Brennan Q&A April 2003

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TOM BRENNAN has more than 35 years of fire service experience having responded to 33,000 fire alarms. His career spans more than 20 years with the Fire Department of New York as well as four years as chief of the Waterbury (Conn.) Fire Department. He has a bachelor of science degree, summa cum laude, John Jay College; Alumnus of the Year Award, John Jay College; chairman of the Connecticut Fire Chiefs Association and a charter member of the National Fire Protection Association, Fire Service Section. He has delivered courses and seminars throughout the United States and has instructed at the National Fire Academy. He was the editor of Fire Engineering Magazine for eight years, is currently a technical editor, and his column “Random Thoughts,” is a regular monthly feature. He is co-editor of The Fire Chief’s Handbook, Fifth Edition. He is the recipient of the 1998 Fire Engineering Lifetime Achievement Award.

APRIL 2003

Question: I'm looking for information on cinder-block / pumice-block construction in residential high-rises (10+ stories). How do they react in moderate-to-heavy fire situations? Do building codes require more structural support for multi-story buildings? I have seen how they hold up in major commercial fires in one- or two-story buildings, but I'm curious how they hold up in unsprinklered residential high-rise situations.

Answer: Your question has enough parts in a small paragraph to fill a chapter in a text. Let’s start with a few “agreed” concepts.

What do you mean by moderate-to-heavy fire conditions? In New York City training bulletins there are definitions:

Light Fire Condition — contained and extinguished with a single handline or less.
Medium Fire Condition — contained and extinguished with 2 handlines.
Heavy Fire Conditions — contained and extinguished with 3 or more handlines.

It is my experience that the construction in high-rise residence buildings behaves very well to all those conditions and usually prevents the condition from getting to my definition of heavy fire. High-rise construction with small halls, stairs and rooms creates oven-like fire conditions, and usually the second handline is required to get the first down to the fire apartment if the door was left open. This is presuming that manning is adequate and we did not pull the “plug” on aggressive tactical and orderly thinking!

With prompt and proper horizontal venting of the fire apartment, these fires become relatively routine.

In reference to the last part of your question concerning unsprinklered residential buildings, I first want to note that if you have a properly operating sprinkler system, you really have NO PROBLEM, at least with fire spread and control.

Now for cinder-block or pumice-block construction! I remember a great fire in the Standish Arms Hotel in Brooklyn in the 1960s. The structure was about 200 feet by 350 (or more) feet, and when we arrived, we had fire (by auto exposure and high winds) throughout the top three floors into apartments whose ceilings were 10 to 15 feet high. Our 144-foot aerial with a six-foot extension failed to reach the 11th floor.

All walls — bearing and non-bearing enclosure — held up nicely ... until we gained the floors and began overhauling. The non-bearing enclosure walls were of varying thicknesses of cinder or pumice. (Bearing walls are usually cement block and stronger simply for the load they carry.)

These cinder walls fell with the simple pressure of being struck by a tool or being “bumped” into by firefighters. The dangerous part was that they enclosed all kinds of shafts that any of us could have blindly stepped into. (Another reason there is a God in this job).

The good part during the overhaul of this fire was that the line could simply push through the enclosure walls to the next room when necessary.

Your building-code question is interesting, and the answer lies in today’s writings, as opposed to yesteryear’s.

Before the mid-1960s, building codes were Specification Codes; that is, every construct was spelled out in construction terms such as eight inches of concrete block; 12 inches of hollow block or tile, four inches of Portland cement (whose aggregate mix was also spelled out). All loads were given at a minimum for occupancy and height of construction and so were the options of building materials — specifically.

New developments were rapid and were clogging the courts with variance procedures, so many officicials rewrote the regulations and focused on a Performance Code, which allows any material that supports the load specified for the occupancy type. The result is that there is a plethora of materials found in buildings on fire today that were not adequately tested in all fire conditions and can be safe or not, depending on the NEXT experience.

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Write if you agree or don’t agree or on anything. Tbrennan@firenuggets.com

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