Africa Energy Indaba

Noise Pollution

Getting Rid Of Unwanted Noise

The classroom learning environment can be disrupted by pupils who are distracted by unnecessary noise. For example, a  school built next to a motorway or an airport where there is constant outside noise will have a direct impact on the pupil’s comprehension, language learning, attention and other cognitive functions. The challenge is to categorise the unwanted noise you experience at your school. Once the type of noise is identified, then it can be measured and corrective action can be taken. We usually measure noise in decibels (dB) with a sound level meter but noise can also be measured with a dosimeter (what is a dosimeter?) or a devise like a laptop with audio recording software.

The Three Main Types Of Noise Pollution

There are three main types of noise that can affect learning. Firstly, there is noise intrusion, which usually comes from outside the school but also inside the school where construction or maintenance work is taking place. This noise can travel and be increased in volume if the layout or design of the school allows it. Secondly, there is background noise from within the classroom. This noise is typically consistent and caused by equipment in operation. This equipment often services the in-class environment and can take the form of a projector, laptop or heating and ventilation systems amongst others. Lastly there is the noise generated by students engaged in learning inside the classroom which can vary according to the nature of in class exercise or activity.

Ways To Reduce Noise Levels

The noise level standard for an empty classroom is 35 dB set by World Health Organisation. This standard may vary from country to country and is also dependant on climate.

Ways to reduce noise is to install the correct windows, insulation and roofing. Another less costly option is to apply strict ‘no noise’ rules when classes are in session and reinstate these rules with strategically placed signage. We are all different; some may be more sensitive to noise than others. Persistent disruptive noise can make us all lose the plot. Use your break time to let it all out!

Window Glazing

Windows strongly influence the use of the School and the productivity and comfort of its occupants. Most countries now specify minimum glazing requirements for all new schools. Not only does glass have a direct effect on energy consumption but it also offers insulation from outside noise. Double glazing in particular offers excellent insulation from outside noise while still offering thermal comfort and natural light to filter into the classroom.  Double glazing is manufactured using two panes of glass separated by a “warm edge” spacer before dehydrated air is trapped between the two glass panes. This dehydrated air forms a buffer between the external exposed glass and the internal pane offering reduced noise coming in from the outside. What type of windows do you have in your classroom and do they offer reduced noise levels from the outside?

Insulation

A well-insulated school classroom can go a long way in improving the thermal comfort for its pupils and teacher by regulating heat loss or gain more efficiently. Apart from the energy saving benefits in terms of in-class thermal comfort, insulation also offers very good acoustic value by reducing the inflow of noise from outside the classroom. It can also insulate a classroom from the noise happening in the classroom next door. Insulation is typically installed in the roof and /or the classroom walls. The type of insulation depends on the design of your school building, solar orientation, climate and budget. Its best to get a qualified insulator in to advise on the right type of insulation for the desired noise levels required at your school.

Roofing

Roofing also offers protection from noise intrusion which is typically caused by bad weather in the form of a hailstorm or gusting winds. Animals like birds can also rustle up much noise through their movement and general day to day activity on a building’s roof. Unfortunately, most schools are built on a low budget without acoustic levels considered. Corrugated sheet metal is often used for roofing which offers very little acoustic insulation value. It’s important to consult a roofing expert who considers climate and the general school environment, to specify the most appropriate roofing materials. More recently, recycled tyres are being used to manufacture roof tiles. This recycled rubber tile offers excellent value in terms of insulation and noise absorption.

Receive the week’s most popular stories in your inbox every Saturday morning