Roof Venting Tactics

Before the Hurriquake hit here in Va I was on a series of Roof venting posts, if you have not read them yet take a look at them here: https://averagejakeff.wordpress.com/2011/08/18/truss-and-stick-built-roof-burn-tests/ , https://averagejakeff.wordpress.com/2011/08/20/more-roof-venting/ ,  https://averagejakeff.wordpress.com/2011/08/22/yes-even-more-vent-stuff/ You all caught up now? Good lets continue.

Like I have said in the posts depending on a ton of factors (some we can control, and some we can not) roof venting may or may not be a tactic that we can do in our individual departments. However if you do choose to do it you still have to contend with the dangers of fire loading, and building construction.

Look lets face it even after all of the reading, about self assessment for your department I know there are still people out there who are not buying it. It’s human nature to rebel and to succeed were others see a failable situation, so instead of continuing to drone on and on with that it is time to give you the reader a tangible skill that you can employ in your department. So without further a due I give you the “Aerial Ladder Vent”

There are some fires out there that do need to have the roof vented, it is still the most effective way to ensure that the smoke and super heated gases leave a structure by utilizing the natural characteristics of fire, however by the time we arrive the roof itself may be in no position for us to operate on. This leads us to a dilemma so how can we accomplish the task of venting the roof, and maintaining relative safety.

In the situation described above, we can still accomplish venting the roof with relative safety from the stability of the aerial ladder. This allows us to minimize our exposure to the possibly unstable roofing material, and still accomplish the goal to provide the relief of smoke, gases, and fire from the structure.

Here is another view, there are several variations to this technique that can increase your safety. One thing is that you can clip into the ladder with a ladder belt, this will keep you tethered to the ladder in case of a sudden movement, or accidental fall.

Another tip is to place the tip of the ladder at your target and to lay down on the ladder, the point being that you can not fall if you are laying down. Utilizing the tip of the ladder you can still cut a decent sized hole, or cu the hole in sections. Starting with the cuts you can reach, then signaling to the aerial operator to move the ladder over so that you can finish the cut.

Lastly if you have an aerial device that has a basket (platform, bucket, whatever you call it) you can still utilize the lay down in the basket technique (just like the lay down on the ladder technique) but place another fireman in the basket with you and have them utilize the basket aerial controls to allow you to seamlessly cut the hole with only having to change saw position.

Now I will say that these techniques may sacrifice some speed for increased safety, and they do take actually getting out on the drill ground especially utilizing the basket cut technique. However they do allow you to accomplish the goal, and remain safer in the dynamic fire development terrain the fire service finds itself in.

I am still tirelessly searching for basket cut photos to demonstrate that technique, but I literally have thousands of pictures to look through and it takes time. If anyone has some pictures, or other thoughts on this or any other topic on the blog send them on via email, and I will feature them on the blog (be sure to send all of your info so I can give the proper credit). You can always leave comments in the comments section, and also contact us via twitter @averagejakeff.

As usual thanks for reading, spread the word, and STAY SAFE!

 

 

Yes….even more vent stuff

A few days ago I posted a video and subsequent post on Truss Roof Burn Testing. The video was intended to give you the reader a healthier respect for how fast a roof system itself may collapse when challenged by fire.

Brian Brush from www.fireservicewarrior.com made the comment on that post that this may not tell the entire story, and could be used as a scare tactic to encourage people not to perform vertical ventilation. I responded to him that I thought my intent was self-explanatory, but I do not want anyone to think I am not telling a full truth, or encouraging a less aggressive fire service. What I am advocating is a more informed, intelligent, and safer operating fire service by providing preparation on the front end (training, physical fitness, wearing all of your gear). Simply put the old adage of “balls, water, and firemen put out fire” in my opinion is caveman like and is no longer acceptable in today’s fire service.

Thats is why I posted the below video. It is a joint test from NIST, and the City of Phoenix Fire Department. In the portion seen in the video they take 4 identical structures (dimension, and contents wise) and perform burn tests on them to show how long the structure would last without fire department intervention (water on the fire) They do also add firefighters weight in gear to the roof structure to get an idea of how that impacts collapse time. The only thing that changed in the study was the material used in the structural elements, and the roof covering.

You can see for yourself no matter the building material, or the roof covering the collapse times were almost identical. Remember these fires were not started in the roof structure they were started in the “living space” of a sheet rocked room.

So again what we have to do is take these results and put them into terms that impact us on the street. Do we look at these numbers as gospel, probably not, several influences could impact these numbers in either shortening, or lengthening collapse time. What we can do is take them as a baseline for the average home, and use them as a training tool.

In the average home we found in the study that no matter the construction, the contents of the room generated a large enough fire to cause building collapse around the 17 min mark from time of ignition. You take that number and look at your department and ask some of these questions.

What are our response times?

What is our staffing level?

What is our apparatus responding on a fire, and how long will it take for a full complement to arrive on scene?

Do we have the people arriving to impact a fire in this time frame?

Like I have said before the answers are different for everyone. For my full-time department with lower response time (5-7mins) I can say with relative certainty that if the situation presented itself with our staffing, and response we can do a marginal job of going to vent a roof. In my part-time department with 2 man staffing, no ladder truck, and response times ranging from 5-20mins it would be almost impossible to be succesful at venting a roof. FDNY, DC, Baltimore, Chicago, and other large urban departments will have a higher success rate, but just because they can do it does it mean we should it not in the same situation.

I do not question the skill level of a FDNY fireman, and I have learned a lot from several of those guys in classes all over the country. However what they do does not always apply to me and my department as our districts, staffing, and tools are different. While I have only vented 2 flat roofs in my career, I would venture to say very few big city fireman have vented the roof on a log cabin (which I did in the rural section of the county I vollied in).

Like I have said in previous posts, you have to perform a self assessment of you and yours and determine your capabilities, and how you do business. Maybe roof venting is not for your department, and that is ok. You then have to decide how you are going to ventilate a structure in order to control fire spread, and allow for relief to the interior crews.

I plan on having a post up within the week on some alternative methods to perform roof venting, i just have to search through the thousands of pictures I have and locate some training photos we took a few years ago.

Please feel free to leave any comments, or feedback in the comments section, email, or on twitter (@averagejakeff)

As usual thanks for reading, spread the word, and STAY SAFE!

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Yes….even more vent stuff, posted with vodpod

More Roof Venting

 

Continuing on with our roof venting thoughts please direct your attention to the below video.

 

While viewing it you will see a roof prop, and 2 fireman going through a training evolution. Once the hole is cut you see the fireman “louver” the roof decking, and then make a “punch” with the hook in order to push down the ceiling below effectively venting the fire room.

 

Now while this has been an accepted practice for years, times are changing and with the economy being what it is, homeowners have started to finish attic spaces, in order to provide additional storage, or even living space.

 

Take a look at this attic interior, making the punch through this plywood, from an elevated position will be virtually impossible and that is before it is loaded with clothes, holiday decorations, and all of the other things people put in their attic. So the effort to vent the roof will have been essentially wasted as you will not be able to vent the room with fire in it, giving no relief to the interior crews, and wasting valuable on scene resources for no gain.

This is not just a phenomenon on residential roofs, a lot of times commercial structures originally constructed with flat roofs add a “rain roof”

This is a picture during the construction of a rain roof, essentially what this is a peaked roof above a flat roof in order to shed rain and prevent the flat roof from leaking. However under fire conditions it may appear that this is the only roof on the structure. I remember a hotel fire a few years ago were a trench cut was ordered. The companies took the roof and spent a lot of time cutting the peaked roof only to get finish the cut and find a flat roof below them. Needless to say they did not cut off the fire spread.

So what does all this mean? Whats the point? Well the point is to fully evaluate your ability to perform a successful roof vent operation in your department. Do you have the skills, knowledge, staffing, and ability to do this? Is roof venting your best option, or is horizontal vent giving you the most bang for your buck. If you think you can vent the roof, can you do it in a timely fashion? What are your options for venting the roof?

These and many other questions must be answered prior to engaging in roof ops.

If you have any thoughts, comments, or feedback of any kind please feel free to contact us through the various forms of social media we have to offer.

As usual thanks for reading, spread the word, and STAY SAFE!

 

 

 

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Truss and Stick Built Roof Burn Tests

With the recent death of Dallas Fire Lt. Todd Krodel, and his tragic fall through a roof while attempting to vent it, I am going to post a few of my thoughts about roof ventilation. Again this is not to point fingers at anything the Dallas FD, or Lt. Krodel did wrong but to take this instance to focus on something that we may not think about everyday and reinforce it to increase or fireground operations, and safety.

I thought the video below would be a great place to start. In it you see 2 burn tests down by a students from a fire science program. You get a description of the “Truss Roof” and “Stick Built” roof construction. Then you see that during the burn tests the “Truss” failed in 5 mins, and the “Stick Built” failed in 17 mins.

While this is a great test and can give a baseline we need to take it a step further. The burn tests were conducted with class A combustibles, so is the test fully accurate of what we are facing out in the field. Go into your attic and pick out how many class A combusitbles are in your attic. While there are some Im sure it is more on the side of plastics, foam, PVC etc. which as we know have higher heat release rates and cause fires to progress faster. So the time to roof structure failure could be significantly reduced based on the involved combustibles.

Second response time and staffing play a huge role into whether ir not venting the roof is right for your department. In my career department even with 20 engines, 5 trucks, and 3 squads all staffed with 3 person crews and pretty fast response times we would be pushing it to get to the roof in time to vent a “Stick Built” type roof, with class A combustibles only involved (using the aforementioned 17 min time frame). In my Part Time department with 2 person crews no ladder truck and possibly 10-20 min response times venting the roof is not an option almost ever.

We must not only take into account what our fire is doing, but where we are, how fast we can get there, and who we have in order for this operation to be succesful.

Do you know what types of roofs are in your district? If you do not then how do you know what sort of challenge is awaiting you? Always inspect the roof structure of an occupancy any chance you get, and on a residential fire alarm, check the attic even if you do not think the problem is there just to get that look.

Stay Tuned for subsequent roof vent posts!

As usual thanks for reading, spread the word, and STAY SAFE!

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Truss and Stick Built Roof Burn Tests, posted with vodpod