Noise – What???

DOH Fall Workshops 2017

Eric E. Dickson, CIEC

Industrial Hygienist, ESD 101

(509) 789-3518

edickson@esd101.net

Definition

Noise - sound; one that lacks agreeable

musical quality or is noticeably loud, harsh,

or discordant.

Discord – harsh or unpleasant sound

Webster’s Dictionary

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Noise – Irritating to Dangerous

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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”.

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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...

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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 Level Allowable Exposure Time

85 decibels 8 hours

90 decibels 4 hours

100 decibels 1 hour

105 decibels 30 minutes

110 decibels 15 minutes

115 decibels 0 minutes

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Types of Noise

LoudnessWhisper 10 decibels

Conversation/3 ft 60 decibels

Street sounds 70 decibels

Sander 85 decibels

Sporting event 100 decibels

Motorcycle riding 112 decibels

Concerts 125 decibels

Shooting range 130 decibels

“Rock on”!!! …huh?

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Portable ear blasters – then and now!

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DOSH Permissible Exposure Limits

WAC 296-817 (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

DOH School Rules for Noise

WAC 246-366-030 Site Approval

Hourly average < 55dBA

Hourly maximum of 75 dBA

WAC 246-366-110 Sound Control

Classrooms < 45 dBA, when HVAC system is

operating

Shops < 65 dBA, when all fume and dust

collection systems are operating

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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

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Hearing Protection Devices

Ear Muffs

Ear Plugs (disposable and reusable)

Custom-Molded Ear plugs

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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

Correction factor for dual hearing protection = 2dB less

than the higher NRR

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Instruments for Measuring Noise

Sound Level Meters

Measures noise at a given moment

Area monitoring – develop a “noise map”

May not reflect worker exposure

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Sound Level Meter settings

‘Slow’ response time

‘A’ scale for continuous monitoring

‘C’ scale to measure impact/impulse noise

Range

Low: 35-100 dB

Hi: 65-130 dB

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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

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Dosimeter Settings & Standards

WAC 296-817

PEL: 85 dBA TWA

Weighting: ‘A’

Exchange (doubling) Rate: 5dB

Response: Slow

115dBA (> 1 second duration sound)

140 dB (< 1 second duration sound)

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Noise Control

Three methods – in this order.

Engineering Controls

Administrative Controls

Personal Protective Equipment (PPE)

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Noise Control – Engineering (1st)

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

Sound barrier examples:

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Noise Control – Administrative (2nd)

Job rotation

Work process change

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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.

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Your hearing is as fragile as an egg

shell. It can only be damaged once!!