Cfm Flow Flexible Vent Vs Sheet Metal Ducting

Without it there would be tons more labor and material to make that final connection.

Cfm flow flexible vent vs sheet metal ducting. Use insulated duct or duct board in unheated spaces. The rectangular dimensions and the air flow volume are adapted to the equal friction loss. Flexible duct work must be stretched tightly for maximum air flow. Never locate ducts at the end of the trunk line run.

I don t know why but i have taken metal pipe apart to find a lot of crud which i don t think would live in flex duct. Flex ducts are better for existing trunk and branch heating and cooling systems. Sheet metal ducts are less likely to incur dangerous mold and growths because their surfaces are non porous and smooth. I am not hating on metal pipe but flex duct is more practical in many applications.

In comparison to metal duct flex duct is easier and faster to install. Always stagger take off ducts by 12 to maintain pressure. 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. Like regular hvac duct flex duct work needs to be sized appropriately in order to flow the air volume which is measured in cubic feet per minute cfm correctly.

I have seen many leaky metal ducts in crawl spaces as well. Flex duct 05 on most metal duct calculator round metal pipe 06 on most metal duct calculators field duct sizing chart rectangular sheet metal duct 07 on most metal duct calculators duct size. Metal ducts are more rigid due to the nature of steel making them ideal to build an entire hvac system. Also i think spider webs are more likely to form in metal versus flex.

The table is based on the ducts friction loss formula. I ve only been building since 1995 so i can t say for certain why we left the sheet metal guys behind but i suspect it was manly for cost reasons. Flexible ducts are fairly easy to install and will often cost less than the rigid ductwork. In order to maintain velocity reduce duct size.

Last take off run to be located 12 18 from end. This is because they re more versatile and flexible. Flex duct allows easy connection from the main duct trunk to the hvac grille.