The document discusses heating, ventilation, and air conditioning (HVAC) duct sizing and airflow (CFM) requirements. It explains that duct and vent size is determined by the CFM needs of the room, with larger rooms requiring larger ducts. It also notes that as supply ducts branch out from the air washer, both duct size and CFM decrease at each branch point to match the needs of the rooms served. The same principles apply to exhaust duct sizing as well.

1. HVAC

2. VENTILATION
Inline fan
Exhaust duct
A/W duct

3. passing through it whereas a larger area will have a larger CFM requirement
•The CFM requirement of a room decides the
and hence a larger duct.
•In the lower basement plan we notice that when a duct originates from an AIR WASHER
its size is large (here, 1300x350) and as we move further the size decreases to 1250x300, 500x300,etc.Simultaneously the CFM also decreases from 6650, 6150,
size of the ductwork and vents needed there. A
•Same principle applies for the exhaust network of ducts.
room with less CFM requirement will have a
smaller duct passing through it whereas a larger
area will have a larger CFM requirement and
hence a larger duct.
•In the lower basement plan we notice that when
a duct originates from an AIR WASHER its size
is large (here, 1300x350) and as we move
further the size decreases to 1250x300,
500x300,etc.
•Simultaneously the CFM also decreases from
6650, 6150, 4650, 3650 & 1000,etc.
•Same principle applies for the exhaust network
of ducts.

4. DUCT SIZE AND CFM DECREASES
1000 CFM
500X300
6650 CFM
1300X350