Choosing Steel Pipework: Galvanised, ERW and BS1387 Tube, Plus Fittings and Flanges

Choosing the right steel pipework for a project shapes everything that follows from how quickly installation goes to how long the system lasts. The wrong product in the wrong application leads to premature corrosion, failed joints, or materials that fall short of the required standard.

At South West Steel Supplies, based in Portishead, Bristol, we stock an extensive range of tube, fittings, and associated products. This guide covers the three main tube types you are most likely to need what each one is, and where each one belongs.

Why the Right Steel Tube Type Matters

Steel pipework is used across a wide variety of applications: water distribution, gas and steam systems, compressed air, heating, HVAC, fire protection, and structural support. Each environment places different demands on the material different pressures, temperatures, and levels of moisture exposure.

Steel handles immense internal and external pressures, performs well across extreme temperature ranges, and offers good durability under mechanical loads. It is also 100% recyclable without any loss of quality, which makes it a sound choice for commercial and industrial projects over the long term.

The question is rarely whether to use steel it is which type. Below we break down the three products most commonly specified.

Not sure which option suits your project? Contact our team and we will point you in the right direction.

Galvanised Tube

What is Galvanised Steel Pipe?

Our galvanised tube is a mild steel product, and mild steel is available in five different grades. The zinc layer acts as a barrier against moisture and corrosive elements to help prevent rust, and galvanised steel pipe is corrosion-resistant and low maintenance. It meets EN 10255 and EN 10219 standards, requires no painting, and is available in lengths of 1.5m, 3m, and 6m.

Galvanised Tube: Common Applications

Galvanised tube is a practical choice across a wide range of applications. While copper pipework is ideal for hot and cold water distribution, galvanised tube is commonly used for heating pipework in commercial and industrial buildings, where its corrosion resistance provides longer-term reliability. It is also a popular choice for handrail and barrier systems, particularly when used alongside Fastclamp fittings. Where a non-potable service is acceptable, galvanised tube is equally well suited to compressed air pipework.

It has historically been common in drinking water systems, though modern specifications often call for alternative materials in potable supply. Always check your project requirements when specifying for water.

ERW Tube

What is ERW Tube?

ERW stands for Electric Resistance Welded. Our ERW tube is a cold-formed hollow section produced to EN 10219, manufactured by welding the seam of formed strip using high-frequency electrical resistance. It is used primarily for structural and fabrication work rather than pressurised fluid conveyance.

ERW Tube: Common Stainless Steel Applications

This is a popular choice for builders and fabricators across the South West because of its mechanical strength, accurate dimensions, and straightforward weldability. Typical applications include structural frames and support steelwork, machinery guards and enclosures, and engineering projects requiring precision hollow section. It is also widely used for gates, barriers, and general mild steel fabrication. Because ERW tube is mild steel, it should be protected or treated where ongoing exposure to moisture is expected. For technical dimensions and specifications, Engineering ToolBox carries a useful EN 10255 reference table covering nominal bore sizes from DN8 to DN150.

BS1387 Metal Pipe

What is BS1387 Tube?

BS1387 tube now formally referenced under EN 10255 is a non-alloy steel tube designed for welding and threading, available in light, medium, and heavy wall thicknesses. Our BS1387 tube stock is the standard product for threaded systems in gas, steam, and process applications, and remains one of the most widely used tube types in the UK. By comparison, stainless steel pipework is available as seamless or welded, with common steel pipe options in size ranges from ½” to 4” and larger diameters from 28mm to 304mm, making it suitable where corrosion resistance is required.

BS1387 Tube: Where It Is Specified

BS1387 tube is commonly specified for natural gas installations, steam and process pipework, compressed air systems using medium or heavy wall grades, and industrial settings, while stainless steel is often chosen for hygiene-critical environments across different industries. It is also used in fire sprinkler systems and general heating and plumbing applications. It is available in both black (self-colour) and galvanised finishes, with plain or pre-threaded ends to suit screwed fittings, while 316L grade stainless steel pipes are used in food processing and stainless steel fittings are used in food and beverage industries.

Which Type Should You Order?

You may be asking: what is the simplest way to decide which tube to specify? The answer comes down to three questions what will it carry, what environment will it sit in, and does it need to be threaded or welded?

Use the table below as a quick reference:

	Galvanised Tube	ERW Tube	BS1387 Tube
Best for	Water, heating, handrails	Structural, fabrication	Gas, steam, process systems
Corrosion resistance	High (zinc coated)	Moderate (paint/treat)	Depends on finish
Standard	EN 10255 / EN 10219	EN 10219	BS1387 / EN 10255
Available lengths	1.5m, 3m, 6m	3m, 6m	3m, 6m

If your application falls outside these categories for example, you need steel pipework for higher-pressure systems or hygiene-critical environments speak to the team directly. We can also source non-stock items at competitive prices with a quick turnaround.

Ready to order? View our full pipework range or call us for a same-day quote.

Fittings and Flanges

Tube alone rarely completes a system. We stock malleable fittings elbows, tees, sockets, and reducers designed for use with BS1387 and EN 10255 threaded tube. These are held in stock alongside flanges for bolted connections, and weld elbows and fittings for welded applications. Order tube and fittings together and receive everything in a single delivery.

If you are working with galvanised tube in a handrail or barrier application, ask about our Fastclamp tube clamp range a bolt-together alternative to welding that works directly with standard tube diameters.

Cutting and Processing Your Order

Standard lengths do not always suit every job. Our in-house cutting service lets you order your steel pipework cut to the exact lengths you need. We also offer threading for the tube where required one supplier, one delivery, finished to your specification.

Orders are dispatched via our own fleet of six delivery vehicles, covering Bristol, Bath, Somerset, Swindon, Gloucester, and the wider South West. Same-day quotes are available.

South West Steel Supplies is a UKCA/CE and BS EN 1090 accredited stockholder based in Portishead, Bristol. We supply trade, commercial, and domestic customers across the South West with steel pipework, tube, fittings, and structural steel from a single length to a full project load.

To order the right steel pipework for your project, visit our homepage or contact us to speak to the team today.