photo.jpg

The primary lesson here is that you can never be far enough away from a wall as described previously - one with rafters resting on a truss that has the potential for a sudden collapse. Responders must take defensive positions. Ground-level forces must withdraw to a distance at least 2 1/2 times the...

The primary lesson here is that you can never be far enough away from a wall as described previously - one with rafters resting on a truss that has the potential for a sudden collapse. Responders must take defensive positions. Ground-level forces must withdraw to a distance at least 2 1/2 times the height of the wall - a distance quite unnecessary for most collapse zones. This position may not be possible at many buildings due to narrow streets or side-yard setbacks. In that case, there are only two other options in most instances: flanking positions off to the sides of the threatening wall or a position above the wall, as in the basket of an elevating platform. The flanking position must ensure that firefighters aren't endangered by other, less obvious threats. It would not do to move out of the collapse zone of one wall into the collapse zone of the intersecting sidewall. Beware of trees, telephone poles, and overhead power lines that could be brought down by the primary collapse. The elevating platform, as well as positions in higher exposed buildings, isn't totally without risk, either. When roofs such as these fall in, there is a sudden release of a huge fireball in some cases 50-60 ft high. Don't be perched directly over this roof, particularly on the downwind side. Otherwise, you could be severely burned.