By John W. Mittendorf
In our last article, we considered a dangerous type of building construction that suppression personnel can encounter on the fireground – unreinforced masonry construction (URM). Fortunately, this type of construction is often easily recognizable and can be expected to present a specific hazard when exposed to fire – collapse. Now, let’s look the last method of construction in this series: curtain construction.
Curtain
Curtain construction is a recent addition to the building construction industry’s “tool bag.” It goes something like this: if you want to quickly build a nice looking multi-story commercial building (i.e., modern 2, 3, 4 story office buildings with glass exteriors, or high rise buildings), first erect steel beams, coat the beams with fire retardant materials, then attach/bolt exterior panels of glass, slate, concrete panels, brick veneer, or other similar materials to the steel beams.
Although this method of construction is fast, it also provides a vertical passageway to fire and smoke. When the exterior panels are attached to the steel beams, you can normally see a “gap” about the size of your fist between the beams and exterior panels. Although this gap can assist the upward travel of air within the building and enhance the operation of the building’s HVAC system, it can also vertically spread fire, smoke, and other dangerous by-products of fire. Even though some building owners have sealed the gap, it still exists on numerous buildings with this gap. The next time you are on Fire Prevention, take a look at new multi-story buildings in your district and determine if this hazard is common to your area. Remember, there are five ways fire and it’s byproducts can vertically spread in newer multi-story buildings:
- Poke-thru construction;
- Lapping;
- Radiated heat through flooring;
- HVAC ducting; and
- The gap between the exterior panels and interior beams.
Curtain construction is the final installment for methods of construction. But before we look at the next area of building construction size up, consider two subtle hazards that do not fall into a specific classification – vinyl siding and ABS plumbing.
Vinyl siding is becoming more popular as a replacement and retrofit to common wood “lap” siding. As it is basically a plastic based material, it will easily melt and burn in a fire, spread fire faster than thicker conventional siding, and give off toxic fumes that are not associated with wood lap siding.
ABS plastic is used in plumbing applications. If fire contacts this material it suddenly becomes a “wick” throughout the structure, and gives off great quantities of black stringy smoke. The first time I experienced this material in a residential fire, fire personnel assumed it was an arson fire due to multiple fires in remote locations. If you open walls and find this material and/or roof personnel see smoke issuing from plastic plumbing vents, you may have a fire in plastic plumbing that is spreading through the walls and attic spaces.
The next article will cover the age of a building.
John W. Mittendorf joined the Los Angeles City (CA) Fire Department (LAFD) in 1963, rising to the rank of captain II, task force commander. In 1981, he was promoted to battalion chief and in the year following became the commander of the In-Service Training Section. In 1993, he retired from LAFD after 30 years of service. Mittendorf has been a member of the National Fire Protection Research Foundation on Engineered Lightweight Construction Technical Adisory Committee. He has provided training programs for the National Fire Academy in Emmitsburg, Maryland; the University of California at Los Angeles; and the British Fire Academy at Morton-in-Marsh, England. He is a member of the editorial advisory board of Fire Engineering and author of the books Truck Company Operations (Fire Engineering, 1998) and Facing the Promotional Interview (Fire Engineering, 2003).
