What happens to ductwork after years of leakage? Although new systems are light tested, we know from our own records that over 95% of the new systems we test fail the initial water leak test even after the light or air pressure testing. Many of these systems do not show the leakage for months or years due to the fire wrap or other fire enclosures plus their locations are in hidden areas above the ceilings and hoods. However, the leaking grease exhaust vent systems are a huge fire danger plus these leaks compromise any fire containment. Here is a perfect example of a system that leaked over years that went unseen and hidden behind the fire enclosures and above the hood area. However, the continued grease leakage seeped through the fire rated duct enclosure over the years and was finally noticed both by the cleaning company and when the grease leaked down the back wall plus through the lights from above. All of this is above the hood and ceiling and in areas where there is no fire protection. Notice how saturated the fire enclosure becomes and instead of counting a fire for the 2 hour requirement, it can actually cause or accelerate a grease fire with all of the years of leaking grease.
Originally published April 20, 2017 on Tales of the Greaser.