European Standard · Hearing Protection
EN 352 – Hearing Protectors: The Complete Guide to the European Standard for Ear Protection
EN 352 is the family of European standards that sets the general safety and performance requirements for hearing protectors used at work — earmuffs, earplugs, and specialised electronic hearing protection. It is a multi-part standard, with EN 352-1 through EN 352-8 each covering a specific product type. This guide explains the scope, the part-by-part breakdown of the EN 352 family, how attenuation is rated (SNR, H/M/L), how to select the right hearing protector for a noise level, inspection and care, and the standards referenced alongside EN 352.
1. Scope
EN 352 specifies general requirements, physical and acoustic test methods, and marking rules for hearing protectors intended to reduce the wearer's exposure to hazardous workplace noise. It applies to passive earmuffs and earplugs as well as electronic hearing protectors that amplify or level-limit ambient sound. Each part of the EN 352 family adds requirements specific to a construction type, while the physical and acoustic test methods used to measure attenuation are set out in EN 13819-1 and EN 13819-2.
2. Exclusions & Related Standards
EN 352 does not cover eye, head or respiratory protection, which fall under their own standards. Related and referenced standards include:
- EN 13819-1 – physical test methods for hearing protectors
- EN 13819-2 – acoustic test methods for hearing protectors
- EN 397 – industrial safety helmets, often combined with EN 352-3 attachable earmuffs
- EN 166 – eye protection, commonly worn together with hearing protection
- EN 458 – guidance on the selection, use, care and maintenance of hearing protectors (informative, not a certification standard)
For head protection commonly combined with attachable earmuffs, see EN 397 industrial safety helmets. For eye protection worn on the same tasks, see EN 166 eye protection.
3. The EN 352 Family: Parts and Product Types
| EN 352-1 | Earmuffs – standard passive over-ear protectors |
| EN 352-2 | Earplugs – foam, pre-moulded and banded types |
| EN 352-3 | Earmuffs attached to industrial safety helmets |
| EN 352-4 | Level-dependent earmuffs – amplify quiet sound, attenuate loud impulses |
| EN 352-5 | Active noise reduction (ANR) earmuffs |
| EN 352-6 | Earmuffs with electrical audio input (communication headsets) |
| EN 352-7 | Level-dependent earplugs |
| EN 352-8 | Multiple-position earmuffs for entertainment audio |
4. Attenuation Ratings: SNR and H/M/L
Every certified hearing protector is tested and marked with an attenuation rating:
- SNR (Single Number Rating): a single dB value subtracted from the measured C-weighted noise level to estimate the protected exposure
- H (High): estimated attenuation against high-frequency noise
- M (Medium): estimated attenuation against mid-frequency noise
- L (Low): estimated attenuation against low-frequency noise
- APV (Assumed Protection Value): the practical, real-world protection value used for selection, generally lower than the lab-tested SNR
Higher SNR is not always better: over-protection can isolate a worker from warning signals, alarms and colleagues, and can itself be a safety hazard.
5. Selecting the Right Hearing Protector
Match the attenuation rating to the measured daily noise exposure level (LEX,8h) and peak sound pressure of the task, aiming to bring exposure comfortably under the exposure limit without excessive over-protection. Earmuffs generally suit intermittent noise and easy on/off use; earplugs suit hot environments, long shifts or use under other head PPE; level-dependent and electronic types suit environments where situational awareness or communication is essential. Always check compatibility with safety helmets, eyewear and respiratory protection worn on the same task.
6. Inspection, Care and Maintenance
- Inspect ear cushions, headbands and foam tips before each use for cracks, hardening or loss of shape
- Replace foam or pre-moulded earplugs after each use or per manufacturer guidance for hygiene
- Replace earmuff cushions and foam liners on the manufacturer's stated schedule, as attenuation degrades over time
- Check headband tension regularly; a stretched or loose band reduces the seal and the attenuation achieved
- Store in a clean, dry case away from solvents, oils and extreme temperatures
- Replace batteries and check electronic function on level-dependent, ANR or communication headsets before each use
7. Product Examples
- Passive earmuffs (EN 352-1) for general workshop and machinery noise
- Disposable foam earplugs and reusable pre-moulded earplugs (EN 352-2)
- Helmet-mounted earmuffs (EN 352-3) for combined head and hearing protection
- Level-dependent earmuffs (EN 352-4) for shooting ranges and intermittent impulse noise
- Active noise reduction headsets (EN 352-5) for aviation and heavy plant cabins
- Communication headsets with electrical audio input (EN 352-6) for control rooms and team coordination
8. Standard Information
- Status: Active harmonised European standard (multi-part family)
- ICS code: 13.340.20 – Eye, face and head protection / Hearing protection
- Committee: CEN/TC 159 – Hearing protectors
- Related standards: EN 397, EN 166, EN 13819-1, EN 13819-2, EN 458
- Full standards library: Browse all EN standards
Frequently Asked Questions about EN 352
What does EN 352 cover?
EN 352 covers the general safety and performance requirements for hearing protectors, including earmuffs, earplugs and electronic hearing protection, used to reduce noise exposure at work.
What is the difference between EN 352-1 and EN 352-2?
EN 352-1 covers standard passive earmuffs, while EN 352-2 covers earplugs, including foam, pre-moulded and banded types.
What does SNR mean on hearing protection?
SNR stands for Single Number Rating, a single decibel value used to estimate the noise reduction a hearing protector provides when subtracted from the measured environmental noise level.
What do the H, M and L values mean?
They represent estimated attenuation at high (H), medium (M) and low (L) frequency noise, giving a more detailed picture than the single SNR value alone.
Can hearing protection provide too much attenuation?
Yes. Over-protection can isolate a worker from warning signals, alarms and verbal communication, which is itself a safety risk, so protection should be matched to actual exposure rather than always maximised.
How often should earplugs and earmuff cushions be replaced?
Foam and pre-moulded earplugs are generally single-use or short-term use items and should be replaced regularly for hygiene, while earmuff cushions and foam liners should be replaced on the manufacturer's stated schedule as attenuation degrades with age and wear.
What is the difference between EN 352 and EN 458?
EN 352 is the certification standard that hearing protectors are tested and marked against, while EN 458 is an informative guidance standard on selecting, using, caring for and maintaining hearing protectors, not a product certification standard.