Ventilation Basics

Ventilation is an important tactic at structural firefighting operations

There are two types of ventilation we deal with all the time at fires: horizontal and vertical. Within that subset, horizontal ventilation can be broken down further into two areas: venting for life and venting for fire. In my experience, venting for life always presents the greatest hazard. I was always taught that if fire doesn’t vent from the window that you picked for access, get in and begin your search.

I recall a fire at a two-story wood-frame dwelling while I was still a firefighter in Brooklyn. I was assigned to assist in the vent, entry and search of the second floor. Due to the amount of fire on the first floor, I was forced to access the front of the building via a portable ladder off a porch area. The truck firefighter serving as the OVM (outside vent man) was already venting the three-window front at this level; he told me it was too hot to enter and that the fire would be venting out at any moment. I heard radio reports of people trapped inside, and due to the early morning hour I figured they would be in the bedrooms on the second floor. I took a chance and entered through the exposure 4 side (D side) window in the front.

Amid intense heat, I hit the floor and started my search. When I reached the door to the room, I could see the fire venting down the hallway about fifteen feet away. Almost immediately, the fire quickly roared down the hall, over my head and vented out the windows. The heat became so intense it forced me back out the window; I was fortunate to get onto the set-back with no burns. My mask and hand light strap were completely burned off. The encounter served as a good reminder that venting for life brings the inherent risk of pulling fire in your direction. Although essential, it must always be performed for a specific reason.

As illustrated in the story above, ventilation is a very important tactic at structural firefighting operations in residential type dwellings. When coordinated and done properly, it can assist in all fire ground operations by allowing firefighters to accomplish their tasks under less punishing conditions, as well as increase survival time for trapped victims.

There are two types of ventilation that are used during structural firefighting operations: vertical ventilation and horizontal or lateral ventilation. Using both types of ventilation techniques simultaneously makes for a safer, more effective operation.

Vertical ventilation is a tactic used in the initial stages of fire operations and is employed for a variety of reasons. When done properly, it relieves the uppermost portions of the building of heat, smoke and gases. It can also prevent mushrooming; a condition caused when heat and smoke spread horizontally and push down to lower areas of the structure assisting fire extension.

Perhaps most importantly, vertical ventilation can increase survival time for evacuating, trapped or unconscious victims. Victim searches above the fire area can be more effective due to the less punishing conditions that will be encountered by firefighters conducting the search.

In regard to fire attack, vertical ventilation relieves stairways from heat and smoke, permitting rapid advancement of the attack hose line. If venting to assist the rapid advance of the hose line, always remember this must be coordinated, if you vent prematurely the fire will extend. Vertical ventilation also provides advance over the original fire area to search for and cut off extension of fire. Ventilate openings in the roof, such as bulkheads, skylights or scuttles; if necessary, cut the roof to provide vertical ventilation.

The technique of horizontal or lateral ventilation involves the opening or removal of windows in the structure and accomplishes several things in aiding in the extinguishment of the fire.  It permits rapid advance of the attack hose line to the fire area, and it reduces the danger of heat or fire passing over or around the nozzle team by allowing heat and smoke to escape through the newly created openings. It also allows for thorough search procedures on the fire floor and the floors above to be carried out. Remember, a charged hose line should be in position before horizontal ventilation commences; otherwise, rapid extension could occur due to fire trying to escape through these openings. As a former engineman I learned to appreciate the truckies busting their hump to provide the ventilation making for a safer, smoother advance of the line.

You should delay ventilation — a technique used to facilitate the advance of the attack hose line — until the engine has water and is ready to move in.  This coordinated ventilation will allow the engine to move aggressively through the fire area, providing rapid extinguishment. It also allows the heat, smoke and gases to be pushed ahead of the nozzle team and assist in removing them through these openings.   

Venting for life is conducted to permit searching firefighters to access areas of the structure where there is a potential life hazard. This is risky because of the likelihood of pulling fire and having it extend. As I stated in the beginning of the article it builds in an extra danger to you the firefighter and you must take into account these additional risks. Remember to always weigh the risk versus the benefit factor especially if you are the incident commander at the scene.

When entering a window that was vented for searching, remember to completely clear the window opening. Remove window bars, window sash, curtains and shades, if present, as well as other articles attached to the windows, such as air conditioners or flower pots. Make sure the opening is completely cleared to allow for easy removal of a victim or, more importantly, an escape route should you become trapped. Try to close the door after clearing out the window and then commence with your search. By closing the door, you will allow yourself more time and less punishing conditions for the search.

It is very important that horizontal ventilation be coordinated between the ventilation team and the members inside the structure. Uncoordinated or ill-timed horizontal ventilation can cause the fire to spread rapidly, subjecting personnel inside to punishing conditions and hampering operations.

When coordinated and performed correctly, proper ventilation techniques are tactics that greatly assist in conducting a successful operation. Although we cannot control all aspects of ventilation, proper ventilation techniques can make for safer operations as well as increase survival time for occupants and victims. Nothing beats a team-coordinated attack on a fire, and ventilation is an integral part.

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