Considerations in the Manufacture of Rectangular Ducts

Juan Carlos Fernandez 10 Jan, 2023 Home 0 Comments

At the time of manufacturing the Rectangular Ducts and Pieces, it is important to mention the following:

1. All the ducts and parts of the ductwork will be manufactured with Galvanized Steel according to the Third Edition 2005 of the SMACNA Standard “HVAC DUCT CONSTRUCTION STANDARDS”.

2. G-60 Galvanized Sheet will be used, with ASTM A 653 specification. In cases where the project requires it, G-90 Galvanized Sheet can be used, complying with the same ASTM A 653 specification.

3. According to the working pressure (1", 2" or 3" pressure), the Maximum Dimension of the rectangular duct or piece of ductwork (elbows, reductions, boots, etc.) varies both the caliber of the sheet, as the type of connection for its manufacture as shown in the following table.

Pressure in Inches	Duct Dimension	Type of Connection	Nominal Length (Max S&D, TDF) 1.18, 1.12m
1"	Up to 16"	G/Z	Gauge 26
	From 17" to 36"	TDF	Gauge 26
	From 37" to 48"	TDF	Gauge 24
	From 49" to 60"	TDF	Gauge 22
	From 61" to 72"	TDF	Gauge 22 MPT
	Costura: Snap Lock
2"	Up to 16"	G/Z	Gauge 26
	From 27" to 36"	TDF	Gauge 26
	From 27" to 36"	TDF	Gauge 24
	From 37" to 42"	TDF	Gauge 22
	From 43" to 48"	TDF	Gauge 20
	From 49" to 60"	TDF	Gauge 22 MPT
	From 61" to 72"	TDF	Gauge 20 JRT
	Type: Snap Lock
3"	Up to 14"	G/Z	Gauge 26
	From 15" to 16"	TDF	Gauge 26
	From 17" to 30"	TDF	Gauge 24
	From 31" to 36"	TDF	Gauge 22
	From 37" to 42"	TDF	Gauge 24 MPT
	From 43" to 48"	TDF	Gauge 22 MPT
	From 49" to 60"	TDF	Gauge 20 MPT
	From 61" to 72"	TDF	Gauge 20 MPT/JRT
	Type: Snap Lock, if the duct is greater than 48" it must be done with Pittsburgh Lock

G/Z: Connection with Clip and Zeta. TDF: Connection with Corners. MPT: Reinforcement in Central Part. JRT: Reinforcement at 3 Points.