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360-ID604-01-IMDO © 2026, Workplace Safety & Prevention Services (WSPS)
1 877 494 WSPS (9777) | 905 614 1400 | WSPS.CA
SELECTION CRITERIA RESULT
Noise level in the workplace (L
ex,8
)
85 dBA
HPD Make and Model Make, Model
HPD Type (e.g. Foam Plug, Custom, Earmuff etc.) Earmuff with ANR
Noise Reduction Rating (NRR) of HPD 30 dB(C)
De-rating Coefficient for Earmuff 0.7 (70%)
Noise Reduction ((NRR x Derating) - 2)
((30 x 0.7) - 3) = 18 dBA
Passive Resulting Noise at the Ear
(L
ex,8
) - (Noise Reduction)
85dBA - 18 dBA = 67 dBA
ANR Selection – Noise Limiter Specification 82 dBA
ANR Selection – Intrinsically Safe No
ANR Selection – Voice Passthrough Yes
ANR Selection – Connectivity Wire, Bluetooth
*Note: Optimal protection is between 75 dBA and 80 dBA. When noise and useful sounds are limited
through protection below 70 dBA the results can be missed verbal and alarm cues.
RISK COMMENTS/CONTROLS
Reduced voice transmission If the HPD with ANR has voice passthrough then voice transmission
usually increases. If HPD with ANR has no voice passthrough then voice
transmission may be significantly reduced.
In situations with highly variable noise and a strong need for
communication, HPDs with ANR can be especially useful because they
help reduce overprotection.
Reduced communications Some HPDs with ANR have additional functionality through connection
with electronic/radio communication systems. In locations where
communication is of high importance these devices can increase
communication and reduce overall noise by limiting radio volumes.
HPDs with ANR without media connection can reduce communication
and/or require an increase in radio volume.
Reduced alarm recognition The recognition of alarms should be tested on site before use is
accepted. Some ANR HPDs can reduce alarm levels (typically frequency
dependent).
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