Question
Yes,
My farther is putting in an automatic sprinkler system, and I myself would like to start installing them for a living. I'm not that great when it comes to numbers, but what is the best, and easiest way to figure your G.P.M. for any type system.
                       Thanks,
                          Randy

Answer
First you need to find out static pressure of the water source. Then you need to find out pressure loss from the water source to the point of connection. Then you need to lay out the system on paper and calculate the pressure loss to the farthest head in the farthest zone. Decide at that point how many gpm you can get while maintaining at least 35 lbs at the farthest head. Remember that pipe sizing is very important.