## Rules of Thumb: Flow Parameters - The Chemical Engineer

A rule of thumb that incorporates pipe size is to choose liquid lines to handle a velocity of 1.5 +d/10 where "d" is the pipe diameter, inches. This gives 1.6 m/s for 1-inch and 2.5 m/s for 10-inch piping, and about 20 kPa/100 m pressure drop. Similarly, gas lines can be sized for 20d m/s and steam lines 35 m/s (maximum).