Corridors and stairs are frequently used areas. People come and go in a steady stream. These areas act as transport routes for people and objects as well as for noise. Corridors also offer opportunities for individual study and discussions.
Open areas encourage conversation at a distance, which results in people tending to raise their voices, trying to be heard over others. Sound breeds sound, creating a disturbing "cocktail of noise".
Hard surface materials create problematic sound amplification and sound propagation. The sound is transported a long way and so disturbs a large number of people in adjacent classrooms.
Hard flooring creates noisy footsteps.
Parallel walls can create problematic flutter echoes.
Corridors - reverberation time of 0.6 seconds. To achieve this, a full acoustic ceiling is needed of sound absorption class B (in accordance with EN ISO 11654).
Stairs - reverberation time of 0.8 seconds. To achieve this, an acoustic ceiling of sound absorption class A (in accordance with EN ISO 11654) covering 60% of the ceiling surface is needed. In practice, this means covering the underside of the landing.
Building codes and standards
UK Regulations Building Bulletin 93 (BB93), states: The objective is to absorb sound in corridors, entrance halls and stairwells so that it does not interfere with teaching and study in adjacent rooms. The requirement is to include additional absorption in corridors, entrance halls and stairwells. The amount of additional sound absorption should be calculated according to Approved Document E, section 7.
Swedish Standard 02 52 68 recommends a reverberation time of 0.6 or 0.8 seconds in corridors, and 0.8 or 1.0 seconds for stairs, depending on the selected quality level. This applies to normally furnished but unoccupied spaces. The above figure is the highest recommended value for the frequency range 250 - 4,000 Hz. At 125 Hz a value 20% higher is permitted.