GARAGE FIRES...What's the Risk?
TACTICAL VENTILATION & ROOF OPERATIONS OVER GARAGE FIRES....
If you’ve been following us here at the WCO then you understand that our community possesses a strong belief in the beneficial effects of vertical ventilation and roof operations as a whole. However, we have a question. Do you and your company understand when it’s appropriate to take this level of risk and when it isn’t? Yes, you heard us correctly. Unlike other fire ground zealots, we fully realize that as strong as we feel about this tactic, there are many times when it should not be attempted. Furthermore, passion and proclivity set aside, we should only ever perform fire ground operations that we thoroughly understand and can explain not only the “how” but also the “why”. So with that said, do you and your company possess an “operation” for attacking garage fires? Well you should….
In order to answer this question we should briefly touch upon why it is we go to the roof in the first place. Generally 2 reasons: Venting for the lives of the interior operating firefighters by attempting to achieve “lift” of the heat, smoke, and fire gases. It is this “lift” that allows the hose team to locate, CONFINE, and extinguish the fire. The second reason has to do with the protection of the structure itself and its interior furnishings. By getting and staying ahead of the fire we will begin to regain control of the building. The idea is to halt or slow the horizontal spread of the fire. This is “venting for fire control”. To reiterate, we send firefighters to the roof to SUPPORT and facilitate a faster stretch and knockdown of the fire. To achieve the often communicated but rarely understood “coordinated fire attack”. So in order to discuss Truckwork, we need to cover some Enginework first.
Let’s take a closer look at the options for fire extinguishment of garages. The fire attack team has 2 general choices on nozzle placement. A Line through the front door and into the interior of the home or a hose line up the driveway, force the garage door, and attack the fire from the exterior. Both scenarios are valid considerations in the right circumstances.
Let's expound upon these tactical choices:
Scenario: Engine arrives to a single story, ranch style, home with a well-involved garage. Nozzle firefighter pulls a 200’ hoseline of sufficient diameter for the fire conditions observed. Officer heads to the front door of the home, forces the front door, and assesses the interior conditions of the home.
The hierarchy of hose line placement should be decided based off the smoke / fire conditions encountered on the interior of the home. Not the conditions in the garage. Always living space over storage space! Remember our incident priorities are still Life safety first, Incident stabilization second, and Property conservation last (L.I.P.). Do not become a “moth to the flame”.
Let us explain.
Engine arrives and the front door is forced. Moderate to heavy smoke conditions are discovered inside the home. First hose line is stretched through the front door of the home. Placing the nozzle between the uninvolved living space and the interior “2 hour man” door that leads to the garage. The goal or objective of this hose stretch is to confine the fire from any civilian victims, firefighters searching for them, and the rest of the uninvolved structure including the homes attic. Based off the level of extension into the home, the decision will need to be made whether or not the extinguishment of the garage will be attempted through this interior man door or will this interior line simply hold this position and allow the attack to be made from the exterior driveway via a second line? Please keep in mind that attacking the garage fire from the interior through the man door will continue to expose the interior of the home to potentially heavy fire conditions from the garage. This should be avoided whenever possible. However, if a heavy condition is encountered on the interior of the home due to significant extension then that concern is negligible.
Engine arrives and the front door is forced. Light smoke is found on the interior of the home. Officer directs the first line up the driveway to attack the garage fire from the exterior. The officer makes his way to the interior, garage, “2 hour man” door to ensure it is still intact and preventing extension to the interior. He or she then ensures the home is evacuated. The officer then directs a second line to be stretched to the interior of the home to ensure this man door stays shut and to check for fire extension in the overhead attic. The “roll up” garage door is partially forced open and knockdown is affected via the driveway.
Engine Co. Tip: If the garage door is still intact and in place then use it’s compartmentation and confinement of the fire to your hose teams advantage. We see many companies hold off on extinguishment of the garage fire until the entire door has been removed. Why? This gives the fire a very large air inlet that will cause rapid growth thus requiring significantly more fire flow to effect a knockdown. Create two fairly small openings in both upper corners of the garage door. This facilitates an entry point for extinguishment and an exhaust point opposite the attack for steam, heat, smoke. Yes, this is much less glamorous but much more efficient and faster in the extinguishment of the fire. Lastly, if someone is residing within the garage, keeping temps low prior to water is a much better scenario to remove them from than a fully involved garage. Remember, civilians can come back from elevated gas concentrations not elevated temeratures.
Back to the operation...
In both of the above scenarios, assigning a company to the roof is still an important tactical decision but lets cover some critical points to consider when faced with this assignment:
In older homes, the garage roof systems are often unprotected by sheetrock and are open to direct flame impingement.
Most garages have more than sufficient fuel loading for a significant fire condition including the presence of considerable quantities of flammable liquids. The potential for early roof system collapse, especially the decking, exists even in an older, conventional “cut and stack” roof that contains a true ridge beam and rafter system.
Consider the high likelihood of overloaded trusses due to storage in the garage truss space. Sheets of OSB are slid across the bottom chords of the trusses to create make shift shelving. This is both added weight and fuel loading and will be very difficult to punch through for access.
Consider the possibility of “scabbed-in” or altered roof systems within the garage. Space created for storage, etc. See attached pictures of a recent vacant, attached garage fire that shows an open, “unprotected” truss system without any “web".
FF’s can typically use the reach of their streams from the safety of the driveway or interior of the home without fully committing to the interior of the garage early on in the fire.
Vertically "venting for life" is typically not required and should not be performed directly over the top of garages as no one generally resides within them. Moreover, no firefighters will be immediately operating inside this area prior to knockdown. Yes, following the economic “bubble” pop, it is not uncommon to see garages that have been converted into some primitive level of habitation but will you be able to identify this from the street upon arrival every time? One example we see is when the garage door is left in place and a wall has been framed and erected directly behind the garage door with no exterior indications. Wall mounted A/C ‘s should raise suspicions but are by no means a dead giveaway that the garage has been modified into an illegal domicile. Perhaps the homeowner wants to keep it cool. Furthermore, and perhaps the most critical factor is that none of the above pieces of information indicates that the open, unprotected roof system has been sheet-rocked and “finished”. Smoke conditions from the garage roof and the eve-line or soffits should be assessed closely and continuously.
The garage door is a very large, effective, horizontal vent. Use it accordingly.
Review close calls reports from the FRESNO, MODESTO and SAC METRO F.D. INCIDENTS.
In short. With all of the information listed above, ROOF OPERATIONS DIRECTLY OVER TOP OF GARAGES THAT ARE HEAVILY INVOLVED IN FIRE SHOULD BE AVOIDED.
INCIDENT COMMANDERS should still consider assigning the truck to the roof. Roof operations / vertical ventilation over the living space of the home may still be needed if extension has occurred or the “2 hour” door has failed. The roof team will make their way to the fire wall that separates the home from the garage, give a roof report, and prepare to combat fire extension into the home and attic. Communication with interior companies will be needed to ascertain the level of extension into the home.
PROPER SOUNDING of any roof is always a critical function used to constantly assess the condition of the decking and the support system beneath. The appropriate tool (6’ trash or rubbish hook) should be used. The sounding firefighter should lower their stance and use the reach of the hook to sound well out in front of them. The roof decking should be struck hard to simulate the firefighters weight of the firefighter who is about to step into that area. This action should be repeated non-stop.
PATH OF TRAVEL: Realizing that the vast majority of the fire service is faced with fires in homes constructed of pre-engineered, “light weight” trusses, the correct path of travel along the roof is critical. Cutting the hole is the least difficult part of the operation. Arriving to and departing from are of equal importance. Understanding the construction differences between conventional “cut & stack” or “ridge & rafter” roofs versus pre-engineered trussed roofs is of critical importance in selecting the correct path of travel. In short, roof teams should be traveling the exterior load bearing walls whenever possible. We call this “traveling at right angles”. Understanding the differences between these systems should keeps us from traveling the FALSE RIDGE. Remember that pre-engineered trussed roof systems do not possess a “true” ridge board or pole. Unfortunately this was graphically demonstrated in the video of the Fresno incident involving a fire captain falling through the garage roof. Even in older conventional construction, where the ridge is a strong point of the system, under prolonged heavy fire conditions, these roofs can fail rapidly as well. Remember garage fuel loading is not the same as the living space fuel loading. When they do, every FF operating on them flees back out to the exterior wall as the roof pancakes down and on top of the ceiling joists. Why not travel from this position to begin with?
Conventionally constructed roof system in the above diaghram. Below picture of pre-engineeed truss system with 24" ridge stiffener or blocking in between each truss. Some regions of the country do not require this ridge blocking. DO NOT TRAVEL INTO THE FIRE AREA ON THE RIDGE...
In conclusion, we want you to continue to maintain an “intelligently aggressive” mindset at the scene of your emergencies. The key word being intelligent. This indicates that you understand the “how” as well as the “why” to the risk that you and your company are taking. Again, the descriptor is intelligent, not blind. Blind aggression leads to problems. The term “blind” indicates that you cannot explain why it is you’re doing what it is you’ve been assigned or have decided to do.
Performing Vertical Ventilation just because your agency has a culture of aggressive vertical vent without setting any tactical limitations on the performance of this or any other tactic can lead to firefighters getting themselves into very bad positions. Risking ourselves for the unprotected civilian and their property is still an expected attitude within the fire service. But to be able to do this successfully, we must all be students of this profession. Know your job and have an operation. Have an operation for most every common scenario or assignment we carry out at the scenes of our incidents. Train on these operations so that the roles of each member and the choreography are seamless. That is the mark of a professional.
The West Coast Offense