Noise Measurement and Control CWU – May2, 2011 Eric E. Dickson, CIEC, CIAQC Industrial Hygienist, ESD 101 (509)

2 Noise – Irritating to Dangerous

3 Purpose of Noise Measurement Identify overexposed workers and quantify their exposures. Assess noise situation for engineering controls Assess background levels in audiometric test rooms.

4 Effects of Noise Exposure Our ears can recover from short exposure to loud noise, but over time nerve damage will occur. The longer and louder the noise, the greater chance permanent damage will occur. There is really no such thing as “tough ears” or “getting used to it”.

5 of 35 Permanent effects of noise Small “hearing hangovers” add up slowly Hearing aids can’t fix hearing loss This is your ear... This is your ear on noise...

6 Effects of Noise on Humans Hearing loss Dilation of the pupils Secretion of thyroid hormone, adrenaline, adrenaline cortex hormone Heart palpitation Movements of stomach and intestines Muscle reaction Constriction of the blood vessels

7 Allowable Exposure Times The table below shows noise levels and how long a person can be exposed without hearing protection before there is damage to the ear. Noise LevelAllowable Exposure Time 85 decibels8 hours 90 decibels4 hours 100 decibels1 hour 105 decibels30 minutes 110 decibels15 minutes 115 decibels0 minutes

8 Types of Noise Loudness Whisper 10 decibels Conversation/3 ft 60 decibels Street sounds 70 decibels Sander 85 decibels Sporting event100 decibels Motorcycle riding112 decibels Concerts125 decibels Shooting range130 decibels

“Rock on”!!! … huh? 9

Portable ear blasters – then and now! 10

11 DOSH Permissible Exposure Limits WAC (DOSH) 8-Hour Time Weighted Average (TWA) 85 dBA Maximum Level (sustained noise of > 1 second in duration) 115 dBA Peak Level (impact/impulse noise of < 1second in duration) 140 dBC

12 Hearing Conservation Program Required if worker 8-hour TWA is higher than 85 dBA Mandatory audiometric testing Make hearing protection available Place warning signs in areas > 115 dBA Record keeping Employee access to records. Engineering and/or Administrative controls required if TWA > 90 dBA

13 Hearing Protection Devices Ear Muffs Ear Plugs (disposable and reusable) Custom-Molded Ear plugs

14 Noise Reduction Rating (NRR) Each hearing protection device has an NRR. Usually range from 20-30dB. Chose appropriate level of protection for the noise exposure. Too little protection won’t block out enough noise Too much can block essential noises such as warning alarms, etc. Correction factor = NRR-7dB

15 Instruments for Measuring Noise Sound Level Meters Measures noise at a given moment Area monitoring – develop a “noise map” May not reflect worker exposure

16 Sound Level Meter settings ‘Slow’ response time ‘A’ scale for continuous monitoring ‘C’ scale to measure impact/impulse noise Range Low: dB Hi: dB

17 Instruments for Measuring Noise Dosimeters Measure worker exposure for full work shift Assess compliance w/ noise standard Calculates TWA, LAVG (average for actual sample period), Maximum Levels, and Peak Levels Prints a chart w/ minute-to-minute noise levels

Dosimetry Measurement s Place dosimeter at top of shoulder Avoid windy days if outdoors Measure all identified noise sources Keep itinerary of tasks and equipment used For retired claimants, chose person whose job most closely matches the claimant Same shift, equipment, routine if possible 18

19 Dosimeter Settings & Standards WAC PEL: 85 dBA TWA Weighting: ‘A’ Exchange (doubling) Rate: 5dB Threshold: 80dB Response: Slow Ceiling: 115dBA (Max), 140 dBC (Peak)

20 Noise Control Three methods – in this order. Engineering Controls Administrative Controls Personal Protective Equipment (PPE)

21 Noise Control – Engineering (1 st ) Control the source Mufflers, soundproofing, enclosures, fan speed, etc. Control the path Sound absorbing materials on walls or ceilings Barriers (walls, curtains, etc.) Control receiver’s environment Build sound booth, etc. Move farther away from equipment

22 Noise Control – Administrative (2 nd ) Job rotation Work process change

23 Noise Control – PPE (last resort) If you can’t reduce noise exposure by Engineering or Administrative controls, the last resort is to use Personal Protective Equipment (PPE). PPE should never be the first choice for a permanent solution. Ear muffs, ear plugs, etc.

24 Your hearing is as fragile as an egg shell. It can only be damaged once!!