HVAC question- The residence "stack" for ductwork? Does it refer to all ductwork other than the probability & end...

Does it refer to all ductwork other than the probability & end pieces such as elbows, diffusers, etc?
Leak within tub after repairs but singular after...
Answers:    The term stack is used (Thermal stack).grill rises, cold drops so if you're trying to blow cold air up stairs the thermal stack is going to work against you. friction loss is the term used to integer the drag on the air going thru the pipe and around the elbows and ect.
How frequent plenty of conrete do I entail...
Normally the "stack" or riser is a portion of the duct work the that is installed vertically, usually between floors, such as a flue surrounded by a "chimney stack".
I hold an discount 7 storage oven is...
The stack I believe is going to be the duct work that feeds the branches either between floors or the primary trunk.