BS 1387 Threaded Pipe Specifications
BS 1387 threaded steel pipe is a traditional product designation for welded non-alloy steel tubes supplied with threaded and socketed ends or plain ends suitable for welding and threading. BS 1387:1985 was withdrawn in 2006 and replaced by BS EN 10255, but the BS 1387 designation remains widely used in product searches and legacy project specifications.
For new procurement, BS EN 10255:2004+A1:2007 provides the relevant technical reference for circular non-alloy steel tubes suitable for welding and threading. It covers specified outside diameters from 10.2 mm to 165.1 mm, with thread sizes from 1/8 to 6.
| Parameter | Product Information |
| Product Type | Welded Non-Alloy Steel Pipe |
| Traditional Designation | BS 1387 Threaded Steel Pipe |
| Historical Standard | BS 1387:1985 (Withdrawn) |
| Successor Standard Reference | BS EN 10255:2004+A1:2007 |
| EN 10255 Outside Diameter Range | 10.2–165.1 mm |
| EN 10255 Thread Size Range | 1/8–6 |
| EN 10255 Pipe Series | Medium / Heavy |
| Pipe End | Plain End / Threaded End |
| Connection | Threaded / Threaded and Socketed |
| Surface Finish | Black / Hot-Dip Galvanized |
| Manufacturing Process | ERW |
Specification Note: BS 1387 historical dimensions and EN 10255 dimensions should be checked against their respective standard editions. The Light, Medium and Heavy classifications shown in historical BS 1387 references should not be used as a direct substitute for the EN 10255 classification. Buyers should specify the applicable standard, pipe series, outside diameter, wall thickness, thread requirements and end finish when requesting a quotation.
For additional technical details, including the chemical composition and mechanical properties of BS 1387 steel pipes, refer to our BS 1387 steel pipe specifications page.
BS 1387 Threaded Pipe Dimensions and Weight Chart
BS 1387:1985 steel pipes are classified into three wall thickness series: Light, Medium and Heavy. Each series covers different nominal bore sizes, outside diameters and wall thicknesses to meet varying piping requirements.
The following tables provide reference dimensions for BS 1387 steel pipes, including nominal bore (DN), thread size, outside diameter and wall thickness.
BS 1387 Light Series Dimensions
Dimensions in mm | Unit weight in kg/m
| DN | Thread Size | OD (mm) | WT (mm) |
| 8 | 1/4″ | 13.2–13.6 | 1.8 |
| 10 | 3/8″ | 16.7–17.1 | 1.8 |
| 15 | 1/2″ | 21.0–21.4 | 2.0 |
| 20 | 3/4″ | 26.4–26.9 | 2.3 |
| 25 | 1″ | 33.2–33.8 | 2.6 |
| 32 | 1 1/4″ | 41.9–42.5 | 2.6 |
| 40 | 1 1/2″ | 47.8–48.4 | 2.9 |
| 50 | 2″ | 59.6–60.2 | 2.9 |
| 65 | 2 1/2″ | 75.2–76.0 | 3.2 |
| 80 | 3″ | 87.9–88.7 | 3.2 |
| 100 | 4″ | 113.0–113.9 | 3.6 |
BS 1387 Medium Series Dimensions
| DN | Thread Size | OD (mm) | WT (mm) |
| 8 | 1/4″ | 13.3–13.9 | 2.3 |
| 10 | 3/8″ | 16.8–17.4 | 2.3 |
| 15 | 1/2″ | 21.1–21.7 | 2.6 |
| 20 | 3/4″ | 26.6–27.2 | 2.6 |
| 25 | 1″ | 33.4–34.2 | 3.2 |
| 32 | 1 1/4″ | 42.1–42.9 | 3.2 |
| 40 | 1 1/2″ | 48.0–48.8 | 3.2 |
| 50 | 2″ | 59.8–60.8 | 3.6 |
| 65 | 2 1/2″ | 75.4–76.6 | 3.6 |
| 80 | 3″ | 88.1–89.5 | 4.0 |
| 100 | 4″ | 113.3–114.9 | 4.5 |
| 125 | 5″ | 138.7–140.6 | 5.0 |
| 150 | 6″ | 164.1–166.1 | 5.0 |
BS 1387 Medium Series Dimensions
| DN | Thread Size | OD (mm) | WT (mm) |
| 8 | 1/4″ | 13.3–13.9 | 2.9 |
| 10 | 3/8″ | 16.8–17.4 | 2.9 |
| 15 | 1/2″ | 21.1–21.7 | 3.2 |
| 20 | 3/4″ | 26.6–27.2 | 3.2 |
| 25 | 1″ | 33.4–34.2 | 4.0 |
| 32 | 1 1/4″ | 42.1–42.9 | 4.0 |
| 40 | 1 1/2″ | 48.0–48.8 | 4.0 |
| 50 | 2″ | 59.8–60.8 | 4.5 |
| 65 | 2 1/2″ | 75.4–76.6 | 4.5 |
| 80 | 3″ | 88.1–89.5 | 5.0 |
| 100 | 4″ | 113.3–114.9 | 5.4 |
| 125 | 5″ | 138.7–140.6 | 5.4 |
| 150 | 6″ | 164.1–166.1 | 5.4 |
Pipe Weight and Thread Specifications
In addition to outside diameter and wall thickness, pipe weight and thread dimensions are important for procurement and installation. Actual unit weight varies according to wall thickness and whether the pipe is supplied plain-ended or threaded and socketed.
Buyers should confirm the nominal bore, thread designation, pipe series, end configuration and socket requirements when placing orders.
Note: The above tables are intended as historical BS 1387:1985 reference data. BS 1387:1985 has been withdrawn and superseded by BS EN 10255. Confirm the applicable standard edition and dimensional requirements before ordering.
Threaded and Socketed Steel Pipe Options
BS 1387 threaded pipes can be supplied with external BSP threads for connection with compatible fittings and valves. Thread size, pitch and profile should comply with the applicable BS 21 requirements and be confirmed before production.
Threaded and Socketed Connections
Threaded and socketed pipes use matching female-threaded sockets to connect individual pipe sections. Sockets can be supplied separately or as complete pipe fittings, with thread compatibility confirmed according to project requirements.
Plain-End Steel Pipes
Plain-end pipes are supplied without machined threads and are suitable for welding or further end processing. They can also be threaded according to project specifications, provided the pipe dimensions and wall thickness are suitable for machining.
For a detailed explanation of BSPT thread dimensions, taper specifications and thread compatibility, see our guide to BSPT threaded pipe specifications.
Black and Galvanized BS 1387 Steel Pipes
BS 1387 steel pipes are commonly supplied in black and hot-dip galvanized finishes to meet different corrosion protection and installation requirements.
Black steel pipes feature an untreated or mill-finished surface without a zinc coating. They are suitable for general water and low-pressure fluid transmission, as well as applications where additional surface protection can be specified.
Hot-dip galvanized pipes are coated with zinc to improve corrosion resistance and extend service life. The coating can cover both internal and external surfaces, depending on the galvanizing process and product requirements.
Threading and galvanizing sequences should be confirmed before production. Threaded ends require appropriate coating protection, while any post-galvanizing thread processing should include suitable corrosion protection to maintain coating continuity.
BS 1387 vs EN 10255 Steel Pipe
BS 1387 and EN 10255 are closely related product specifications, but their classifications and procurement references should not be treated as identical.
| Comparison | BS 1387:1985 | BS EN 10255:2004+A1:2007 |
| Standard Status | Withdrawn in 2006 | Successor standard reference |
| Product Type | Welded steel tubes and tubulars | Circular non-alloy steel tubes |
| Main Applications | Welding and threaded connections | Welding and threaded connections |
| Wall Thickness Classification | Light / Medium / Heavy | Medium / Heavy series with three designated thickness types |
| Outside Diameter Range | Refer to historical BS 1387 dimensions | 10.2–165.1 mm |
| Thread Size Range | Refer to applicable BS 21 requirements | 1/8–6 |
| End Configuration | Screwed, socketed and plain end | Options for welding and threading |
| Procurement Reference | Legacy project specifications | Applicable EN 10255 edition or national adoption |
BS 1387:1985 was withdrawn on 1 June 2006. BS EN 10255 was introduced as its successor and specifies technical delivery conditions for circular non-alloy steel tubes suitable for welding and threading.
Although buyers may still use the term “BS 1387 threaded pipe” when searching for products or referring to older project documents, new orders should identify the applicable EN 10255 edition or its relevant national adoption. The required pipe series, designated thickness type, dimensions, thread specifications, end configuration and coating requirements should also be stated clearly.
Applications of BS 1387 Threaded Steel Pipes
BS 1387 threaded steel pipes are commonly used in building services, water distribution and industrial utility systems. Their threaded ends and socket connections allow convenient installation, maintenance and replacement. Depending on pipe dimensions, wall thickness, surface coating and operating conditions, typical applications include:
- Water Supply and Distribution:Used in building water supply networks where galvanized steel pipes provide additional corrosion protection.
- Fire Protection Systems: Used in selected sprinkler branches and fire protection piping where pipe specifications meet applicable fire safety requirements.
- Building Plumbing and HVAC Systems:Applied in water circulation, heating and auxiliary mechanical piping, with threaded connections simplifying installation.
- Industrial Utility Piping:Used for conveying water, compressed air and other compatible low-pressure fluids in industrial facilities.
Application and Pipe Selection
| Application | Recommended Pipe Type | Key Selection Criteria |
| Water Supply | Galvanized Steel Pipe | Corrosion resistance and water quality requirements |
| Fire Protection | Galvanized / Black Steel Pipe | Fire protection standards and pressure rating |
| Building Plumbing | Galvanized Steel Pipe | Thread compatibility and installation requirements |
| HVAC Systems | Black / Galvanized Steel Pipe | Operating temperature and pressure |
| Industrial Utilities | Black / Galvanized Steel Pipe | Fluid compatibility and operating conditions |
Standards Reference: BS 1387:1985 is a withdrawn standard. For new projects, buyers should confirm the applicable BS EN 10255 edition or relevant national adoption. Historical BS 1387 dimensions in this article are provided for reference only and should not be used as a substitute for EN 10255 dimensional requirements.
