Standard Rectangular Duct Sizes

The hvac model that you re interested in should offer information regarding the maximum airflow per cubic foot per minute or cfm to help you determine adequate.

Standard rectangular duct sizes.

Equivalent diameter rectangular and circular hvac ducts equivalent diameter for rectangular and circular ducts air flows between 100 50000 cfm maximum size of duct or pipe through steel joists k series joists and maximum size of ducts and pipes. The master flow 36 in. The rectangular dimensions and the air flow volume are adapted to the equal friction loss. For screen reader problems with this website please call 1 800 430 3376 or text 38698 standard carrier rates apply to.

The table is based on the ducts friction loss formula. The table below can be used to compare equivalent diameters for rectangular and round circular ducts. Sizing is based on airflow needs per cubic foot per minute as well as velocity. Last take off run to be located 12 18 from end.

Always stagger take off ducts by 12 to maintain pressure. These duct chart are based on equal friction method with a friction loss value 0 1 inch 100ft. The equivalent diameter is the diameter of a circular duct or pipe that gives the same pressure loss as an equivalent rectangular duct or pipe. Galvanized steel flat sheet can be cut to size for a tough hvac job that requires a customized fitting.

The minimum duct sizes and recommended duct sizes based on a hood fan s cfm rating are as follows. The length of the rectangular duct size would range from 0 7mm to 0 9mm galvanised mild steel depending on size. Wrap around duct l shape duct all sizes shall be listed using outside. A 0 to 400 cfm fan requires a 4 inch minimum duct size but a 6 inch duct is recommended.

They are as follows. Ductwork is fabricated with either snap lock or pittsburgh longitudinal seams. Flexible duct work must be stretched tightly for maximum air flow. In order to maintain velocity reduce duct size.

Duct work is otherwise called as duct system. Duct size chart calculate duct dimensions for both rectangular and round ducts. Never locate ducts at the end of the trunk line run. Download free duct sizing chart pdf according to ashrae standard.

Master flow 24 in. All ductwork comes standard with stiffening beads. Use insulated duct or duct board in unheated spaces. Sealant is available in the seams upon request.

Rectangular or square ducting comes in standard sizes ranging from 3 by 7 inches to 35 by 40 inches. Rectangular ductwork is manufactured in three different styles.