A common rule of thumb is that you can pump through frac iron at 42 Fps. An easy way to compute how many barrels a minute that is; square the diameter and multiply by 2.0. It gets you close.

The real formula is **D x D x FPS _{rating} x .0583**

If you have and internal diameter of 3.74 then:

3.74″ x 3.74″ x 42 Fps x .0583 = 34.25 Bpm Rate_{Max}

The Constant .0583 comes from dividing 60 seconds by 1029.4 = 0.058286

You hopefully remember 1029.4 from the ‘Learn section’ – you’re basically multiplying Feet per Second_{(FPS)} to get Feet per Minute_{(FPM)} and then divide by the 1029.4 [volume of tubulars constant].

Internal Diameter of commonly used Iron..