Direct answer
For transmission mains, spiral (SSAW) pipe, 273 to 3,600 mm OD, is the usual choice, with LSAW pipe where a straight seam is specified. For supply and service lines up to 300 mm OD, GI hot dip galvanized pipe is the usual steel option. Joints, linings and coatings follow the specification. Gram Bangla Tubes Ltd (GBTL) makes all three.
At a glance
| Point | Spiral (SSAW) pipe | LSAW pipe | GI pipe |
|---|---|---|---|
| Line type | Transmission mains, trunk lines | Transmission mains where a straight seam is specified | Supply and service lines |
| GBTL outside diameter | 273 to 3,600 mm | 300 to 2,500 mm | 12 to 300 mm |
| GBTL wall thickness | 3.0 to 25.0 mm | 3.0 to 17.0 mm | 1.0 to 8.0 mm |
| Seam | Helical, submerged arc welded | One straight seam, submerged arc welded | ERW, then hot dip galvanized |
| Joints | Welded on site, or as specified | Welded on site, or as specified | TODOplain or threaded ends, fittings supplied |
| Corrosion protection | TODOcoating and lining options | TODOcoating and lining options | Zinc layer inside and outside |
| Pressure class | TODOpressure classes quoted | TODOpressure classes quoted | TODOpressure classes quoted |
| Testing at GBTL | Hydrostatic, weld, dimensional and mechanical checks on every batch | Hydrostatic, weld, dimensional and mechanical checks on every batch | Hydrostatic test on every batch |
| How to buy | Quote per project | Quote per project | District dealers, online shop, or direct from 20 MT |
Match the pipe to the line
A water network has three kinds of line. Transmission mains carry raw or treated water over long distances at large diameter. Distribution mains carry water through a town or district. Service lines take it the last stretch to a building or a standpost. Each has a different pipe.
Spiral (SSAW) pipe for transmission mains
Spiral pipe is efficient at large diameter and long runs, which is exactly what a transmission main is. GBTL makes spiral pipe from 273 to 3,600 mm OD in 3.0 to 25.0 mm wall, and it is the only SSAW spiral pipe manufacturer in Bangladesh. Pipes are welded end to end on site or joined as the project specification directs. Typical wall per diameter for a water main: TODOtypical wall by OD for water transmission.
LSAW pipe where a straight seam is specified
Some water authority and consultant specifications call for a straight seam pipe. LSAW pipe meets that requirement from 300 to 2,500 mm OD in 3.0 to 17.0 mm wall. The choice between the two large diameter routes is covered in the GBTL guide on spiral vs LSAW pipe.
GI pipe for supply and service lines
For smaller lines, from 12 to 300 mm OD, GI hot dip galvanized pipe is the usual steel choice in Bangladesh. Galvanizing after forming gives a zinc layer inside and outside. GBTL GI pipe comes in 1.0 to 8.0 mm wall and is hydrostatically tested every batch. Standard sizes are sold through the GBTL dealer network by district, and projects of 20 MT or more can buy direct from the mill. End finish and joints: TODOconfirm whether GBTL GI pipe is supplied plain end or threaded, and which fittings GBTL supplies.
Pressure, linings and coatings
Working pressure, test pressure, internal lining and external coating are set by the project specification, not by the pipe type alone. Pressure class: TODOpressure classes GBTL quotes for water mains. Internal lining: TODOlining options GBTL offers or arranges, for example cement mortar or epoxy. External coating: TODOexternal coating or wrapping options. State all three in your quote request.
Ordering and delivery
For spiral and LSAW mains, send GBTL Engineering the OD, wall, length per pipe, quantity in MT, pressure and coating requirements and the delivery site. For GI pipe, contact your district dealer or order online at the GBTL shop. Mill test certificates are supplied on request and the plant runs under ISO 9001:2015 and BSTI. Delivery is available across Bangladesh.
Frequently asked questions
What pipe is used for large water mains in Bangladesh?
Among steel options, spiral (SSAW) pipe covers 273 to 3,600 mm OD and is the usual route for transmission mains. LSAW pipe, 300 to 2,500 mm OD, is used where the specification calls for a straight seam. Both are made by GBTL at Sonargaon, Narayanganj.
Is GI pipe suitable for water service lines?
GI pipe is the common material for water service lines in Bangladesh. Hot dip galvanizing after forming gives a zinc layer inside and outside. Check your project specification for any lining or water quality requirement before you order.
GI or GP pipe for water?
GI. GI pipe is galvanized after forming, so the zinc covers the inside and the outside, and walls run 1.0 to 8.0 mm. GP pipe is made from pre-galvanized strip with lighter walls, 0.6 to 2.3 mm, and is sold for construction work. Its cut ends and weld seam need protection, and the zinc layer is lighter than on GI, so GI is the choice for water lines.
What is the maximum diameter of water pipe GBTL makes?
3,600 mm OD, as spiral (SSAW) pipe. LSAW pipe goes up to 2,500 mm OD and GI pipe up to 300 mm OD.
How do I get a price for water main pipe?
For spiral and LSAW pipe, send the OD, wall, length, quantity in MT, pressure and coating requirements and the delivery site to info@grambanglatube.com or call +88 01907 084 261. GI pipe prices are on the GBTL GI pipe price page and in the online shop.