BS 1387


BS 1387 Steel Pipe

BS 1387, also known as EN 10255, is a British standard for welded black pipes designed for screwing to BS21 pipe threads. These pipes are hot galvanized, making them suitable for threading and widely used for gas, air, and water transmission, as well as for civil and other structural purposes. At UNIACERO, we offer BS 1387 ERW (Electric Resistance Welded) galvanized steel pipes ranging from nominal sizes DN8-DN150, available in light, medium, and heavy thicknesses. Our commitment ensures that you receive products of the highest quality, tailored to your specific needs.

BS 1387 Specification

Our BS 1387 steel pipes come in various specifications. They are Carbon Welded Steel Pipes with outer diameters ranging from DN8mm-DN150mm. The pipes adhere to the BS1387 standard and come in three thickness categories: Light, Medium, and Heavy. The production procedures involve state-of-the-art techniques ensuring durability and reliability. The pipes undergo various finishes such as Bare, Oiled, Mill Varnish, Galvanized, and more. The end finishes include Beveled, Square Cut, Threaded, and Coupled, ensuring versatility for different applications. Additionally, we offer joint methods and machining services tailored to your requirements.

Steel GradeCarbon Steel
ManufactureTube:  Welded
Socket:   Seamless or Welded
Chemical CompositionCMnPS
Mechanical Properties
at room temperature
Tensile Strengtn
Yield Strength
Elongation on
gauge length
320-460 N/mm2195 N/mm220%
DimensionLight tube1/4”-4” DN8-DN100
Medium tube1/4”-6” DN8-DN150
Heavy tube1/4”-6” DN8-DN150
ThicknessLight tube1.8mm-3.6mm
Medium tube2.3mm-5.0mm
Heavy tube2.9mm-5.4mm
Pipe LengthRandom Length4m-7m
Mill Length≥6.4m
Approximate Length
Exact Length
ToleranceOn ThicknessLight tube:  -8%
Medium tube: -10%
Heavy tube: -10%
On MassFor quanlity of 150 M and over
one size
For single tube: +10%/-8%
Pipe EndPE,BE,Thread & Coupled
Corrosion PreventionBare,Oiled,Mill Varnish,Hot-dip Galvanized,FBE,3LPE

BS 1387 Dimension Table


The dimensions of our BS 1387 steel pipes adhere strictly to the BS EN 10255:2004 standard. They are supplied in self-color, black varnished, or galvanized finish. The pipes range in nominal bore size from 8mm to 150mm, with specific outside diameters and thicknesses corresponding to each size. The exact dimensions ensure that our clients receive products that fit seamlessly into their projects without the need for adjustments.

Dimensions of Steel Tubes: Light
Nominal sizeDesignation of ThreadOutside DiameterThicknessMass of Black Tube
(DN)max.min.Plain EndScrewed and Socketed
8 1/413.613.21.80.5150.519
10 3/817.
321 1/442.541.92.62.542.57
401 1/248.447.
652 1/27675.23.25.715.83
NOTE Dimensions and masses are in accordance with ISO 65 (light series 2).
Dimensions of Steel Tubes: Medium
Nominal Size of ThreadDesignation of ThreadOutside DiameterThicknessMass of Black Tube
(DN)max.min.Plain EndScrewed and Socketed
8 1/413.913.32.30.6410.645
10 3/817.416.82.30.8390.845
321 1/442.942.
401 1/248.8483.23.573.61
652 1/276.675.43.66.436.55
NOTE  Maximum and minimum outside diameters meet the requirements of ISO 65.
Dimensions of steel tubes: heavy
Nominal sizeDesignation of ThreadOutside DiameterThicknessMass of Black Tube
(DN)max.min.Plain EndScrewed and Socketed
8 1/413.913.32.90.7650.769
10 3/817.416.
15 1/221.721.13.21.441.45
20 3/427.
321 1/442.942.143.83.83
401 1/248.84844.384.42
652 1/276.675.44.57.938.05
NOTE  Maximum and minimum outside diameters meet the requirements of ISO 65.

Chemical Requirements of BS 1387

The chemical composition of our BS 1387 pipes is meticulously maintained to ensure durability and resistance. The pipes have a Carbon (C) content of 0.2%, Manganese (Mn) of 1.2%, Phosphorus (P) of 0.045%, and Sulfur (S) of 0.045%. This composition ensures that the pipes are robust and can withstand various environmental conditions.

Chemical Composition (Ladle)

Mechanical Requirements of BS 1387

Our BS 1387 pipes exhibit excellent mechanical properties. They have a tensile strength ranging from 320 to 460 N/mm2, a yield strength of 195 N/mm2, and an elongation percentage of 20%. These properties ensure that the pipes are resilient and can handle significant stress and pressure.

Mechanical Properties At Room Temperature
TensileYieldElongation On Gauge Length
Strength, RmStrength Re(min.)Lo=5.65 √So A (min.)
320 to 46019520

Steel Grades in BS 1387

The steel grades used in our BS 1387 pipes are of the highest quality, ensuring that the pipes are durable and can withstand various conditions. The specific grade is chosen based on the application and the requirements of the project. Our team is always available to guide you in selecting the most appropriate steel grade for your needs.

Production Tolerance of BS 1387

At UNIACERO, we maintain strict production tolerances to ensure that our clients receive products of the highest quality. For light tubes, the thickness tolerance is + Not Limited, – 8%. For medium and heavy tubes, it’s + Not Limited, -10%. On mass, for quantities of 150 Mtr. and over of one size, the tolerance is +/- 4%, and for a single tube, it’s +10% / -8%.

Production Tolerance of BS 1387

– Mass. The mean consignment mass forquantities of 150 m and over of one size shall notdeviate by more than + 4 % from the mass oftheconsignment calculated from the masses given inTable 3, Table and Table 5 as appropriate. Nosingle tube shall deviate by more than ?!0 %from the mass given in Table 3, Table d andTable 5 as appropnate.

– Thickness.
Light tubes -8%
Medium and heavy tubes -10 %

-Outside diameter

Light tubes: as given in Table 3

Medium and heavy tubes: as given in Table 4 andTable 5 respectively

– Length (see note).1) Random lengths. When random lengths areordered, tubes shall be supplied in one of thefollowing ways:

– in random lengths from 4 m to 7 m;b) (for orders of over 150 m of any one size oftube) in random lengths from 4 m to 7 m butincluding short random lengths from l.8 mto 4 m provided that the number of suchlengths does not exceed 7.5 % of the totalnumber oflengths for DN 65 to DN 100inclusive, and 5 % for all other sizes.c) as for (b) but including tubes with twolengths joined together to make a randomlength, provided that the number of suchjointed lengths does not exceed 7.5 % of thetotal number oflengths for DN 65 to DN 100inclusive and 5 % for all other sizes.

-Mill lengths. When mill lengths are requiredtubes shall be supplied in lengths of 6.4 mminimum. No tube shall exceed this length bymore than 150 mm.

– Approximate lengths. Where approximatelengths are required, either for screwed andsocketed tubes orfor plain end tubes, each tubeshall be within + 150 mm of the specifiedlength.

– Exact lengths. Where exact lengths arerequired either for screwed and socketedtubes or for plain end tubes, each tube shall bewithin +6mm of the specified length.

Our Advantages

  1. Over 25 years of experience in pipeline production and installation.
  2. Comprehensive inspection equipment.
  3. Independent product serial numbers for traceability.
  4. Advanced production equipment – Seamer high-frequency welding machine from the United States.
  5. Complete qualifications – API 5L/API 5CT/FM/UL fire pipe certification, etc.
  6. Wide range of products – independently developed solar torque tubes, highly favored in the European market.
  7. Customers spread across the globe.
  8. Excellent after-sales service and sense of responsibility.

Application Scenarios

Our steel pipes are engineered to withstand high temperatures, corrosive environments, and varying pressures, ensuring reliability and safety in the complex petrochemical processes. 

Whether it’s transferring crude oil, natural gas, or chemical intermediates, the robustness and versatility of steel pipes make them indispensable components of the plant’s infrastructure, contributing to efficient production and maintenance of stringent safety standards.

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