Firefighting 101                                                         by:  Dan Howell

Horizontal Ventilation

Ventilation is the systematic removal of smoke and heated fire gases from a burning structure.  Horizontal ventilation is the process of allowing heat and gases to travel in a lateral direction out of the structure. Horizontal ventilation will normally be accomplished by breaking windows and opening doors. Windows vented should be completely cleared of all glass, framing, screens, and curtains. Doors that are opened may need to be blocked open to ensure they do not later shut. Once ventilation is complete, firefighters assigned to venting can be reassigned or may continue tasks previously started.

There are a number of advantages to horizontal ventilation. First, horizontal ventilation is safer than vertical ventilation. Most of the time, horizontal ventilation can be performed from the ground, which is safer than the roof. Second, horizontal ventilation is much faster than vertical ventilation. It is much easier to break windows than it is assemble a crew and make difficult roof cuts. Third, horizontal ventilation requires fewer resources. Vertical ventilation requires a team of firefighters and many tools. Much of the time, horizontal ventilation will only require one firefighter with a minimum of tools. This is a critical advantage for departments with limited personnel since effective ventilation can still be provided for crews on the interior. A disadvantage of horizontal ventilation is that it less effective than vertical ventilation since heated gases will still mushroom inside the structure. Another disadvantage is that heavy winds can negatively influence horizontal ventilation. Care should be taken to place vents so that heavy winds are not feeding the fire.

            Horizontal ventilation can be used in any of the basic ventilation situations. It is most effective when used to assist fire attack, rescue, and overhaul. When used for fire attack, the windows on the burning side of the structure should be vented. Ventilation should continue until all windows with hot pressurized smoke are removed. It is imperative to coordinate ventilation with fire attack so that there will not be a long delay between the two. Horizontal ventilation can be used to support rescue. This form of ventilation will often occur from the interior. Firefighters operating inside can use horizontal ventilation anytime they need to reduce heat, improve visibility, orientates them or provide for an escape route. Ventilation used in this manner can help firefighters to save themselves and those they are for which they are searching. Firefighters should keep in mind the effect the ventilation will have on the fire. This is especially true if they are operating without the protection of a hose line. Horizontal ventilation is also preferred for overhaul since minimizing damage is the goal. Windows can be opened instead of broken and further damage to the structure can be avoided.