HMMH conducted an acoustical analysis for the Neonatal Intensive Care Unit (NICU) at St. Joseph’s Hospital Health Center. The purpose of the study was to assess potential interior noise impact due to a proposed helipad to be located on the roof above the NICU facility, and to provide noise-insulation building design recommendations as necessary.
The exterior noise exposure of the NICU facility was modeled for helicopter arrival and departure operations, as well as during static idling on the helipad, to estimate the worst-case exterior sound levels at the upper-floor facade and on the rooftop of the building. The exterior noise level estimates were then combined with detailed acoustical modeling of the outdoor-to-indoor sound transmission loss for the existing building construction to compute the worst-case interior helicopter noise exposure for rooms along the exterior facade and also for interior rooms with no direct facade exposure.
The interior helicopter noise estimates for the existing building were projected to exceed the applicable Facility Guidelines Institute (FGI) noise limits for NICU facilities. Noise insulation measures were therefore designed for exterior facade rooms and the effect of adding the rooftop helipad was also considered for interior rooms directly below. Overall, the interior noise exposure estimates for the sound-insulated building design and including the future helipad structure are projected to meet the FGI acoustic criteria.