Clothes Dryer Exhaust Safety – 6 Requirements You May Not Know

Before & After a Dryer Vent Cleaning

Did you know that lint and debris can build up in your clothes dryer duct? When lint buildup occurs, it can create potentially hazardous conditions, like dryer fires that can turn into devastating house fires, and carbon monoxide buildup that can poison people and pets – and even result in death. Therefore, it’s important that your clothes dryer exhaust system is properly vented outside your home.

To reduce potential hazards associated with clothes dryer exhaust, the industry has adopted certain standards. Here are 6 requirements by the International Code Council you may not know about dryer exhaust systems:

1. Dryer vents must be independent of all other systems and must exhaust moisture and combustion products outdoors – not into attics, crawl spaces, basements, chimneys, wall cavities or any interior room.
2. Dryer ducts must be constructed of rigid aluminum or galvanized steel. Plastic transition ducts cannot be used since they’re flammable. Duct interiors must have smooth surfaces with the joints running in the direction of the airflow. There shouldn’t be any sheet-metal screws, rivets or other fasteners used to connect the duct joints since these can catch lint and obstruct airflow.
3. Dryer ducts must be at least 4 inches in diameter and at least as large as the dryer outlet. The dryer duct can’t go into or through HVAC ducts.
4. Dryer ducts cannot exceed 25 feet in length. Note: Each 90-degree turn that the duct makes, adds 5 feet to the actual length. Often newer homes have laundry rooms that are located away from outside walls, which results in longer venting distances and more possible bends. This can make dryer ducts harder to access and create more surfaces for lint to build up on.
5. Flexible transition ducts cannot be used in an attic, crawl space or inside a wall.
6. The exhaust vent termination hood must be equipped with a back draft damper to keep moisture/exhaust from coming back into your home and small animals out of your home. This exhaust termination outlet must not be covered with a screen.

To make sure your dryer exhaust system is sized and installed correctly, have it checked by T.J.’s Chimney Service. Also schedule a dryer vent cleaning by calling us at 317-455-5310. An annual dryer vent cleaning will ensure your clothes dryer continues to work safely and efficiently.