What to do — and what to avoid — to keep things safe and efficient.
To many homeowners, building codes are arbitrary, confusing and expensive. I’ve found this to be especially true when it comes to dryer vent materials. However, codes exist to keep you safe and your dryer vent in proper working order, so it’s crucial to abide by them.
One of the biggest code offenders is the wrong kind of dryer venting material. I find that homeowners have improper materials not on purpose but because of a lack of knowledge on the subject. Let’s take a look at the codes related to dryer vent exhaust systems, or the part that goes from the back of your dryer to outside your home.
Safety first: Most building code requirements are safety related, and this is certainly true of dryer vent codes. Dryers cause 92 percent of all reported appliance fires, according to the National Fire Prevention Association. Ensuring a dryer vent is constructed of proper material is one important step in reducing the risk of a dryer-related fire.
Why exactly is it so important? Think about it this way: The inside of a dryer contains all three elements for a healthy fire.
1. Ignition source: The heating element within the machine
2. Oxygen: Continuous airflow in and out of the machine
3. Combustibles: Clothes to help catch and spread any sparks
How to avoid sparking a fire: Air must circulate regularly to cool the appliance. A dryer pulls in fresh air from the room, circulates it through the dryer, moves it into the dryer vent and then pushes the air outside the home. Proper vent materials create better airflow. The better the airflow, the slower the lint builds up inside the machine, which lowers the risk of sparking a fire.
Proper venting material: A code-compliant dryer vent is constructed of a rigid pipe of nonflammable material with a smooth interior finish. The smooth interior inhibits lint buildup in grooves, and it is not easily crushed or broken.
While building codes differ around the country, two code-compliant vent material options are solid aluminum pipe that is at least 0.4 millimeters thick or galvanized steel pipe. Of the two options, I prefer to use aluminum pipe as it does not rust.
Note: You should always check your local city building codes to make sure you are using compliant materials and installation methods for your dryer vent exhaust system.
Improper venting material: These are common venting materials that are non-code compliant, as determined by the guidelines of the International Residential Code and International Mechanical Code.
1. Foil: Foil is a non-code-compliant venting material because it is extremely flammable. Additionally, foil does not have a smooth interior finish. Rather, the material features grooves on the inside, which allows lint to accumulate and clog the vent, creating a fire hazard.
2. PVC: This material is not compliant with standards because the material itself is flammable. Additionally, a PVC pipe causes static electricity to form as the dryer circulates air to move lint outside. This static electricity attracts lint and creates an extra “glue” for the lint to attach to the inside of the vent line. Lint buildup provides additional flammable material.
3. Vinyl: Vinyl is also flammable and does not have a smooth interior finish. In addition, over time, vinyl will dry out and crack, which will compromise the vent line. The flimsy material puts the dryer vent at higher risk to be crushed, which will restrict airflow and cause lint buildup, creating a fire hazard.
Identifying code compliance: Although these materials are not code compliant and a fire hazard, I’ve come across them many times, as have other Dryer Vent Wizard technicians, when completing inspections. Identifying compliant versus noncompliant materials can be tricky because many of these materials look similar.
In addition to the type of material used, there are also specific regulations on the thickness of the pipe, the kind of tape used to connect joints, proper suspension of the line and other installation factors.
Find help, if needed: If you are unsure whether your dryer vent system is code compliant or you are looking to replace it, consult a local dryer vent installation or repair professional. He or she will know the local code requirements and can help you address any issues or concerns.
The goal is to ensure dryer vents are installed and functioning properly to help keep you, your family and your home safe.