Hot Dip Galvanized Round Pipes

Hot dip galvanized round pipe, widely known in the UAE as GI pipe or galvanized pipe, is steel tube dipped in molten zinc so it is protected inside and out. It is the standard material for water lines, handrails, fencing posts, shade structures and scaffold style frames. Seen Steel supplies hot dip galvanized pipe from ½" to 6" nominal bore in light, medium and heavy series, plain end or threaded and socketed, delivered to all seven emirates.

Sizes and weights

EN 10255 (formerly BS 1387) sizes, shown as Light / Medium / Heavy wall thickness with black plain end weight per metre. Galvanizing adds a few percent. Standard length is 6 m.

For more sections, see the steel weight chart. For uncoated pipe and ASTM A53 Schedule 40 sizes, see our mild steel CHS and pipe.

Light, Medium or Heavy

Light pipe suits fencing, handrails and non pressure uses. Medium is the general purpose series for water services and structural frames, and the safe default if you are unsure. Heavy is for threaded pipe under higher pressure and for members that take knocks. Threaded pipe loses wall at the thread, which is why pressure lines use Medium or Heavy.

How much zinc: EN ISO 1461

Hot dip galvanizing to EN ISO 1461 sets a minimum average coating thickness by steel thickness. Because the pipe is dipped, the zinc coats the inside as well as the outside.

Zinc adds roughly 3 to 7 percent to the black steel weight. Our guide to GI coating classes explains how this compares with pre-galvanized Z120 to Z275 material.

Standards and grades

• EN 10255 (replacing BS 1387), grade S195T, Light, Medium and Heavy series
• ASTM A53 Grade A or B, galvanized, Schedule 40
• Galvanizing: EN ISO 1461 or ASTM A123
• Plain end, bevelled, or threaded and socketed to BS EN 10226 (BSP) threads

GI pipe sizes chart: nominal bore, wall thickness and weight

GI pipes are ordered by nominal bore, written NB, not by outside diameter. A 2" NB pipe has an outside diameter of 60.3 mm, and that OD stays the same across all three wall thicknesses. This chart covers the sizes in everyday supply in the UAE to BS 1387 and EN 10255. The weight column is for medium wall, which is what most orders use.

Weights are for the bare steel. Hot dip galvanizing to EN ISO 1461 adds roughly 3 to 5 per cent on the smaller bores and less on the larger ones, because the coating is a surface and the surface to mass ratio falls as the pipe gets bigger.

GI pipe Class A, Class B and Class C

Half the enquiries we take name a class and half name a wall thickness, and they are the same thing under two naming systems. Older BS 1387 practice, which is still how most UAE specifications and consultants write it, uses classes. EN 10255 uses words. The mapping is direct:

• Class A is light wall. The thinnest of the three. Used for low pressure water, conduit, handrail and light structural work where the pipe is not carrying much.
• Class B is medium wall. The default across most UAE projects, and what you get if the enquiry says GI pipe and nothing else. Plumbing risers, fire fighting lines, general service.
• Class C is heavy wall. The thickest. Specified for higher pressure, buried service, or anywhere the line takes mechanical load or impact.

If a drawing says Class C and you order medium, the lot gets rejected on site, so it is worth stating the class and the wall thickness together on the enquiry. Where a consultant has written only a class, quote the class back on the order so the certificate matches the specification.

What to state when you order GI pipes

A GI round pipe enquiry prices fastest when it carries these six things:

• Nominal bore in inches or millimetres, for each size on the list
• Class or wall thickness, light, medium or heavy
• Quantity, in lengths or in metres
• Plain ends, or threaded and socketed
• Whether the pipe is being cut, and to what lengths
• Delivery location

Standard length is 6 metres. Threading and socketing is done to order, so say at the enquiry stage rather than after the pipe is cut, because a threaded end needs the length allowance built in.

Common applications

• Water supply and irrigation lines
• Handrails, guardrails and pedestrian barriers
• Fence posts and chain link fencing frames
• Shade structures, greenhouses and carports
• Scaffold style frames and temporary works
• Sleeves and conduit

Cutting and delivery

We supply 6 m lengths, plain end or threaded and socketed, or cut to your list. Deliveries go to workshops and sites across all seven emirates, including Al Quoz, Jebel Ali, Mussafah, Sajaa, Ajman Industrial and Al Hamra. Mill test certificates are supplied with the material.

Frequently asked questions

What is GI pipe?
GI pipe means galvanized iron pipe, which in practice is galvanized steel pipe. Hot dip galvanized pipe has a thicker coating than pre-galvanized tube and protects the inside of the pipe too.

What is the difference between BS 1387 and EN 10255?
EN 10255 replaced BS 1387. The sizes and the Light, Medium and Heavy series are essentially the same, so the names are often used for the same pipe.

What is the weight of a 2 inch medium GI pipe?
About 5.0 kg per metre black, plus the zinc, so roughly 5.2 kg per metre galvanized.

Do you supply threaded and socketed pipe?
Yes, in the EN 10255 range. Tell us with the enquiry.

Do you supply mill test certificates?
Yes, MTCs are issued with the material.

Send your galvanized pipe requirement through the steel quote request form or on WhatsApp at +971 56 227 5722.