Classroom Acoustics

Unwanted noise in schools poses a serious threat to the learning process. It affects not only students with hearing disabilities, but children with normal hearing. It also affects the ability of teachers to instruct effectively on a daily basis. Fiber glass duct insulation solutions from Johns Manville help combat these issues and improve the acoustical environment in educational settings.

While the most obvious victims of "noise pollution" are students with hearing disabilities, they are not the only ones. Noise impairs learning for students with other types of learning or behavioral disabilities or those for whom English is a second language. An often overlooked factor is temporary hearing impairment - on any given school day as many as 25 percent of the students in a class may be "hearing disabled" due to ear infections or other medical conditions.

Children with normal hearing and abilities also suffer from unwanted noise. According to the Acoustical Society of America (ASA), many U.S. classrooms have so much background noise that the speech intelligibility rating is 75 percent or less. This means that children with normal hearing can hear clearly fewer than three out of four words spoken. The adverse impact this has on learning is particularly severe for young children who are less able than older students and adults to put what they hear in context and fill in the gaps. Once younger students miss a few words, they are likely to have missed the whole message.

HVAC systems are notorious contributors to nuisance noise. Attempts to reduce energy use often aggravate acoustical problems in classrooms. Many schools rely on in-room heaters or portable air conditioners and heat pumps to cut energy consumption. This puts the source of equipment noise right next to, or even inside, the classroom. In the worst cases, this reduces to a negative number the signal-to-noise ratio, a number that defines how much of the teacher's speech can be heard above ambient room noise.

The American National Standards Institute (ANSI) has developed a standard specification and design guideline that can help eliminate acoustical problems in the design stage. The standard, ANSI S12 60-2002, acts as a resource for architects, school superintendents, audiologists and even parents by identifying the minimum requirements for an effective learning environment. Industry experts will find it a helpful tool for selecting the right equipment and accessories for efficient acoustical design.

Lining sheet metal with fiber glass duct liner insulation is an especially attractive option for schools. It is less expensive than other noise control solutions and requires no additional space. It is effective in reducing the transmission of equipment noise and the noise of cross-talk between classrooms.

Lining sheet metal ducts with fiber glass duct liner insulation can also offer another financial benefit. The ASA reports that teachers must raise their voices to maintain the +10 dB signal-to-noise ratio necessary for good speech intelligibility. This results in teachers taking several sick days each year as a result of vocal strain, costing schools money.

Educators and architects are beginning to understand the importance of classroom acoustics and the impact of unwanted noise on the ability to learn. The HVAC system can be a large contributor to noise pollution in schools. Investing time in the design stage and a few extra dollars during construction to reduce the noise from the air handling system can pay off handsomely in improved student performance. Please take some time to find out about JM insulation products that help in this mission.

Get a free ASA booklet on classroom acoustics