More on Venting Private Dwellings

More on Venting Private Dwellings

Volunteers Corner

Venting a peaked roof is one of the more difficult tasks that faces the fire service. When we work with tools on a peaked roof, a sure footing is very important —and very difficult to achieve. Even with roof ladders, footing is limited because the foot doesn’t pass through the rounds. This puts the firefighter in a very awkward position. One slip on wet or icy surfaces could prove disastrous.

The best and safest access for peaked roof venting operations is via an aerial ladder or tower ladder.

Working from a bucket is the safer of the two because the firefighter can work with one foot on the roof and one in the bucket. The unit can be moved in order to enlarge the area to be cut. Aerial ladders and roof ladders should be vacated before they are moved.

You may be thinking, “Wait a minute! We move our aerial with firefighters on it all the time.” That doesn’t make it right! Our thinking can’t be so narrow that we overlook all the deaths and injuries to firefighters that have occurred because someone moved an occupied aerial ladder.

Vertical venting is important, but the risks must be weighed against the return. The equation is simple: The steeper the pitch, the higher the risk factor. Place a power saw on a dangerously high-pitched roof and disaster is almost a certainty. There’s a simple rule-of-thumb that I use: If you can’t walk on the roof, then don’t bring the power saw.

A peaked roof should be vented high —about two feet below the ridge pole. With a fire on the top floor or in the attic space, the hole should be cut directly above it and the ceiling pushed down. If possible, this vent should be on the leeward side of the roof, so that the wind works to assist venting, rather than fight it. While this hole is being cut, another firefighter can pull the soffits (if present) on the windward side. This action will cause a considerable and favorable draft. If soffits are not present, cut a second hole close to the gutter line on the windward side.

Let’s talk about fire on a lower floor. Now, where do you think the hole should be cut? Directly above the fire? Think about it. A fire on the first floor (or in the cellar) of a multistory private dwelling will be exposing a compartmentalized second floor. Think about some of my past articles and place the cut. Where is the smoke and heat going? You’ve got it—up the interior stairs. What’s directly in line with the stairway? You’ve got it again —the front door. By relieving this crucial artery, firefighters can ascend, civilians may be able to descend, and the mushrooming effect of fire will be reduced or negated on the upper floor(s). Remember, the fire will usually burn up; thus, vertical arteries of private dwellings are subject to extension. Vertical ventilation will not stop or reduce upward fire travel; rather, it will eliminate horizontal extension.

My wife looks at the older Victorian private dwellings (the “Queen Anne” style) and says, “Wow! They don’t build like that anymore.” I say, “Thank God!” The very old homes in your district require strategies and tactics that differ somewhat from modern homes.

The balloon construction of the older buildings requires quick vertical venting of the roof directly above the fire, regardless of which floor the fire is on. Once the fire enters the wall or ceiling space, it flows not only unimpeded but very rapidly (like a blow torch) to the upper floors. If a vertical vent is not established, the fire will command the attic in very short order. A good cellar fire in one of these buildings will tax your fire department to the limit. Even when fire originates in the cellar of a “Queen Anne,” it’s not uncommon for the arriving fire department to be faced with fire on every floor (fire that’s sometimes visible, sometimes not).

Old homes in your district need different strategies and tactics than those of more recent construction.

These buildings often have unwalkable roofs. Some have multiple gables and cupolas. Originally, most had wood shingle roofs that may have been simply covered with asphalt. Be very careful on this type of roof. They sometimes look safe; an unsuspecting firefighter can easily fall through. Again in this situation, the best and safest access will be via aerial or tower ladder. If multigables are present, vent the tallest and most prominent near the ridge pole.

These older buildings should be the subject of many drills so that these concepts of ventilation become engrained in the firefighter’s mind.

The action taken to fight fire in an old-style Victorian must be aggressive and offensive to be successful. Older private dwellings may have been built before codes were in place or strictly I enforced. Beautiful, ornate exteriors may be hiding spliced two-by-fours, substandard wiring, randomly spaced roof rafters, multiple interior stairways, tin ceilings, and a host of other problems. Drill on these buildings separately so that firefighters are kept abreast of the inherent problems associated with such structures.

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