Residential Building Inspector B1General Administration, Legal, and EnforcementMedium
A residential building inspector observes that a newly installed dryer exhaust duct is connected with screws that penetrate the ductwork. According to the 2021 IRC, what is the primary concern with using penetrating fasteners in dryer exhaust ducts?
- AThey create obstructions that can accumulate lint and reduce airflow, posing a fire hazard.
- BThey can cause the ductwork to separate under vibration.
- CThey violate the manufacturer's warranty for the dryer appliance.
- DThey can lead to corrosion due to condensation inside the duct.
Show answer & explanationAnswer & explanation
Correct answer: A. They create obstructions that can accumulate lint and reduce airflow, posing a fire hazard.
The 2021 IRC, Section M1502.4.6.1, specifically prohibits screws or other fasteners that penetrate the exhaust duct, as these create obstructions that can trap lint, leading to reduced airflow and an increased risk of fire.
Why the other options are wrong
- B. While possible, the primary concern specified by code is lint accumulation and fire hazard.
- C. Manufacturer's warranties are not a direct concern for a building inspector enforcing the IRC.
- D. Corrosion is a less direct and less significant concern compared to fire hazard from lint accumulation.
Dryer Exhaust Duct Fasteners
Specific requirements in the IRC regarding the type of fasteners permitted for dryer exhaust ducts, primarily to prevent lint accumulation.
- Non-penetrating fasteners (e.g., foil tape, clamps) are required.
- Penetrating fasteners create fire hazards.
- Ensures proper airflow and reduces blockage risk.
Memory trick: No Screws in Ducts, or Lint's a Fire Hazard, No Buts!