If it is not possible to reduce noise to a non-hazardous level (i.e. to below 85 dB(A) noise exposure level), hearing protection equipment must be worn. As soon as the trigger threshold of 80 dB(A) is reached, ear protection equipment has to be made available. In cases of permanent noise exposure or when workers wear glasses, the use of earplugs or cotton wool are advisable; if workers frequently put on and remove ear protection equipment or are inclined to develop external otitis, capsule-type ear protectors are recommended. The noise insulating effect of the different types of ear protection devices is similar (approximately 20 – 30 dB reduction of the noise level), but hearing protection equipment must be worn consistently and regularly in order to be effective. All devices have to bear the CE marking and must have been tested by an accredited testing institution. Effective noise level reduction in dB at the ear depending on the time during which ear protection devices are not worn at a nominal noise level reduction by 30 dB, 20 dB and 10 dB on the basis of an eight-hour working day, Period during which ear protection devices are not worn, in minutes, Hearing can be protected only if ear protection equipment is consistently worn!