Soot Damage and Carbon Monoxide Poisoning

Case description:

An ARCCA engineer investigated a claim of damage due to an unusual amount of soot occurring in a home. A resident in the home had complained that all the white fixtures were getting “dusty”. Upon bathing the family dog, it was discovered that the dust was really a fine layer of dark soot.

Steps Taken:

• ARCCA’s expert performed a site inspection.
• A gas fireplace had been recently installed.
• ARCCA inspected the device, the installation, and the warnings and instructions on the fireplace.
• ARCCA lit the pilot light, and tested the fireplace.

The gas fireplace was designed to operate on either propane or natural gas. At the rear of the fire place, there was a switch to direct the fuel gas to either a propane or natural gas fuel nozzle. The gas fireplace was being fueled from a propane tank located outside of the home, but the fireplace was set to natural gas. The gas fireplace was designed to be a ventless fireplace where both the intake air and the combustion products are shared with room air.



Final Findings:

Due to the difference in chemistry of the fuel, natural gas fuel nozzles are much larger than propane gas fuel nozzles. As a result, when the pilot light was lit, instead of a small blue pilot light flame, there was a 3 inch long yellow flame with soot feathers at the tip. Instead of getting a nice clean combustion, the pilot light and subsequent fireplace fire was operating with a high degree of inefficiency, producing incomplete products of combustion (soot) as well as high levels of carbon monoxide (CO).

The homeowner was advised that the switch was turned to the proper fuel source and should be kept at the proper fuel source. Luckily for the homeowner, the house was a larger home with two other vented fireplaces, which provided enough ventilation to have prevented CO poisoning and/or death. The Consumer Products Safety Commission (CPSC) recognizes CO as the “silent killer” due to it being colorless and odorless.

After switching the gas valve to the proper position for propane, the homeowner no longer had risk of soot damage or CO poisoning from the subject fireplace.