The challenge: Tall and super-tall buildings: Fire and life safety

 

Participants:

Jason Heffelmire, PE Gulf Coast operations director, TLC Engineering for Architecture, Tampa, Fla.

Mehdi Jalayerian, Executive vice president, Environmental Systems Design, Chicago, Ill.

Jim Quiter, PE, FSFPE, LEED AP, Principal, Arup, San Francisco, Calif.

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CSE: What unique fire suppression systems have you specified or designed in a manufacturing/industrial facility?

Quiter: The biggest challenge for fire/life safety is not unique fire suppression systems, but the coordination of all the systems in the building to combat a single-hazard fire. Therefore, the structure, the mechanical smoke control, the egress system, the power system, and the alarm and notification system must all work together with the recognition that contents may vary and people’s decisions will vary. It is an overall systems approach to fire that is needed, not a system-by-system approach. The first is scenario-based; the second is at risk of becoming a checklist.

Heffelmire: Some of the more unique fire suppression systems we have designed included high- and low-expansion foam systems for aviation facilities like airplane and helicopter storage areas. We have also designed special mist fire protection systems for historical buildings and nitrogen-charged systems for drinking and fire protection water for a remote island.

Heffelmire: The costs and complexity of fire protection systems have mostly risen in our area of Florida due to the usual labor and material increases, but I think we are still lower than most other states.

Quiter: One of the risks in a very tall building is to add complexity that isn’t needed. With more complexity comes decreased reliability (and more costs). The overall cost of fire protection has not increased disproportionately over the years. Where complex systems have been installed, the cost of maintenance often has increased disproportionately.

Quiter: In a very tall building, the biggest challenge is stack effect, or the natural tendency for the smoke to rise up in the building. With stairs, elevators, and vertical shafts, this must be overcome. Elevators are often staged by floor sections, but stairs sometimes rise the entire height of the building. It is necessary to put in separate pressurization systems, and may be necessary to provide physical breaks in the stairs in order to not under- or over-pressurize portions of the stair. Very tall atriums also present particular issues. It is best to do smoke modeling in those cases.

Heffelmire: Some unique smoke control solutions consisted of a microprocessor-based air sampling system that included piping in the walls and ceilings. The control system determines the type of fire and makes the decision to fight the type of fire by activating the life safety system equipment and fire control equipment. 

Heffelmire: In Florida, like many other states prone to natural disasters, tornado and hurricane shelters are a necessity. These buildings serve as an area of safe refuge and must provide an adequate water supply for either drinking or firefighting, and other necessary supplies and equipment. These buildings are unique for their design and particular limited use. 

Quiter: In the Stratosphere Tower, we used an area of refuge at the base of the pod. When doing so, the designer must make sure the space truly provides “refuge.” How do people leave the space? Are they protected from smoke while in the space? Is the space adequately separated from a potential fire? Is there enough room to hold the people comfortably? Are we properly communicating with the people about the presence of the area of refuge, the location, what to do when they get there, whether they are safe when there, and what is going on around them? In Asia, refuge floors are commonly used, both as a holding area for people and as a fire brigade staging area. All of the above questions apply.

Quiter: A lot of thought must be given to communication with the occupants. Do we want all of them to move, or some of them? Where to you want them to go? How can they and the fire service know what is going on around them? In this case, it is not the technology that is difficult, it is specifying the right technology and using the technology intelligently.

Heffelmire: MNS are a part of tornado and hurricane shelter designs, and the systems communicate with all disaster relief crews, health care professionals, and residents.