Last year I made a bunch of videos showing simulated fires happening inside of clothes dryer transition ducts. I made these by filling various 4′ sections of dryer ducts with shredded paper, lighting the paper on fire, and then directing the blower end of a wet/dry vac at the duct to help simulate a clothes dryer blowing into the ducts.
These tests made for some dramatic failures, but one fairly unrealistic part of the tests was the amount of air being blown into the ducts. The air that comes out of the blower end of a wet/dry vac is way more than what comes out of a clothes dryer.
To make the tests a little bit more realistic, I measured the airflow out of the back of my clothes dryer and used an 18-volt power blower. I also obstructed the end of the blower until the airflow was similar to that of a clothes dryer.
This time, there was only one failure; as you might imagine, it was the foil duct. The UL-listed semi-rigid dryer transition duct and the Dryerflex transition duct never burned through. I recorded all of the tests and trimmed the uneventful parts of the videos to make a single video under three and a half minutes long.
Author: Reuben Saltzman, Structure Tech Home Inspections