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,and Best Practice in Developed Countries

K. Allen Woo

September, 2010

1



Contents

•Noise at Work Regulations in US and Europe

•

Noise at Work Regulation’s Impact to ContactCenter

•Reduce the Noise by Choosing the Right

Audio Device•Beyond Audio Device, Other Suggestions toReduce Noise in Contact Center

•Benefit of Noise Reduction in Call Centers

2



Regulations in U.S.A.

OSHA 29 CFR 1910.95

• 140 dB

Continuous Noise Ex osure

• 115 dB(A)

Time Weighted Average Daily Noise Exposure

• Exposure limit: 90 dB(A)/8 hours working day

• Action limit: 85 dB(A)/8 hours working day

,between exposure time and level applies

• 80 dB(A) threshold applies

3



Regulations in EU

EU Directive 2003/10/EC

• Exposure limit: 140 dB(C)

• Upper action value: 137 dB(C)

• Lower action value: 135 dB(C)

Daily Noise Exposure• Exposure limit: 87 dB(A)/8 hours working day

• Upper action value: 85 dB(A)/8 hours working day

• Lower action value: 80 dB A /8 hours workin da

• For other exposure duration, a linear 3 dB trade betweenexposure time and level applies

4



Industry Standards

• International

ITU-T P.360

IEEE 269IEC 62368-1

- -

•North America

UL/CSA 60950-1

•EU

ETSI EG 202 518

•AusraliaACIF G616

5



Existing Telecom Requirements

Impulse Noise Exposure

140, 137 and 135 dB(C) in the EU (same as the Directive)

118 dB(A) @ ERP in both the US and EU

Daily Noise ExposureNone (US)

87, 85 and 80 dB(A) in the EU (same as the Directive)

ar e reven on102 dB @ DRP only in Australia

6



Headset Compliance

•Different sound fields

•

Different measurement reference points• audible frequencies

relevant sound field before comparingthem to the re ulator re uirements

7



Acoustic Head and Torso Simulators

8



Human Ear Amplifies Sound Levels

Free Field and Eardrum Responses

to a Same Sound Source30

20

25

Eardrum

Response

10

15

d

B

0

5

-10

-

100 1000 10000

Frequency (Hz)

Free Field Microphone

Response

9



Safety Applications in Audio Devices

•In headset limiting devices

ass ve o es an var s ors

Active discrete transistor circuits

Automatic gain control (AGC)

. .

Frequency dependent limiting

• E.g. Plantronics AP15 and M15D

Advanced DSP audio processors

• E.g. Plantronics DM15 and M15D

10



I/O of an Ideal In-Headset Limiting Device

0

( d B V )

-20

-10

r i v

e V o l t a g

-40

-30

R e c e i v e r

-50

-40 -30 -20 -10 0 10 20

Input Voltage (dBV)

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Compression: Automatic Gain Control

RECEIVE COMPRESSION/LIMITING

∆dB OUTPUT < 1

∆dB INPUT

∆dB OUTPUT ~ 1

∆dB INPUT

∆dB OUTPUT > 1

∆dB INPUT

R e l a t i v e )

20

30

PEAK LIMIT

COMPRESSION

REGION

R G A I N

DYNAMIC LIMITING

u t

p u t ( d B

10

0

VOLUME

THRESHOLD

L I N

S I O N

R e c e i v e

-10

-@ FIXED

E X P A

-10 0 10 20 30 40 50

-30

60EXPANSION

THRESHOLD

12

Receive Input (dB Relative)REGION



Advanced DSP Audio Processors

Automatically monitor and control daily headset noiseexposure inline with regulatory acoustic safety requirements

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Other Steps to Reduce Call Center NoiseExposure

• Use binaural headset in noisy environment

• Educate agents to correctly position the headsets during the uses

• Educate agents to adjust receive volume control regularly if available

• Encourage agent to lower their listening levels

• Encourage agent to use higher gain microphone and lower their own

voices

• Reduce ambient noise level

• Improve noise absorption in the working area

• Reduce densit of a ents

• Remove equipment that generate noise

• Remove social gathering and conference areas away from working area

14



Benefit of Noise Reduction in Call Center

• Improves customers’ satisfaction

• Improves agents’ productivity

’

•

Improves work force retention• Improves working environment

•Protects agents’ hearing

•Reduces costs of business

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