BS 1387

BS 1387 'Light'

-- Dimensions and masses are in accordance with ISO 65 'Light Series II'

BS 1387 'Medium and Heavy'

-- Maximum and minimum outside diameters meet the requirements of ISO 65. Thicknesses and masses are in accordance with ISO 65.

Methods of Calculation

-- The values have been calculated to at least five significant figures in accordance with the formula in ISO 65 viz:
For the metric system, m=0.0246615* (D-t)t kg/m (A)
For the inch system, m=10.68142† (D-t)t ld/ft (B)

( D = specified outside diameter, t = specified thickness )
( * This coefficient takes into account a density equal to 7.85 kg/cm2
( † This coefficient takes into account a density equal to 489.8 lb/ft2

The lb/ft value (3) is then converted to kg/m value (c) by multiplying by 1.4882.
The mean value in kg/m (D)={(A)+(C)}/2 and this is rounded to three significant figures.
The equivalent mean value in lb/ft (E) is found by dividing the rounded value (d) by 1.4882. The value (E)is then rounded to three significant figures.

*Note: The Socket Length shown in Table meets the requirments of the ISO 50, but the minimum length B has been increased to allow for the chamfer at the ends of the sockets and is based on B= 2L + 3.5P

Tubes and Sockets

1. Manufacture

Manufacture of the steel: The steel shall be produced by the electric or one of the basic oxygen processes and shall be fully killed, semi-killed or rimmed.
Manufacture of the product: Tubes shall be manufactured by a welled process. Sockets shall be manufactured by a seamless or welded process.
Chemical composition: The chemical composition of the steel shall comply with Table 1.
Heat Treatment: Tubes shall be supplied in the anneal or normalized condition, the as-welded condition, the as-welded condition with the weld zone heat treated, or after a hot finishing process.
*Note 1: Chemical analysis of the finished product is not required.
*Note 2: This steel is regarded as being weldable. However, care should be taken and welding should be carried out in accordance with the appropriate British Standards.

2. Mechanical properties

The mechanical properties at room temperature shall be as given in Table 1.

3. Appearance and soundness

-- Small imperfections which do not intrude on the minimum thickness or which can be dressed out such that the thickness after dressing remains within the tolerance limit shall be deemed not to affect compliance with this standard. Surface imperfections shall shall not be peeled.
-- Screw threads shall comply with the requirements of BS 21
-- The ends shall be cut cleenly and normally square with the axis of the tube and be free from excessive burrs.
-- The tubes shall be straight to within 1 in 500 as measured at the centre of the length.
-- The tubes shall not include welds used for joining length of strip.

4. Joints

-- All screwed tubes and sockets shall be threaded in accordance with BS 21 except as provided below and except that on light tubes the length of useful thread shall be reduced to 80% of that shown in column 12 of table 2 of BS 21:1985.
-- Where light tubes approch the lower limits of outside diameter some 'black' threads(perfect at the root and imperfect at the crest) are to be expected beyond the gauge plane, but such 'black' threads shall be deemed not to affect the compliance of the tubes with this standard.
-- Tubes shall be supplied screwed with taper threads and fitted with one screwed socket having a parallel thread unless it is specifically requested by the purchaser in his enquiry or order (see appendix A) that the tubes shall be supplied without sockets or supplied with a socket having a taper thread.

5. Dimensions and Tolerances

Dimensions: The dimensions of tubes shall be given in Table 3, 4 and 5. Dimensions of sockets shall be as given in Table 6.
Tolerances: The tolerances on the outside diameter, thickness, mass and length shall be as follows: (a)Outside diameter

Chemical composition & Mechanical properties at room temperature

Chemical compostion				Mechanical Properties at Room Temperature
C	Mn.	P	S	Tensible Strength	Yield Strength	Elongation on gauge Length
max.	max.	max.	max.	Rm	Ro (min)	LO=5.65 So A (min)
%	%	%	%	N/mm2	N/mm2	%
0.20	1.20	0.045	0.045	320 to 460	195	20

6. Testing

A. Visual Inspection: Each tube shall be inspected to ensure compliance with 2.3.

B. Tensile test:
-- When the tubes are subjected to a tensile test the test shall be in accordance with BS 18 : Part 4 and the following requirements shall apply.
-- The tensile strength, Rm, the yield strength, Ro and the elongation A shall be determined and the results obtained shall comply with the requirements given in table 1, for the yield strength either the upper yield stress Ro or the 0.5% proof stress (total elongation) A, 0.5 shall be determined.
-- The percentage elongation shall be reported with reference to a gauge length of Lo=5.65 √So. If other gauge lengths are used, the corresponding percentage gauge length Lo=5.65 √So shall be obtained with reference to BS 3894: part 1. In cases of dispute a gauge length of Lo=5.65 √So shall be used.

C. Bend test (whole tube)
-- The bend test applies to tubes upto and including DN 50. When tested in accordance with the following bend test the finished tubes shall withstand the test without showing any signs of fracture or failure.
-- The test shall be carried out using a tube bending machine and the tube shall be bent round a grooved former of the radius given in (a) or (b) as appropriate. Tubes shall be bent with the weld at 90° to the plane of bending. The tubes shall not be filled for this test.
(a) Tubes which have not been hot-dip zinc coated shall be bent cold, without cracking, through 180° round. The diameter of the groove shall be equal to six times the outside diameter of the tube as given in Tables 3, 4, 5.
(b) Hot-dip zinc coated tubes shall be bent cold without cracking in cold condition through 90° round former having a radius at the bottom of the groove equal to eight times the outside diameter of the tube.

D. Flattening test
-- The flattening test applies to tubes greater than DN 50. When the tubes are tested in accordance with the flattening test the following requirements shall apply.
-- A ring not less than 40 mm in length taken from one end of each selected tube shall be flattened cold between parallel flat platens without showing eithercrack or flaw. Until the distance between the platens, measured under load is not greater than 75% of the original outside diameter of the tube and no cracks or flaws in the metal elsewhere than in the weld shall occur until the substance between the platens is less than 60% of the original outside diameter.
-- The weld shall be placed at 90° to the distance of flattening
*Note: Slight premature cracking at the edges would not be deemed to affect compliance with this standard.

E. Leak Tightness tool
-- Black tubes shall be tested in leak tightness at the manufacturer's works. The test shall be either a hydraulic test at a pressure of 50 bars, the pressure being maintained sufficiently long for proof and inspection or alternatively an eddy current test in accordance with appendix B.
*Note: The choice of test is at discretion of the manufacturer.

F. Bore test (hot-dip zinc coated tubes only)
-- When the tubes are tested in accordance with the bore the following requirement shall apply.
-- Hot-dip zinc coated tubes of DN 8 up to and including DN 25 shall after hot-dip zinc coating have a rod 230mm in length, of the appropriate diameter specified in table passed through them and shall have a free bore.

7. Manufacturer's Certificate

-- The manufacturer shall provide for the issue of certificate which shall certify that the tubes supplied comply with this British Standard.
*Note: This certificate will only be provided when specified or requested by the customer in accordance with appendix A.