Our firm has recently been asked to look at upgrading and modifying an existing rooftop Hospital Heliport. The Client is upgrading the heliport to now be able to land 2 helicopters on the existing pad and wants to upgrade the Fire Suppression system.
After Reviewing NFPA 418-11 my understanding is that the amount of foam agent needed cover the landing area is based on the dimensions of the helicopter, its calculated critical fire area and the overall helipad dimensions. First is my understanding correct and if so do these calculation need to be completed per helicopter? ie does the existing amount now double due to the addition of the second aircraft?
In addition 18.104.22.168 it states that there shall be 2 or more oscillating monitors/nozzles around the perimeter. The question that comes up is the placement of these nozzles. If two nozzles were placed on opposite corners of the pad with Helicopters are parked would there be a "dead" zone in between then two aircraft that the nozzles would not reach? Is there a minimum distance that these nozzles need to be place apart from each other?