Thanks to everyone for their comments and concerns. I have participated in a control burn of 3-400 acres (attended by local extension agent.) I have since attended a controlled burn seminar.
Not to worry, I will only start a fire if conditions are within acceptable parameters and forecast to be there for 12 hrs. Nevertheless you need water based fire suppression to control a controlled burn. I don't intend to try to stop a "head " fire, especially in a high wind. Some minimum suggested parameters were 3/4 inch min hose with 125 PSI and a min of 7 gal/min. Mind you this isn't for fighting a "WILD FIRE" this is for controlling a controlled burn. I wouild like to err on the side of more capability.
Yes roller pumps are positive displacement (my pasture sprayer is an example.) It has an adjustable regulator that bypasses the extra back to the tank. Unfortunately I did not size it for working a burn, just killing weeds and it is not up to the job. I expect to replace it with a more capable pump. I also want to make a mount for my 2 inch engine driven pump to use to fill the spray tank from a pond. I have 10 suitable ponds on 160 acres so refilling the tank will not be a logistical nightmare. I expect to use a floating filter assembly as a pickup so no debris will get to the tank.
I don't understand everything I learned but increased pressure reduces the gal/min requirement. Adding a little detergent to the tank to get better wetting reduces the volume requirement too.
Again, thanks to all who contributed.
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