The sound level in a classroom or nursery is typically between 60 and 75 dB(A), which is equivalent to a normal to loud conversation. However, classrooms are often not acoustically designed for modern teaching methods, which can lead to higher noise levels. Noise levels above 85 dB(A) are considered harmful to hearing. If the noise level in a common room exceeds 85 dB(A) on a permanent basis, adequate noise protection is required by law.