They were great for landlords in the 70s torching buildings. They provide a path to the roof that turns into a little firestorm. Basically, by the time anyone

They were great for landlords in the 70s torching buildings. They provide a path to the roof that turns into a little firestorm. Basically, by the time anyone notices anything, you have about 5-7 minutes until the roof is involved and the building is a total loss. Unmodified balloon frame buildings are similar.