Page 27 - Fall 2008

Fig. 2. View of the acoustically absorptive treatment in the remodel of a burn acute care unit. An absorptive panel is wall mounted behind the sink in the interior of a debridement treatment room (Reprinted with permission from ref. 46. Copyright 2008, Institute of Noise Control Engineering).
patient distress sounds in adjacent spaces. The L1 values were reduced from 88 dB(A) before remodeling to 55–58 dB(A) after the remodel. As a result, privacy and acoustical comfort was markedly enhanced within the remodeled debridement treatment facility and between the debridement facility and the rest of the ward.
Acoustical remodeling of a hematological cancer unit
This project investigated the ben- efits of adding acoustical absorption
30
patients.
Sound absorbing panels were
created and installed in a noise inter- vention effort. The panels consisted of 2-in.-thick fiberglass wrapped in anti-bacterial fabric. The fabric was affixed to the back of the panels with wallpaper paste. The panels were installed on the ceiling and high on the walls of corridors, as shown in Fig. 3. A concentration of absorbers was placed in circular architectural features at the nurses’ stations and on corners where cabinets tended to reflect sound from one corridor to another. The selection and the place- ment of the absorbing panels were coordinated with the hospital archi-
tect to provide an aesthetically pleasing design.
The impact of the noise interven- tion was evaluated using both objective and subjective measures. After installa- tion of the panels, the noise (as meas- ured by Leq) was reduced by 5 dB(A) and the reverberation time dropped by a fac- tor of 2. Anecdotal evidence revealed that the immediate impact of the panels was to permit occupants to lower the level of their speech while still being well understood. Additionally, subjective data collected through surveys of staff and patients before and after the treat- ment showed that perception of noise improved after the installation of the panels. For example, nearly 30% of the patients surveyed felt that noise inter- fered with daytime rest before the treat- ment compared to 0% afterward. The majority (92%) of the nurses surveyed reported problems hearing during
rounds prior to treatment and only 8% reported problems hearing after treatment.
Staff dosimeter study
During these studies, a great deal about measurement methodologies and metrics was learned. For example, we are investigating the differences between staff and patient noise exposure levels.22,23,47 In the Neuro-ICU study discussed
Fig. 3. View of the acoustically absorptive treatment in the remodel of a hematological cancer unit. Sound absorb- ing panels are mounted high on the walls and on the ceiling of the corridor, as well as in the large circular architec- tural feature at the nurses’ station. Note a person shown at the bottom center for scale (Reprinted with permission from ref. 30. Copyright 2007, Acoustical Society of America).
The unit was perceived as relatively noisy by staff prior to the addition of absorption with an average Leq of 55 dB(A). As in the burn acute care unit study, sound absorbing treatment options were limited as the cancer unit housed immuno-suppressed
in a hematological cancer unit.
26 Acoustics Today, October 2008