Wind-Driven Fires

Replies to This Discussion

Permalink Reply by Chris Piepenburg on January 12, 2009 at 3:45pm

We have a few dozen highrises in our district and we consider them as highrises. We do have SOGs detailing what each company is to do, but we don't have anything for dealing with a wind-driven fire in any of these structures. There are those of us who work in the heart of the highrise district who have an "idea" of what we would do in the event of a highrise fire with wind pushing, but nothing in stone!

Permalink Reply by Art Zern on January 12, 2009 at 9:06pm

Gents,

Significant wind conditions, under the right (wrong) set of circumstances can create a very dangerous situation for both civilians and firefighters. The presence of a significant wind, introduced into a structure will greatly increase the rate of energy release of a fire and increase the spread of heated gasses, smoke and fire through the building. This condition creates a momentous problem for firefighters attempting to attack, confine and extinguish even what would normally be considered “routine” fires. Wind-driven fires have been the cause of many injuries to firefighters and civilians and several firefighter LODDs. In a later post, I will detail some of the fires that have significance to the topic.

As Jim and other CSF members have already detailed, this is not strictly a high-rise or “big city” problem. We have all likely experienced wind-driven fires; however, until recently, they weren’t identified in that way. Keep posting your experiences, we can all learn from each other’s experiences.

So…to continue this discussion, I’ll throw out some thoughts on the wind-driven phenomenon and it’s requirements. Then we can get into strategic and tactical changes that should be considered. At the end of the post, I’ll add some links for your further research or information.

The FDNY, Chicago FD and NIST have partnered in a research project that is closely related to their work on PPV. Some of the information and results are available on the NIST web-site and more will follow I’m told.

The wind-driven phenomenon has the following requirement:
- A significant wind
- A wind inlet (windows, patio door, etc.)
- An outlet (unit door and beyond)

There are several keys to operating safely when wind is an issue. The first being a recognition that wind is or could be an issue. When dealing with a structure that is 1 or 2 stories in height, it is easier to assess the wind condition and to have a level of comfort that the conditions will be fairly consistent. In dealing with taller buildings, you will not be able to accurately access wind conditions from the ground. This means, you have to get an assessment from a location near to the fire, either above or below. The wind conditions will determine the next moves.

Second, ventilation decisions are critical in a wind-driven environment. Our normal ventilation tactics, especially in a high-rise, must be revised in order to provide for the safety of our members preparing to attack the fire. If there is a significant wind condition at the ground level and you have or suspect a significant wind condition at the upper levels, ventilation must be delayed until the wind conditions are assessed at the upper level near the fire. The decision to vent must be approved by the IC after approval of the attack companies. The decision is based on the wind, the condition of the windows and the status of the unit door, which leads to the third point.

Third, the status of the hallway door to the fire unit has to be determined. Additionally, the status of the unit’s windows also needs to be determined. As you know, the wind-driven phenomenon is triggered when the window(s) are vented by us, or when they fail due to fire/heat conditions. The problem usually occurs when the engine company is stretching the line and preparing to make the attack. If/when they open or force the unit door they will be met by tremendous fire conditions, extreme heat and potentially un-survivable conditions if:
- The window(s) have failed due to fire/heat conditions or
- They were vented by us or
- The pressure differential caused by opening the door causes them to fail
If the unit door is determined to be closed, the attack crew can complete the hose stretch with some degree of safety. If the door is open, alternative methods of attack should be considered. We can discuss these later.


Well, there is some information on assessing the potential. Please jump-in, I know there is a great deal of knowledge out there.

Art


NIST:
http://www.fire.gov/WDF/index.htm

FDNY:
http://www.nyc.gov/html/fdny/html/events/2008/022508a.shtml

Virginia LODD, wind-driven fire:
http://www.cdc.gov/niosh/fire/reports/face200712.html

Permalink Reply by Jim Mason on January 28, 2009 at 7:23pm

Guys
Sorry I haven't been on the last few days kids w/ the flu and writting assignements due.
I'd like to address the positioning of apparatus on the scene of low rises during hi wind conditons. This has alot to do with dealing with the high wind conditions in depts without high rises. This thread is specifcally to the use of forward lay hose lines (from the source) with engine companies ending up at the fire building. Even with the second engine supplying the first engine. I question if this is something that should be re-considered in hi wind times. Here in Chgo, we've had many incidents that have gotten out of hand of the first due units because of hi winds. Just before I got in there was about 12 homes burned down over the course of about 3 city blocks. From the sky, it looked as if a tornado had gone through. This was in the summer, without frozen hydrants. By the way, Chgo isn;t the windy city because of the winds but becasue of the politicians (go figure, right?)

So my question is this, has any body that exclusively uses the forward lay for the positive source every had a fire that has gotten out of the orginal fire building and actually started to burn the exposures? And if so, what happened? Did the wind have anything to do with it?

The reason we do the reverse hose lay is becasue we are always planning ahead for the fire getting out of hand. If it does, the engines are either out of the way or can be driven farther down the street . This allows the trucks and elevated streams to enter the street so we can stop it. What do you guys think?

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