Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 Hearing Conservation & Noise Exposure 2 Objectives What is sound? What is sound? How the ear works How the ear works How to measure noise How to measure.

Similar presentations


Presentation on theme: "1 Hearing Conservation & Noise Exposure 2 Objectives What is sound? What is sound? How the ear works How the ear works How to measure noise How to measure."— Presentation transcript:

1

2 1 Hearing Conservation & Noise Exposure

3 2 Objectives What is sound? What is sound? How the ear works How the ear works How to measure noise How to measure noise What does OSHA says about noise? What does OSHA says about noise? Reading hearing tests Reading hearing tests Hearing Protection Hearing Protection

4 3 What is Sound? Hertz (Hz) Hertz (Hz) –Frequency a high or low pitch Decibels (dB) Decibels (dB) –The loudness of the sound

5 4 Frequency Humans can typically hear between ,000 Hz Humans can typically hear between ,000 Hz You can hear different frequencies better than others You can hear different frequencies better than others

6 5 Decibels The quietest sound most humans can detect is 0 dB The quietest sound most humans can detect is 0 dB Some humans can even hear sounds as quiet as -5 dB Some humans can even hear sounds as quiet as -5 dB

7 6 The Loudness of Common Sounds Noise Thermometer Click Here

8 Anatomy of the Ear Cochlea Ear Drum Ear Bones Semi-Circular Canals

9 8 How do we Hear? The outer ear collects the sound waves The outer ear collects the sound waves The waves hit the eardrum, and cause it to vibrate The waves hit the eardrum, and cause it to vibrate The vibrations are sent through the ear bones to the cochlea The vibrations are sent through the ear bones to the cochlea

10 9 Inside the Cochlea (snail shell) Delicate hair cells vibrate to different frequencies Delicate hair cells vibrate to different frequencies Hair cells detect the vibration, and send a signal to the brain Hair cells detect the vibration, and send a signal to the brain Loud sounds destroy the hair cells, and they stop functioning FOREVER! Loud sounds destroy the hair cells, and they stop functioning FOREVER!

11 10 The Ear does something else too! The Semi-circular canals The Semi-circular canals –Three tubes laying perpendicular to one another –Filled with fluid and tiny hair cells –When your head is tilted, the fluid moves the hair cells, and they send a signal to your brain Responsible for balance Responsible for balance

12 11 How to measure noise Decibels are measured on a logarithmic scale Decibels are measured on a logarithmic scale Every time you add 5 dB, you double the sound. Every time you add 5 dB, you double the sound. 80 dB85 dB An addition or reduction of 5dB causes either an addition or reduction of 100% in noise according to OSHA.

13 12 Example In the field, we determined the loudness of two compressors right next to each other In the field, we determined the loudness of two compressors right next to each other How loud is this area? How loud is this area? –Do we add? –Do we add and take the average? 89 dB87 dB ?

14 13 Neither, Neither, because it is a log scale We We use the following chart dB + 83 dB = 86 dB dB + 89 dB = 91 dB

15 14 How does the Safety Person determine noise levels Sound level meter Sound level meter –Determine the loudness (dB) of noise at any given moment Personal Dosimeters Personal Dosimeters –Worn by employees –Measures the average loudness in an 8 hour work shift “8hr. TWA” (Time Weighted Average) –Can also measure noise dose

16 15 What does BLS say? At 85 dB (8hr. TWA) (50% Dose) At 85 dB (8hr. TWA) (50% Dose) –Train employees –Make hearing protection available –Sample for noise levels –Do hearing tests –Notify employees of results At 90 dB or more At 90 dB or more (100% Dose) –We must keep levels at or below 90 dB –Or require hearing protection that will lower noise levels to to 90 dB

17 16 Hearing Tests Determine a baseline audiogram Determine a baseline audiogram Hearing test every year to determine if you have experienced a hearing loss (Standard Threshold Shift) Hearing test every year to determine if you have experienced a hearing loss (Standard Threshold Shift) Standard Threshold Shift - A loss of 10 dB or more at 2000, 3000, or 4000 Hz. Standard Threshold Shift - A loss of 10 dB or more at 2000, 3000, or 4000 Hz.

18 17 Hearing Loss Impact - One loud bang Impact - One loud bang Cumulative - Years of a noisy environment Cumulative - Years of a noisy environment Tinnitus - Ringing in the ears Tinnitus - Ringing in the ears Presbycusis - Hearing loss due to aging Presbycusis - Hearing loss due to aging

19 18 Hearing Protection NRR - Noise reduction rating NRR - Noise reduction rating –Ear Plug - 25 NRR –Ear Plug - 29 NRR –Ear Plug - 30 NRR DO NOT Subtract the NRR from the noise level DO NOT Subtract the NRR from the noise level –WRONG (109 dB - 25 NRR = 84 dB) You must use the “Safety Factor.” explained on separate slide You must use the “Safety Factor.” explained on separate slide

20 19 Safety Factor OSHA says the hearing protection is designed to reduce the noise by the NRR, but that is unlikely to happen due to : OSHA says the hearing protection is designed to reduce the noise by the NRR, but that is unlikely to happen due to : –Leaks in the seal –Vibration –Improper insertion

21 20 Example of NRR Protection The noise from an average chainsaw is 110 dB The noise from an average chainsaw is 110 dB You are wearing the foam plugs with an NRR of 25 You are wearing the foam plugs with an NRR of 25 Do you have enough protection to place you below 90 dB level? Do you have enough protection to place you below 90 dB level?

22 21 (NRR ) = 18 (NRR ) = / 2 = 9 18 / 2 = = - 9 = YOU ARE ABOVE OSHA LIMITS OF 90 dB YOU ARE ABOVE OSHA LIMITS OF 90 dB dB

23 22 Final Thoughts Hearing is important Hearing is important In time, noise levels at 85 dB can permanently damage your hearing In time, noise levels at 85 dB can permanently damage your hearing Wear your hearing protection both at work and at home Wear your hearing protection both at work and at home Choose hearing protection with a proper NRR, and wear it properly Choose hearing protection with a proper NRR, and wear it properly

24 Resources SafetyWorks! SafetyWorks! OSHA- OSHA- NIOSH – NIOSH – CDC - CDC -


Download ppt "1 Hearing Conservation & Noise Exposure 2 Objectives What is sound? What is sound? How the ear works How the ear works How to measure noise How to measure."

Similar presentations


Ads by Google