Corporations, television stations, police and firefighters use helipads, even high-end residential estates. The noise from the helicopters as they approach, land, and take off can be extremely disruptive to anyone within earshot. At Thorburn Associates our Engineers can provide the acoustical solution. We start by working with the architect, the end-user and the helipad planner to determine the usage, helicopter models and available flight profiles.
We model the helipad with different pad locations and flight path profiles in respect to nearby noise sensitive receptors. The modeling results help determine the best combination of the variables to produce the least noise at the receptors.
Having just completed work on the new Kaiser Permanente Santa Clara Hospital campus, we’ll use that facility as an example. As Kaiser Santa Clara is not a trauma center, the helipad will be used for emergency transport of patients to Stanford Medical Center for specialist procedures. The anticipated usage is 1-2 transports per month. Due to the existing rooftop mechanical equipment, the helipad could not be located on the roof, but is on an elevated platform, adjacent to the hospital and in close proximity to the residential neighborhood.
Thorburn Associates worked closely with the Kaiser Facility project architect,* Anshen + Allen (http://www.anshen.com/) to evaluate the noise impact of the proposed helipad on the adjacent residential neighborhood and the hospital itself.
To perform our evaluation, we used the HNM 2.2 (Helicopter Noise Modeler) software, which is currently recognized by the federal government as the official modeling software for heliports/helipads. For our evaluation, we modeled two anticipated flight paths using two different helicopter models commonly used for local EMS operations. To reduce impact on the adjacent residential neighborhood, the arrival and departure paths are in an east to west orientation. This allows the helicopter to fly along the Lawrence Expressway, the primary noise source in the area, for most of the flight path prior to final descent and take off.
Our evaluation indicates that the helipad will not pose a significant impact on the residential neighborhood, with the given helicopter models and flight paths; however, the helipad will impact the hospital itself. This was addressed by using windows with higher acoustical performance.
Using modeling software, we were able to meet the city of Santa Clara and Kaiser Permanente’s needs of a noise impact evaluation for their new helipad, assisting them in their attempt to be a “good neighbor” to the adjacent residential area.
*Ashen + Allen was acquired by Stantec in 2010