GI Pipe Guide: Galvanised Iron Pipe Light, Medium and Heavy Classes, Sizes in Inches, Threaded Fittings, Uses for Water and Gas, Corrosion, Indicative Rates Per Metre and Plastic Alternatives in Pakistan
GI pipe is galvanised iron pipe, a steel pipe coated with zinc, and it was the standard for water and gas lines before plastic pipes. It is still used for gas, fire lines and outdoor work. Prices run from about PKR 350 to PKR 1,800 per metre depending on size and class. This page covers light, medium and heavy classes, sizes in inches, threaded fittings, uses for water and gas, corrosion, indicative rates and plastic alternatives. For related pages see gas pipes, PPRC pipes and PPR pipe fittings.
Classes
- Light. Thin wall, for low-pressure and conduit use.
- Medium. The common class for water and gas.
- Heavy. Thick wall, for high pressure and fire lines.
Indicative rates per metre
These ranges show common retail figures for medium class pipe.
| Size | Indicative range |
|---|---|
| 1/2 inch | PKR 350 - 700 |
| 3/4 inch | PKR 500 - 950 |
| 1 inch | PKR 700 - 1,300 |
| 1.5 inch | PKR 1,000 - 1,900 |
| 2 inch | PKR 1,400 - 2,600 |
| Threaded fittings, each | PKR 50 - 600 |
Prices move with brand, model, size and stock. Use these ranges to judge a quote, then compare the exact model and what is included.
Sizes
It is sold by nominal bore in inches, such as half, three-quarter, one, one and a half and two inches. The actual outside diameter is larger than the name. Match fittings to the nominal size.
Threaded joints
Pipes are cut and threaded, joined with threaded fittings, thread tape or hemp and paste. Threading is skilled work, and poorly cut threads leak. Use unions so lines can be dismantled.
Uses
This pipe suits gas lines, fire fighting lines, outdoor and exposed runs and some water mains. It is strong and fire resistant. For internal hot and cold water, plastic pipes are cheaper and do not rust. See gas pipes.
Corrosion
The zinc coating wears, especially in aggressive water and where threads are cut, so these pipes rust and scale from the inside over 10 to 20 years, reducing flow and causing brown water. Replace badly corroded pipe.
Plastic alternatives
PPR and CPVC pipes do not rust and weld or cement easily. Many homes replace the old steel with PPR. For gas, only approved materials may be used, so check regulations. Plumbing and gas work should be done by licensed tradespeople and pressure tested before it is covered.
What to check before buying
- Class. Medium or heavy
- Coating. Even galvanising
- Threads. Clean, tested
- Use. Suits water or gas
Before you decide
Look for a printed mark showing class and maker, and avoid pipe with thin walls or flaking coating. Choose the class for the job, thread carefully and test for leaks. It remains strong and fire-resistant, but plastic suits most internal water work. Keep an off-cut of any existing pipe to match when you extend a line, and check for rust inside before connecting new pipe to old.
Frequently Asked Questions
Steel pipe coated with zinc to resist rust. Ask for the specification in writing so you can compare quotes on the same basis. Check the warranty terms and who honours them before you pay. Measure carefully and confirm sizes with the seller before ordering.
As indicative ranges, half inch medium pipe is about PKR 350 to 700 per metre and one inch about PKR 700 to 1,300. Check the warranty terms and who honours them before you pay. Measure carefully and confirm sizes with the seller before ordering.
It works but rusts over time, so plastic pipes are common now. Measure carefully and confirm sizes with the seller before ordering. Rates and stock change, so confirm the current position before you commit. If you are unsure, send a photo and the measurements and we will advise.
With threaded fittings. Rates and stock change, so confirm the current position before you commit. If you are unsure, send a photo and the measurements and we will advise. Ask for the specification in writing so you can compare quotes on the same basis.
Medium for most water and gas lines and heavy for high pressure. If you are unsure, send a photo and the measurements and we will advise. Ask for the specification in writing so you can compare quotes on the same basis. Check the warranty terms and who honours them before you pay.
Usually the same working day once you send the quantity, the size or rating and a photo. The reply is a written rate with the model, warranty and delivery listed, so you can compare it against other quotes line by line. Rates and stock change, so confirm the current position before you commit.
Choosing GI pipe?
Send the details and a photo. We reply with a written rate.