Peak hour calibration vs Hydrant Flow calibration

I am considering whether or not I should use fire hydrant test for calibration or if I can simply collect field data during peak hours. From what I understand this would be dependent on the amount of velocity of the water traveling within the pipes. So my question is at what velocity's can the modeler be assured that they would be capturing the impact of ,pipe roughness, closed valves and demand errors to a significant degree. Because if  the velocity in my system is reaching that velocity during peak hours I could simply set out a bunch of pressure and flow loggers during peak hour and calibrate based on that instead of having to conduct a bunch of fire flow tests.