In Part I of this series we discussed typical construction methods and issues with the front and rear, Part 2 focused on roof and basement issues typically encountered in these buildings. This article, Part 3, will address interior issues affecting fire extension and attack.
Main Street Part 1|Part 2|Part 3
Fire Extension
The number one concern when dealing with Type III construction is fire extension through voids, you’re basically dealing with a balloon frame house on steroids when it comes to these buildings. The key is to think ahead of the fire, where will the fire be in five minutes, ten minutes?
These fires are going to be personnel sponges; the failure of many incident commanders is the error in thinking the staffing you arrive with at the bread and butter residential fire will handle the fire in a 40 x 100 three story ordinary with a working basement fire. When preplanning or even simply daydreaming about a fire on your Main Street think about how many truck companies are available via your department or mutual aid, truck work type activities are going to dominate so find out how and where your department is going to acquire these resources prior to the event.
I like to use the saying “hooks and hoses” when reviewing and training for these events, wherever you have crews using hooks to open up concealed spaces you must have a hoseline ready to combat fire, as stated previously these fires are going to be like a balloon frame residential fire, officers must be alert for rapid changes in conditions and also be pessimistic in the approach when checking for extension. If you are not sure, open up the area you are concerned about and do it sooner rather than later. Thermal imaging cameras are going to be invaluable at these events but they will probably be at a premium on scene so you may not be able to totally rely on them on every floor and room involved, you will most likely find that these fires will necessitate back to basic old school firefighting techniques when checking for extension. You may have to take a glove off and feel the walls with the back of your hand, you may have chuckled at this statement but with today’s technology we sometimes forget the basics.
Voids, Voids, Voids
Energy conservation one hundred years ago wasn’t really on the radar when these buildings were constructed, there was not central air conditioning and so the need was there to give room for the heat that built up in these buildings to elevate hence the large original ceiling heights of ten, twelve or even fifteen feet. In the winter the hot air rising really didn’t matter as the cost to heat was really not a concern, you simply put more coal in the boiler. Another reason for the large ceiling heights was the need to allow enough light into the structure, electric wiring was standard by the late 1800s but fluorescent lighting wasn’t really common place until after World War II, getting natural lighting was a major concern with these buildings, hence the large windows compared to today.
Over the years then these ceiling heights were naturally lowered when renovations eventually took place creating large voids that cause us headaches when fire breaks out. Voids also bring up another concern, the backdraft or smoke explosion, always use caution when opening voids these spaces allow for a large buildup of heat and all that is missing many times is the oxygen you give it when opening a ceiling. A ventilation controlled fire may be ripe for a smoke explosion to occur, the key is to always be pessimistic and keep in mind that these large voids can hold a ton of fire, heat and smoke which is fuel. (Photos 1, 2, 3)
FIRE ATTACK CONSIDERATIONS
Basement Fires
A basement fire will be the most difficult and worst case scenario you will face when responding to your Main Street because the fire can go basically wherever it wants and of course its favorite place to travel is up! Access from the interior stairway under heavy heat and smoke conditions is going to be difficult if not impossible, if you are the incident commander, it is wise to keep a clock running in your head and be ready to pull the members out quickly. If you’re faced with a first arriving suppression force that is understaffed you may be wise to simply focus first arriving resources on exposure protection, it all depends on the correct size up of conditions.
If the building on your Main Street has a sloped rear or Charlie side exposing direct access to the basement you’re in luck when combating a basement fire, remember however that forcing entry may be difficult and as recent research and studies have shown it is imperative that the door be controlled so it may be prudent if stretching into the rear to not destroy the door when gaining entry.
There is a tremendous amount of literature from some of the best fire service authors available it will certainly behoove you to research and study basement fire tactics, this article simply scratches the surface and is meant to motivate you to research further, the key here is to know that the commercial basement fire will challenge you unlike any other type of fire and if you must be well read and mentally prepared as a firefighter, officer and especially an incident commander. (Photo 4, 5, 6)
If the cellar fire is too intense to reach via interior consider these three quick points:
- Examine adjoining cellars/position hand lines for exposure control
- Prepare for collapse as the fire will soon control the building
- Set up defensive operations and be prepared and have the resources for a long battle
First Floor and Above Fire Attack
If your department responds with a small compliment of staffing, consider teaming multiple companies in getting a “big line” in service to attempt a hit on the fire. You may have a limited amount of time before fire takes over so it could be a one shot deal to get the bulk of the fire knocked down. It is also a sound tactic to stretch lines via safest, most effective paths of least resistance to engine crews obviously the fire floor is first, followed by the floor above and finally the top floor of BOTH adjacent exposure in case the need to cut the fire off is necessary
Hoseline Management
As with the residential dwelling, it will be best to follow the “two hoselines max through the door rule”, additional hoselines may have to be stretched via fire escape or ladder, avoid companies congregating on the interior stairs.
UL/NIST
The UL and NIST studies certainly must apply to these buildings, the same as they do for residential. Strict control over ventilation and attack must be conducted; this will certainly require chief level officers to be assigned to buildings and areas affected by the fire. One thing that can be forgotten is just because we are fighting a fire in an one-hundred year old building doesn’t mean the furnishings inside will be of the same legacy construction, the UL and NIST studies have concluded that legacy furnishings can flashover in as little as 8 ½ minutes after ventilation of room, modern furnishings may flashover in 2 minutes again, this is AFTER ventilation. Coordination again is the key item to remember. (Photo 7, 8, 9)
In Part IV of this series we will examine renovations, search, apparatus placement, and final overall safety considerations, until then, stay safe.
