Collection: 400 Gallon Air Tanks

400 gallons is 53.5 cubic feet of air storage. At the common rule of 4 gallons per CFM for a reciprocating compressor and 2 gallons per CFM for a rotary screw, that puts this tank size on systems somewhere around 100 to 200 CFM, which in practice means a 25 to 50 HP plant.

Storage does one job well. It covers short, heavy demand spikes so the compressor does not have to chase them. A 400 gallon receiver gives up about 36 cubic feet of free air for every 10 PSI you let the pressure drop, so a blowdown, a cylinder bank, or a bank of pneumatic tools that fires for twenty seconds comes off the tank instead of off the machine.

Here is where it stops working. Storage cannot fix a compressor that is undersized on average. If your machine already runs loaded most of the hour, 400 gallons buys you a minute or two and then you are back in the same hole. Fix the CFM first. And if all you actually need is a little surge for a blowgun and an impact wrench, a 120 gallon tank does that in a fraction of the floor space and a fraction of the freight.

Decide wet or dry before you plumb it. A wet receiver ahead of the dryer drops condensate and buffers the dryer; a dry receiver after it protects your dew point. Most plants want both. Our air receiver tank guide and the storage sizing article cover the math, or step up to 400 to 660 gallon tanks.