In late February, we were brought in to restore a town home in Fairfax that had an accidental fire in the kitchen. Even though the fire was not a cooking-related event, kitchens often contain an ample supply of fuel. These combustible items, such as wooden wall cabinets and drawers, and a large quantity of plastics (Tupperware, OXO) for food preparation and storage can provide sufficient fuel to cause substantial damage from fire and smoke, as you will see in the photos below.
Besides the fuel load, fire, and the nature of resulting smoke and residues carried by smoke is largely dependent on the rate of combustion and the amount of available oxygen. Fast burning, oxygen rich fires produce fast moving hot smoke, whereas oxygen starved fires tend to smolder lack the heat and intensity of fast burning fires. The type of damage we found indicated the fire was well supplied by oxygen (oxygen rich).
What Caused the Fire to Spread so Quickly?
Such was the case in our townhouse fire. Not only was the fuel in abundance because the fire originated in the kitchen, but the client had also opened his windows prior to the fire breaking out. New windows had been installed that same week and the owner was attempting to ventilate the odor caused by the off gassing of the new vinyl framed windows. These opened windows provided ample oxygen to feed the flames. The fire broke out when no one was at home; neighbors saw smoke billowing out the open windows and called the fire department.
Structural Damage to the Kitchen
The resulting damage to the kitchen was atypical as far as fire damage goes; breached drywall ceiling, burnt drywall, smoke staining, burnt upper cabinets, heat damage to appliances, light fixtures, melted vinyl window trim, etc., as seen in the photos below:
Outside the kitchen, the conditions were anything but atypical. Each of the following photographs will need to be explained to understand the smoke distribution and deposit patterns.
Smoke Damage to Adjacent Rooms
Just outside the kitchen, the dining room, being an adjacent room, took in a great deal of hot smoke. However, the drywall was not breached. The smoke plume interacts with cooler air to form the visual anomaly seen in these photos, where there is literally a distinct division between the black smoke and the much less affected walls below. The resulting effects are referred to as a heat line, or plume line. Hot smoke is trying to rise, (remember high school physics?) but meets an obstruction, the ceiling. This forces the smoke plume to descend the wall. Cooler air from below, (remember the abundance of oxygen because the windows are open, as shown in this photo) is being entrained in the smoke plume. The forces between the cooler air from below meeting the hot air descending from the ceiling results in an abrupt halt in the descending smoke.
The photo on the left allows a closer look at what the heat did to the clock on the wall. In the previous dining room photo above, you can see the dining room furniture appears significantly less damaged. This explains why restorers refer to this effect as the ‘heat line’. Items above the heat line show greater damage from heat than items below.
The photo on the right is the hallway leading from the dining room to the living room. What you are seeing in the white rectangle is where we wiped the ceiling with a smoke removal tool (a cellular rubber sponge) revealing the actual color of the painted ceiling underneath the smoke. This is a bit unusual to have this intensity of smoke, yet the drywall beyond the smoke appears intact, not blistered, or scorched. More on this later.
Smoke Damage Changes as it Moves Throughout the House
As we move further from the kitchen, the smoke begins to cool and behaves differently. In the photo on the left, notice that the wall ceiling interaction caused by the heated smoke is not as intense as it was in the dining room. What is interesting in this photo is the visual appearance of the nail or screws that are holding the drywall in place. This illusion that the nails have ‘popped’ outwardly is actually the magnetic attraction of smoke particles to the metal in the nail or screw. Smoke particles have polarity which creates this attraction. What you are seeing is a greater concentration of smoke particles directly on the surface where the nail head is located than are present on the surrounding drywall.
In the photo on the right, we see another visual anomaly in smoke deposition called thermophoresis, or thermal bridging. The dark streaks on the wall are the actual location of the wooden studs to which the drywall is attached. Heated smoke is also attracted to cooler surfaces. The portion of the wall where the stud is located is cooler than the surrounding drywall.
In most homes that have fires in colder months, this visual effect is more evident on exterior walls (walls that are barriers to the outside as opposed to interior walls that separate rooms as an example) where the cooler outdoor temperatures convey the temperature outdoors through the exterior surface and onto the wall framing, which in turn conveys the cooler temperature to the surface of the finished drywall, where the wooden studs act as a ‘bridge’ between the exterior and interior space.
This being a town home, many of the interior walls were barriers to other townhouses. In addition, it’s cold in February, indoor spaces are conditioned by heat in Winter and air conditioning in Summer. This conditioning of the air does not extend into wall and ceiling cavities, as a result, they remain cooler than the heated indoor air of the living spaces.
The temperature of the smoke, the attraction to cooler surfaces, and additional effects of the polarity of fire particles cause other visual anomalies and varying distribution patterns throughout the home. The type of fire residue we encountered on various surfaces further away from the kitchen and smoke penetrations into wall cavities will be discussed in the next blog. In future blogs, we will discuss what fire residues look like and how they deposit when the environment is oxygen depleted (starved).
Fire Damage Restoration in Fairfax, VA
If you are looking for professional fire damage restoration, RestorTech, Inc. is ready to help! Contact us at (703) 204-0401. Located in Herndon, VA, RestorTech proudly serves Fairfax, Arlington, Loudoun, and Prince William counties, as well as Alexandria, VA, and all nearby areas. For more information, see our FAQ and about us pages.