Description
BS EN 10255 Pipe
BS EN 10255 is a European standard that sets the technical requirements for non-alloy steel tubes designed for welding and threading. These tubes are primarily used in water, gas, air, and steam systems, making them an essential component in various industrial and mechanical applications. Formerly known as BS 1387, this standard has evolved to align with European norms and includes critical parameters such as dimensions, tolerances, mechanical properties, and surface finishes.
BS EN 10255 tubes are manufactured from carbon steel and are widely recognized for their durability, corrosion resistance (when coated), and mechanical strength. These tubes are produced in both medium and heavy wall thicknesses, and they are available with or without threading and ends prepared for welding.
Scope of BS EN 10255
The BS EN 10255 standard applies to:
- Welded and seamless circular tubes
- Steel tubes with specified external diameter and wall thickness
- Tubes suitable for welding, bending, flanging, and threading
The tubes covered by this standard are not intended for high-temperature or high-pressure critical applications, but are ideal for low to medium pressure fluid systems.
Key Features
- Material: Non-alloy carbon steel
- Manufacturing Process: Seamless or welded
- Coatings: Black (self-colored), hot-dip galvanized, or varnished
- Threading Options: Threaded or plain ends
- Pressure Ratings: Suitable for low to medium pressure systems
- Compliance: Complies with European Pressure Equipment Directive (PED)
Types of Tubes under BS EN 10255
BS EN 10255 tubes are categorized based on wall thickness and coating type. The main types include:
1. Light Series (L)
- Thinner wall thickness
- Used in applications where weight is a concern
- Not ideal for high mechanical loads
2. Medium Series (M)
- Most commonly used
- Suitable for general plumbing, air, and gas pipelines
3. Heavy Series (H)
- Thicker walls for higher mechanical strength
- Used in more demanding applications such as compressed air systems and industrial steam lines
Coating Types:
- Black (Self-Coloured) – Untreated steel for welding and further fabrication.
- Galvanized – Coated with zinc to prevent corrosion; commonly used in outdoor or moisture-prone areas.
- Varnished – Coated with a protective layer of varnish to resist rust during transport and storage.
BS EN 10255 Specification
Mechanical Properties
| Property | Requirement |
|---|---|
| Tensile Strength | 320 – 520 MPa |
| Yield Strength | ≥ 195 MPa |
| Elongation (L0 = 5.65√So) | ≥ 20% |
| Impact Energy (Optional) | ≥ 27 J at 0°C (if required) |
Chemical Composition
| Element | Max Content (%) |
|---|---|
| Carbon (C) | 0.20% |
| Manganese (Mn) | 1.20% |
| Phosphorus (P) | 0.045% |
| Sulfur (S) | 0.045% |
BS EN 10255 Dimensions
|
Nominal Bore |
Outside Diameter | Thickness | Weight | ||||||
| Light |
Medium/
Heavy
|
Light | Medium | Heavy | Light | Medium | Heavy | ||
| in | mm | mm
|
mm
|
mm
|
mm
|
mm
|
kg/m
|
kg/m
|
kg/m |
| 1/4 | 8 | 13.6 | 13.9 | 1.80 | 2.3 | 2.9 | 0.515 | 0.641 | 0.765 |
| 3/8 | 10 | 17.1 | 17.4 | 1.80 | 2.3 | 2.9 | 0.670 | 0.839 | 1.020 |
| 1/2 | 15 | 21.4 | 21.7 | 2.00 | 2.6 | 3.2 | 0.947 | 1.210 | 1.440 |
| 3/4 | 20 | 26.9 | 27.2 | 2.30 | 2.6 | 3.2 | 1.380 | 1.560 | 1.870 |
| 1 | 25 | 33.8 | 34.2 | 2.60 | 3.2 | 4.0 | 1.980 | 2.410 | 2.940 |
| 1 1/4 | 32 | 42.5 | 42.9 | 2.60 | 3.2 | 4.0 | 2.540 | 3.100 | 3.800 |
| 1 1/2 | 40 | 48.4 | 48.8 | 2.90 | 3.2 | 4.0 | 3.230 | 3.570 | 4.380 |
| 2 | 50 | 60.2 | 60.8 | 2.90 | 3.6 | 4.5 | 4.080 | 5.030 | 6.190 |
| 2 1/2 | 65 | 76.0 | 76.6 | 3.20 | 3.6 | 4.5 | 5.710 | 6.430 | 7.930 |
| 3 | 80 | 88.7 | 89.5 | 3.20 | 4.0 | 5.0 | 6.720 | 8.370 | 10.300 |
| 4 | 100 | 113.9 | 114.9 | 3.60 | 4.5 | 5.4 | 9.750 | 12.200 | 14.500 |
| 5 | 125 | – | 140.6 | – | 5.0 | 5.4 | – | 16.600 | 17.900 |
| 6 | 150 | – | 165.1 | – | 5.0 | 5.4 | – | 19.700 |
21.300 |
End Finishes
BS EN 10255 tubes can be supplied with various end finishes:
- Plain Ends (PE) – Suitable for welding or flanging
- Screwed Ends (Threaded) – BSP (British Standard Pipe) threading as per ISO 7-1
- Screwed and Socketed (S&S) – One end threaded with a coupling for easy jointing
Dimensions and Tolerances
BS EN 10255 specifies dimensions based on outside diameter (OD) and nominal wall thickness. The common OD ranges from 17.2 mm to 323.9 mm, while wall thickness varies according to the series (L, M, H).
Dimensional Tolerances:
- Outside Diameter: ±1%
- Wall Thickness: ±10%
- Straightness: 0.002 x length
- Length Tolerance: ±50 mm for random lengths; exact tolerance for specified cut lengths
Standard delivery lengths range from 6 meters, but tubes can be supplied in custom cut lengths upon request.
Applications
Due to their versatility and strength, BS EN 10255 tubes are widely used in:
- Plumbing systems (hot and cold water)
- HVAC systems (heating, ventilation, and air conditioning)
- Compressed air lines
- Firefighting systems (sprinklers)
- Gas distribution networks
- Industrial steam and water systems
- Irrigation and agricultural piping
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