Acoustical Lagging: Perkins School for the Blind

Challenge

Perkins School for the Blind in Watertown, Massachusetts, founded in 1829, is an innovative leader in serving people with visual impairments. Like many schools, the facility's HVAC and mechanical systems generated noise through lightweight galvanized ductwork and PVC piping that transmitted sound into occupied spaces. However, the impact at Perkins was intensified because the students' loss of sight makes them more dependent on auditory information. Background noise from mechanical systems created distractions that directly affected the students' ability to learn and focus in the classroom.

Solution

The B20LAG-QFA9 was specified for this application, the highest rated acoustical lagging product available. This composite material features a two-pound-per-square-foot reinforced-foil-faced loaded vinyl noise barrier bonded to a 2 inch thick quilted fiberglass absorber/decoupler.

The B20LAG-QFA9 achieves an STC 34 rating, equivalent to the sound transmission class of most standard wood stud residential walls with half-inch drywall on both sides and no insulation in between. The product is twice as heavy and dense as most acoustical lagging products on the market, and the extra inch of fiberglass absorber provides superior low-frequency performance critical for attenuating the broadband noise spectrum produced by HVAC systems.

The reinforced-foil exterior accepts matching lag tape for efficient installation and serves as a protective jacket. The product provides both acoustic attenuation and thermal insulation, with an R-factor of 9.0, a temperature range of negative 20 to positive 200 degrees Fahrenheit, and flame spread index of 12.5.

Results

After the acoustical lagging was installed on the HVAC ductwork and piping, teachers and faculty observed that students appeared less distracted and were better able to focus in the classroom. The reduction in mechanical noise background improved the learning environment for students who depend primarily on hearing for instruction and communication.