The Campaign For Improved Acoustics in Schools
By Peggy B. Nelson, Ph.D., CCC-A
Department of Communication Disorders, University of Minnesota
Hearing Rehabilitation Quarterly - Special Edition (2001)
During the past thirty years, a body of literature has evolved that strongly suggests that noise in the classroom interferes with children's learning, cognitive and reading skills (http://www.lhh.org/noise/archives/). Yet, despite these findings on the adverse impact of noise on children's learning, many of our nation's schools lack a suitable acoustical environment. For hard-of-hearing children these acoustically poor classrooms are even more detrimental. But thanks to the efforts of one mother who claimed her hard-of-hearing child was deprived of full access to education in his noisy classroom, an important campaign to improve the acoustics in American classrooms has been launched.
When this mother argued that the noise in her son's classroom prevented him from fully participating in classroom activities, the U.S. Access Board put together a multi-disciplinary task force of audiologists, engineers, architects, and acoustic consultants to examine the impact of classroom noise on learning. Now after two years of working on this matter, this task force has concluded that nationwide standards limiting classroom noise and reverberation are in order. A draft of the task force's proposed standards for classroom acoustics will soon be available for public comment and it is hoped that readers of this article will lend their voices to this most critical issue (www.access-board.gov).
Below is an advanced summary of some of the conclusions reached by members of the U.S. Access Board's task.
1. All children need good acoustics to hear and to learn. Young children need better acoustics to hear and understand their teachers than do older children and adults because they are less familiar with language. Young children can repeat words and sentences in quiet or in environments with minimal noise levels. However, when these background noise levels increase, young children have difficulty in understanding what is being said to them. Whereas adults can understand most familiar words when the noise level and speech level (or the signal level) are approximately equal, young children between the ages five and seven years cannot. Children in the early grades need background noise levels significantly lower than the signal they are trying to hear.
2. Children with hearing loss, those learning a second language, and those with auditory or attention problems need even more favorable acoustics. Children suffering from temporary hearing loss because of an ear infection, children with some permanent hearing loss as well as children learning a second language, and those children with auditory or attention problems need even more favorable classroom acoustics. We know that there are large numbers of hard-of-hearing children in our public schools. Some estimates suggest that at any given time as many as 25% of young children have ear infections and 10-15% have slight hearing losses due to more permanent conditions. These children require lower background noise levels and higher signal levels for understanding than children with normal hearing. Hard-of-hearing children suffer from reading deficits and experience other academic delays because of their reduced ability to hear and associate speech sounds with written letters; thus, underscoring the need for a quieter learning environment for these children. Essentially, all children would do better academically in classrooms with favorable acoustics.
3. Even without the noise generated in a classroom by the children themselves, especially in large, crowded classes, empty classrooms are still too noisy for optimal learning. Noisy heating, ventilating and air-conditioning equipment (HVAC) raise the levels of noise in the classroom. In some schools the AC system pumps out 65 dBA into the center of the room, the same level as the teacher's voice at 1 meter's distance. Children in these rooms who sit farther than 1 meter from the teacher can hear the AC better than they can hear the teacher. Some teachers told task force members that they are forced to alternate between talking (teaching) and cooling the room because they simply cannot raise their voices above this intrusive noise. Unquestionably, the HVAC system, especially in warm areas of the country, is a major noise source.
Many schools are located at sites that expose their students to traffic noise either from busy highways, overhead aircraft, or nearby elevated trains. Frequently these schools do not have double-glazed windows that could abate some of the intrusive noises. In other schools, the primary noise source comes from students in adjacent rooms and hallways, with noises passing through substandard walls and doors. Schools using temporary partitions or moveable walls also create problems, frequently permitting the talker's voice from the adjacent room to reach a child in the back row at the same level as the voice of the teacher in that child's own room.
As research has demonstrated, children who are being taught in noisy classrooms experience learning and reading deficits.
The proposed standard, if adopted, will provide maximum sound and reverberation limits for all new school construction projects as well as projects involving significant renovation. The standard will mandate that sound levels in core learning spaces not exceed 35 dBA throughout the room. This maximum sound level will ensure that the level of teachers' voices, (usually 50-65 dBA, depending on the location of the student and teacher), will achieve the positive signal and sound levels needed by children. In order to achieve that low sound level, classrooms will need high-quality doors and windows that close tightly without leaks and high-quality walls that are installed properly so that they isolate one room from another. Schools will also need quiet central HVAC systems with ducts to each classroom; wall or window air conditioners cannot achieve the quiet levels needed by many students.
Some people will ask why we should make classrooms quieter. Why don't we just make the teachers voices louder? In fact, there are devices that do, in a sense, make the teachers voices louder. These devices are called FM systems, and have been used in classrooms with children who are hard of hearing and deaf for many years. FM systems involve the use of a microphone worn by the speaker a few inches away from the mouth. The speech is transmitted via frequency modulated, or FM signals, to either a receiver worn by the child, or to speakers placed around the room. When FM systems are used, the signal to noise level is improved simply by effectively reducing the distance between the teacher's voice and the child. However, much of classroom learning is peer-based and interactive. The teacher is frequently a guide to group discussions, rather than a lecturer. In these situations, the signal source changes frequently. The signal may be a teacher one moment, a child on the right the next, and a child on the left immediately after. While it is possible to pass the FM microphone around the room, in practice this rarely occurs. Thus, while FM systems are an important factor in improving classroom acoustics, physical modifications of the environment are required as well.
The U.S. Access Board's proposed standard will face an uphill battle with respect to implementation. Improving classroom acoustics will be costly, especially the costs associated with HVAC requirements. Estimates from heating and cooling engineers suggest that quiet HVAC systems may add 1-5% to the total cost of a school construction project. Members of the task force believe, however, that when schools begin requiring manufacturers of HVAC systems to produce quiet systems, the cost of quiet air conditioners and heaters will come down. Less expensive solutions, e.g. adding carpet and sound absorbing tiles, to improve the reverberation of sound are less effective in reducing noise levels.
Too often, school planners do not consider the impacts of noise in the design phase. Noise only becomes an issue after the school is built and the parents of hard-of hearing children complain about their children's noisy classrooms. Obviously, it is more expensive to renovate noisy classrooms after the schools are built than to design quieter new schools. We must encourage those in charge of school districts to design and build quiet classrooms from the start.
Perhaps surprisingly, some current educational trends are working against quiet classrooms. For example, some states have mandated smaller class sizes, but the mandate has left some schools without a sufficient number of self-contained rooms to accommodate all the classes. This means that some rooms are divided to serve two groups of students with two teachers. In some cases, classes are being moved to a larger multi-purpose room with children engaged in different activities. In these cases, noise from one class' activity obviously spills over directly to the other class. In addition, some award-winning school architectural designs have reverted to the "open classroom" concept with large common spaces and few closed doors. Architects might protest the proposed sound level standard because it could limit them to designing less visually pleasing 'egg-carton' schools with rows of adjacent classes. On the other hand, teachers have informed us that they would like to think that the "open classroom" design is no longer in vogue.
It is hoped that architectural and HVAC solutions will be found that will provide students with both beautiful and quiet classrooms in which to listen and learn. The evidence is overwhelming that all children, especially those with auditory challenges, learn better in quiet classrooms. We further believe that the investment in quiet classrooms will result in students' improved learning, reduced cost of special education, and greater academic success. The public will soon have the opportunity to commit on the draft standard of classroom acoustics and we encourage feedback on this proposal. All of us should speak out in favor of providing our children with a classroom setting that enhances and enriches their education.
