Noise Monitoring

1
Noise Monitoring Your Hearing Conservation
Program

• Monitor noise exposure at your Mine site using a
  Sound Level Meter or Dosimeter, and develop a
  Hearing Conservation Program,
• Michigan Mine Safety Health Training Program

2
Introduction

• 30 CFR Part 62 is the new MSHA Noise Standard.
  The following presentation provides current
  information on this regulation, and is based on
  material that was presented to Michigan mine
  operators in hands-on noise sampling workshops in
  2001.
• No specific claims are made concerning the
  accuracy of the information presented here.

3
Printed Materials Needed for this Presentation.

• Printed Materials
• There are hardcopy forms, tables and examples
  that go with this presentation. Make sure they
  are available.
• Please note that the MSHA Noise standard does not
  dictate the format of forms. The forms presented
  here are suitable for recording purposes, but you
  may design your own.
• The Printed Materials we've provided have been
  numbered in the order that they are presented.
• Form numbers are in the upper right-hand corner
  of the form.
• Some forms consist of more than one page.

4
Minimum Equipment Needed for this Presentation.

• A slow-response 'A' scale Sound Level Meter (SLM)
• Make sure you have the manufacturers
  instructions.
• SLMs may be purchased for as little as 40 from
  electronics stores.
• Field Calibrator for the SLM
• Instrument Calibrators confirm the accuracy of
  readings.

5
Other Equipment Included in this Presentation

• Dual-Threshold Dosimeter
• Simultaneously measures Action Level PEL noise
  doses.
• Must be able to be set to slow response on the
  'A' scale. (This is the default setting for most
  dosimeters.)
• Field Calibrator for Dosimeter.

6
Purpose of this Presentation

• Objectives
• To provide you with basic Noise Hazard
  Information
• To show you how to do proper Noise Sampling,
  Noise Dose Calculation, and Record Keeping.
• To prepare you to administer a Hearing
  Conservation Program (HCP) meeting MSHA's
  requirements.
• Regulations of Concern
• Noise Sampling - CFR 30 62.110
• Hearing Conservation Program - CFR 30 62.150

7
Noise Basics

• The two factors that determine how hazardous
  noise is are
• Intensity (Loudness) measured in dBA
• Time of Exposure measured in Hours and Minutes
• The louder the noise, the more hazardous it is.
  Also, the longer the exposure time, the more
  hazardous the noise is.
• A Noise Dose combines both loudness and time
  and is a convenient way of describing the
  relative hazard of the noise.

8
Noise Basics

• Loudness is measured using a logarithmic scale.
  This
• means that a 10 decibel increase does not simply
  add 10
• to the previous level. It multiplies the previous
  level by 10.
• Threshold of Hearing 0 dBA
• Quiet Room 45 dBA
• Conversation 55 dBA 45 dBA x 10
• Car (50 mph at 50 ft) 65 dBA 45 dBA x 100
• End Loader (In Good Cab) 75 dBA 45 dBA x
  1,000
• Haul Truck (In Good Cab) 85 dBA 45 dBA x
  10,000
• Crusher 95 dBA 45 dBA x 100,000
• Old Dozer (No Cab) 105 dBA 45 dBA x 1,000,000
• Air Track Drill (No Controls) 115 dBA 45 dBA x
  10,000,000
• 115 dBA has 10 million times more sound energy
  than 45 dBA and is
• capable of causing 10 million times more damage
  to hearing.

9
Noise Basics

• Allowable Noise exposure is based on Noise Dose.
• Noise Dose is expressed as a percentage of the
  allowable
• limit. How high it goes depends on both noise
  intensity
• and time of exposure to noise.
• Louder (More dBA) More Noise Dose
• Longer (More Time) More Noise Dose
• Absolute Quiet 0 Noise Dose.
• 85 dBA for 8 Hrs 50 Noise Dose.
• 90 dBA for 8 hrs 100 Noise Dose.
• 95 dBA for 8 Hrs 200 Noise Dose.
• 95 dBA for 12 Hrs 300 Noise Dose.

10
Noise Basics
Different combinations of Loudness and Time can
produce the same Noise Dose. The following
combinations can all produce about 75 Noise Dose.

• 84 dBA for 14 Hrs 76
• 85 dBA for 12 Hrs 75
• 87 dBA for 9 Hrs 74
• 88 dBA for 8 Hrs 76
• 93 dBA for 4 Hrs 76
• 95 dBA for 3 Hrs 75
• 98 dBA for 2 Hrs 75
• 103 dBA for 1 Hr 76
• 108 dBA for 30 Min 76
• 113 dBA for 15 Min 76

Note this table is based on using the 80 dBA
(Low) threshold.
11
Noise Dose Table
For the next several slides, refer to the Noise
Dose Table in your printed materials. This is
Table 1. A Noise Dose table is used to look up
the Noise Dose when 'noise-level exposure-time'
are known. (Please note that the table shown in
the following slides are not an exact duplication
of the real Noise Dose table.)
12
Exposure Time
Exposure times (in Hours) are listed across the
top of the table. (Shown here in red.)
NOI SE LEVEL IN dBA
Exposure Time (Hours)
.25 .5 1 2 3 4 5 6 7
8 9 10 11 12
85 86 87 88 89 90 91 92 93 94 95
13
Noise Levels
Noise Levels (in dBA) are listed down the left
side of the table. (Shown here in green.)
NOI SE LEVEL IN dBA
Exposure time in Hours
.25 .5 1 2 3 4 5 6 7
8 9 10 11 12
85 86 87 88 89 90 91 92 93 94 95
14
Estimating a Noise Dose Using the Table
1. Measure the Decibel Level. (We will discuss
methods for doing this later.) 2. Measure or
estimate Exposure Time. 3. The Noise Dose is
found at intersection of Decibel Level and
Exposure Time. (Yellow Box)
NOI SE LEVEL IN dBA
Exposure time in Hours
.25 .5 1 2 3 4 5 6 7
8 9 10 11 12
85 86 87 88 89 90 91 92 93 94 95
Noise Dose for 92 dBA for 6 hours
15
Using Noise Dose Table if Noise Levels vary.
1. If Noise Levels vary, divide shift into
separate tasks. 2. Determine Dose for each task,
then add the doses.
NOI SE LEVEL IN dBA
Exposure time in Hours
.25 .5 1 2 3 4 5 6 7
8 9 10 11 12
85 86 87 88 89 90 91 92 93 94 95
16
REVIEW

• 1. Loudness is measured in dBA
• Quiet Room 45 dBA
• Crusher 95 dBA
• Air Track Drill 115 dBA
• 2. Noise Dose Loudness Exposure Time
• Quiet (45dBA)for 8 Hrs 0 Noise Dose
• Crusher (95dBA) for 8 Hrs 200 Noise Dose
• Air Track Drill (115dBA) for 8 Hrs 3,200
  Noise Dose
• (The dBA level alone does not define noise
  hazard!)
• 4. Use Noise Dose Table to determine the hazard.
• 5. Noise Dose defines the noise hazard.

17
Noise Table Exercises
(Answers on next slide.) Use the Noise Dose
Table to figure out the Noise Dose for the
following conditions 1) Noise exposure is 88
dBA for 10 Hr What is Noise Dose ? 2) Noise
exposure is 84 dBA for 4 Hrs and 94 dBA for 6
Hrs. (Remember Figure the two noise doses
separately and then add them.) What is the
total Noise Dose ?
18
Noise Table Exercises - Answers
1) 88 dBA for 8 hours 95 Noise Dose 2) 84 dBA
for 4 hours, plus 94 dBA for 6 hours 152
19
Noise Table Exercises

• 3) Noise exposure is 79 dBA for 2 Hrs, 92 dBA for
  3
• Hrs, 81 dBA for 3 Hrs, 87 dBA for 30 Min, 90
  dBA
• for 1 Hr, and 82 dBA for 30 Min.
• What is Noise Dose ?

20
Noise Table Exercises - Answer
Answer to Exercise 3 79 dBA is under 80 dBA and
is not counted toward the Noise Dose. The Noise
Dose is obtained by adding the rest of the
calculated doses is 79.
21
Time Weighted Average (TWA8)
The 'TWA8' is the Noise Level (dBA) which, if
constant over 8 hours, would result in the same
Noise Dose as the one calculated using the actual
exposure time. Example If a worker's Noise Dose
from a 10 hour shift is 400, what constant Noise
Level (in dBA) over 8 hours would produce the
same Dose? The answer is on the Noise Dose
Table. Find "400" in the the "8 hour" Exposure
Time column. Follow the row left to the Noise
Level, which, in this case, is 100 dBA. The TWA8
value for any Noise Dose equaling 400 is 100 dBA
.
22
Time Weighted Average (TWA8) - Continued
Why use TWA8? Why not just use Noise
Dose. Because the "TWA8" (which is expressed in
dBA, rather than a percentage) is easier to use
when applied to noise controls. Example If one
knows that the noise level in an area is kept
below 90 dBA, for the full 8 hour work shift,
then the 90dBA PEL has not been exceeded. Trying
to think of this in terms of percentages is
awkward. Action Level 85 dBA
(TWA8) Permissible Exposure Limit 90 dBA (TWA8)
Double Hearing Protection Level 105 dBA (TWA8)
23
Noise Sampling And Hearing Conservation Program
To obtain the full benefit of this section, make
sure any noise sampling equipment you have is at
hand.
24
62.110 - Noise Exposure Assessment

• The mine operator must establish a system of
  monitoring
• that evaluates each miners noise exposure
  sufficiently
• to determine continuing compliance with this
  part.
• Note that 'monitoring' is not the same thing as
  'sampling'.
• Self-sampling is only one of several types of
  'monitoring'
• allowed by the standard. Other types of
  monitoring can
• include the following
• 1. MSHA compliance sampling. (MSHA does the
  sampling.)
• 2. Equipment Manufacturer Specifications. (The
  equipment manufacturer does the sampling.)
• Regardless of the method, adequate records must
  be kept
• to prove that monitoring is being done.

25
How Often Is Noise Sampling Required ?

• There is no mandatory sampling schedule. However,
  employee noise exposure records must accurately
  reflect the current noise conditions at the mine.
• The mine operator must decide whether existing
  records (Self sampling, MSHA sampling,
  Manufacturer Specs., etc.) reflect current
  conditions.
• If noise exposure has not changed, further
  sampling may not be needed.

26
Noise Sampling

• Two types of instruments commonly used for
• measuring noise are
• Sound Level Meter (SLM)
• Cost as low as 40. Takes single noise
  measurements. (Because of this, a great deal of
  work must be done to calculate Noise Doses.)
• Noise Dosimeter
• High-cost instrument (2000 and up). Takes
  measurements constantly and does all the work of
  calculating Noise Dose.
• Your printed documentation includes detailed
  sampling checklists for both an SLM and a Noise
  Dosimeter.

27
Sound Level Meter (SLM)

• Sound Level Meter (SLM)
• Only gives instantaneous Noise Level readings.
• The readout is in dBA.
• Normally used to spot check Noise Levels.
• Can be used to determine Noise Dose (with
  calculations).
• The accuracy is 2 dBA.
• Readings tend to err on the low side. Add 2 dBA
  to SLM readings before recording them.
• Always read manufacturers instructions for proper
  SLM operation.

28
Dosimeter

• Always be familiar with manufacturer's
  instructions for proper operation.
• A typical dosimeter is usually capable of
  displaying the following information
• Run Time From Start Of Sampling
• Low Threshold (Action Level) Noise Dose
• Low Threshold Average Noise Level
• High Threshold (PEL) Noise Dose
• High Threshold (PEL) Average Noise Level
• Sound Level Meter (Readout in dBA)
• Maximum Noise Level Over A 1-Second Period
• Time After Start Of Sampling When Max 1-Second
  Noise Level Occurred
• Maximum Noise Level Over 1/16 Second Period
• Projected 8-Hr Noise Dose
• Time After Start Of Sampling When Noise Level
  Greater Than 115 dBA Occurred

29
SLM Exercise 1- Calibration

• For these Exercises you will need a calibrator.
  This can be either be
• a single or a multiple noise level calibrator.
  You will also need your
• Sound Level Meter (If you have a Dosimeter,
  switch it to SLM mode.)
• 1. Insert instrument microphone into the
  calibrator.
• 2. Turn on instrument and set it to read on the
  'A scale' and at the 'slow response' setting. If
  you are using a dosimeter, switch it to Sound
  Level Meter (SLM) Mode.
• 3. Turn the calibrator to the lowest dB level.
  What is the Noise Level ? Your instrument should
  read within 1 dBA of the level indicated on the
  calibrator.
• 4. If your calibrator is a multi-noise level
  calibrator, repeat the above step for all noise
  levels on the calibrator.

30
SLM Exercise 1- Calibration Continued

• You have just calibrated your Sound Level Meter.
• Calibrate your instrument whenever you do noise
  sampling.
• One Pre-Sampling Calibration and One Post-
  Sampling Calibration per day is acceptable.
• If the SLM readout is within 1 dBA of
  calibrator setting, then instrument is reading
  accurately.

31
SLM Exercise 2 - Proper fit

• 1. Turn the calibrator on (Any Noise level will
  do).
• 2. Leave microphone in the calibrator
• What is the Noise level?
• It should be within 1 dBA of Noise level
  indicated on the
• calibrator.
• 3. With the calibrator on, slowly remove the
  microphone.
• What happens to the Noise level?
• It should drift down. This illustrates the need
  for a proper fit
• between the calibrator and instrument.
  Calibrators are
• usually designed to be used with only one type
  of
• instrument. Some calibrators come with special
  collars or
• fittings that allow them to be used with
  different instruments.
• 4. Always follow the calibrator manufacturer's
  recommendations.

32
Using A Sound Level Meter (SLM)

• 1. Set the SLM to read on the 'A' scale at 'Slow
  Response'.
• 2. Always put the windscreen over the
  microphone. Wind noise can seriously effect
  accuracy. Windscreens are precision manufactured
  from special materials. Do not use a substitute.
• 3. If the needle (analog readout) or the number
  (digital readout) is bouncing on the SLM, take
  the highest value as your official reading.
• 4. Add 2 dBA to this value before recording it.
• 5. Take frequent measurements at different times
  of the day, and whenever the task or the noise
  exposure changes.
• 6. Hold SLM at arms length away from your body.
  Point the microphone up. Do not place your body
  between the SLM and the noise source and, do not
  place the SLM between your body and the noise
  source.
• 7. If measuring personal exposure, hold SLM next
  to subjects ear on the Noisiest side.
• 8. Document, Document, Document

33
SLM Documentation Forms

• Your printed material includes SLM documentation
  forms. (See Blank Forms 1.1 thru 2.2, and filled
  out Example Forms 3.1 thru 6.2)
• Always record your name, date, location, time,
  noise sources, noise controls, work activity, SLM
  data, and calibration.
• If you are simply spot checking noise levels, you
  can record this information on Table A of Form
  1, and nothing further need be done.
• If you are measuring personal noise exposure, you
  must
• Complete Table A on Form 1.1, 1.2
• Complete Table B on Form 1.2
• Complete Entire Form 2 (both 2.1 and 2.2)
• Instructions for filling out forms are on the
  forms.

34
SLM Documentation - Sample Forms 3.1, 3.2
Loader Operator

• Note that in table A, fractional dBAs are
  rounded up to the next whole number.
• Note the number of sound level readings taken and
  the accompanying activity documentation.
• The more thoroughly you document the monitored
  activity, the more accurate will be your final
  estimate of noise exposure.
• Measure often.

35
SLM Documentation - Sample Form 3.2
Loader Operator - Continued

• Go to Table B On Form 3.2. The estimated total
  shift times spent at
• various noise levels are recorded here. Note that
  any readings from
• Form 3 that were below 80 dBA were not counted.
• Noise Level Total Estimated Shift Exposure time
• 80 dBA .....1 hr.
• 83 dBA (100 200 300). 6 hr.
• 84 dBA .....1 hr.
• 85 dBA .....1 hr.
• Remember The more measurements made, the more
  accurate the
• estimates.

36
SLM Documentation - Sample Forms 5.1, 5.2
Crusher Operator

• In this example, the job of Crusher Operator is
  more complex than the Loader Operator. Therefore,
  it is even more important to measure often and
  thoroughly document the activity. (Table A)

37
SLM Documentation - Sample 1b Continued
Crusher operator - Continued

• Go to Form 5.2, Table B. The estimated total
• shift time at the various as noise levels are
• recorded as follows.
• Noise Level Total Shift Exposure Time
• 83 dBA for 215 .rounded up to 300
• 84 dBA for 115 100 350 ....600
• 87 dBA for 015 .015
• 92 dBA for 045 040 ....rounded up to
  200
• 112 dBA for 003 ...rounded up to 015

38
Figuring the Noise Doses from SLM Data

• How much noise is TOO MUCH ?
• Two Noise Limits are defined in the Part 62 Noise
  Rule
• Action Level (AL)
• Permissible Exposure Limit (PEL)

39
New Noise Rule - Action Level

• The minimum Noise Dose at which you must take
  action.
• The Action Level is defined as a 50 Noise Dose
• (using the 80dBA Low Threshold instrument
  setting),
• which is equal to a TWA8 of 85 dBA
• The Action Level Noise Dose includes the all
  noise
• between 80 dBA and 130 dBA called the Low
  Threshold
• Noise Dose.
• If a miner's Noise Exposure over an entire work
  shift
• equals or exceeds the 50 Action Level, the miner
• must be enrolled in the company's Hearing
• Conservation Program as per 62.150

40
New Noise Rule - Permissible Exposure Limit

• Permissible Exposure Limit (or PEL) is defined as
  a 100
• Noise Dose, which is equal to a TWA8 of 90 dBA.
• The PEL Noise Dose includes all noise between 90
  dBA
• and 140 dBA This is called the High Threshold
  Noise
• Dose.
• If a miner's exposure exceeds the PEL
• Feasible engineering and administrative controls
  must be applied.
• The miner must enroll in the company's Hearing
  Conservation Program as per 62.150.
• Double hearing protection must be worn if Noise
  Dose is higher than 800 (where the TWA8 105
  dBA.)
• No exposures above 115 dBA are allowed (based on
  a 30 second average reading.)

41
Sampling for the Action Level and the PEL

• Sampling must include Action Level Noise Dose AND
  PEL Noise Dose.
• The Action Level Noise Dose must include all
  noise from 80 dBA to 130 dBA (80 dBA Threshold).
• The PEL Noise Dose must include all noise from 90
  dBA to 140 dBA (90 dBA Threshold)
• For a Sound Level Meter, use the Noise Dose
  Table. (For the PEL use only the Noise Level
  values above 90 dBA. The Action Level uses the
  entire chart.)
• If you have a Dosimeter, it must be capable of
  doing measurements for both PEL and AL.

42
Figuring Noise Doses

• Forms 2.1 2.2 are the blank Sound-Level-Meter
  Noise Dose calculation forms.
• See Loader Operator example - Forms 4.1/ 4.2.
• The estimated exposure times at various decibel
  levels from form 3.1 have been transferred to the
  appropriate spaces on Forms 4.1/4.2
• The same has been done for the Crusher Operator
  on Forms 6.1/6.2.

43
Noise Doses for the Loader Operator

• The Noise Dose Table is then used to figure the
  Noise Dose for each Noise Level. This Noise Dose
  is then recorded in the third column of Forms
  4.1/4.2 for the Loader Operator (forms 6.1/6.2
  for the Crusher operator.)
• When you are calculating your own Noise Doses,
  follow the same steps as these examples.
• Finally, add all the separately calculated Noise
  Doses to get the final Noise Dose for the full
  work shift.

44
Dosimeter Sampling

• Noise Dosimeters
• Measure accumulated exposure to varying noise
  levels over time period.
• Give readouts in Noise Dose.
• Most Dosimeters also provide
• Sound Level Meter (SLM) capability.
• Average Noise Level. (Time Weighted Average)
• Projected 8 Hr Noise Dose.

45
Dosimeter Exercise 1

• This exercise illustrates how quickly the noise
  dose can accumulate at high noise levels.
• 1. Insert microphone into calibrator.
• 2. Turn on dosimeter.
• 3. Set calibrator to 124 dB (or as high as it
  will go).
• 4. With dosimeter set to display High-Threshold
  Noise Dose , turn the calibrator on for exactly
  5 minutes.
• 5. While waiting, watch how fast the Noise Dose
  is adding up. (NoteSome dosimeters may require
  you to press the 'Noise ' button continuously to
  get a running readout.)
• 6. Turn the calibrator off after 5 minutes.
• 7. The Noise Dose would be somewhere around 125
  for a calibrator set to 124 dB and 17 for a
  calibrator set to 110 dB.

46
Dosimeter Exercise 2

• This exercise demonstrates the ability of a
  dual-threshold dosimeter to
• distinguish between Low Threshold and High
  Threshold Noise Doses.
• 1. Write down the High Threshold Noise dose you
  obtained from the previous exercise. (Do not
  clear or reset the dosimeter.)
• 2. Leave microphone in the calibrator and switch
  the dosimeter display to SLM.
• 3. If calibrator is multi-level, turn calibrator
  to the lowest dB setting.
• 4. Slowly remove the microphone until the
  dosimeter display reads 83 dB.
• 5. Try to hold the microphone in this position
  for exactly 5 minutes.
• 6. Switch the dosimeter display back to High
  Threshold Noise Dose .
• There should be no increase in the Noise Dose
  because the noise being measured is below the
  High Threshold Limit of 90 dBA.)
• 7. Now, switch the dosimeter display to Low
  Threshold Dose . This reading should be slightly
  higher than the High Threshold Noise Dose because
  the noise being measured is above the Low
  Threshold Limit of 80 dBA.

47
In Review

• Dosimeters are Dual Threshold
• The Noise Dose is accumulated simultaneously at
  both 80 dBA and 90 dBA thresholds
• 80 dBA is the threshold for the Action Level
• 90 dBA is the threshold for the PEL

48
Noise Sampling with a Dosimeter

• 1. Make sure the microphone is inserted into the
  Windscreen.
• 2. Clip the dosimeter to the subjects belt, or
  put it in the subject's pocket.
• 3. Clip the microphone to the center of the
  shoulder, pointing up. (Pick the subject's
  Noisiest shoulder.)
• 4. If necessary, use clips or duct tape to attach
  the microphone cord to the clothing.
• 5. Document, Document, Document

49
Dosimeter Documentation - Form 7

• Always record your Name, Date, Employee Name,
  Location, Time On, Time Off, Noise Sources, Noise
  Controls, Work Activity, Hearing Protectors,
  Dosimeter Data, and Calibration
• Throughout the sampling period, record the
  accumulated Noise Dose as often as the task
  changes or at least every 2 hours if the task
  does not change.
• Spot check the Noise Levels with an SLM (to
  verify Dosimeter readings).
• Record the Final (or Projected) Noise Dose.

50
Projected Noise Dose

• You can sample for less than 8 hrs, and the
  dosimeter will calculate what an 8 hr exposure
  would be if the noise had continued at the same
  average level.
• This is called the Projected Noise Dose.
• It is less accurate than sampling for a full 8
  hours.
• It does not project for 10 hr, 12 hr, or 14 hr,
  etc. work shifts. These you must estimate
  yourself or sample the entire shift.
• Projected Noise Dose Exercise
• Place the microphone in the calibrator.
• Turn on the dosimeter and the calibrator.
• Switch dosimeter to 'Projected 8 hour Noise
  Dose'.
• Depending on the Noise Level that the calibrator
  is set at, you will now get an 8 hour projected
  estimate of the Noise Dose for that Noise Level.

51
Noise Sampling - General Sequence

• Pick your sampling method. (SLM, Dosimeter, or
  both.)
• Pick individuals, tasks, or areas to be sampled.
• Conduct the sampling.
• Observe the employees sampled document these
  observations.
• Record SLM readings at various worker locations
  and note time worker spends at each location.
• Evaluate the sampling results.
• If necessary, control exposure.
• See Noise Checklist in your written material.

52
Interpretation of Noise Sampling Results

• Every noise measurement involves error related to
  the accuracy and precision of the sampling
  instrument (dosimeter or SLM).
• Most dosimeters and SLMs are accurate to 2 dBA.
• For an SLM reading to be on the safe side, add 2
  dBA to all measurements when you record them.
• For a dosimeter, multiply final end-of-shift
  measurement by 1.32 to get final Noise Dose.
• Example If the end of shift Noise Dose Reading
  is 87, multiply this by 1.32 and round the
  results up to the nearest whole number. In this
  case it would be 115.

53
Interpretation of Noise Sampling Results

• If the Action Level Noise Dose (i.e. the Low
  Threshold Noise Dose) is less than 50
• No action necessary
• Continue to maintain noise controls
• Spot check levels from time to time

54
Interpretation of Noise Sampling Results

• If the Action Level Noise Dose is equal to, or
  greater than 50
• You must enroll all effected employees in the
  company's hearing conservation program.
• Review noise controls. (You may wish to upgrade
  controls, but it is not required.)
• Spot check Noise Levels from time to time.

55
Interpretation of Noise Sampling Results

• If the PEL Noise Dose (High Threshold Noise Dose)
  is 100 or more
• You must enroll the affected employees in the
  company's HCP.
• You must require Hearing Protectors.
• You must implement feasible engineering
  administrative controls to reduce noise exposure.
• If the PEL Noise Dose is more than 800, dual
  hearing protectors (Muffs Plugs) are required.
• No employee can be exposed to 115 dBA for any
  length of time. MSHA issues a citation for a
  30-second slow response average reading greater
  than or equal to 117 dBA.

56
Hearing Conservation Programs

• At the Action Level, Hearing Conservation Program
  enrollment becomes mandatory, not voluntary!
• See examples of Hearing Conservation Program
  Forms in your printed material.
• Hearing Conservation Training Program Record
  Forms 8 or 9. (Records Hearing conservation
  Training.)
• Hearing Conservation Program Employee Enrollment
  Record - Form 10 (Lists dates when all the
  various aspects of an HCP are completed.)

57
Hearing Conservation Programs

• MSHAs HCP rules are similar to OSHAs, except
  that MSHA doesn't require a written program.
• An HCP MUST include the following five elements,
  as per CFR 30 62.150
• System of noise monitoring
• Provide hearing protectors
• Audiometric testing
• Hearing conservation training
• Record keeping
• The HCP must not cost the employee any money or
  time.

58
System of Noise Monitoring - Methods

• The monitoring method is not specified in the
  MSHA standard (62.110), therefore
• Your own SLM or Dosimeter may be used.
• MSHA compliance sampling data may be used.
• Equipment manufacturer's noise specifications may
  be used.
• Whatever the monitoring method used, the data it
  generates must represent full shift exposure.
• Employees may observe monitoring, however, the
  company does not have to pay a worker for this
  activity.
• Employee notification is required if the noise
  exposure equals or exceeds the Action Level. (See
  example of Notification Letter in your printed
  materials.)

59
System of Noise Monitoring - Records

• Noise monitoring records may be requested by an
  inspector during an MSHA inspection
• In your printed materials there is an example of
  a form entitled "Employee Noise Exposure Record".
• Part 62 does not specify the record-keeping
  format. The forms provided here are an example of
  what you might use to show MSHA that you are,
  indeed, monitoring your employees for noise
  exposure.

3 x 5 File Card
Action Level Noise Dose PEL
Noise Dose
Enrolled in HCP? No Yes Date