How is custom hearing protection tested for fit and attenuation?
Whether a custom earplug still protects comes down to one thing: does it still seal? A small gap lets sound leak past the plug, and you cannot see that from the outside. So we test digitally, in your own ears.
The leak test, step by step
- We first clean your earplugs thoroughly (ultrasonically).
- You put them in yourself, and we connect a thin air tube.
- We build up a little pressure in the ear — about 5 millibar. You barely notice it.
- After five seconds the measurement is done; then we do the other ear.
On request we draw up a test certificate with the results. We can test almost any custom earplug, including those from other suppliers.
Why the fit changes
Your ear canal keeps moving throughout your life. Research by the Royal College of General Practitioners found that our ears grow an average of about 0.22 mm per year, and the ear canal is partly elastic cartilage, so it changes shape too. Substantial weight gain or loss plays a part as well.
Experience shows that after an average of five years a custom earplug often no longer seals well enough. That says nothing about the quality of the plug — only about the fit.
For companies
Since 21 April 2019, hearing protection for companies falls under PPE category 3 (Regulation (EU) 2016/425), the strictest category. Periodic checks with a test certificate are part of that.
You can read more about the test and book one on the fit test page.
