Standard galvanized iron ductwork — rectangular, circular, and oval profiles for all HVAC applications. Manufactured at the Tawreed Trading & Contracting duct factory in Qatar.
GI Duct
GI Duct · GID-001
GI Duct (Standard)
SMACNA Standard
QCS 2024
QCS 2024 compliance statement available on request.
Galvanized steel to ASTM A527 / A653, coating G90 / Z275; fabricated to SMACNA and DW 142 / DW 144
Available profiles: rectangular, circular, and oval
Sheet thickness: 0.4 mm up to 3 mm; SMACNA tables 0.60–1.5 mm by duct size and pressure class
Seams: Pittsburgh lock, grooved, standing seam, drive slip and S slip; flanged or plain-end joints
Zinc coating weight: minimum 275g/m² per BS EN 10346
Suitable for supply, return, and exhaust air systems
Factory-made or site-fabricated per project BOQ
Compatible with CoolX flanging profiles and accessories
GI duct is galvanized steel ductwork for supply, return and exhaust air. Tawreed fabricates it at its factory in Birkat Al Awamer, Qatar, in rectangular, circular and oval profiles, to SMACNA and DW 142 / DW 144 and QCS 2024 Section 22, from galvanized steel to ASTM A527 / A653 with a G90 / Z275 coating. The datasheet covers sheet from 0.4 mm up to 3 mm; for rectangular duct, the SMACNA tables below give 0.60 to 1.5 mm by duct size and pressure class. The duct can be factory-made or fabricated on site to the project BOQ, and it is not insulated when it is made: insulation is added on site after installation.
Technical specifications
Specification
Detail
Product code
GID-001
Category
GI Duct
Available profiles
rectangular, circular, and oval
Sheet thickness
0.4 mm up to 3 mm; SMACNA tables 0.60–1.5 mm by duct size and pressure class
Seams
Pittsburgh lock, grooved, standing seam, drive slip and S slip; flanged or plain-end joints
Download the GI Rectangular Duct & Fittings – SMACNA datasheet (PDF). It covers: Product list and brands; rectangular duct, TDF / TDC flanges and seams; fittings and branch connections; SMACNA conformity letter; gauge vs. duct size and joint tables (500 / 750 / 1000 Pa).
Plain end or flange; black mild steel; aluminium; stainless steel
Sheet thickness range
0.4 mm up to 3 mm
Standard straight length
1200 mm
Cross-break beading
At every 305 mm interval, up to 18 ga steel thickness; standard straight lengths only
Longitudinal seams
Pittsburgh lock (small Pittsburgh for 26–22 ga, larger for 20–18 ga), grooved seam, standing seam, drive slip, plain and hemmed "S" slip
Transverse joint T-24 (formed flange)
Corner pieces min. 0.064" steel with min. 3/8" bolts; gasket min. 1/4" × 1/2" continuous; clips within 6" of each corner and at ≤ 15" centres for ≤ 3" w.g. (≤ 12" for higher pressures)
Raw material and components
GI duct fabrication: Tawreed Trading & Contracting; GI sheet: Jindal; flanges and corners: FireShield
Standard GI and pre-insulated (PI) duct orders are usually ready within 2 working days of order confirmation. Large or special orders are scheduled with you when we quote.
Do you supply GI duct only, or also install it?
We offer both supply only and supply and installation.
How fast will I get a quotation for GI duct?
Send your BOQ or product list through the quote form or WhatsApp (+974 7097 0111) and our technical team replies with a formal quotation within 4 business hours.
What sheet thickness is used for a 1000 mm duct at 750 Pa?
0.80 mm. In the SMACNA table in our GI duct datasheet, 750 Pa ducts with a longer side of 601–1200 mm use 0.80 mm sheet.
Which transverse joint is used on a 1200 mm duct?
A 30 mm flange, snapped on the sides with corners and clips, for a longer side of 1050–1200 mm. The joint table is the same for 500, 750 and 1000 Pa.
