The Professor

BY GLENN P. CORBETT

Photo 1: Cornices, the decorative trim at the top of exterior walls of many 19th-century buildings, were typically made of stone, wood, sheet metal over wood, or just metal. This side view of a 21st-century descendent shows its synthetic polystyrene core and plywood backing. These new cornices still pose a collapse potential and can spread fire just like their ancestors.

Photo 2: This is an 1850s iron beam in an old mill. The inability of early 19th-century rolling mills to create flanges on the top and bottom necessitated the inclusion of this iron rod; the rod is used to deal with the tensile forces at the bottom of the beam.

Photo 3: The March 25, 1911, fire at the Triangle Shirtwaist Company in New York City is one of the most famous fires in American history. Fire spread quickly throughout the Asch Building’s 9th floor; a locked egress door and a collapsed fire escape were the primary reasons a total of 146 people died in the fire. Many people, primarily women, were forced to jump out windows. The fire led to many changes, including improvements in factory fire protection regulations and the strengthening of workers’ unions. This month marks the 100th anniversary of the fire.

Photo 4: This interior photo of a mill under renovation highlights a red flag for firefighters and inspectors. The presence of downward-pointing “drops” with sprinklers indicates that they will be positioned below a yet-to-be-installed ceiling. Concealed spaces—including dropped ceilings—are not permitted in buildings of heavy timber construction under the model building codes.

Photo 5: This is a wooden lintel over an opening into a storage area in a mill. Although the wood member is of heavy timber construction-compliant dimensions, moderate to heavy fire conditions for extended periods of time will cause it to fail, dropping the entire wall section above.

GLENN P. CORBETT, PE, is an associate professor of fire science at John Jay College of Criminal Justice in New York City, is a technical editor for Fire Engineering, and was an assistant chief of the Waldwick (NJ) Fire Department. He previously held the position of administrator of engineering services with the San Antonio (TX) Fire Department. Corbett has a master of engineering degree in fire protection engineering from Worcester Polytechnic Institute in Massachusetts and is pursuing a Ph.D. in public administration from Rutgers University. He authored two chapters on fire prevention/protection in The Fire Chief`s Handbook, Fifth Edition (Fire Engineering Books, 1995) and is the coauthor of the late Francis L. Brannigan’s Building Construction for the Fire Service, 4th Edition. He is the editor of Fire Engineering’s Handbook for Firefighter I and II. Corbett is an FDIC Executive Advisory Board member. He has been in the fire service since 1978.

More Fire Engineering Issue Articles
Fire Engineering Archives

The Professor

3

BY GLENN P. CORBETT

Photo 1: Some firefighters call the push bar across the center of the door “panic hardware.” It is actually called “fire exit hardware,” since it is used on a rated fire door in this photo. Panic hardware can only be used on nonfire-rated doors. Found in places of public assembly, both types of hardware are very similar in appearance—the only difference typically is the extra vertical rods to latch the fire door at the top and bottom in addition to the latch on the left side of the door frame. Fire exit hardware is also not permitted to be “dogged,” where the push bar is fixed in the “depressed” mode and is not latched.


1.

Photo 2: This wood-frame structure carries not only its own weight and everything inside but also these two massive billboards. What would be the result of a cockloft fire burning below? What is the combined dead load of these signs?


2.

Photo 3: The masonry “face” of the American Museum of Natural History in New York City is under repair. While protecting passersby from the resulting dust cloud, the “cloak” hinders access to the building’s windows, making ventilation and potential rescues difficult. The sheeting also hides an enormous amount of scaffolding used for the repair work. Is the sheeting material combustible?


Photo 4:Multistory open parking garages are typically equipped with Class III standpipes (21⁄2-inch hose valve with 11⁄2-inch hose station, as seen here) that are supplied with water by a dry pipe alarm valve, or a completely dry Class I standpipe (21⁄2-inch hose valves only), to which you supply all of the water through a fire department connection. Be aware that getting the air out of the system, particularly the completely dry Class I system, will take time. Vandalism and lack of maintenance on both types of systems are common.


4.

Photo 5: The 100th anniversary of the Rhoads Opera House fire, which occurred on January 13, 1908, and killed 171 people, was recently commemorated in the small town of Boyertown, Pennsylvania. The fire is believed to have started when a magic lantern stereopticon projector (the forerunner of the old slide projector), which used a hydrogen-oxygen mix to create a bright projection light, leaked flammable hydrogen gas into the room, which subsequently ignited. This month’s “History on Fire” photo reminds of the special construction required for today’s motion picture projection rooms. Rooms must be separated from the theater and be specially ventilated, including individual ventilation for each projector.


Photo 6: Both of these buildings appear to be of ordinary construction. Although that is true for the building on the right, the building on the left is actually a wood balloon-frame building. It was a derelict burnt-out structure that has been completely rehabilitated, including the use of a fake brick veneer face. It still has all of the problems of a balloon frame but now presents a more difficult situation for firefighters who might have to access the stud channels from the exterior to stop upward fire spread.


GLENN P. CORBETT, PE, is an associate professor of fire science at John Jay College of Criminal Justice in New York City, is a technical editor for Fire Engineering, and was an assistant chief of the Waldwick (NJ) Fire Department. He previously held the position of administrator of engineering services with the San Antonio (TX) Fire Department. Corbett has a master of engineering degree in fire protection engineering from Worcester Polytechnic Institute in Massachusetts and is pursuing a Ph.D. in public administration from Rutgers University. He authored two chapters on fire prevention/protection in The Fire Chief`s Handbook, Fifth Edition (Fire Engineering Books, 1995) and is the coauthor of the late Francis L. Brannigan’s Building Construction for the Fire Service, 4th Edition. He is editor of the upcoming Fire Engineering book Firefighter I and II Handbook. Corbett is an FDIC Executive Advisory Board member. He has been in the fire service since 1978.