Using the Noise Exposure Index as a Risk Ranking Tool

Using the Noise Exposure Index as a Risk
Ranking Tool
Kevin Hedges
Senior Principal Occupational Hygienist (Northern Region)

AS1269 “Noise Management”
Consists of 5 parts.
Part 0 Overview and general requirements.
Part 1 Measurement and assessment of noise
emissions and exposure.
Part 2 Noise control management.
Part 3 Hearing protector program.
Part 4 Auditory assessment.

• In part 2 there is a requirement to rank
exposures so that a priority action
plan can be developed.

Priority should be given to those
noise sources that expose
people to peak noise above
140 dB(C) and to those that
contribute to the highest
exposures affecting the
largest number of people.
NOHSC:2009 (2004)

• The noise exposure index (NEI) is one
tool that will assist in developing a
priority based noise abatement plan.

Concept originally developed by Macpherson
J and Tickell C. Development and use of
Noise Exposure Index (NEI) in Occupational
Noise Management in proceedings
Australian Acoustical Society. 1996
Conference Brisbane.
Is referenced in AS1269.

The noise exposure index
takes into account the
number of workers in a
similar exposure group
(SEG).
Presented at AIOH
Conference Albury 1997

N = the number of employees exposed in
the range of noise level measured.
CLeq = a risk coefficient for the exposure
level range, based on the calculated
hearing loss for 30 years exposure.

LAeq range Coefficient
70 to 80 dB(A) 0.05
80 to 85 dB(A) 0.1
86 to 90 dB(A) 1.0
91 to 95 dB(A) 2.0
96 to 100 dB(A) 4.0
> 101 dB(A) 5.0

Number of people in similar exposure
group.

SEG LAeqT
dB(A)*
Number C NEI Rank
Jumbo 93 7 2 1302 1
Service 93 7 2 1302 1
Shot
creter
92 4 2 736 2
Loader 86 4 1 344 3
Haul 86 4 1 344 3
Nipper 80 4 0.1 32 4
* Normalised for 8 hours

Shifts 10 hours or greater must be
normalised using the following formula:
LAeq, 8h = LAeq, T + 10log10(T/8)
For subsequent shifts the following
applies:
9hr to 13hr to 19hr + 2dB
> 18hr to

SEG LAeqT
dB(A)*
Number C NEI Rank
Jumbo 93 7 2 1302 1
Service 93 7 2 1302 1
Shot
creter
92 4 2 736 2
Loader 86 4 1 344 3
Haul 86 4 1 344 3
Nipper 80 4 0.1 32 4
* Normalised for 8 hours

NEI
700
600
500
400
300
200
100
0
Noise Exposure Index (NEI) 2010 - 2014
Jumbo Service prod Haul truck Loader
Similar Exposure Group (SEG)
NEI 2010
NEI 2011
NEI 2012
NEI 2013
NEI 2014

After ranking the noise exposure index for each
SEG the next steps are:
• Evaluation and assessment of the noise
control alternatives (engineering and cost).
• Ranking priority for the noise control plan
actions.
• Activities timing and costs.
• Implementation and ongoing assessment
and monitoring.

SEG LAeqT
dB(A)*
Number C NEI Rank Options $
Jumbo 93 7 2 1302 1
Service 93 7 2 1302 1
Shot
creter
92 4 2 736 2
Loader 86 4 1 344 3
Haul 86 4 1 344 3
Nipper 80 4 0.1 32 4
* Normalised for 8 hours

• The cost to retrofit is 10 - 13 times more
than to establish a buy quiet policy and that
the least expensive noise control is to
relocate.
• Compare people in a noisy factory with
people in an airport standing at a baggage
carousel. It would be more logical if
people can stand away from the carousel
and only approach the carousel when their
baggage is available.