Noise-Induced Hearing Loss - American Academy of Audiology

Assessing Hearing Protectors in the
Clinic- How to Perform CPT 92596
Bureau of Labor and Statistics
Occupational Injuries for 2007
Hearing loss was the 2 nd highest specific reported
illness in all of the last four years since OSHA has
required separate reporting of hearing loss.
Hearing Protection Devices
workplace noise effective employee exposure
A-Weighted Sound Level (dBA)
125
115
105
95
85
dBC - NRR = dBA
C – A Differences
Mean C-A = 2 dB
-2 0 2 4 6 8 10 12 14
C - A Value (dB)
Combined Industrial Noises
Special Noises (see text)
C-A > 7 dB = 4%
Linear Curve
Tom Thunder, AuD, INCE ( tthunder@comcast.net)
Relative Sound Pressure Level in dB
Over Reliance on Hearing
Protection Devices
With OSHA’s lax
enforcement policy
of the 80s,
management of the
90s and beyond
have relied on
protection to the
extent that if HPDs
were issued, the
noise problem
vanished.
20
10
0
-10
-20
-30
-40
-50
-60
-70
-80
16
Weighting Scales
31.5
63
125
250
American Academy of
Audiology (April 2009)
500
1000
Frequency in Hz
2000
4000
8000
C-weighting
A-weighting
Questionable Perception of
HPD Performance
Most HR
officers and
safety
managers
believe that
the higher the
NRR, better
the
protection.
NRR (dB)
30
25
20
15
10
5
0
Labeled vs. Field Values
Down
Custom
Laboratory
Field
16000
Sound-Ban 10/20
UltraFit
V-51R
POP/Soft
EP-100
Misc. 3-flange
Classic
Peltor H9A
Misc. M uffs
M SA Mk IV
Hlbrg. No-Noise
Bilsom 2313
Peltor H7P3e
Bilsom UF-1