What is ducting and how does it work?

Ducting is a conduit or passage allowing air to be transported from one place to the next. A good example of this would be your air conditioning system in your home, which is sometimes referred to as HVAC (Heating, Ventilation, and Air Conditioning). Ducting for dust collection is to move dust from a machine to the dust collector.

In a shop there are “Main” ducts which usually refers to the large duct that runs overhead on the ceiling:

        * Main duct is runs horizontally.

        * Main duct has a recommended air velocity (or speed) of 3500 FPM (feet per minute) in woodworking environments.

There are also “Branch” ducts, which refers to duct that drops from the main duct to the machine:

        * Branch duct runs vertically.

        * Branch duct has a recommended air velocity of 4000 FPM in woodworking environments.

Ducting can be made of different materials:

    * Galvanized steel - most favorable type of ducting

    * PVC (polyvinyl chloride) - plastic. Debated to cause a lot of static

    * Flexible or Flex hose - commonly used; least favorable type of ducting

        * Suggested to usually use very short amounts to connect branch duct to machine.

        * Flex hoses are “flexible” so it can cause air to be slowed down when it running into a bend or turn

        * Flex hoses have “ribs” inside the hose which can slow down or cause dust to get stuck in the ribbed section of the hose.

Ducting layout is usually calculated at furthest machine from the dust collector:

    * Ducting is commonly seen at 4”, 5”, 6” and more.

    * Ducting is very important for proper/efficient dust collection

    * When setting up a shop, Ducting is usually the first thing a person should look into before buying a dust collector. 

    *Shop layout and placement of the machine is an important factor to effectively determine the efficiency of ducting         and dust collection in general.

    * Machines that requires least amount of “CFM” (Cubic Feet per Minute; also referred to airflow) should be placed             the furthest from dust collector

    * Ex. Ambassador C14 bandsaw requires about 400 cfm

    * Ex. Alpha HW110LC table saw requires about 470 cfm

There are a lot of websites that can help calculate ducting and it’s recommended to have customers reach out to companies that provide ducting products for help setting up a shop. Companies such as:

    * Air Handling System (www.airhand.com)

    * Nordfab (www.nordfab.com)