Consumption and Real Estate
How to convert Area of a building times annual rail fall to get gallons?
Question : How to convert Area of a building times annual rail fall to get gallons?
Watching a program on the discovery channel with a building under construction. It is a “green building”. They plan on using the rail fall as gray water in the building. It seems like a HUGE expense just for that small amount of water.
The roof surface is approx. 49,000 sqft
Average rain fall for NY 47.5 inches per year
green building plans
Best answer:
Answer by Davis P
47.5 inches/year is 47.5/12 feet/year = 3.9583333 feet/year
49000 sqft * 3.9583333 feet = 193958.3333 cu ft per year
7.48051948 gal/cu ft
or
1,450,909 gallons/year
nearly a million and a half gallons.
[1] First find the answer using cubic inches.
[2] Then convert to gallons via conversion factor
[1] Area of roof is 49000 ft^2
convert to in^ sq by using the conversion: (12 in/ft) twice, since it’s an area and the units are squared:
49000 ft^2 x (12 in/f) x (12 in/ft) = 7,056,000 in^2
How much water in a year:
7,056,000 in^2 x 47.5 in = 335,160,000 in^3
1 Cubic Inch = 0.00432900433 Gallons
335,160,000 in^3 x 0.004329 gal/in^3 = 1,450,908 gallons
Report in proper sig figs: 1.45 x 10^6 gallons annually <— ANSWER