Abstract
This white paper critiques Note 1 of Section 15.1.2.3 in the South African National Standard SANS 10083:2023, a standard for occupational noise and hearing conservation. This recently added note implies that if the sound-blocking capability (attenuation) of an audiometric device cannot be easily field-measured by users with basic equipment, the device is unsuitable. We argue this note is scientifically flawed, misinterprets acoustic measurement principles, and effectively renders most, if not all, forms of earphone-based audiometry non-compliant, as the prescribed field measurement method is impractical for any type of headset. It also conflicts with related standards like SANS 10182 and ISO 8253-1, which already accommodate advanced audiometric technologies.
Note 1 wrongly confuses lab-validated device performance with impractical user field checks, ignores valid device attenuation data, and contradicts established best practices. Its inclusion in a previously respected standard raises concerns that it may unfairly target advanced technologies and has inadvertently created a situation where even conventional audiometry is difficult to justify under its narrow terms. This flawed note could limit access to hearing tests, increase costs, stifle innovation, and reduce test quality. We recommend removing Note 1 entirely or substantially rewriting it to align with scientific principles and support proven technologies, thereby restoring the standard’s integrity and effectiveness.
A Flawed Note
How a single note in SANS 10083:2023 undermines hearing conservation and ignores established science.
The Problematic Clause
A recent change to the SANS 10083 standard introduced 'Note 1' to section 15.1.2.3, creating a significant and scientifically questionable barrier for modern audiometry.
SANS 10083:2023, Section 15.1.2.3, Note 1
"Insert earphones, circumaural earcups (headphones) or a combination thereof or any similar device of which the actual attenuation cannot be measured physically with a type 1 or 2 sound level meter equipped with an octave filter should not satisfy this requirement of the testing environment (see SANS 10182)."
The Flawed Interpretation
This note implies that if a user cannot personally verify a headset's sound-blocking capability with basic field equipment, the device is unsuitable. This incorrectly links a device's lab-validated performance to an impractical field check, a standard that most, if not all, audiometric earphones fail to meet.
A Three-Fold Scientific Failure
Note 1 is scientifically unsound because it confuses established principles, ignores valid data, and contradicts best practices.
Confuses Lab Validation with Field Checks
A headset's sound attenuation is precisely measured in a lab using standardized methods. Note 1 wrongly demands that users replicate this with basic, unsuitable field equipment—a scientifically inappropriate requirement.
Ignores Validated Device Data
The note dismisses robust, scientifically determined attenuation data that already exists for advanced systems. The focus should be on the validity of this data, not on an end-user's ability to re-measure it.
Contradicts Best Practice
It clashes with related standards like SANS 10182 and ISO 8253-1, which allow for "other types of earphone" and support outcome-based environmental checks—a flexible, scientifically sound approach that Note 1 undermines.
The Evidence: Validated Attenuation Data Exists
Contrary to the implication of Note 1, advanced audiometric headsets have well-documented attenuation performance, determined through rigorous laboratory testing. This data is the correct basis for ensuring a valid test environment.
Example: Kuduwave Combined Sound Attenuation (dB)
This chart shows the significant sound attenuation provided by a modern boothless audiometer across key frequencies, demonstrating that "actual attenuation" is known, quantified, and reliable.
The Correct Scientific Approach
International standards provide a clear, two-step process for determining a valid test environment with an attenuating headset. Note 1 ignores this established method.
Step 1: Baseline MPANL
Start with the standardized Maximum Permissible Ambient Noise Level (MPANL) for "ears not covered".
Step 2: Add Device Attenuation
Add the headset's lab-validated attenuation value to the baseline.
Device-Specific MPANL
This result is the correct, scientifically valid maximum noise level for that specific device.
Baseline MPANLs are Already Standardized
Key standards from ANSI, ISO, and SANS provide the "ears not covered" baseline data, forming a consistent scientific foundation.
The Negative Impact of a Flawed Note
By creating an illogical barrier, Note 1 harms the very hearing conservation programs it's meant to support.
Reduced Access
Hinders portable, boothless systems crucial for remote and on-site testing.
Increased Costs
Forces reliance on traditional, inefficient, and more expensive sound booths.
Stifled Innovation
Discourages development and adoption of better, more effective audiometric tools.
Creates Confusion
Leads to inconsistent application of the standard due to its ambiguity and contradictions.
Recommendations for a Sounder Standard
To restore the integrity of SANS 10083 and support effective hearing conservation, action is required.
Primary Solution: Remove Note 1
The most straightforward and scientifically justified course of action is the complete removal of Note 1. It is flawed, contradictory, and unnecessary. Existing standards already provide a robust framework.
Alternative: Rewrite Note 1
If a note must be retained, it must be fundamentally rephrased to be scientifically accurate. It should guide users on how to properly use device-specific MPANLs based on lab-validated attenuation data and permit psychoacoustic checks.