On most UAE projects the GI pipe and the GI fittings come from different suppliers: the pipe from a steel stockist, the fittings from a fittings specialist. That is normal, but it means somebody has to check that the two actually fit together before the order is placed. This guide covers the four things to check: the pipe series, the thread, the size and the finish.
1. Know which GI pipe you are joining
Galvanised steel pipe sold in the UAE is mostly made to BS EN 10255 (the standard that replaced BS 1387), in the medium or heavy series. Medium is the usual choice for water and general building services; heavy is common on fire lines and where the specification asks for a thicker wall. The series changes the wall thickness, not the outside diameter, so the same TUPY fitting fits medium and heavy pipe of the same nominal size.
2. Match the thread: BSP or NPT
UAE GI pipe is normally threaded BSP taper (ISO 7-1 / EN 10226-1). TUPY BSP fittings are made to EN 10242 / ISO 49 with the same thread form, so they make up with that pipe directly. Pipe threaded NPT, which you will meet on US-specified plant and some fire-protection packages, needs NPT fittings to ASME B16.3 instead. Mixing the two leaks or cracks, so state the thread on every enquiry.
| Pipe threaded | Order this range | Typical use in the UAE |
|---|---|---|
| BSP taper (ISO 7-1) | TUPY BSP, EN 10242 | Water, plumbing, general building services, most fire lines |
| NPT (ASME B1.20.1) | TUPY NPT Class 150 or Class 300, ASME B16.3 | US-specified plant, oil and gas, some NFPA fire packages |
3. Convert the size: NB to inches
Pipe is often ordered in millimetres of nominal bore (NB or DN) and fittings in inches. The two are the same nominal size, not a measured diameter:
| NB / DN (mm) | 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 150 |
|---|---|---|---|---|---|---|---|---|---|---|
| Fitting size (inch) | 1/2 | 3/4 | 1 | 1-1/4 | 1-1/2 | 2 | 2-1/2 | 3 | 4 | 6 |
4. Choose the finish and check the approvals
Use galvanised (GI) fittings with GI pipe, so the zinc protection is not broken at the joint. Black fittings stay the normal choice for gas, steam and compressed air, and for fire lines that are painted after installation. For sprinkler and hydrant work, check that the exact figure and size you order carries UL Listing and FM Approval, and ask for the certificates with the quotation.
Where to go next
For the full range of galvanised fittings, stock in Dubai and delivery across the seven emirates, see GI fittings supplier in the UAE. For malleable iron fittings, NPT Class 150/300 and datasheets, see MI pipe fittings in Dubai. The figure number cross-reference lists every TUPY figure in BSP and NPT.
