I need your expertise

I have an issue here in Okinawa, Japan that I need your help with.

We have several firing ranges here where ammunition sets off fires. These fires can quickly move off the ranges and into open lands. We would like to build fuel breaks to help prevent (or slow) the spread.

My question's are:

1. Is there a formula for basing the width of the lines?

2. If so, where did the formula come from (I.E. NFPA XXX.XXX)

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Brian Johnson
Assistant Chief
Okinawa, Japan

The formula is known as experience. I would start with 30 feet wide. It is what I have experienced to be the minimum separation distance on prescribed fires to limit radient heat spotting, and close-in spotting from lofted fire brands. It also correlates well with the radient heat spotting to structures from intense crown fire. The width also has to correlate with your mobilization time to get to the fire when first detected, so you may wish to widen a touch to accomodate detection time and travel time to the start. Hope this helps.

Brian

Off the top of my head, I can say 3X flame height for line width. This is from the NWCG. Like I said, that is off the top of my head. Not knowing exactly the fuels you have and the type of fire behavior, I don't know if this will work. Obviously here in the western states, this rule of thumb gets thrown out in some situations (i.e Yellowstone, 1988). But if a handline/dozer line wouldn't be enough, you could reduce the fuels prior to your line by thining out the vegetation.

Hope this helps.

Dave

Brian:

I sent your query along to one of the best in the business. He is from Cherryvale FPD near Boulder, Colorado. He has sent you the definitive answer. Be careful and Good Luck!

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DFCWINS