The events on September 11, 2001 changed many things about our lives, and the way that we must forever view our objectives, goals, and operational procedures. But for many of us absolutely nothing has changed, mainly due to not having a magical or easily implemented plan of action to fix what needs to be fixed. Basically, there is no simple answer.

In the case of the world trade center catastrophe, lets first understand what possibly caused the structure to fail. An airliner traveling at 400+ mph can cause rather severe damage to any structure, including disastrous failure. 

Some years ago a B-25 bomber flew into the 79th and 80th floors of the 102-story Empire state building killing 14 people, while visibility had been reduced due to fog. The building received severe damage, but was eventually repaired. The difference between then and now, the airplanes weighed more, considerably more fuel loading, higher rate of temperature of the JP-8 fuel, the speed at which the planes struck, and where they struck all played important roles. 

The difference in construction technology also played and important role in the WTC collapse and the Empire State incident. An interesting side notes to the WTC tragedy, The Lamont-Doherty observatory located 21 miles from ground zero was also able to record on seismographs the two aircraft striking the huge buildings. The impacts measured 0.7 and 0.9 in magnitude. The WTC towers were designed to have a sway distance of three feet from center to compensate for wind gust. 

Give credit to the engineers who designed the WTC, that many safety engineers who watched as the catastrophe unfolded were amazed at how long both towers stood before eventually failing due to the skeletal steel construction, and the lives that were saved in and hour and forty five minutes due to them not having immediately collapsed upon impact. But why did both structures fail? 

The I-beam supports were damaged and in some cases were completely breached. Even some of the main support columns located around the elevators shafts were severed by the impact, engineers studying the removed steel from the WTC have determined this. Any fire resistive insulation or materials surrounding the I-beams was damaged or removed, combined with the intense fire and heat from thousands of pounds of burning jet fuel and the fire load already in place within the building. The lack of working fire suppression systems due to being damaged, all contributed somehow to the failure of both these structures.

The fire protection of these structures, even if intact would have still been overcome, due to the system being designed for extinguishing fires within a business occupancy, not aviation fuel. One thing that engineers studying the steel from the towers have been amazed at is the fact that the points, which bolts connected the beams together, did not fail. 

Distance also played an important factor. Due to the height, which suppression teams had to transverse in order to combat the fire and the crowding of the stairways by people trying to exit. 

Many people who decided to leave the building instead of waiting for instructions saved their own lives. Another point of interest, why did the second tower that was struck collapse first? Basically, the plane crashed into the tower lower than the first plane and slightly off center. This combined with the additional floors on top and their weight over the damaged and missing supports lead to the rapid failure that took place in forty-seven minutes. 
 

While the damage at ground zero was indescribable, can anyone image if one of those towers would have toppled over? This was the original intent of the terrorist during the 1993-bombing attempt was to topple one tower into the other. The destruction could have been magnified by as much as 10 to 20 times. What type of structure is considered to be a high-rise? One definition that I have heard over the years is that a high-rise is defined as “a structure larger than the aerial apparatus that would respond to the structure.” Well this would be an acceptable definition, but for one thing.

First off, how close can you get to the structure, and second, if you cannot place the apparatus close to the structure, then to what floor can you reach. Another one I have recently heard is any building that is higher than you can jump from. The building code officials define a high-rise as any building more than 75 feet in height or more than four stories. When preplanning allow for 10 to 12 feet in height per floor. If calculating 12 feet then six stories would equal 72 feet.

One problem with tall structures is that in most cases you could not position the fire apparatus close enough to the building due to sidewalks, landscaping, and other objects and design features that would impede positioning of apparatus.

Look at any high-rise that you would respond to, what floor could you reach with a 100-foot stick? In most cases only to the fourth or fifth floor? In the Baltimore City high-rise fire at the Charles Center Apartments the seventh floor was as high as department aerial apparatus could reach, the fire started on the 16th floor. This is the main concern when determining if a building is a high rise by how high your ladder companies stick is. 

The main problem with high-rise firefighting is simple, how to get people to the upper staging area fast. The staging area is either one to two floors below the fire floor. I feel the staging area should be two to three floors below the fire floor or by the division officer’s discretion. The reason for the two to three floor division is due to the fire attack being initiated just one floor below the incident were your connection to the riser should be, and were to stage your RIT or FAST team. 

In most cases you cannot use the elevators in these structures due to uncertainty of the elevators or departmental SOP’s. So now the only option is to traverse the stairways. This action requires time, and in high-rise firefighting time is not a luxury.

Studies have shown that when firefighters use stairways to ascend high-rise structures it takes an average of two minutes per floor. Just like fighting fires in residential one and two story SFD’s, if the assignment is not adequately staffed, or the other companies have extended response times, the possibility of you saving the structure diminishes. Getting personnel on the scene, coordinating their assignments, and overcoming obstacles that prevent safe fireground operations is the main ingredient to success in most tactics used during the fire fight.
 

Can we make high-rise structures safer by imposing limits on height, increased insulation on steel supports, widening and reinforcing stairwells? All of these are ideas worth a try. Maybe we should focus our attention on evacuation systems that would enhance getting people out of these buildings, also wider and better-lit stairwells, as well as the use of elevator systems.

Before 9-11, BOCA recently approved a reduction in stairway width, and the NFPA were considering giving reductions as well in the Life Safety Code. But for now this has been shelved. Many would like to see wider stairwells but these increases are always trade-offs in cost to the building owner and the building associations. Many owners and trade groups always oppose such changes. But one way to cure this is either go with the wider stairwell allowances or limit the structure height. 

More High-Rise Model SOP

About the author:
Thomas Cunningham currently serves as a career firefighter at The US Naval Academy Fire Department in Annapolis, Maryland since 1988. He has also served as a line officer with the Glen Burnie Volunteer Fire Company in Glen Burnie, Maryland. He is the state coordinator for the National Fire Academy Alumni Association, and is also finishing his B.S. degree in Fire Safety Engineering at Western Illinois University. He also holds IFSAC Certification as a Fire officer IV, Instructor III, Investigator, Inspector II, Safety officer, and HAZMAT incident commander. Questions or comments welcome