What are the dimensional requirements for bs2871 copper alloy tube?

BS 2871 is the long-established British Standard for copper and copper alloy tubes. Although it has been formally superseded by EN 1057 and EN 12451 for many applications, the standard is still widely cited in marine, HVAC, refrigeration, and heat-exchanger specifications around the world. Specifiers, inspectors, and procurement teams continue to use the original tables when they verify tube dimensions, tolerances, and mechanical properties on the shop floor. Understanding the BS 2871 copper alloy tube dimensional requirements, outside diameter, wall thickness, and the related tolerance bands is therefore essential before signing off on an order.

This article walks through the dimensional requirements of BS 2871 in plain engineering language, summarises the tables that engineers most often ask for, and explains how a modern manufacturer translates those requirements into today's production practice.

Structure of BS 2871

BS 2871 was published in three parts, each covering a different end use:

• Part 1 (1971) — Copper tubes for water, gas and sanitation, supplied in four conditions from annealed coils to hard drawn straight lengths. This is the part most people mean when they refer to "Table X, Y, W, or Z".
• Part 2 (1972) — Copper and copper alloy tubes for general engineering purposes.
• Part 3 (1972) — Solid drawn copper and copper alloy tubes specifically for heat exchangers, covering outside diameters from 6 mm up to and including 50 mm.

Part 1 in particular remains the de-facto reference for sanitary, heating, and gas copper tube sizing, even though BS EN 1057 has officially taken over. For alloy grades such as CN102, CZ111, and CN107 used in condensers and heat exchangers, the relevant part is Part 3, and most manufacturers now dual-certify to EN 12451 or ASTM B111 alongside BS 2871.

Part 1 Dimensional Tables (Water, Gas, Sanitation)

Part 1 defines four tables that pair a nominal size with a wall thickness and an associated working pressure. The widely quoted figures are:

Table X is the half-hard, light-gauge option typically used for general water services. Table Y is the heavier half-hard or annealed tube for higher-pressure or buried service. Table Z is the hard-drawn, thin-wall tube used where the line will not be bent and where weight matters. Imperial equivalents (such as 1/4", 3/8", 1/2" and so on, in 6 ft to 10 ft lengths) appear in older specifications and remain useful for retrofit projects.

Tolerance on Outside Diameter and Wall Thickness

BS 2871 — and its successor EN 1057 — apply two distinct tolerance families, one to the mean outside diameter and one to the maximum measured diameter at any cross-section. The reference values that inspectors use most are:

• Mean outside diameter tolerance: ±0.04 mm for sizes 6–18 mm, ±0.05 mm for 18–28 mm, ±0.06 mm for 28–54 mm, ±0.07 mm for 54–76.1 mm, and ±0.20 mm for sizes above 108 mm.
• Any-point diameter tolerance: typically ±0.09 mm for small sizes, rising to ±0.40 mm for 159 mm tube.
• Wall thickness tolerance: ±10% for thin-wall tubes below 1 mm, ±13% for tubes 18 mm and above, with a special ±10% allowance for R250 (half hard) 35/42/54 mm tube at 1.2 mm wall.

Concentricity is controlled indirectly through the wall thickness tolerance. The standard also requires that the deviation from circularity falls within the any-point diameter band, so ovality rarely causes a separate rejection at the receiving dock.

Part 3 — Heat Exchanger Tubes

Part 3 of BS 2871 focuses on solid drawn copper and copper alloy tubes for heat exchangers, with an outside diameter range of 6 mm to 50 mm. The standard lists three tables (commonly referenced as Tables 1, 2 and 3) covering different alloy families, and the dimensional requirements follow the same philosophy as Part 1 but with tighter mechanical-property controls because heat-exchanger duty usually involves higher temperature and pressure cycling.

In practice, today's condenser and heat-exchanger tube orders are usually dual-certified to BS 2871 Part 3 and EN 12451, with the alloy chosen from CN102 (90/10 Cu-Ni), CN107 (70/30 Cu-Ni), CZ111 (admiralty brass), or C106 (phosphor bronze) depending on the fluid. Outside diameter steps of 6, 8, 9.5, 10, 12, 12.7, 15, 16, 19, 19.05, 20, 22, 25, 25.4, 28, 30, 32, 35, 38, 38.1, 42, 44.5, and 50 mm are typical, with wall thicknesses commonly produced from 0.5 mm up to 2.5 mm. Lengths are usually supplied between 1 m and 12 m to suit tube-sheet layouts.

Mechanical Properties Linked to the Tables

Dimensional specification is only half the story. BS 2871 and EN 1057 both require the tube to meet a temper designation that determines tensile strength, elongation, and hardness. The two tempers most commonly referenced are:

• R250 (half hard) — minimum tensile strength 250 MPa, minimum elongation 30%, typical hardness 75–100 HV5. Used for general plumbing, heating, and Table X/Y tubes up to 54 mm.
• R290 (hard) — minimum tensile strength 290 MPa, minimum elongation 3%, minimum hardness 100 HV5. Used for Table X tubes from 66.7 mm upward and for Table Y in the larger sizes where bending is not required.

A third temper, R220 (annealed), applies to soft coils in Table W and Table Y coils. Its lower tensile strength makes the tube easy to bend by hand or with a simple spring, but the same soft condition limits its use to lower pressure, smaller diameter applications.

Marking, Length, and Documentation

BS 2871 tube from 10 mm to 159 mm is normally die-stamped at intervals of no more than 600 mm. The marking includes the manufacturer, the standard reference (for example "EN 1057" or "BS 2871"), the temper, and the date of manufacture. For alloy tubes, the UNS designation (C70600, C71500, C26000, C51000 and so on) is added.

A full Mill Test Certificate to EN 10204 3.1 is the accepted norm for industrial orders. It records the actual measured outside diameter, the average wall thickness, the mechanical test results, the chemical composition, and the hydrostatic or eddy current test outcome. For nuclear, offshore, or ship-class work, the MTC is often supplemented by third-party inspection certificates from Lloyds, DNV, BV, or the customer's own surveyor.

How EZ Steel Industrial Supplies BS 2871 Copper Alloy Tube

At EZ Steel Industrial we manufacture BS 2871 copper alloy tube alongside EN 1057, EN 12451, and ASTM B111 equivalents from our Lishui facility, with phosphor-deoxidised copper, 90/10 and 70/30 copper-nickel, admiralty brass, aluminium brass, and phosphor bronze available as standard stock grades. Outside diameters run from 6 mm to 50 mm for heat-exchanger duty and up to 159 mm for plumbing and gas service, with wall thickness options from 0.5 mm to 2.5 mm and cut lengths from 1 m to 12 m. Every batch is produced under ISO 9001 with full PMI, hydrostatic, and eddy current testing, and a 3.1 MTC ships with the order.

When a project calls for a non-standard diameter or a dual-certified batch — for example BS 2871 plus ASTM B111 plus EEMUA 234 for a marine retrofit — our engineering team can adjust the draw schedule, the anneal cycle, and the inspection plan to match the specification. To discuss a quotation, send your size schedule, alloy grade, and quantity to export@ezsteelpipe.com or call +86 731 8870 6116. The full stainless steel tube and copper-alloy tube portfolio is also available on the website for cross-reference when you are standardising a project. The same engineering team also supports alloy steel tube orders for high-temperature and high-pressure service when the project needs both copper and ferritic alloy materials on the same vessel.

Practical Tips for Specifying BS 2871 Copper Alloy Tube

• Always quote the standard, the part number, the table, and the temper together — for example "BS 2871 Part 1 Table X R250 (half hard)" — to avoid ambiguity at the receiving inspection.
• Decide the temper from the installation method first. If the tube will be bent on site, R250 is the safe choice; if the run is straight and pressure is the limiting factor, R290 gives more headroom.
• For heat-exchanger or condenser work, confirm whether the order must also meet EN 12451, ASTM B111, or the marine EEMUA 234 / BS 2871 combination. Dual certification costs little extra at the mill but saves a lot of audit time later.
• Check the marking interval on delivery. The 600 mm maximum die-stamp spacing is the easiest way to spot non-compliant product in the warehouse.
• Specify the 3.1 MTC requirement up front, including any additional tests (PMI, hardness survey, intergranular corrosion) that your quality plan demands.

BS 2871 is no longer the newest specification on the desk, but it remains the cleanest short-form reference for copper tube dimensions in the English-speaking world. Used alongside EN 1057 and EN 12451 it covers almost every sanitary, HVAC, refrigeration, and heat-exchanger requirement a piping engineer will meet, and a manufacturer that still keeps the tables in its production plan — like EZ Steel Industrial — will save you both time and re-inspection cost on the next project.