Chemical Feed Pump Suction Chemical Feed Pump Suction ohiowater (Civil/Environmental) (OP) 21 Feb 03 11:31 What is a good recommended minimum and maximum velocity to maintain in chemical feed pump suction pipe sizing? Also, is there much concern with drawing 2 - 3 ft suction with typical mag-drive transfer pumps (pump centerline a couple feet above the bulk tarnsfer tank outlet)? RE: Chemical Feed Pump Suction Chris73 (Civil/Environmental) 21 Feb 03 14:22 If you choose between 0.5 and 3 m/s you are in a good range. If it is a diaphragm pump you can suck 2-3 ft head without a problem. RE: Chemical Feed Pump Suction waterexpert (Chemical) 21 Feb 03 16:17 You need to know the fluid, the line size and length, and the desired flowrate to answer this question. These can be used to work out net positive suction head. Fluids may allow up to approximately 10 meters of suction line vertical height depending on their vapour pressure at the working temperature, and pressure losses in the line.Line velocities (assuming you do not wish to keep solids in suspension, and are not dealing with something like 98% sulphuric acid) of around 1m/s are a reasonable approximate first guess for suitable materials of construction.