Under Index D guidelines, how many vehicles are needed to ensure a minimum of 6,000 gallons of water for foam production?

Under Index D guidelines, ensuring a minimum of 6,000 gallons of water for foam production typically requires multiple vehicles due to the standard operational procedures that dictate the amount of water each apparatus can carry. In this context, if one vehicle generally holds an average of 1,500 to 2,000 gallons of water, a single vehicle would not suffice to meet the total requirement of 6,000 gallons.

Having two vehicles would not be adequate either, as it would provide a total of 3,000 to 4,000 gallons, still falling short of the requirement. While three vehicles are often the minimum needed to achieve the 6,000-gallon mandate, this allows for sufficient redundancy and ensures that enough foam solution is available for effective firefighting operations, particularly in high-risk scenarios such as large aircraft incidents.

Thus, three vehicles provide the necessary capacity, and the guideline reflects the need for readiness and ample supply during fire emergencies at an airport, ensuring that foam delivery systems can operate effectively in critical situations.