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Roof Ventilation

http://www.fireengineering.com/index/articles/display/3599238959/articles/fire-engineering/firedynamics/2010/08/Primary-Roof-Ventilation-Operations-for-Flat-Roof-Structures.html

The above article from Fire Engineering is from a DC ladder company captain and it focuses primarily on flat roof ventilation operations specifically on residential flat roofs. It’s a great article and well worth the read.

Having been previously assigned to a ladder company for about 2 years (I needed a break from doing real work) and having done some ladder work in my volunteer days, I have had the chance to operate on a few roofs. My roof experience is typically in the suburban environment but i have had the chance to operate on commercial, and urban roof environments and they are all different and all brought unique challenges. I have never gotten to vent a roof on a row house, or tax payer, but I doubt that many from an urban environment have gotten to vent a roof on a log cabin.

Here in the suburban setting residential roof venting is a lot different. There is typically no security set up to prevent you from roof access, and with the exception of louver vents, and sky lights built-in roof openings are limited or non existent. The construction is also a very different factor. In the urban setting you typically deal with older style true wood construction, while in the suburban environment newer construction with engineered structural elements are the norm severely limiting you from roof operations from a safety standpoint.

Here in the suburban fire setting staffing also seems to be an issue. Typically you have a ladder company driver doubling as an OVM (outside vent man). Venting the roof is a labor intensive task and will take time when this person has to set the ladder out riggers, spot the ladder to the roof, gather tools, climb and then finally begin the roof work. It is not impossible but it does take time and time is usually not on our side so in order to get quick ventilation needed for interior crews the driver/OVM will default to horizontal vent in order to vent quickly and give the interior crews an alternate exit point. This in my opinion give you more bang for you buck (accomplishing 2 tasks with one person), but you do sacrifice some effectiveness.

The biggest problem facing any department venting a roof is the utilization of the attic space. In the past attics were used for storage and in some places had full floors. In todays economic times I have personally seen attics crammed full of “stuff”, attics converted into living spaces, and converted into entertainment rooms. In all of these instances the attic space was fully floored and carpeted. If you had a fire on the top floor of this occupancy and tried to vent the roof, making the punch through to the actual room would be impossible, thus all you would have vented is the attic.

This is again is another reason why horizontal vent is usually a prefered method vs. vertical vent.

This is really a topic I could talk all day about. There are so many nuances, tricks of the trade, and styles of doing business that this is one of those endless topics. While I do plan on expanding this topic in later posts (tools selection, basket/ladder cuts) I want to hear from you out there.

What if any kind of roof operations are you doing? What tools are you taking? What kind of construction issues are you encountering? What kind of tricks, or techniques are you using? Leave some feedback in the comments section, and spread the word about the blog.

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