Fitting Function Geometry Category Sequential Number S Supply D Round (dia) 1 Entries 1, 2, 3 … n E Exhaust/Return R Rectangular 2 Exits C Common O Oval 3 Elbows 4 Transitions 5 Junctions 6 Obstructions 7 Fan & system interactions 8 Duct-mounted equipment 9 Dampers 10 Hoods Examples: Fitting ED5-1 is an Exhaust fitting with a round shape (Diameter). Numeral 5 indicates that the fitting is a junction, and 1 is an identifying sequential number. Fittings SR3-1 and ER3-1 are Supply and Exhaust fittings, respectively. R indicates that the fitting is Rectangular, and 3 identifies the fitting as an elbow.
Fitting ED5-1 is an Exhaust fitting with a round shape
(Diameter). Numeral 5 indicates that the fitting is a junction, and
1 is an identifying sequential number.
Fittings SR3-1 and ER3-1 are Supply and Exhaust fittings,
respectively. R indicates that the fitting is Rectangular, and 3
identifies the fitting as an elbow.
