Introduction

If you have any questions about the appropriate type of hearing protection equipment required for your work activity, contact your Supervisor or the Facility Support Representative, Industrial Hygiene (IH) Representative, or ESH Coordinator assigned to your organization.

Two main types of hearing protection equipment are used to protect workers’ hearing from noise in the workplace:

1) earplugs that are inserted into the ear canal and;

2) earmuffs that are worn over the head to cover the outer ear.

The ability of the hearing protection equipment to attenuate (reduce) noise is expressed as a Noise Reduction Rating (NRR).

The higher the NRR, the more protection the device provides.

The NRR is a theoretical value.

OSHA recommends adjusting the NRR to account for variability in the fitting of the devices to the individual.

Types of Hearing Protection Equipment:

Earplugs

Soft, smooth foam is molded for maximum comfort, Tapered design with rounded tip aids insertion, typically NRR to about 29 dB (field use NRR = 11
dB).

Fit into and seal the ear canal; generally treated as “disposable” after each use.

Banded Plugs

High visibility headband for easy compliance checks, typically to NRR 22 dB (field use NRR = 8 dB).

Earmuffs

Soft ear cushions improve comfort, typically Dielectric design for use around electrical hazards, Noise Reduction Rating typically range for NRR 20 to 30 (field use NRR = 7 to 12 dB), tested in accordance with ANSI S3.19.

Use when frequent removal and replacement of hearing protection is necessary.

Noise Cancellation Muffs

Headphones that use a small microphone mounted in each earpiece to monitor the outside noise getting to the ear.

A special electronic circuit then creates a signal perfectly opposite to the outside noise so as to cancel it out before it reaches the ear.

Typically they are only able to reduce noise by about 10 dB over a limited frequency range.

They cancel low frequencies best and typically do not cancel high frequencies effectively.