DSD Polyethylene Outside Diameter (OD) conversion to Nominal Diameter (DN)

The Hong Kong Drainage Services Department (DSD) publishes a conversion table in Appendix 5A, to ensure proper ID alignment when connecting Polyethylene pipes with other pipe materials used in its pressure and drainage network.

PE pipe size is defined by its outside diameter (DN/OD for pipes and dn for fittings), whereas Ductile Iron, Reinforced Concrete, Earthenware and other wastewater pipe materials are defined by their nominal Bore (DN).

It should be noted that PE pipes internal dimension varies depending on the pipes wall thickness (SN / SDR Rating). The table below provides the official DSD PE OD to DN conversions, as given in DSD Appendix 5A, for both pressure and gravity drainage.  

PE Nominal Size (DN/OD)/Nominal Outside Diameter (dn)

(Outside diameter of PE Pipes/Fittings)

Equivalent Size in DN / ID

(DSD nominated matching size DN)

110

100

160

150

225

200

250

225

280

250

355

300

400

375

450

400

500

450

560

500

630

525

710

600

800

675

900

825

1000

900

1200

1050

1400

1200

1600

1350

1800

1650

2000

1800

Note: Larger sizes are not stipulated in Appendix 5A, but are available up to DN/OD 2800 in PN8 SDR21.

 

Page from DSD Appendix 5A for reference.

DSD PE OD DN Conversion Table Page

Page from DSD Specification for Gravity Sewer and Stormwater Drain Connection for Reference

Cover Page From DSD Short Spec 22.08.16