Noisy classrooms

Noise levels in classrooms are distressing preschool children

The problem of noisy classrooms is widespread amongst schools, affecting children of all ages as well as teachers.

With offending buildings it can usually be shown that it is a problem by calculating the reverberation time, as this is often the main problem. It is then a case of proposing some judicious changes by way of introducing some soft furnishings and possibly some changes to floor, wall and/or ceiling surfaces.

New problems often arise from “echo” nuisance experienced in recently refurbished rooms. This produces discomfort and some degree of irritability affecting occupants due to noise characteristics of the rooms.

A good approach is to analyse likely reverberation time of normal speech within classrooms. The value in seconds obtained from such an analysis indicates the time taken for sound to decay a level of 60 decibels (dB). This is a standard method of measuring sound characteristics within built spaces. For many classrooms, the desirable reverberation time is about 0.7 - 1.0 second. The actual calculated value for some rooms we have seen due to the surface materials used is 1.45 seconds, almost twice the optimum value. Such a result is consistent with the reported difficulties experienced by occupants, and of the types of interior surface finishes used in many classrooms.

We have also observed new refurbishment work that has produced considerable noise transfer from the floor of the upper levels. Typically in these cases, before the building work commenced there were acoustic ceiling tiles, and they are replaced with ceiling finishes of smooth plaster-board. The perception of the increased noise from the upper levels is often consistent with the change of ceiling lining type.

Often the answer for acceptable noise levels in classrooms is the judicious selection and use of floor, wall and ceiling surfaces.