IAQ and Noise tools - IHSA · review the noise information supplied with them, which is often...

IAQ and Noise tools Masood Ahmed MS, CIH, CRSP

Occupational Hygienist

OHCOW – South Central/Hamilton

Disclaimer……….

The purpose of this presentation is to provide information and education about noise. This presentation should not be used for

training or certification purposes.

Occupational Health Clinics for Ontario Workers (OHCOW) • An inter-disciplinary occupational health team:

• occupational physicians • occupational health nurses • ergonomists • occupational hygienists • customer service coordinators • leadership/administration

• Funded by MoL Prevention Services (from compensation premiums)

• BoD majority from organized labour

Regional Clinics:

Services:

1. Medical diagnostic service for workers who may have work-related health problems.

2. Group service providing educational and investigative support for joint health and safety committees and workplace parties.

3. Inquiry service to answer workplace health and safety questions.

4. Outreach and education service to make people aware of health and safety issues and promote prevention.

5. Research service to identify, investigate and report on illness, injury & disease trends.

Overview: 1. Physics

2. Health effects

3. Regulations

4. Measuring noise

5. Noise control

6. Other noise issues

7. Noise apps and tools

A little noise physics:

• Speed of Sound - 1100 feet per sec at room temp

(or 750 mph or 1200 km/hr).

• As frequency (pitch) goes higher, the wavelength

gets smaller (more cycles per second).

- at 100 hertz (Hz) the wavelength is ~ 10 feet

- at 1000 hertz the wavelength is ~ 1 foot

- at 10,000 hertz (10 kHz) wavelength is ~ 1 inch

• Human audible range – 20 Hz to 20,000 Hz

obligatory frequency diagram:

exit to frequency audio file

One wave is a complete cycle, the

number of cycles (waves) per

second is the frequency

http://amazing-space.stsci.edu/resources/explorations/groundup/lesson/glossary/glossary_terms/graphics/igt2_wvlngthfreq.gif

20 Hz – 20,000 Hz

Octave bands (Hertz)

http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm

Decibels (dB)

http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm

obligatory diagram of the ear:

http://www.tinnitus.asn.au/ear1.htm

….what we’re trying to prevent …

normal hearing cells damaged hearing cells

How it is measured?

progression of NIHL (noise induced hearing loss)

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pre-employment: worker starting first job

progression of NIHL (noise induced hearing loss)

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after 3-5 yrs exposure

progression of NIHL (noise induced hearing loss)

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after 15-19 yrs exposure

progression of NIHL (noise induced hearing loss)

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after 25-29 yrs exposure

What are the chances?

• depends on the intensity of the noise (how loud it is – measured in decibels (dBA))

• depends on the frequency – high pitch (treble) sounds more damaging than low (bass) sounds

• depends on the length of time exposed (yrs)

• depends on the age (natural hearing loss due to age - presbycusis)

presbycusis (age hearing loss)

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presbycusis (age hearing loss)

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High frequency loss happens first

stats

• “last five years, the annual costs for noise induced hearing loss claims for all sectors in Ontario exceeded $50 million per year,” (MOL 2014)

• the WSIB showed a steady increase in NIHL registered claims from 3653 claims in 2005 to 5416 claims in 2009 (WSIB, 2011)

• Masterson et al. (2013) found 18% of 1,122,722 worker audiograms collected from the NIOSH OHL Surveillance Project met the NIOSH criteria for NIHL

• Stekelenburg (1982) noted that: “… even if 80 dBA is taken as a time weighted average limit … 10% of the exposed population will not be protected against impaired social hearing caused by noise.” (page 408)

exit to Hearing Loss Simulator

What are the symptoms of NIHL (noise-induced hearing loss)?

• usually gradual (not noticeable) but can be immediate (if close to an “explosive” noise)

• tinnitus • ringing, buzzing, or roaring in the ears or head

• can be intermittent or continuous

• extremely annoying and not curable

• screening questions handout

How Much Noise is too Much?

• Anything above 65 dBA will eventually wear down your hearing.

• Years of exposure above 80-85 dBA will lead to a percentage of workers with a hearing disability (legally deaf).

• Trying to carry on a conversation over the phone with a background noise level of 60-65 dBA is very stressful.

Noise: Ontario OEL = 85 dBA ACGIH TLV = 85 dBA

http://www.cdc.gov/niosh/pdfs/98-126-b.pdf

Noise Induced Hearing Loss:

• WSIB recognizes noise-induced hearing loss (NIHL) compensation after an exposure of 90 dBA for 8 hrs/day for a minimum of 5 years or equivalent noise exposure;

• the policy also lists equivalent exposures as 84 dBA for 40 yrs or 28 yrs at 85 dBA

• Tinnitus is also compensable • Allowed NIHL

• Two or more years of sever tinnitus

• Diagnosed by a specialist

WSIB Hearing Loss Exposure Equivalencies

The minimum hazardous noise exposure of 90 dB(A) for 8 hours per day for 5 years has the following equivalencies*:

84 dB(A) for 40 yrs 89 dB(A) for 7 yrs

85 dB(A) for 28 yrs 91 dB(A) for 3.5 yrs

86 dB(A) for 20 yrs 92 dB(A) for 2.5 yrs

87 dB(A) for 14 yrs 93 dB(A) for 1.8 yrs

88 dB(A) for 10 yrs 94 dB(A) for 1.25 yrs

* ISO 1999-1990. Acoustics – Determination of occupational noise exposure and estimation of noise-induced impairment. Internat. Standard ISO 1990. 2nd ed. Geneva, 1990.

NIHL does not normally develop in less than 1.25 years.

Other than hearing loss health effects:

• “… what the non-auditory effects of noise are is still not certain. In general, the suspected effects include: • cardiovascular function (hypertension, changes to blood pressure and/or heart rate), • changes in breathing, • annoyance, • sleeping problems, • physical health and • mental health.

• This wide range of effects has led researchers to believe that noise has the ability to act as a general, non-specific stressor.”

http://www.ccohs.ca/oshanswers/phys_agents/non_auditory.html

http://ehp.niehs.nih.gov/1307272/

Vocal Cord Nodules

How is noise regulated in Ontario?

Noise Legislation: O.Reg. Regulation 851, section 139

• employers take all measures reasonably necessary in the circumstances to protect workers from exposure to hazardous sound levels.

• protective measures against noise exposure include engineering controls, work practices and personal protective equipment.

• assessment of noise levels shall be done without regard to any use of personal protective equipment.

• every employer shall ensure that no worker is exposed to a sound level greater than an equivalent sound exposure level of 85 dBA, Lex,8.

O.Reg. 851 s.139 (continued)

• the employer shall protect workers from exposure to a sound level greater than 85 dBA, Lex,8 without requiring the use of personal protective equipment.

• personal protective equipment is only to be used if engineering controls, a) do not existence or are not obtainable; b) are not reasonable or not practical to adopt, install or provide

because of the duration or frequency of the exposures or because of the nature of the process, operation or work;

c) are rendered ineffective because of a temporary breakdown of such controls; or

d) are ineffective to prevent, control or limit exposure because of an emergency.

O.Reg. 851 s.139 (continued)

• if engineering controls can’t be used then workers shall wear and use personal protective equipment appropriate in the circumstances to protect them from exposure to a sound level greater than 85 dBA, Lex,8

• a clearly visible warning sign shall be posted at every approach to an area in the workplace where the sound level regularly exceeds 85 dBA.

• “An employer who provides a worker with a hearing protection device shall also provide adequate training and instruction to the worker in the care and use of the device, including its limitations, proper fitting, inspection and maintenance and, if applicable, the cleaning and disinfection of the device.”

Ontario Regulation 381/15

• New noise regulation, essentially the same as O.Reg. 851 s.139 except that it covers all workers in the province (not just those covered by the industrial regs (O.Reg. 851))

Column 1 Column 2

Sound Level

— in

Decibels

Duration —

Hours per 24

hour day

90 8

92 6

95 4

97 3

100 2

102 1½

105 1

110 ½

115 ¼ or less

Over 115 No exposure

previous table: current table:

Measuring noise:

• no measurement – everyone agrees its too noisy and let’s do something about it

• voice effort scale – do you have to raise your voice at an arm’s length away – if so probably over 80-85 dBA

• $50-100 type III sound meter (lots online) – can work well for area measurements (but no guarantee – calibration needed)

• dosimeter $1000-4000, does datalogging and acts as a sound level meter (usually downloadable) – measure individual exposures averaging over time

• octave band analyzer $3000-12,000, gives you noise frequency analysis usually used for acoustics and noise control engineering

Voice effort noise assessment:

voice level:

(1 meter away) normal loud very loud shouting

maximum

shouting

noise level:

(in dB(A)) 50 70 85 90 100

perception:

hazard level: slight

distraction

annoying,

unpleasant

some risk

of hearing

loss

medium

risk of

hearing

loss

high risk of

hearing

loss

Noise Measurement

There’s an App for that! • NIOSH has reviewed various

noise measurement apps and found that some do a reasonable job of measuring sound (and some not so reasonable)

• SPLnFFT

https://itunes.apple.com/ca/app/splnfft-noise-meter/id355396114?mt=8

http://www.cdc.gov/niosh/surveyreports/pdfs/349-12a.pdf

Noise Map

http://civil.utm.my/zaitonharon/

What next after measuring?

Prevention Opportunities

source > path > exposure > target > disease

check on effectiveness of controls

too late!!

Best Good Temporary

effectiveness of hearing protectors

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effectiveness of hearing protectors

ww

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effectiveness of hearing protectors

This is not the permanent solution!

… nor even a very effective temporary one.

Preventing noise • purchasing policy (new machinery <75 dBA)

• vibration control (isolators, damping)

• quiet materials for conveyors, bins (noiseless steel, plastic coatings, etc.)

• silencers, mufflers, specially designed compressed air nozzles

• balancing rotating parts, avoiding harmonic frequencies, etc.

• avoiding impacts in process flow (slide instead of drop)

• enclosures, barriers, curtains

• sound absorbing acoustic wall/ceiling treatment

• increasing distance from source

• OHCOW worksheet “Doing something about noise”

Noise control principles & examples …

“Buy Quiet” • “To buy quiet in today’s market purchasers need a high level of understanding

of noise and noise control and must have a high degree of determination to achieve noise control in their workplace.

• Purchasers who successfully buy quiet seek out quieter machines and critically review the noise information supplied with them, which is often flawed.

• Such purchasers sometimes need to write, and check conformity with, their own specification for noise.”

Brereton & Patel, “Buy Quiet as a Means of Reducing Workplace Noise”, Acoust Aust DOI 10.1007/s40857-016-0051-x, online Mar 29,2016

http://www.cdc.gov/niosh/topics/buyquiet/

http://www.hse.gov.uk/noise/buy-quiet/index.htm

“Quiet” air guns

Compressed air nozzles & exhaust silencers

Tool Redesign

• Using a jacket over the tubular outlet in the jacket, the high frequency noise given off by a jack hammer can be partially shielded. The low frequency noise in the exhaust air is effectively reduced. The enlarged sections are between the barrel and the jacket functions as an expansion chamber.

Simple Noise Reduction

Vibration Transmission

Vibration & Damping

Vibration Transmission

Vibration Isolation

Vibration isolators are made of various materials

Vibration Damping Coatings

… or line metal conveyors with old rubber conveyor belts

“Noiseless Steel”

Surface area transmission

Enclosure

Noise Barriers & Enclosures

Enclosure of Electric Motor or Compressor

Effects of Openings in Enclosures (hypothetical)

Degree of enclosure decibel reduction

full enclosure 60 dB

0.1% open 30 dB

1% open 20 dB

5% open 13 dB

10% open 10 dB

30% open 5 dB

50% open 3 dB

Noise Absorbing Baffles

Barriers to Prevention:

• Complacency: it’s always been that way, things will never change …

• Expertise: we need an expert with one of those fancy noise meters to come in and measure the noise …

• Expense: noise control is just too expensive!

• Shift the Blame: they should have worn their ear plugs …

Hearing Conservation Program

1. Noise surveys and data analysis

2. Education and motivation

3. Noise control

4. Hearing protection devices

5. Audiometric monitoring

The Noise Manual – 5th Edition

What about office noise?

• Background office noise usually comes from the ventilation system and is usually measured in an unoccupied office (or when things are quiet if occupied)

• The American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) has developed standards for background noise due to ventilation system to ensure adequate conditions for concentration and communication

Design Guidelines for HVAC-related Background Sound

2011 ASHRAE Handbook –

HVAC Applications (SI) Table 1 page 48.3

open-plan offices: Room Criteria (RC): RC ≤40 (equivalent to 45 dBA)

private offices: Room Criteria (RC): RC ≤30 (equivalent to 35 dBA)

Quality-Assessment Index (QAI): QAI ≤5 dB (N)

N= neutral (balanced sound spectrum) LF= rumble (low frequency dominant) LFVB= rumble (low frequency with moderately perceptible vibration) LFVA= rumble (low frequency with clearly perceptible vibration) MF= roar (mid-frequency dominant) HF= hiss (high-frequency dominant)

Cost-effective Open Plan Environments (COPE project)

• The National Research Council Canada (NRCC) has developed standards for open plan office environments (COPE)

• For noise the COPE recommendations are: • Ensure that all noise sources (e.g., ventilation systems, office

equipment and water coolers) do not exceed 40 dBA.

• The COPE research finding identified the optimum noise level (background & foreground) for open plan offices was determined to be between 42-48 dBA

http://irc.nrc-cnrc.gc.ca/pubs/ctus/63_e.html

Acoustics

• RevMeter Pro – an app to estimate the reverberation time in a room (≈ $7)

• ANSI S12.60-2002. Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools • “Unoccupied classroom levels must not exceed 35 dBA • The signal-to-noise ratio should be at least +15 dB • Unoccupied classroom reverberation must not surpass

0.6 seconds in smaller classrooms or 0.7 seconds in larger rooms”

https://itunes.apple.com/ca/app/revmeter-pro/id357421594?mt=8

http://www.asha.org/public/hearing/American-National-Standard-on-Classroom-Acoustics/

Noise Tools/Apps

Noise Legislation: O.Reg. 381/15

• employers take all measures reasonably necessary in the circumstances to protect workers from exposure to hazardous sound levels.

• protective measures against noise exposure include engineering controls, work practices and personal protective equipment.

• assessment of noise levels shall be done without regard to any use of personal protective equipment.

• every employer shall ensure that no worker is exposed to a sound level greater than an equivalent sound exposure level of 85 dBA, Lex,8.

solution: on-line calculator …

http://www.ohcow.on.ca/uploads/noisecalculator.xls

Sound Level

Duration

(85 dBA Lex,8)

Duration

(80 dBA Lex,8)

(in db(A)) (hrs/24 hr day) (hrs/24 hr day)

80¼ 24 7½

81½ 18 5⅔

82 16 5

83¼ 12 3¾

84 10 3¼

85 8 2½

86¼ 6 2

88 4 1¼

89¼ 3 1

91 2 40 min

92¼ 1½ 30 min

94 1 20 min

97 30 min 10 min

100 15 min 5 min

101¾ 10 min 3 min

104¾ 5 min 1½ min

111¾ 1 min 20 sec

114¾ 30 sec 10 sec

(hrs) (min)

Activity 1 45Activity 2 1 10Activity 3 3 30Activity 4 2Activity 5 2 35Activity 6 35Activity 7 5Activity 8

Activity 9

Activity 10

Activity 11

Activity 12

Activity 13

Activity 14

Activity 15

Activity 16

Activity 17

Activity 18

Activity 19

Activity 20

Activity 21

Activity 22

Activity 23

Activity 24

Activity 25

27.6%46.1%14.9%

2.0%7.9%

Dose

86.2

0.0%0.0%

0.0%0.0%

0.0%0.0%

132.0%

Total

838073

10074

Equivalent Noise

Exposure Level

Total

(%)

Dose

Time Weighted Average Calculator: This table calculates the 8 hr equivalent sound exposure

level for different noise levels and for specified lengths of exposure time. To use this chart, enter

the amount of time spent performing each activity and the corresponding noise level.

Exposure Time

8790

0.0%

10.67

Time

Noise Level

(dBA)

0.6%32.9%0.0%0.0%0.0%0.0%0.0%0.0%

0.0%

0.0%0.0%0.0%0.0%

Who can measure?

Noise Apps

http://pad2.whstatic.com/images/thumb/e/ee/Measure-Decibels-Step-2.jpg/aid1456686-v4-728px-Measure-Decibels-Step-2.jpg

https://itunes.apple.com/ca/app/splnfft-noise-meter/id355396114?mt=8

http://www.cdc.gov/niosh/surveyreports/pdfs/349-12a.pdf

https://www.youtube.com/watch?v=jGVN7m3Wd1M

SPLnFFT

SoundMeter App

https://itunes.apple.com/ca/app/soundmeter/id287615105?mt=8

app to measure reverberation

• RevMeter Pro – an app to estimate the reverberation time in a room (≈ $7)

• ANSI S12.60-2002. Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools • “Unoccupied classroom levels must not exceed 35 dBA

• The signal-to-noise ratio should be at least +15 dB

• Unoccupied classroom reverberation must not surpass 0.6 seconds in smaller classrooms or 0.7 seconds in larger rooms”

https://itunes.apple.com/ca/app/revmeter-pro/id357421594?mt=8

http://www.asha.org/public/hearing/American-National-Standard-on-Classroom-Acoustics/

whole body vibration app

• free app which measures whole body vibration (WBV)

• well researched with published study to show validity

• i-Tunes store search for WBV

https://itunes.apple.com/ca/app/wbv/id797629017?mt=8

Online Audiometric test:

http://hearingtest.online/

Questions? mahmed@ohcow.on.ca