WWP Flange Landing

Mill-Pro supplies a full range of PE100 Flange adaptors (Stub Flanges) manufactured by injection moulding from our own tooling or machined from extruded hollow bar, in accordance with ISO 9624.

Flange Adaptor is a standard PE stub only, complying to ISO 9624, supplied without a backing flange. These standard flange adaptors with a matching backing ring are used for connecting PE to PE. (For connecting to valves valves use a flange assembly / full face assembly).

Flange Assembly is a PE stub or PE full-face stub, complete with a matching loose backing ring sold as a single item. Our Full Face flange adaptor assemblies are a proprietary Mill-Pro design, they are only sold complete with the matching backing flange. 

Flange Selection is a function of the pipes SDR (thickness) and the nearest nominal DN of best fit. When connecting PE pipes to another material (such as a pump, valve or fitting) use a Full Face flange assembly and select the best fit based on the PE pipes SDR rating and the EN 1092 nominal flange DN.  If connecting PE pipe to PE pipe with a flange joint, use a standard flange assembly.  

Flange Adaptors are available from 90mm OD (DN80) to 2000mm OD (DN1800) in pressure ratings from PN4 to PN25.  Mill-Pro flange adaptors are designed with extra-long spigots to allow assembly and disassembly using standard bolts after the spigot is fused in position, even when using long series Electrofusion couplers.

Standard loose backing flanges comply to BSEN 1092-1 PN16 drilling and ring thickness. However, other drillings, pressure ratings and dimensions, such as ANSI, JIS, AS/NZS to match other equipment can also be supplied.  Typical Loose backing flange materials are:

Fusion Bonded Epoxy (FBE) a Polymeric anti-corrosion (Barrier) coatings for buried applications. Mill-Pro's coatings are applied and tested in accordance with the UK Water Industry Standard WIS 4-52-01  WIS 4-52-01 

Stainless Steel for exposure in above ground and in marine environments, click here for Stainless Steel grade recommendations depending on the proposed application.  

Flange Type selection table select the best fit flange type for PE to DI or Steel flanges using the table below.

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

Equivalent Size in DN / ID Recommended BS EN1092 Flange DN for PE Pipe
SDR / Pressure rating
Outside diameter PE pipes / fittings DSD nominated matching size DN All Pipe to pipe SDR21/PN8 SDR17/PN10 SDR13.6/PN12.5 SDR11/PN16 SDR9/PN20
110 100 100 100 100 100 100 80
160 150 150 150 150 150 150 150
225 200 200 200 200 200 200 200
250 225 250 250 200 200 200 200
280 250 250 250 250 250 250 200
355 300 350 300 300 300 300 300
400 375 400 350 350 350 350 300
450 400 450 400 400 400 350 350
500 450 500 450 450 450 400 400
560 500 600 500 500 500 450 450
630 525 600 600 600 500 500 500
710 600 700 600 600 600 600 600
800 675 800 700 700 700 700 600
900 825 900 800 800 800 700 -
1000 900 1000 900 900 900 800 -
1200 1050 1200 1000 1000 1000 - -
1400 1200 1400 1200 1200 1200 - -
1600 1350 1600 1400 1400 1400 - -
1800 1650 1800 1600 1600 - - -
2000 1800 2000 1800 1800 - - -

Note:
1. Recommended Flange DN is the best fit for matching the pipes ID when connecting equipment such as: valves, fittings & pumps etc. Use a Full face Assembly if indicated in Orange or use a Standard Flange Assembly if indicated in Green.
2. Recomended Flange DN for connecting PE pipe to PE pipe using a flange joint, use a Standard Flange Assembly.

Note 1: Full-face flange adaptor designs are proprietary. Each supplier has its own design. Hong Kong Drainage Services Department (DSD) Appendix 5A, Clause 5.10, specifies dimensional and testing requirements for flange adaptors, including the provision of Type Testing (TT) results for a suppliers design in accordance with BSEN 12201-3 Table 4: Hydrostatic strength test at 80º C for 1000 hours. The supply of such independent Type Tests is essential to demonstrate the supplier's Full Face design will perform leak-free long term. 

Note 2: Fusion Bonded Epoxy (FBE) coating on loose backing rings is not recommended for prolonged direct UV exposure, due to the chalking effect occurring over time when epoxies are exposed to UV. We recommend stainless steel.

CONNECTING PE FLANGES TO DUCTILE IRON FLANGES IN SIZES ≥ DN200

In larger sizes (≥ DN200) flange drilling patterns between standard PE and DI flanges no longer line up with the nominal bore of Ductile Iron (DI) or steel pipe sizes.  This is especially true of PE pipes ≤ SDR11, due to its significant wall thickness in larger diameters.  So a Full Face flange adaptor (slim flange adaptor) must be used to make the connection.

Full Face flange adaptors are designed to align the internal bore of Polyethylene pipes, with the equivalent nominal size Ductile Iron valve or fitting at a flanged connection joint.  In smaller sizes, ≤ DN150 the internal diameters of PE and DI line up (within < 10%) of standard PE ISO 9624 flange adaptors, so Full Face are not required. Click on the illustrations below to understand why Full Face flange adaptors are required DN200 and above.