Malleable Iron Pipe Fittings | Galvanised NPT Pipe Fittings

Malleable iron pipe fittings are threaded fittings cast from malleable (annealed) iron — white cast iron that is heat-treated so it becomes ductile enough to absorb shock, vibration, thermal expansion and mechanical stress without cracking. This makes them one of the most dependable and widely used fittings for threaded pipe systems across plumbing, gas, fire-protection and general pipework in Singapore.

We supply the most complete line of SA/TUPY pipe fittings in malleable cast iron, used in the transportation of liquids, gases, and fuse for residential, commercial, and industrial use. Our NPT threaded pipe fittings are supplied in several types of surface finishing and according to domestic and international standards, including 150 LBS and 300 LBS Galvanized Malleable Iron Pipe Fittings.

Key characteristics

• Pressure ratings: available in 150 LBS (standard duty) and 300 LBS (heavy duty) classes for both low- and high-pressure applications.
• Surface finish: supplied in black (self-colour) and galvanised (hot-dip zinc) finishes. Galvanised fittings add corrosion resistance for water, humid and outdoor lines.
• Thread standard: cut to NPT (National Pipe Taper) threads; BSP thread forms are also common in the malleable-iron family for regional pipework.
• Strength: high tensile strength with good shock and corrosion resistance, and easy to machine and install on site.

Galvanised NPT pipe fittings are malleable iron fittings that combine two properties in one part: a hot-dip galvanised zinc coating for corrosion protection, and an NPT (National Pipe Taper) thread for a tight, tapered, self-sealing mechanical joint. They are the standard choice where a threaded line must resist rust, moisture and weather over a long service life.

Why galvanised?

Galvanisation coats the fitting in a layer of zinc that shields the underlying iron from oxidation. This is what allows the same fitting to be used on water lines, damp environments, external runs and marine-adjacent installations where a plain black fitting would corrode. When galvanised with high-purity zinc, malleable iron fittings are suitable for potable (drinking) water systems.

Why an NPT thread?

NPT is a tapered thread — the diameter narrows along its length, so the flanks wedge tighter as the joint is tightened, forming a seal that (with thread sealant or PTFE tape) holds pressure without a gasket. This makes NPT fittings fast to assemble and reliable under pressure.

NPT vs BSP — what’s the difference?

Both are threaded pipe standards, but they are not interchangeable. NPT (common in the US and much of Asia’s industrial supply) uses a 60° thread angle; BSP uses a 55° angle and is common in UK/European-standard pipework. Mixing the two causes leaks and cross-threading, so it is important to confirm which thread form your existing line uses before ordering. Our SA / TUPY galvanised range is supplied in NPT.

Chuan Hock Hardware stocks the full SA / TUPY malleable iron and galvanised NPT range. Common fitting types include:

• Elbows & bends — 90° and 45° elbows, street elbows, reducing elbows, and M&F / female bends to change direction.
• Tees & crosses — tees, service tees, side-outlet tees, crosses and reducing crosses to branch a line.
• Couplings & unions — couplings, long & short compression couplings, and unions (conical brass seat, iron-to-iron seat, flat seat, reducing) to join runs.
• Reducers & extensions — reducing fittings and extension pieces to change bore or extend a run.
• Terminations & accessories — caps, plugs, nipples, locknuts, wastenuts, round flanges and floor flanges.

Sizes are available across the common range from small bore up to larger diameters. For a specific size, quantity or pressure class, please send us an enquiry and our team will confirm stock and lead time.

Malleable iron and galvanised NPT pipe fittings are used wherever a strong, sealed, threaded connection is needed. Typical applications include:

• Plumbing & water reticulation — cold and hot water lines (galvanised for potable water).
• Gas installation — LPG and natural gas lines in commercial and industrial premises.
• Fire protection — sprinkler and hose-reel systems.
• HVAC, cooling & air conditioning — chilled-water and condenser pipework.
• Compressed air & pneumatics — pressurised air pipework in workshops and plants.
• Oil, lubrication & process lines — transfer of oils and process fluids.
• Marine & M&E contracting — general mechanical and electrical services pipework across Singapore projects.

• SA / TUPY range — a complete, internationally-certified line of malleable iron and galvanised NPT fittings.
• Local Singapore stock — held ready for fast collection or delivery, minimising project lead time.
• Decades in the trade — a long-established hardware and pipe-fitting supplier serving contractors, plumbers and industry.
• Trade & project support — bulk quantities, mixed orders and trade enquiries welcomed.
• Full pipe-fitting one-stop — malleable iron, carbon steel, cast bronze fittings, valves and flanges under one roof.

Need a quote? Add items to your enquiry list or call (+65) 6294 3818.