Black Steel Ducts

Fully welded up to 4.0 mm, for heat and smoke

Thickness: 1.25 – 4.0 mm
Construction: Fully welded, leak-proof
Welding: MIG, CO2 shielded
Standard: SMACNA

SMACNA Duct construction
ISO 9001 Quality management

Overview

Engineered for extreme heat and safety. Black steel ducts are made from hot or cold rolled mild steel sheet (0.16 – 0.29% carbon) and fully welded rather than locked, so the run is leak-proof and inherently fire resistant.

Square ducts are bent from a single sheet in standard 1,250 mm lengths, with 90° angle flanges cut and punched on a CNC angle line. Fittings are cut on plasma CNC and every seam is MIG welded in a CO2 shield. Round ducts are rolled to the diameter, seam welded in 1,240 mm lengths, with flanges and bolt holes laser cut.

That construction makes them the choice for kitchen hood exhaust, car park ventilation and smoke evacuation. Fabrication follows SMACNA, and the finish is powder coating or paint, with three coats of red oxide as an option.

Configurations & options

Kitchen hood exhaust
Car park ventilation
Smoke evacuation

Materials & finishes

Hot or cold rolled black steel sheet
Steel angle flanges
Powder coat, paint or red oxide finish

Technical specifications

Construction

Material: Hot or cold rolled mild steel, 0.16 – 0.29% C
Sheet thickness: 1.25, 1.5, 2.0, 3.0 or 4.0 mm
Joints: Fully welded (MIG CO2), leak-proof
Flanges: Steel angle, 25×25×3 to 60×60×6 mm
Standard: SMACNA

Fabrication

Square duct: Bent from one sheet, 1,250 mm lengths
Round duct: Rolled and seam welded, 1,240 mm lengths
Cutting: Plasma CNC; laser-cut flanges and holes
Bending: CNC bending

Finish

Standard: Powder coating or paint
Option: Three coats of red oxide
Welders: Certified

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.

Why black steel for kitchen exhaust?

Kitchen exhaust carries grease and heat, and codes expect a duct that will not leak or fail in a fire. A fully welded mild steel duct is leak-proof and inherently fire resistant, which a locked galvanized seam is not.

What thicknesses do you weld?

1.25, 1.5, 2.0, 3.0 and 4.0 mm, chosen for the duty and the SMACNA class.

How are black steel ducts protected from corrosion?

With powder coating or paint as standard, or three coats of red oxide as an option.

Products that work alongside it, then the rest of Ductwork Systems & Fabrication.

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