S12.60 could be difficult to apply to classrooms
ANSI/ASA Standard S12.60-2002, Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools, was developed so children who are mildly hearing-impaired can hear their teachers speak above the background noise of outdoor and indoor sources.
The standard is controversial because the highest background-noise level allowed is 35 dBA (about NC25). To put that into perspective, a home at night with all appliances off has a background-noise level of 30 to 50 dBA. Concert halls shoot for NC 15.
Clearly, schools endeavoring to meet S12.60 will require careful engineering, proper construction materials and furnishings, and commissioning/testing services that verify compliance. Even one of the standard’s chief architects admitted that 35 dBA is quiet and will be hard to meet.
It is held as a certainty by manufacturers, engineers, and the Air-Conditioning and Refrigeration Institute that the standard will prohibit the use of unit ventilators and wall-mounted package units – as currently designed and manufactured—and other types of equipment having compressors, fans, and condensers from being installed in classrooms. Central air-conditioning systems with ducted ventilation, according to them, will be the rule.
Although I view such generalizations with a grain of salt, significant impacts will be felt architecturally as well. Perimeter classrooms with windows facing street traffic will have a hard time meeting the standard, as will modular classrooms, More attention will have to be devoted to classrooms adjoining gymnasiums, auditoriums, and the like.
On the other hand, debates on the impacts of standards and regulations often are based on the status quo and “all things remaining equal.” Yet this never happens. Increasingly tight standards drive innovation. Look at what the Montreal Protocol did for chillers with respect to increasing energy efficiency and reducing emissions.
However, tighter standards and better equipment do not always result in better systems over the long run. S12.60’s testing requirement will help ensure better performance initially, but will noise build up over time, or will rooms be checked periodically to ensure continuous compliance? Curtains and carpets are being discussed as means to help passively quiet classrooms, These measures, however, could lead to indoor-air-quality problems by providing a continuous source of airborne particulate matter and make cleaning more difficult. With asthma in children at epidemic levels in the United States, materials used for furnishings need to be considered with great care.
S12.60 exists. It’s a done deal. What’s in question is where it will be adopted and specified. At this time, states such as Connecticut are considering making S12.60 part of their building code. It has not been made part of the International Building Code. However, this does not mean it can be ignored. Hypothetically speaking, it could be adopted by “voluntary” design/construction programs, Any code jurisdiction or project adopting a voluntary guideline that adopts S12.60 could pop up unexpectedly on a project.
Thus begins the debate of the reasonableness of the S12.60 standard and its 35-dBA noise level.