Hearing protection for metal grinders: grinding and cutting

How loud is grinding?

How high the daily exposure is depends on how long the grinding lasts. Because every doubling of sound energy adds only 3 dB, short times are enough: at 107 dB(A), the daily exposure of 85 dB(A) is reached after about three minutes. From 85 dB(A), hearing protection must be worn.

Which hearing protection for grinding?

The target under hearing protection is 70 to 80 dB(A). The table calculates this for three typical levels.

Level at the ear = level − (M − real-world deduction), HML check according to DGUV Rule 112-194 (2024). Target range 70 to 80 dB(A). A calculated guide that does not replace a risk assessment.

Hearing protection	Effective	Belt grindingapprox. 90 dB(A)	Angle grinderapprox. 97 dB(A)	Rough grindingapprox. 107 dB(A)
EP1227BWGDisposable foam earplugs EP1227BWG, SNR 37	26 dB	64 dB(A)Too strong?Check for overprotection	71 dB(A)RecommendedRecommended	81 dB(A)Not rec.Not recommended
EP902EP902 earmuffs EP902, SNR 33	26 dB	64 dB(A)Too strong?Check for overprotection	71 dB(A)RecommendedRecommended	81 dB(A)Not rec.Not recommended
EP001YReusable silicone earplugs EP001Y, SNR 32	24 dB	66 dB(A)Too strong?Check for overprotection	73 dB(A)RecommendedRecommended	83 dB(A)Not rec.Not recommended
EP906EP906 earmuffs EP906, SNR 30	23 dB	67 dB(A)Too strong?Check for overprotection	74 dB(A)RecommendedRecommended	84 dB(A)Not rec.Not recommended
EP100BYBanded earplugs EP100BY, SNR 29	21 dB	69 dB(A)Too strong?Check for overprotection	76 dB(A)RecommendedRecommended	86 dB(A)Not permittedNot permitted
EP904EP904 earmuffs EP904, SNR 28	20 dB	70 dB(A)RecommendedRecommended	77 dB(A)RecommendedRecommended	87 dB(A)Not permittedNot permitted
EP102BOBanded earplugs with conical tips EP102BO, SNR 27	19 dB	71 dB(A)RecommendedRecommended	78 dB(A)RecommendedRecommended	88 dB(A)Not permittedNot permitted

For rough grinding at around 107 dB(A), no hearing protector in the range reaches the target range according to the HML check. The closest are the EP1227 disposable earplugs and the EP902 earmuffs, each with 81 dB(A) at the ear: permissible, but not recommended. The reusable earplugs (83 dB(A)) and the EP906 (84 dB(A)) stay just below 85 dB(A), the highest level DGUV Rule 112-194 accepts at the ear; lighter models are above it. On the angle grinder at around 97 dB(A), every hearing protector in the table is in the target range; for belt grinding at around 90 dB(A), only the lighter ones: the EP904 earmuffs and the EP102BO banded earplugs.

Grinding inside tanks at up to 115 dB(A): no single hearing protector in the range is enough here. Even with 26 dB of effective attenuation (M value minus real-world deduction), 89 dB(A) would reach the ear, above the EU exposure limit value of 87 dB(A). The level must first come down through technical and organisational measures, as set out in the risk assessment. For extreme levels, DGUV Rule 112-194 also mentions combining earplugs and earmuffs, and qualified use: training with practical exercises at least four times a year, documented. The real-world deduction then no longer applies, see Hearing protection training.

Look at the H value

Grinding noise is bright and high-frequency; DGUV Rule 112-194 puts grinders and cut-off grinders in noise class HM. For such noise, the H and M values say more than the SNR. The highest H values in the range belong to the EP1227 disposable earplugs with H 37 dB and the EP903 earmuffs with H 36 dB. More in SNR and H/M/L explained.

In the grinding shop

• Put hearing protection on before switching on and take it off only after switching off. At 107 dB(A), every minute without protection counts.
• With safety glasses, earplugs are the better choice, because spectacle arms break the seal of earmuffs. BG BAU recommends this too.
• Many short grinding passes with breaks in between: earmuffs are quicker to put on and take off.
• Anyone standing next to the grinding work is also at risk. Areas where the daily exposure can exceed 85 dB(A) must be marked as noise areas (Article 5(3) of Directive 2003/10/EC; in the UK, hearing protection zones).