GI flanges make bolted joints on galvanized pipe, so pumps, valves and pipe sections can be removed. They suit larger pipes where unions are impractical.
Threaded GI flanges screw onto the pipe. As a result, no welding is needed and the zinc coating stays intact.
What are GI flanges?
A galvanized flange is a zinc-coated steel ring with bolt holes that joins pipes, valves and pumps by bolting two flanges together. A gasket between the faces makes the seal.
Flanged joints suit larger pipes and equipment that must come apart for service. GI flanges are often threaded, so they screw onto a GI pipe instead of being welded.
Further reading
- Pipe flanges: types and uses (Wikipedia)
- How hot-dip galvanization protects steel (Wikipedia)
- What gaskets do and how they seal (Wikipedia)
Key terms explained
- Galvanized steel
- Steel coated with zinc to slow rust.
- PN rating
- Pressure Nominal, the pressure class of a flange in bar, such as PN10 or PN16.
- Pitch circle diameter (PCD)
- The diameter of the circle through the bolt hole centres. Mating flanges must share it.
- Gasket
- A soft ring between two flange faces that seals the joint.
Features and benefits
- Zinc coating that slows rust.
- Bolted joint that opens for maintenance.
- Threaded bore for GI pipe on screwed types.
- Matches standard flanged valves and pumps when the drilling agrees.
- Suits larger pipe sizes than unions.
Technical specifications
| Product | GI flanges |
|---|---|
| Material | Galvanized steel |
| Bore | Threaded or slip-on, confirm with quote |
| Rating | Confirm PN class with quote |
| Sizes | State your pipe size when you request a quote |
| Supplier | Sparks Plumbing Experts Ltd, Nairobi |
Drilling, rating and thickness vary by standard. Send the size and rating, or measurements of the mating flange.
Applications of GI flanges
- Pump connections. Joins pumps to suction and delivery pipework.
- Flanged valves. Connects gate, butterfly and check valves to GI pipe.
- Water mains. Joins large GI mains in sections that can be removed.
- Tank outlets. Connects pipework to flanged tank nozzles.
- Fire mains. Joins fire water pipework and valves.
- Meters and strainers. Connects flanged meters and strainers.
- Irrigation headers. Joins large irrigation mains to valves and filters.
- Industrial water lines. Joins process water pipework in plants.
How to choose and install
- Match the pipe size and the bore type: threaded or slip-on.
- Match the pressure rating and drilling to the mating flange.
- Use a gasket that suits the fluid and temperature.
- Tighten bolts evenly in a cross pattern.
Why choose Sparks Plumbing Experts
- Valves, flanges and gaskets togetherComplete a pipeline joint with matching valves, flanges, gaskets and bolts.
- Pressure-rated optionsMany items come in PN16, class 150 or class 300 ratings, so you can match the line.
- Stainless and carbon steelChoose stainless for corrosion resistance or carbon steel where it suits the service.
- Plant maintenance sparesKeep critical spares on hand for planned shutdowns and breakdowns.
- Visit or collect in NairobiOur store is at KCB Building, Enterprise Road, in the Industrial Area, so you can see parts before you buy or collect your order.
- Quotes your wayAsk for prices by phone, WhatsApp, email or the online quote form, whichever suits you on site.
- Over 1,600 products in one placeOur catalogue covers 55 categories, so one supplier can handle most of your parts list.
- Help choosing the right partSend a nameplate photo, a drawing or the old part, and we help you match size and specification.
- Single items or project quantitiesWe price a single replacement part just as readily as a full site order.
- Supply across East AfricaWe serve customers across Kenya, and we also supply buyers in Uganda and Tanzania.
Related products and accessories
Browse more: Flanges · GI Pipes & Fittings · Gaskets · Valves.
Ordering from Sparks Plumbing Experts
We supply customers across Kenya, and we also serve buyers in Uganda and Tanzania. You can collect from our store at KCB Building, Enterprise Road, Nairobi, or ask us about delivery to your site. Send your quantities and specifications, and we will reply with prices and availability.
Request a Quote WhatsApp 0726 086 895
Frequently asked questions
Are GI flanges threaded?
Many are threaded to fit GI pipe. Tell us whether you need threaded or slip-on.
Can I order GI flanges in pairs?
Yes. Most joints need a pair plus a gasket and bolts.
What details do you need to quote galvanized flanges?
Tell us the size, the quantity and what the item will connect to. A photo of the old part or a drawing also helps. Then call or WhatsApp 0726 086 895, or use the quote form on this page.
Do you deliver galvanized flanges outside Nairobi?
Yes. We supply customers across Kenya, and we also serve buyers in Uganda and Tanzania. Delivery or courier arrangements are agreed when you confirm the order.
How much does a galvanized flange cost in Kenya?
The price depends on the size, the quantity and current steel prices. Therefore, send your list with a quote request and we will reply with current figures.
Will a galvanized flange match my pump?
Only if the drilling and rating match. Measure the pump flange or send its data plate details.
Do galvanized flanges need a gasket?
Yes. Fit a gasket between the faces, because metal faces alone will leak.
Can I weld a galvanized flange?
It is possible, but zinc fumes are harmful. Threaded GI flanges avoid welding altogether.
How do I tighten flange bolts?
Tighten them in a cross pattern in two or three stages until the gasket is evenly compressed.
What details identify a flange?
Pipe size, pressure rating, bolt hole count, bolt circle and face type.
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