Hearing loss due to workplace noise exposure is a serious concern for many industries. Regular hearing assessments are essential for early detection and prevention. By following best practices and industry standards, businesses can safeguard employees’ hearing and maintain compliance with occupational health regulations. Here’s everything you need to know about best practices for audiometric testing.
Understanding Background Noise Limits
To ensure accurate audiometric results, background noise must remain within permissible levels as outlined in AS/NZS 1269.4:2014 – Occupational Noise Management: Auditory Assessment. Exceeding these levels can compromise test accuracy, so conducting assessments in a soundproof booth or a noise-reduced room is highly recommended.
Maximum Permitted Background Noise Levels (MPANLs)
| Frequency (Hz) | Maximum Allowed Noise Level (dB SPL) |
| 500 Hz | 30 dB |
| 1000 Hz | 35 dB |
| 1500 Hz | 37 dB |
| 2000 Hz | 42 dB |
| 3000 Hz | 45 dB |
| 4000 Hz | 47 dB |
| 6000 Hz | 50 dB |
| 8000 Hz | 52 dB |
Key Conditions for Reliable Audiometric Testing
For optimal test results, the following conditions must be met:
- A quiet, distraction-free testing environment.
- Use of calibrated audiometers meeting AS/NZS 1269.4 standards.
- Properly fitted headphones or insert earphones to prevent noise interference.
Step-by-Step Guide to Audiometric Testing
- Conduct testing well into the work shift, following the SafeWork NSW Code of Practice, to account for temporary hearing changes caused by workplace noise exposure.
- The test subject should be seated comfortably with minimal movement.
- Otoscopy should be performed before testing to check for obstructions like earwax or infections.
- Frequencies tested should range from 500 Hz to 8000 Hz, assessing each ear separately, starting with the better-hearing ear.
- The Hughson-Westlake ascending method (down 10 dB, up 5 dB) should be used for threshold determination.
- If a threshold shift is detected, a repeat test should be conducted within 24 hours.
Pre-Test Preparation
To maximise test accuracy, follow these guidelines:
- Educate test subjects about the process and ensure they understand how to respond.
- Document medical history, noise exposure levels, and hearing protection usage.
What Happens After the Test?
- If significant threshold shifts are detected, immediate further evaluation is recommended.
- Securely store results to comply with privacy regulations.
- If occupational hearing loss is suspected, a workplace noise assessment should be conducted.
Understanding Significant Threshold Shifts (STS)
A significant threshold shift is defined as:
- A ≥10 dB change at any single frequency between 2000 Hz and 6000 Hz in either ear.
- A ≥15 dB shift across multiple adjacent frequencies (e.g., 1000 Hz, 1500 Hz, 2000 Hz) in either ear.
If an STS is detected, a follow-up test within 30 days is recommended to confirm the change. Persistent shifts require an audiological evaluation and a review of workplace noise exposure.
Maintaining Testing Equipment
- Daily checks should be performed on audiometers and headphones to ensure proper function.
- Annual calibration is required by a qualified professional to maintain compliance with AS/NZS 1269.4.
Comprehensive Reporting for Employers
Audiometric test reports should include:
- Employee details (name, date of birth, work history, and noise exposure levels).
- Test results for each ear at all tested frequencies.
- Observations, anomalies, and recommended actions.
- A comparison with previous test results if available.
Employers should be promptly notified of any significant threshold shifts to facilitate occupational health monitoring.
Compliance with AS/NZS 1269.4:2014
Following AS/NZS 1269.4:2014 ensures accurate, reliable, and legally compliant workplace hearing assessments. This helps businesses detect workplace-related hearing loss early and implement proactive noise management solutions.
Take Action Today
Protect your workforce with expert hearing assessments. Hayden Health & Safety specialises in audiometric and occupational noise assessments to ensure compliance and safeguard employee health. Contact us today to schedule your consultation!
