Can the Blackliner burn blacklines in green or wet vegetation?
The Blackliner creates a safe environment in which to do burning—if the fuels are not combustible, using the Blackliner will not change that. The propane burners are not incinerators, merely igniters. And once ignited, the fuels need to be both sufficiently dead and dry in order to burn away completely.
Having said that, it should be mentioned that with sufficient fuel to burn, temperatures inside the burning chamber are extremely high, and the flow of air up through the chimney does facilitate burning. In FWS trials held in South Dakota, results were good so long as there was sufficient combustible material to "fuel" the burning of any green component. Long grass with a green component of up to about 30% burned down to mineral soil. (See images below.) Where this same grass had been mowed short, the green component became more significant and burning was spotty.
What about firebrands escaping from the burning chamber; does this not pose a threat?
Under normal operating conditions, we have never had any problems with or received any reports of firebrands escaping from
the burning chamber. The extremely high temperature inside the burning chamber combined with the height of the chimney almost guarantees that combustible material
will be reduced to ash before it can escape. This is not to say that firebrands cannot escape from the burning chamber, but that the threat may only
surface in very windy conditions—conditions in which you would likely not be burning.
Why not manufacture a wider Blackliner so that a wider strip can be burned?
It may seem like the logical thing to do, but making the burning chamber wide enough to burn an effective firebreak in one
pass would be wholly impractical. The equipment would become too unwieldy for the purpose for which it was built.
Increasing the width of the Blackliner, accompanied by a necessary increase in length, would significantly
increase the weight of the equipment. (As is, the equipment weighs over 1000 lb.) Transporting and handling would
become a major issue, and a more powerful towing vehicle would also be required. The manufacturing cost would increase
significantly as well.
Since anything short of the width of an effective firebreak already requires that one either burn parallel blacklines or burn a
blackline parallel to an existing control line, a more logical proposition would be to concentrate on making the Blackliner
smaller, and therefore easier to transport and handle.