Galvanized Steel Ducts

0.7 to 1.5 mm, formed on automated CNC lines to SMACNA

Thickness: 0.7 – 1.5 mm
Shape: Rectangular and round spiral
Coating: ASTM A653 G90
Standard: SMACNA

SMACNA Duct construction
ISO 9001 Quality management

Overview

Galvanized steel ductwork is the backbone of commercial and residential HVAC. Ours is formed on fully automated CNC lines from galvanized coil: the Auto Duct Line III measures each section's perimeter, cuts the corners and folds it, and plasma CNC cuts the fittings, so every section and fitting comes off the line to the same dimensions.

Gauge follows the duct, not habit. Sheet from 0.7 to 1.5 mm is selected to SMACNA for the duct's size and pressure class, closed with Pittsburgh longitudinal seams, joined with TDF or slide-on flanges, and stiffened with beads or intermediate angles as the width grows. The tables below are the ones we fabricate to.

The steel carries an ASTM A653 G90 zinc coating, 275 g/m² over both sides; independent tests at Cairo University's Measurements and Calibration Labs have measured 331.7 and 375.1 g/m² on our sheet.

Configurations & options

Rectangular
Round spiral
Low pressure
Medium pressure

Materials & finishes

Galvanized steel, ASTM A653 G90
Mill and raw-material certificates with each submittal

Configuration

Round / Spiral Ducts

Spiral ductwork for exposed installations, with every fitting

Spiral duct is the choice where ductwork stays on show, in exposed ceilings and open interiors. It is formed in galvanized steel alongside our rectangular ducts, to the same coating and the same standard.

Elbows are made on a gore locker, reinforcement beads are rolled in on a swaging machine to the pattern the run needs, and power slip rolls form large-diameter sections. Round volume dampers shut off or balance the airflow within the same spiral system.

Type: Round spiral duct
Use: Exposed ductwork
Fittings: Elbows, reducers, branches, all accessories
Reinforcement: Swaged beads

Supplied with it

Flanges & Fabrication Accessories

All types of flanges and fabrication accessories

Every duct run depends on the components between its sections. We form TDF flanges on our own machines and supply slide-on flanges, companion angles, corners, cleats and S-slips, so the joints of a system come from the same source as the ductwork itself.

Turning vanes for elbows, access doors and volume dampers are fabricated to the same details, and every joint is sealed to the pressure class. Send us the duct system, sizes and standard you are working to, and we will confirm the flange types and accessories for it.

Flanges: TDF, slide-on 35 / 40, companion angle
Joints: Corners, cleats, S-slips
Fittings: Elbow turning vanes

Technical specifications

Construction

Material: Galvanized steel coil, ASTM A653 G90
Zinc coating: 275 g/m² min.; 331.7 – 375.1 g/m² measured
Sheet thickness: 0.7, 0.8, 1.0, 1.25 or 1.5 mm
Longitudinal seams: Pittsburgh lock, or snap lock
Transverse joints: TDF, slide-on flange, S-slip, companion angle
Standard: SMACNA

Low pressure (SMACNA)

Up to 700 mm: 0.7 mm (24 ga), beaded
721 – 1,200 mm: 0.8 mm (22 ga), beaded; flange 35 above 1,000 mm
1,225 – 1,800 mm: 1.0 mm (20 ga)
1,825 – 2,400 mm: 1.2 mm (18 ga), flange 40, angle 40/40/4
Over 2,400 mm: 1.2 mm (18 ga), angle 50/50/5

Medium pressure (SMACNA)

Up to 600 mm: 0.8 mm (22 ga), beaded
601 – 760 mm: 1.0 mm (20 ga), beaded
761 – 1,200 mm: 1.2 mm (18 ga), angle 40/40/4
1,201 – 2,000 mm: 1.5 mm (16 ga), flange 40, angle 40/40/4
2,000 – 2,500 mm: 1.5 mm (16 ga), companion angle 50/50/5
Over 2,500 mm: 1.5 mm (16 ga), angle 60/60/6

Fabrication

Forming: Auto Duct Line III: flat sheet, L, U and full duct
Cutting: Plasma CNC
Seam forming: Pittsburgh lock former, up to 1.2 mm
Flanges: TDF flange forming machines

Certifications & standards

What each mark on this product means, who issues it and how it applies here.

All certifications & standards

SMACNA

Duct Construction Standards

Issued by Sheet Metal and Air Conditioning Contractors' National Association (SMACNA), USA

What it is

SMACNA's HVAC Duct Construction Standards set how sheet-metal ductwork is built for a given pressure class: sheet gauge, joints and seams, reinforcement spacing and sealing. Consultants across the region specify ductwork by reference to them.

On this product

Gauges, joints, reinforcement and sealing follow SMACNA for the pressure class the duct is specified for.
ISO 9001

Quality Management Systems

Issued by International Organization for Standardization (ISO)

What it is

The international standard for quality management systems. A certified company works to documented processes, checks its output against them, records what it finds and corrects the cause of any fault, and is audited on all of it by an independent certification body.

On this product

Designed, fabricated and inspected under our certified ISO 9001 quality system: the same documented process for every unit, whichever of our factories builds it.

Which gauge do you use for a given duct size?

The one SMACNA sets for the duct's longest side and pressure class. At low pressure, 0.7 mm up to 700 mm, 0.8 mm to 1,200 mm, 1.0 mm to 1,800 mm and 1.2 mm above; at medium pressure, 0.8 mm up to 600 mm rising to 1.5 mm above 1,200 mm.

Can you prove the zinc coating?

Yes. The sheet is ASTM A653 G90 (275 g/m² over both sides), mill and raw-material certificates go with every submittal, and independent tests at Cairo University's Measurements and Calibration Labs have measured 331.7 and 375.1 g/m² on our sheet.

Has your ductwork been approved by consultants?

Yes. Our galvanized and black steel ductwork submittals have been approved on major projects by consultants including ECG and EHAF, fabricated to SMACNA and to the approved shop drawings.

Do you supply round spiral duct as well?

Yes, in the same galvanized steel, with every fitting and accessory, for exposed installations.

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