years
Leads to:



Permanent threshold shift
Standard threshold shift (STS)
Change in hearing threshold relative to
the baseline - An average of 10 dB or
more at 2K, 3K and 4K Hz in either ear.
May Lead to:



MSHA Reportable Hearing Loss
Change in hearing threshold relative to
the baseline - An average of 25 dB or
more at 2K, 3K and 4K Hz in either ear.
Or, an award of compensation.
Problems:
• Can’t give and receive
instructions
• Can’t hear warning signals
• Hard to communicate
• Can’t hear sounds from machinery
• Reduced communication leads
directly to accidents
30 CFR Part 62: Compliance Levels
• Action level =
TWA8 of 85 dBA or 50% dose (80 - 130 dBA)
• Permissible Exposure Level (PEL) = TWA8 of
90 dBA or 100% dose (90 - 140 dBA)
• Dual Hearing Protection Level =
TWA8 of 105 dBA or 800% dose
(90 - 140 dBA)
• 115 dBA maximum sound level
What triggers an MSHA citation?


Any miner’s full-shift exposure > 2 dB*
above an allowable exposure level (i.e.,
85, 90, 105)
– measured via personal dosimeter using
“A” scale & slow response
Any exposure > 2 dB* above 115 dBA
maximum sound level via SLM using “A”
scale & slow response
* 95% confidence limit
Controlling Noise Exposure


If MSHA (or operator) determines exposure
exceeds PEL (TWA8 of 90 dBA or 100% noise
dose), feasible engineering and administrative
controls required (if capable of achieving
significant reduction).
This requirement applies even if the final noise
level continues to exceed the PEL.
– In addition to engineering and administrative
controls, adequate hearing protectors also
required.
Feasible Control &
Significant Reduction


Feasible Control means:
– The control reduces exposure.
– The control is economically achievable (costs
proportionate to “expected benefits”).
– The control is technologically achievable
(need not be “off-the-shelf,” but must have
realistic basis in present technology).
Significant Reduction means a reduction of
3 dB or greater.
Noise Reduction Methods
• At the Source:
- Select quiet equipment
- Reduce speed, impact or impulsive
force in machines
• In the Transmission Path:
- Separate noise and receiver (booths/cabs)
- Use sound absorbing materials
• At the Receiver:
- Reduce exposure time
- Alter work schedules
- Hearing protective devices (last resort)
Summary: Actions Required By Operator
Section
Condition
Action Required
62.120
TWA8 < 85 dBA
No action required
62.120
TWA8  85 dBA,
but  90 dBA
Enroll miner in HCP per
62.150, HP use optional
62.130
TWA8 > 90 dBA
Use all feasible engrng
and/or admin controls;
enroll miner in HCP;
ensure use of HP; post &
provide any admin controls
62.140
TWA8 > 105 dBA
Ensure use of Dual HP; all
62.120 and 62.130 actions
System of monitoring
• Operator must establish a system of
monitoring that evaluates each miner’s
exposure to determine continuing
compliance
• Evaluation must reflect a full work shift
• Operator must notify the miner of
results and any proposed actions within
15 days if TWA8 of 85 dBA or 50% dose
or higher is measured
What is a system of monitoring?
• A way of relating the miner’s daily noise
dose* to a measurable parameter, such
as:
- Hours worked
- Tonnage produced or consumed
- Other data
*
Expressed as % dose where 8 hours @ 90 dBA
or 100% dose.
Who is covered by the system
of monitoring?
• The system of monitoring must
provide an initial exposure
assessment for all miners on site
• It must ensure continuing
compliance of all miners’ exposures
with the standard (Both Action Level
and PEL)
Does the operator have to do
noise monitoring?
• No - the operator can base the
system of monitoring on exposure
predictions (i.e., other data)
• The operator can protectively place
all miners in the HCP
What Other Data ?
• MSHA’s or other historical
monitoring (available from MSHA Web Page)
• Representative personal monitoring
• Manufacturers’ information (e.g., cab
noise levels in a Front-End-Loader)
When does this have to be done?
• The standard was effective 9/13/00 - a
year after publication.
• Exposure assessments for existing
operations were to be completed by
then.
• Complete audiometric testing by
3/13/01 or 9/13/01*
*
If using mobile van option
What are the operator’s
responsibilities if the miners are
protectively placed into the HCP?
• All provisions of the HCP apply
• This includes notification, provision
of PPE, audiograms, initial training,
& recordkeeping
• Within the established deadlines
• Evaluate exposures for compliance
with PEL!!!
Who should be included if the
operator elects to sample ?
• A least one miner as a representative
of each exposure group (e.g., all
Euclid R-50 haul truck drivers)
• Representative monitoring assumes
that all miners doing the same
operation with the same equipment
have the same exposure
Do I have to sample for the
whole shift?
• No - But, all exposure models have to
reflect the miner’s full-shift exposure
• As long as the exposure interval is
representative of the whole day’s
exposure you can simply adjust for
the rest
How?
• The mine operator can assume* that the
percent noise dose is accumulated in a
predictable fashion
• For example:
 40% in 5 hours = 8% dose per hour
 Therefore, a 12-hour shift @ 8% dose
per hour = 96% dose per shift
*
MSHA inspectors can’t assume - they must
measure miner’s actual full-shift dose!
Hearing Conservation Program:
• If AL (or higher) is exceeded* a Hearing
Conservation Program that includes the
following must be in place (or instituted):
- A system of monitoring
- Provision & use of PPE
- Audiometric Testing
- Training
- Recordkeeping (i.e., monitoring results,
notifications, audiograms, training certification, etc.)
*
Or if miners are protectively placed into HCP
Hearing Protectors
• Provided by mine operator at no
expense to miner (in HCP) including
replacements
• Choice of 2 muff & 2 plug types
• Maintained & fitted per manufacturers’
instructions
• Voluntary use < PEL*, Mandatory at or
above
*
Required until baseline audiogram or if an STS
has been detected
Hearing Protection
• IF WORN CORRECTLY & FITTED
PROPERLY:
- Effective within limits of bone
conduction & transmission through
absorbing material
- Comfortable fit more important than
high NRR
Audiometric Testing
• Under supervision of physician,
audiologist, or qualified technician
• Initial within 6 months of entry into HCP
(or 12 months if a mobile van is used)
• Annually (thereafter, as long as in HCP)
• Voluntary on the miner’s part
• Initial, annuals, and followups* at no
cost to miner
*
unless not occupationally related
Test Procedures
• Must use scientifically valid procedures
(OSHA’s specified procedure is OK)
• Pure tone, air conduction, hearing
threshold, @ 500, 1000, 2000, 3000,
4000, & 6000 Hz in either ear
• Operator provides results within
10 working days
• Followup if indicated
Understanding Audiograms
125
250
500
1K
2K
3K
4K
6K
8K
-10
0
BASELINE
10
20
30
40
50
ANNUAL
Determine if Any Hearing Loss
125
250
500
1K
2K
3K
4K
6K
8K
-10
0
BASELINE
10
20
30
40
50
16
9
8
ANNUAL
Determine if STS or Reportable
125
250
500
1K
2K
3K
4K
6K
8K
-10
0
BASELINE
10
20
30
40
50
16 + 9 + 8 = 33
33 / 3 = 11
Reportable ?
NO
16
9
8
ANNUAL
Determine if STS or Reportable
125
250
500
1K
2K
3K
4K
6K
8K
-10
0
BASELINE
10
20
30
40
50
16 + 9 + 8 = 33
33 / 3 = 11
Reportable ?
STS? YES
NO
16
9
8
ANNUAL
25 Years Later . . .
Is there a Reportable Hearing Loss?
Loss at 2K, 3K, and 4K
(from Baseline to Annual)
27 + 37 + 35 = 99
99 / 3 = 33
Reportable?
YES
What if the initial audiogram indicates
occupational hearing loss?
• On an initial (baseline) audiogram,
this is not reportable, unless there is
an award of compensation under the
local workers’ compensation criteria
• File a 7000-1 if compensation is
awarded
What type of training?
Within 30 days of enrollment in HCP, and
every 12 months thereafter, miner must
be trained in:
B
B
B
B
B
B
effects of noise on hearing
purpose and value of wearing HPDs
advantages/disadvantages of HPDs
care, fitting and use of HPDs
general requirements of Part 62
operator/miner responsibilities regarding
controls
B purpose and value of audiometric testing
Recordkeeping
• Mine Operator maintains a complete
record for length of miner’s employment
plus 6 months
• Copies available to MSHA (DOL) &
NIOSH (HHS) representatives within
1 business day
• Copies of records available to miner,
miner’s written designee, former miners,
& miner’s representatives within 15 days
What happens when a new
operator acquires the mine?
• The baseline audiograms convey for
the purposes of determining an STS
or reportable hearing loss
• Doesn’t apply to a successor
operator hiring a miner who has
never worked at that location
What if the miner moves to a
different mine?
• A miner transferring from one
property to another may still have the
same employer
• And may still meet the local criteria
for workers’ compensation
• The current mine operator is
responsible for submitting the 7000-1
Can the operator hold the miner
responsible for the cost of
replacement hearing protection?
• No - the cost for initial and
replacement PPE is borne by the
operator for each miner in the HCP
• Don’t have to buy the most
expensive if the loss rate is too high
What about fitting &
maintenance of PPE?
• Any required PPE must be fitted &
maintained per manufacturers’
specifications
• Proper fitting is an indicator of good
training
Thank You