A frac tank is a large, steel storage tank that holds and dispenses water or solid particulates called proppants, which, when pumped into a drill hole, open or fracture a layer of earth and then hold the fracture open. Frac tanks typically hold about 20,000 gallons of water and can also store a variety of other fluids, such as run-off water, diesel fuel and glycol. Gas and oil industry well-drilling operations are the primary users of frac tanks.
Frac tanks have a specially designed, converging-pitch floor to ensure that fluid is emptied regardless of the ground slope. This design keeps the fluid from resting on the front wall of the tank and includes a central low point accessible to the exit pipe. A vacuum pump removes the fluid or proppant from the frac tank through the exit pipe. In addition to the traditional heavy-gauge steel frac tank, flexible frac tanks, capable of holding over 200,000 gallons of fluid are available. Constructed of high strength urethane fabric, flexible tanks have a high resistance to ultraviolet exposure and cold temperatures, and they are more easily transported than steel frac tanks.
Other uses of frac tanks include clean-up operations and temporary water storage. Drillers also use frac tanks with a rounded bottom to store and mix drilling mud. Chemical plants, paper mills and wood product industries also use frac tanks.