Glenn Corbett Details Firefighting Concerns for Heavy Timber Construction at FDIC 2011

Fire Engineering Technical Editor and John Jay College Professor Glenn Corbett reviewed heavy timber construction (i.e. “mill construction”) during his FDIC 2011 Friday classroom. This type of construction was common in the 19th century, but many still-standing structures are being renovated and used as factories, multi-dwellings, offices, self-storage facilities, schools, and more.

“Building codes have not kept pace with what’s going on in these buildings,” Corbett said. From a firefighting perspective, one major concern is the creation of large void spaces as retrofitters compartmentalize the large open spaces commonly found inside these structures, in some cases creating spaces for hidden fire and obscuring structural members like trusses. Often these buildings contain doors that are closed only by fusible links, and the links have been burned already and do not function, allowing for heat and gases to travel unimpeded through the structure. Additionally, these old structures usually feature numerous windows which are sometimes sealed with concrete or other materials during renovation, making ventilation virtually impossible.

Corbett made several tactical suggestions for firefighters operating in these buildings, such being sure to supply the fire department connections; using larger (2 1/2-inch) handlines, as well as search lines and thermal imaging cameras during interior operations; and closing the aforementioned doors that once were automatically shut by fusible links.

“Heavy timber construction is one of the oldest types of construction in the U.S. and can be found in communities large and small,” Corbett said. “Recent efforts to rehabilitate these substantial structures have created a new set of building uses and a corresponding new set of issues and concerns for firefighters.

“Frank Brannigan said ‘know your buildings!'” he continued. “Well, we must learn the new 21st century hazards of 19th century heavy timber construction.”