Noise Flashcards
what is noise?
a sound you DON’T want to hear
unwanteded sound
review parts of ear
parts of ear
cochlea
little hairs
if damaged, attachments damaged, breakage, not repairable
How does noise damage hearing
damage attachments of hairs in cochlea
chemicals and hearing
toulene and noise in some kind of DIY thing… increases the effect of the noise…worse hearing loss
frequency
Hz
threshold in dB where we start to lose hearing
40 dB
can’t here 4000 hZ
NIHL
Noise Induced Hearing loss
What is the outcome of NIHL
permanent, irreversible hearing loss
hearing aids can’t correct it
Cochlear implants don’t restore it
Why are’t hearing aids the best
magnify level of ALL noise, background noise too…they don’t know how to differentiate
NIHL more
can endanger people and have social impact
TOTALLY PREVENTABLE
Hearing Loss and the wokrplace
not hearing warning signs=danger
Noises in the US… exposure
5-30 million pppl exposed to hazardous levels of noise
100 million exposed above the EPA “safe level”
Hazardous level of noise
85 dB or over for 8 hours
EPA “Safe” level of noise
75 dB for 24 hrs
exposed for longer if its for less time
protecting from noise
Time
Distance
Shielding
Hearing loss in the US
10 mill with NIHL
12 mill with tinnitus (ringing)
Cost of hearing lost
NO nat. surveillence system
$305 mill spend annually on HIHL by Army
in Washington…they spent $57 million in 1998…which didnt include hearing aids! (which also cost a ton)
NOT covered by worker’s comp in 4 states
High Risk Hearing Loss jobs
mining Agriculture Construction Transportation Manufacturig Metal Workers Military
Recreational noise exposure
take risks… motorcycle, high level of noise in headphones, chainsaw with no hearing protection
recreation and job
how do you know where the majority of the hearing loss is from
maybe use epi…but we don’t have a way to tell whats what currently
Noise thermometor
blenders… threshold, but not at the time
Heavy traffic, jackhammars WAY at the top
Limit exposure to jackhammar
switch out workers, give them hearing protection
rainfall
in a heavy storm, 50dB (thats not even thunder)
OSHA Hearing Conservation Program (mointoring)
annually measure worker hearing
want to make sure no decline while employee works for you
OSHA hearing conservation program…the things it includes
monitor (anual) test protect train keep records
OSHA regulations: Purpose and Scope
- Protect employees from exposure to hazardous noise
- Establish an effective hearing conservation program (HCP)
OSHA regulating a workplace
long time between inspections
- Complaints get OSHA in sooner
Worker responsibility
you have to go to OSHA and make a complaint
Heirarchy of controls…cheapest to most expensibe
Administrative controls
Engineering controls
PPE if the former don’t work
who does OSHA hold accountable
ONLY employeer gets fined, NOT employee…even if they’re the one breaking the rules
Hierarchy of controls…what is least to most effective
PPE (compliance issues in employees) Training Procedures and admin controls Warnings Engineering controls Eliminate noise or substitute
Most effective way to decrease leaf blower exposure
- use a muffler to muffle noise
con: it increases weight… risk of back injury
REVEIW HERIARCHY OF CONTROLS IMAGE
REVEIW HERIARCHY OF CONTROLS IMAGE
Path of Noise
comes straight off you
can hit surface and bounce back to person
floors and noise
carpet..noise can’t bounce as well
fabric coat walls works too
Source-Path-Reciever
Hotel rooftops…incase AC
Cages for inspectors of mechanical plants
made of absorbent material (not hard /dense)
walls between highways and homes
Things that can happen to noise when it meets a surface
absorbed
passes through object
refracted
reflected
Noise: Engineering Controls
Replace/repair equpitment reduce source of noise make enclosures make barriers vibration control use sound absorbing materials
Goals to reduce noise
reduce source of noise
USE ABSORBANT MATERIALS
Noise: Adminstrative Controls
Training! #1
Job rotation
Inc distance between workers and source
equiptment maintenance
first thing you have do to in workplace to reduce noise harm
TRANING
When do you need HCP
must be provided by employer if employees are exposed to noise at levels of 85dB over an 8 hr time weighted average
What is HCP
hearing conservation program
how many dB is the regulation…
85 dB over 8 hrs!!!!!
what is 90dB
you can go up to 90 at some point during the day, so long as your average over the day is 85 or bellow
Time Weighted Average
average out over the day
can exceed for part of work day
under for other part
averages out to the standard (hopefully)
Time Weighted Average equation
Dose= 100*(C1/T1 + C2/T2)
C= duration at each noise level
T=allowable duration at each noise level
Monitoring
employers comes up with monitoring program
notify employees if they are above the level
teach them hot to limit it
testing and retesting
where we lose hearing occupationally
around 4000 Hz level
this means you’re not protecting yourself
standard threshold shift
your hearing is decreasing
Notification if you have a standard threshold shift
TELL employee w/in 21 days
Informed that more eval is needed
REQUIRED to wear hearing protecting
Refited and retrained in use of HP
Hearing Protector
Employers must make it available (its expensive!)
Employees are given the opportunity to chose from a variety
record keeping
very important that employees do this
have to show records to OSHA
Other Noise Metrics and Standards
Mine Safety and Health Admin measure with PEL (permissible Exposure Limit)
Nat. Institute for Occ. Safety and Health uses REL (reccommended Exposure Limit
American Conference of Gov. Industrial Hygienists use TLV (threshold limit Value)
OSHA PELs vs ACGIH TLVs
ACGIH more strict…who you want regulating you as a worker
OSHA PEL
8 hr TWA of 90dBA
ACGIH
8 hr TW of 85 dbBA
