Understanding Decibels & Hearing Protection Ratings

What Do Those Numbers on the Box Mean? Understanding Decibels & Hearing Protection Ratings

When choosing hearing protection, you’ve likely seen decibel (dB) ratings, NRR (Noise Reduction Rating), or SNR (Single Number Rating) on the packaging. But what do these numbers actually mean? Understanding these ratings is essential to picking the right earplugs or earmuffs for your needs, whether you're blocking out snoring, traffic noise, or loud machinery.

In this guide, we’ll break down how decibels work, what NRR and SNR mean, and the key differences between the ANSI S3.19-1974 (USA) and EN 13819-2 (European) testing standards.

How Loud Is Too Loud? Understanding Decibels (dB)

Decibels measure sound intensity on a logarithmic scale, meaning each 10 dB increase doubles the sound intensity. Here’s a quick comparison of everyday noises:

Sounds above 85 dB can cause permanent hearing damage if you're exposed for too long. This is why hearing protection is essential in loud environments.

What Do NRR and SNR Mean?

Hearing protection devices (earplugs, earmuffs) are rated by how much noise they reduce. The two main ratings are:

  • NRR (Noise Reduction Rating) – Used in the U.S. (tested under ANSI S3.19-1974).
  • SNR (Single Number Rating) – Used in Europe/UK (tested under EN 13819-2).

For example, if earplugs have an NRR of 20 dB, and you’re in a 90 dB environment, the noise reaching your ears will be:
90 dB - 20 dB = 70 dB

⚠️ Important Note: NRR and SNR ratings assume a perfect fit. In real-world conditions, the actual noise reduction is often lower due to how earplugs are worn.

Comparing Hearing Protection Standards: ANSI vs. EN

Hearing protection products are tested under two major standards:

Key Differences

  • ANSI tends to report higher NRR values because it’s measured in a perfect lab setting.
  • EN values may be lower but more realistic, accounting for how people actually wear earplugs.
  • NRR ratings in the U.S. are often adjusted down to reflect real-world use (90th percentile of users).

This means that even if two earplugs seem to have different ratings, their real-world performance might be closer than the numbers suggest.

Why Does This Matter for You?

  1. Choosing the Right Protection:
    • For loud workplaces (construction, factories) → Look for high NRR or SNR ratings (25 dB+).
    • For general noise reduction (travel, study, sleep) → NRR 15-25 dB is usually enough.
  2. Understanding Labels:
    • If buying hearing protection in the U.S., check the NRR (ANSI standard).
    • If buying in Europe/UK, look for the SNR (EN standard).
  3. Fit Matters!
    • Even a high NRR earplug won’t work properly if not worn correctly. Comfort and fit are just as important as the rating.

Final Thoughts

  • dB ratings help us understand sound intensity and the need for hearing protection.
  • NRR (USA) and SNR (Europe) indicate noise reduction, but they are tested differently.
  • ANSI ratings may be higher due to lab testing, while EN values reflect real-world use.
  • Choose protection based on your needs but always ensure a proper fit for best results.

By understanding these numbers, you can make smarter choices for protecting your hearing—whether at work, concerts, or even while sleeping.