Flange Connection System
The Lin Sing flange connection system complies in full with DW144 and has been independently tested to the DW/TM1 procedure by Ir HN Lam of the University of Hong Kong. Four profiles across three sizes cover joint classifications J2 to J5 and Pressure Classes A, B and C.
Profile dimensions
Table A| Model | Nominal size | Gauge | H | L | G |
|---|---|---|---|---|---|
| LS2 | 25 mm | — | — | — | — |
| LS3 | 30 mm | — | — | — | — |
| LS4 | 40 mm | 1.0 mm | — | — | — |
| LS5 | 40 mm | 1.2 mm | — | — | — |
Four profiles, three nominal sizes. LS4 and LS5 share the 40 mm nominal size and differ in gauge — 1.0 mm and 1.2 mm respectively.
Test results
Table BIndependently tested by Ir HN Lam, The University of Hong Kong, to the DW/TM1 procedure.
| Joint class | Pressure Class A | Pressure Class B | Pressure Class C |
|---|---|---|---|
| J2 | — | — | — |
| J3 | — | — | — |
| J4 | — | — | — |
| J5 | — | — | — |
Detailed test figures are governed by the University of Hong Kong DW/TM1 test report. A copy is available on request.
Corner pieces
Table C| Model | For profile | Thickness | Length |
|---|---|---|---|
| LS20C | LS2 | — | — |
| LS30C | LS3 | — | — |
| LS40C | LS4 / LS5 | — | — |
Fabrication sequence
Six stepsCut the profile
Cut flange profile to duct edge length, four pieces per joint.
Assemble the frame
Arrange the four lengths into a rectangular frame ready for corner pieces.
Insert corner pieces
Insert the matching corner piece (LS20C / LS30C / LS40C) at each of the four corners.
Fit to duct
Slide the assembled frame onto the duct end and align to the duct wall.
Spot weld or rivet
Spot weld or rivet along the duct wall to lock the flange to the duct.
Seal
Apply sealant to the inside face. The joint is then ready for site installation.
Site installation
On site- 01
Overlap gasket by 30 mm
Gasket ends must overlap by at least 30 mm — do not butt-joint.
- 02
Reinforce corners above 1000 Pa
Where system pressure exceeds 1000 Pa, add supplementary corner bolts.
- 03
Hand-tighten bolts first
Hand-tighten all bolts and confirm alignment on all four sides before driving the clips.
- 04
Clip driving sequence
Drive clips from the centre outwards to distribute clamping pressure evenly.
Downloads
Documents- Flange system specification (PDF)Available on request
- DW/TM1 test reportAvailable on request
- CAD section file (DWG)Available on request
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