How to Choose the Right Hearing Protection: Earmuffs vs Earplugs for Australian Workplaces

Why Hearing Protection Selection Matters

Hearing protection devices (HPD) are frequently the final control in the hierarchy — used after engineering and administrative controls have been optimised. But selecting the wrong HPD, providing inadequate training in its use, or choosing HPD so uncomfortable that workers remove it for relief can undermine an otherwise effective noise management program. An earplug worn correctly for 8 hours provides far more protection than a high-rated earmuff that is removed for 30 minutes.

Australian WHS Regulations require that where noise cannot be controlled to below 85 dB(A) LAeq,8h through engineering and administrative means, suitable HPD must be provided. The HPD must be appropriate for the noise level, fit the worker correctly, be properly maintained, and be actually worn throughout the noise exposure period.

The Australian Rating System: AS/NZS 1270 and SLC₈₀

All HPD sold in Australia must be tested and rated in accordance with AS/NZS 1270:2009. The primary rating parameters are:

• SLC₈₀ (Sound Level Conversion, 80th percentile): The A-weighted noise level reduction in dB that can be expected for 80% of wearers when the device is worn correctly. The 80th percentile value is used (rather than the mean) to provide a degree of conservatism accounting for variability in fit and wearing technique.
• Class rating (1–5): A simplified categorisation derived from SLC₈₀:
  • Class 1: SLC₈₀ 10–13 dB (suitable for environments up to 90 dB(A))
  • Class 2: SLC₈₀ 14–17 dB (up to 95 dB(A))
  • Class 3: SLC₈₀ 18–21 dB (up to 100 dB(A))
  • Class 4: SLC₈₀ 22–25 dB (up to 105 dB(A))
  • Class 5: SLC₈₀ ≥26 dB (up to 110 dB(A))

The class selection is based on the workplace noise level (LAeq or Leq,T) minus the SLC₈₀ of the selected HPD, with the result targeting a protected level of 75–80 dB(A). The target is not to achieve the lowest possible protected level — over-protection creates communication problems and safety risks.

Earmuffs: Advantages and Limitations

Earmuffs consist of rigid cups containing acoustic foam or fluid-filled cushions that seal around the ear on the sides of the head. They offer several practical advantages:

• Easy to don and doff — no insertion technique required
• Can be inspected visually for cushion integrity
• Do not require individual sizing in most cases
• Electronic versions available with active noise reduction (ANR) and communication capability

Limitations include:

• Reduced attenuation when worn with safety glasses — the temple arm breaks the ear cup seal, reducing effective attenuation by up to 5–10 dB
• Hot and uncomfortable in warm environments — compliance issues in summer or indoor high-temperature workplaces
• Impractical in restricted-headspace environments (confined spaces, some underground mining operations)
• Effective attenuation degrades significantly with worn, stiff, or cracked cushions

Earplugs: Types and Correct Insertion

Earplugs are inserted into the external ear canal to create an acoustic seal. Main types:

• Foam earplugs (slow-recovery polyurethane): Highest SLC₈₀ values when properly inserted; lowest cost; disposable. Correct insertion requires compressing the plug, pulling the ear upward and backward to straighten the canal, inserting deeply, and holding for the foam to expand fully. Incorrect insertion (partial insertion, no compression) dramatically reduces achieved attenuation.
• Pre-moulded / flanged earplugs: Reusable; available in multiple sizes; less insertion-technique-dependent than foam; lower SLC₈₀ than foam. Often connected by a cord for hygiene and retrieval.
• Banded (semi-aural) hearing protectors: Held against the ear canal entrance rather than inserted; convenient for intermittent noise; significantly lower attenuation than inserted earplugs — suitable only for moderate noise levels (Class 1–2).
• Custom-moulded earplugs: Made from an impression of the individual’s ear canal; excellent comfort and consistent fit; higher initial cost but preferred for full-time HPD wearers in demanding environments.

Real-World Attenuation: The Gap Between Rated and Actual

A critical challenge in hearing conservation is that laboratory-measured SLC₈₀ values consistently overestimate real-world attenuation achieved in workplaces. Studies comparing laboratory ratings with field measurements (“personal attenuation ratings” or PAR) consistently find that workers achieve only 30–50% of the labeled SLC₈₀ value in real workplace conditions. This is due to incorrect insertion technique, intermittent removal, improper size selection, and degraded or contaminated devices.

The NIOSH (US) recommends applying a 50% derating factor to SLC₈₀ values when making conservative compliance calculations. Safe Work Australia recommends using the SLC₈₀ at face value but emphasises fit testing and training programs to ensure workers actually achieve rated attenuation.

Qualitative fit testing (using the OSHA/ANSI field attenuation estimation system or similar) provides a worker-specific estimate of the attenuation achieved with their specific HPD device. Fit testing is the gold standard for verifying that a worker’s chosen HPD actually protects them at the expected level.

Dual Protection: When to Use Earmuffs AND Earplugs

For very high noise environments (above ~105–110 dB(A)), single HPD may be insufficient. Dual protection — simultaneous use of earplugs and earmuffs — provides combined attenuation. However, dual protection is not simply additive (SLC₈₀ₑₐᵣₚₗᵤg + SLC₈₀ₑₐᵣₘᵤff). Sound also transmits through bone conduction, setting a practical ceiling of approximately 35–40 dB(A) for HPD attenuation regardless of the combination used.

Under AS/NZS 1270 guidance, dual protection combined SLC₈₀ is calculated as: SLC₈₀ (combined) = SLC₈₀ (higher-rated device) + 5 dB.

Frequently Asked Questions

Should I choose Class 5 HPD for my workers in a very loud environment to give them the most protection?

Not necessarily. Over-protection is a real safety risk. If workers cannot hear warning signals, alarms, or spoken communication from colleagues while wearing Class 5 HPD, they may be unable to respond to hazards in time. The target is a protected level of 75–80 dB(A) — just below where hearing damage risk becomes significant. Calculate the HPD class needed based on your measured noise level, not simply by choosing the highest-rated product available.

My workers refuse to wear their earplugs because they are uncomfortable — what should I do?

Refusal to wear HPD due to discomfort is a compliance issue with a practical solution: change the HPD type or provide more fitting options. Workers should be given a choice of HPD types and sizes, properly trained in correct use, and supported in finding options that they will actually wear consistently. A HPD worn correctly for 99% of the shift provides dramatically better protection than a high-rated device removed for comfort during breaks.