Rectangular Duct

HAS Rectangular Ductwork, is intended for both indoor and outdoor use, the constructional requirements for rectangular ductwork depend on the pressure classification, as set out in the tables below.

There are 2 finishes available for this product which are listed below.

  • Standard Galvanised Finish Z275
  • Colorduct II – Painted to any RAL colour specified (data sheet available upon request)

Construction & Sheet Steel Thickness

The ductwork is made from Hot Dipped Galvanised Steel DX51D Z275, all raw material is supplied and certified to the latest version of BS EN IS 9001.

The below specifications cover duct sizes up to a maximum longer side of 3000mm. Duct sizes with an aspect ratio greater than 4:1 are not recommended. Although they offer no problems of construction, they increase frictional resistance and the possibility of noise.

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Rectangular Fittings

See our range of rectangular duct fittings below.

Low Pressure Ductwork

FLANGED JOINTS

Dimensions in mm

1

2

3

4

5

6

7

8

9

10

11

MIN. SHEET THICKNESS

0.6

0.8

1.0

1.2

DUCT LONGEST SIDE

400

600

800

1000

1250

1600

2000

2500

3000

RATING

SHEET

MAXIMUM SPACING BETWEEN FLANGES AND / OR STIFFENERS

J1/S1

PS

3000

1600

1250

625

SS

3000

3000

1250

625

J2/S2

PS

3000

2000

1600

1250

625

SS

3000

3000

1600

1250

625

J3/S3

PS

3000

2000

1600

1250

1000

800

SS

3000

3000

2000

1600

1250

800

J4/S4

PS

3000

2000

1600

1250

1000

800

800

SS

3000

3000

2000

1600

1250

1000

800

J5/S5

PS

3000

2000

1600

1250

1000

800

800

800

625

SS

3000

3000

2000

1600

1250

1000

800

800

800

J6/S6

PS

3000

2000

1600

1250

1000

800

800

800

800

SS

3000

3000

2000

1600

1250

1000

800

800

800

Medium Pressure Ductwork

FLANGED JOINTS AND STIFFENERS

Dimensions in mm

1

2

3

4

5

6

7

8

9

10

11

MIN. SHEET THICKNESS

0.6

0.8

1.0

1.2

DUCT LONGEST SIDE

400

600

800

1000

1250

1600

2000

2500

3000

RATING

SHEET

MAXIMUM SPACING BETWEEN FLANGES AND / OR STIFFENERS

J1/S1

PS

3000

1250

625

SS

3000

1250

625

J2/S2

PS

3000

1250

1250

625

SS

3000

1600

1250

625

J3/S3

PS

3000

1600

1250

1000

800

SS

3000

3000

1600

1250

800

J4/S4

PS

3000

1600

1250

1000

800

800

SS

3000

3000

1600

1250

1000

800

J5/S5

PS

3000

1600

1250

1000

800

800

800

625

SS

3000

3000

1600

1250

1000

800

800

800

J6/S6

PS

3000

1600

1250

1000

800

800

800

800

625

SS

3000

3000

1600

1250

1000

800

800

800

625

High Pressure Ductwork (Class C)

FLANGED JOINTS AND STIFFENERS

Dimensions in mm

1

2

3

4

5

6

7

8

9

10

MIN. SHEET THICKNESS

0.8

1.0

1.2

DUCT LONGEST SIDE

400

600

800

1000

1250

1600

2000

2500

RATING

SHEET

MAXIMUM SPACING BETWEEN FLANGES AND / OR STIFFENERS

J1/S1

PS

3000

625

SS

3000

625

J2/S2

PS

3000

1250

800

SS

3000

1250

800

J3/S3

PS

3000

1250

1250

800

SS

3000

1250

1250

800

J4/S4

PS

3000

1250

1250

1000

800

SS

3000

1250

1250

1000

800

J5/S5

PS

3000

1250

1250

1000

800

800

625

SS

3000

1250

1250

1000

800

800

625

J6/S6

PS

3000

1250

1250

1000

800

800

800

625

SS

3000

1250

1250

1000

800

800

800

625

Types of Fittings

Mitred Throat Bend


For ducts up to 400mm wide

Examples of 'Hard' and 'Easy' bends

'Hard' signifies rotation in the plane of the longer side of the cross section (top sketch).



'Easy' signifies rotation in the plane of the shorter side of he cross section (bottom sketch)

Short Radius Bend


For ducts up to 400mm wide

Medium Radius Bend

(as illustrated)

Long Radius Bend

Similar but radius = W Applies to any angle




Short Radius Bend with splitters

W mm

Splitters

Splitter Position

A

B

C

401 - 800

1

W / 3

-

-

801 - 1600

2

W / 4

W / 2

-

1601 - 2000

3

W / 8

W / 3

W / 2

Splitters not required in bends of 45° or less

Square Bend - with turning vanes


Mitred elbow - 30° max

Radius Tee - with 'radiussed back plates' and, if required, splitters

Angled Offset

Mitred Offset

Radiussed Offset

Concentric Taper

22.5° max in either plane

Splitters are required for angles greater than 22.5° and should bisect the angle between the sid eand the duct centreline.

Ecccentric Taper

22.5° max in either plane

Splitters are required for angles greater than 22.5° and should bisect the angle between the sid eand the duct centreline.

OffsetTaper

Splitters are required for angles greater than 22.5° and should bisect the angle between the sid eand the duct centreline.

Radiussed Twin Bend

Swan Neck Bend - typically found on roof exhausts i.e. 135° angle

Swept Branch

Square Tee with turning vanes

Breeches Piece

'Y' Piece

Rectangular to Round Transformation

Rectangular to Flat Oval Transformation

Square Branch

Angled Branch

Shoe Branch

Branch Duct Width (W) mm

Dimension (A) mm

Up to 200

75

" 300

100

" 400

125

" 600

150

Over 600

200

Bell Mouth Branch

Branch Duct Width (W) mm

Dimension (A) mm

Up to 200

75

" 300

100

" 400

125

" 600

150

Over 600

200

Bell Mouth

Branch Duct Width (W) mm

Dimension (A) mm

Up to 200

75

" 300

100

" 400

125

" 600

150

Over 600

200

Duct Supports

Supports for rectangular horizontal ductwork

Longest Side

HANGERS

BEARERS

Maximum Spacing's

Screwed Rod

Flat Strap Fig 156/164

Stirrups

"Z" cm³ x-x
Fig 155 / 163

Up to 400

6

25 x 0.5 Plain or Perforated

N/A

0.40

3000

401 - 600

8

30 x 3 flat

N/A

0.70

3000

601 - 1000

8

N/A

N/A

1.50

3000

1001 - 1500

10

N/A

N/A

2.10

2500

1501 - 2000

10

N/A

N/A

3.05

2500

2001 - 3000

12

N/A

N/A

4.45

2500

Why Choose HAS-Vent?

The materials we manufacture, purchase and install for our customers are DW144 compliant, meaning they are high quality, sustainable and cost-effective.

Our competitively priced materials have a thicker gauge of sheet material to exclude the chance of leakages, giving you complete ease of mind. You can learn more about our specifications by contacting our team on 01902 895161.
Contact your chosen ductwork experts via phone or email and discover more about the products we offer.

You can also visit our contact page to submit a contact form for us to respond to as soon as possible.

Want to know more?

Download our Engineered Air Solutions brochure or contact our expert team to discuss your requirements today!

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