Inside: Acoustics
Mar 1, 2006 12:00 PM
ADVOCATING FOR ACOUSTICS
The American Speech-Language-Hearing Association says audiologists and acoustical consultants should become more actively involved in seeking better classroom acoustics.
In its “Guidelines for Addressing Acoustics in Educational Settings,” the association recommends that audiologists “become advocates for improvement of the acoustic environment.” This can include being a resource person for teachers, parents and administrators, and disseminating information about classroom acoustics to policymakers and the public.
Acoustical consultants should work with architects “to select acceptable wall, ceiling and floor materials or finishes for the classroom so that the reverberation time of the room meets or exceeds” the ANSI standard.
“Working together, the audiologist and acoustic consultant complement each other and assist in identifying and documenting unacceptable acoustic conditions, specifying acoustic modifications and materials, installing and testing the adequacy of an installation … and documenting behaviorally that a physical modification results in improved speech perception,” the guidelines state.
CONSIDERING COMPUTER NOISE
Schools and universities should make sure they consider noise from computers and other equipment as they try to determine if their classrooms have acceptable acoustics.
In a paper presented last year at the Acoustical Society of America/NOISE-CON 2005 meeting, “Personal Computer, Printer, and Portable Equipment Noise in Classrooms,” authors Robert D. Hellweg, Egons K. Dunens, Terrance Baird and John N. Olsen of Hewlett-Packard note that the acoustical standards for classrooms developed by the American National Standards Institute (ANSI S12.60) did not take into account noise generated by computers and related equipment.
“Noises from portable or permanent built-in equipment used during the course of instruction (such as computers, audiovisual equipment and printers) are excluded,” the paper states. “The fact that computer products and projectors are excluded from (the standards) does not mean that these sources cannot interfere with instruction. In fact, these sources could raise noise levels in the classroom.”
The paper recommends that schools install computers and other equipment in classrooms in a manner to minimize noise levels.
“More powerful printers should be installed away from students and teachers and behind acoustical screens,” the report states. “Projectors should be located away from students and on acoustical mattes to isolate structure-borne-noise from the table and to absorb sound. Mini-tower PCs should be installed on the floor next to the desk instead of on top of desks. Noisier servers should be in a second room or installed with special noise control features behind a screen.”
The authors also suggest that inkjet printers should run in their default or “normal” mode, which is much quieter than the fastest mode.
ACOUSTICAL EXPENSES
A study commissioned by the Air Conditioning and Refrigeration Institute, which has opposed adoption of the ANSI S12.60 acoustical standards for classrooms, has estimated that complying with the standards would increase classroom construction costs by 4 to 19 percent. Most of the schools included in the study were in Minnesota, and the report acknowledges that the results may not be representative of other regions of the country. Here are the study's estimates of the cost increases:
| Building type | HVAC cost per sq. ft. | Other cost per sq. ft. | Total cost increase per sq. ft. | Percent increase |
|---|---|---|---|---|
| New single story | $2.70 to $12.88 | $2.70 | $5.40 to $15.58 | 4 to 12 |
| New multi-story | $2.04 to $13.02 | $8.70 | $10.74 to $21.72 | 8 to 16 |
| Renovated single story | $2.08 to $12.10 | $2.70 | $4.78 to $14.80 | 6 to 19 |
| Renovated multi-story | $1.65 to $9.62 | $2.70 | $4.35 to $12.32 | 5 to 15 |
