The above blue background swimmer icon is the national standard for identifying where a swimming pool is located or other static water sources that are used for swimming. In the event of an earthquake or an urban interface fire, seeking alternative water sources is always going to be a priority for all of us. Swimming pools is a real good option to have pre-planned for using as an alternative water source.
Getting water to the fire can occur using a several different options; but this post focuses on using swimming pools as the primary water source and provides a refresher to help detemine the volume of water (Gallons) available for fire suppression activities. In a prior post called
Wildland Urban Interface Firefighting Water Supplies other means of transferring water from a variety of water source was explored.
In some cases, swimming pools may be provided with a bottom gravity fed outlet to a Jones heads or other means for gaining access to the swimming pool water. In these situations an example sign is provided with a red background hydrant that signifies that there is a pool draft location.
What is the average pool size?
Examples include:
15 x 30 x 5 x 7.5 = 16,875 gallons
16 x 32 x 5 x 7.5 = 19,200 gallons
20 x 40 x 5 x 7.5 = 30,000 gallons
20 x 40 x 9 x 7.5 = 54,000 gallons
Formula: Length x Width x Average Depth x Shape Factor = # Gallons
How much water is in a swimming pool?
Below are equations to help you calculate the approximate number of gallons for pools of various shapes.
Circular Pools: For pools with straight sides, multiply the pool diameter by itself (square the diameter). Then multiply that amount by its average depth in feet. Multiply the results by 5.9.
Oval Pools: For pools with straight sides, multiply full width by full length, by average depth in feet. Then multiply by 5.9.
Rectangular Pools: Multiply the length by the width by the average depth in feet. Then multiply by 7.5.
Irregular Pools: Figuring these are a bit more difficult. If you cannot get the number of gallons from a pool contractor, you can get the approximate figure by dividing the overall shape into smaller geometric forms including: squares, rectangles, circles or ovals - and figuring the gallons in each. Then add them together.
How much water would the fire department use out of our pool?
For engine companies that are equipped with floating pumps, the pump output can be anywhere from 60 to 150 GPM. Thirty minutes of pumping at 150 GPM would equal roughly 4,500 gallons. With a pool capacity in the thousands of gallons, firefighters have reported using about two to three inches of water out of the pool before moving on when conducting bump and roll urban wildland tactics.
Engine companies use the pool water to accomplish fire protection. Once the fire passes through, the engine company leaves to provide protection for other threatened structures. This results in small quantities of water being used out of swimming pools. Typical water storage capacity for an engine company is five hundred gallons.