1、BRITISH STANDARD BS 8451:2004 Rubber hoses for gas welding, cutting and allied processes High kink-resistant heavy duty welding hose (type H) Specification ICS 25.160.30; 83.140.40 BS 8451:2004 This British Standard, having been prepared under the direction of the Standards Policy and Strategy Commi
2、ttee comes into effect on 1 March 2004 BSI 1 March 2004 The following BSI references relate to the work on this British Standard: Committee reference PRI/66/1 Draft for comment 03/310327 DC ISBN 0 580 43363 3 Committees responsible for this British Standard The preparation of this British Standard w
3、as entrusted by Technical Committee PRI/66, Rubber and plastics tubing, hoses and hoses assemblies, to Subcommittee PRI/66/1, Industrial, chemical and petrochemical applications, upon which the following bodies were represented: Energy Industries Council Fire Extinguishing Trades Association Institu
4、te of Petroleum London Fire b) an abrasion resistance requirement; c) a more stringent adhesion requirement; d) requirements for crush and high kink resistance. In addition, marking of the hose has been increased to half metre intervals. WARNING. This British Standard calls for the use of substances
5、 and/or procedures that may be injurious to health if adequate precautions are not taken. It refers only to technical suitability and does not absolve the user from legal obligations relating to health and safety at any stage. This publication does not purport to include all the necessary provisions
6、 of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 13 and a back cover. The BSI copy
7、right notice displayed in this document indicates when the document was last issued.BS 8451:2004 BSI 1 March 2004 1 1 Scope This British Standard specifies requirements for two classes of flexible rubber hose for gas welding and allied processes for use up to a maximum working pressure of 20 bar 1)o
8、ver the temperature range 25 C to +70 C. There is no subdivision of the classes because only the high kink resistant hose is specified. Type H hoses for gas welding, cutting and allied processes are mainly intended for use in long lengths in the construction and military sectors where the full lengt
9、h of hose might not be visible to the welding operative. NOTE The hose is designated Type H, to maintain a relationship with BS 5120:1987. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the reference cited
10、applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS 572:1985, Specification for interchangeable conical ground glass joints. BS 903-A2:1995, Physical testing of rubber Method for determination of tensile stress-strain properties. (ISO
11、 37:1994) BS 903-A35, Physical testing of rubber Temperatures, humidities and times for conditioning and testing of test pieces. (ISO 471) BS EN 560, Gas welding equipment Hose connections for welding, cutting and allied processes. BS EN 28033, Rubber and plastics hose Determination of adhesion betw
12、een components. (ISO 8033) BS EN 27326:1993, Rubber and plastics hoses. Assessment of ozone resistance under static conditions. (ISO 7326:1991) BS EN ISO 1307, Rubber and plastics hoses for general-purpose industrial applications Bore diameters and tolerances, and tolerances on length. BS EN ISO 140
13、2:1997, Rubber and plastics hoses and hose assemblies Hydrostatic testing. BS EN ISO 1746, Rubber or plastics hoses and tubing Bending tests. BS EN ISO 4080:1995, Rubber and plastics hoses and hose assemblies Determination of permeability to gas. BS EN ISO 4671, Rubber and plastics hoses and hose as
14、semblies Methods of measurement of dimensions. BS EN ISO 4672:1999, Rubber and plastics hoses Sub-ambient temperature flexibility tests. BS EN ISO 8330, Rubber and plastics hoses and hose assemblies Vocabulary. BS ISO 188:1998, Rubber, vulcanized or thermoplastic Accelerated ageing and heat resistan
15、ce tests. (BS 903-A19:1998) BS ISO 1817:1999, Rubber vulcanized Determination of the effect of liquids. (BS 903-A16:1999) BS ISO 4649:2000, Rubber, vulcanized or thermoplastic Determination of abrasion resistance using a rotating cylindrical drum device. 3 Terms and definitions For the purposes of t
16、his British Standard, the definitions given in BS EN ISO 8330 apply. 1)1 bar = 10 5N/m 2= 10 5Pa.BS 8451:2004 2 BSI 1 March 2004 4 Classification Two classes of hose shall be specified, dependent upon use: a) Class A: for use with acetylene, oxygen and non-combustible gases such as argon; b) Class B
17、: for gas cutting and welding applications using liquefied petroleum gases (LPGs). 5 Materials and construction The hose shall consist of: a) a rubber lining of minimum thickness 1.5 mm; b) reinforcement applied by any suitable technique; c) a rubber cover of minimum thickness two millimetres. The l
18、ining and cover shall be of uniform thickness, free from air holes, porosity and other defects. The hose shall be mandrel or non-mandrel made and the finish shall be smooth, fluted or fabric marked. 6 Colour identification In order to identify the gas for which the hose is intended to be used, the h
19、ose cover shall be coloured in accordance with Table 1. Table 1 Colour of hose cover 7 Dimensions and tolerances 7.1 Bore sizes When measured in accordance with BS EN ISO 4671, the dimensions of the bore of the hose shall conform to Table 2. Table 2 Nominal bore 7.2 Cut lengths and tolerances The to
20、lerances on nominal lengths specified by the purchaser shall be in accordance with BS EN ISO 1307. Class Gas Colour of cover A Acetylene and other fuel gases, excluding LPG Red A Oxygen Blue A Non-combustible gases, e.g. argon Black B Liquefied petroleum gas (LPG), e.g. propane, butane and mixtures
21、of propane and butane Orange Nominal bore Internal diameter and tolerances Maximum concentricity mm mm 4.0 4.0 0.55 1.00 5.0 5.0 0.55 6.3 6.3 0.55 8.0 8.0 0.65 1.25 10.0 10.0 0.65 12.5 12.5 0.70 16.0 16.0 0.70 19.0 19.0 0.75 1.50 BS 8451:2004 BSI 1 March 2004 3 8 Physical properties of lining and co
22、ver 8.1 Tensile strength and elongation at break When tested in accordance with BS 903-A2:1995, the rubber used in the lining and cover of the hose shall have a tensile strength and elongation at break no less than the values given in Table 3. Table 3 Tensile strength and elongation at break 8.2 Acc
23、elerated ageing When aged in accordance with BS ISO 188:1998 for 168 h at a temperature of 70 C, the tensile strength and elongation at break of the lining and cover shall decrease by no more than 25 % and 50 % from the unaged values, respectively. 8.3 Non-ignition Three samples of the hose lining s
24、hall be tested in accordance with Annex A. If none of the samples undergoes ignition, the hose shall be deemed as having passed the non-ignition requirement. If more than one of the samples shows evidence of ignition in less than two minutes, the hose shall be deemed as having failed the non-ignitio
25、n requirement. If only one sample shows evidence of ignition in less than two minutes, three further samples shall be prepared and tested. If any of the three samples in this second series shows evidence of ignition in less than two minutes, the hose shall be deemed as having failed the non-ignition
26、 requirement. 8.4 Resistance to liquids 8.4.1 Resistance to acetone (class A only) When immersed in boiling acetone for eight hours, the increase in mass of a sample of the hose lining calculated in accordance with BS ISO 1817:1999 shall be no greater than 8 %. 8.4.2 Resistance to n-pentane (class B
27、 only) When tested in accordance with Annex B, a sample of the hose lining shall show an absorption of n-pentane no greater than 15 % and of n-pentane-extractable matter no greater than 10 %. 8.5 Abrasion resistance When tested in accordance with method A of BS ISO 4649:2000, the relative volume los
28、s method, the volume loss of a sample of the cover material, prepared from a moulded sheet vulcanized to the same degree as the hose, shall be no greater than 500 mm 3 . 9 Performance 9.1 Hydrostatic pressure requirements When tested in accordance with BS EN ISO 1402:1997, hoses shall conform to the
29、 appropriate rating given in Table 4 and shall show no cracks or leaks at proof pressure. Table 4 Hydrostatic pressure rating Component Tensile strength Elongation at break MPa % Lining 5.0 200 Cover 7.0 250 Maximum working pressure Proof pressure Minimum burst pressure Maximum change in length at w
30、orking pressure bar abar a bar a % 20 40 60 7 a 1 bar = 10 5N/m 2= 10 5Pa.BS 8451:2004 4 BSI 1 March 2004 9.2 Adhesion When tested in accordance with BS EN 28033, the adhesion between adjacent components shall be no less than 2.0 kN/m. 9.3 Flexibility When tested in accordance with BS EN ISO 1746 at
31、 standard temperature (see BS 903-A35), using a diameter of curvature (C) 10 times the nominal bore (with a minimum of 80 mm), and a coefficient of deformation (K) of 0.8: there shall be no kink in the curved portion of the hose; and the deformation in the curved position shall not exceed 0.80. 9.4
32、Low temperature flexibility When tested in accordance with method 2 of Clause 4 of BS EN ISO 4672:1999 at p25 C, using a diameter of curvature of 10 times the nominal bore (with a minimum of 80 mm), the hose: shall show no signs of cracking or breaking; and shall show exhibit no leakage when subject
33、ed at ambient temperature to the proof pressure given in Table 4. 9.5 Resistance to crushing When tested in accordance with Annex C: the flow rate shall drop to no less than 0.07 m 3 /h; and the hose shall exhibit no leakage during the final pressure tests. 9.6 Resistance to hot surfaces When tested
34、 in accordance with Annex D, the reinforcement of the hose shall not be exposed through the cover in the area under the heated bar after (60 1) s at (360 5) C. 9.7 Resistance to ozone When tested in accordance with BS EN 27326:1993, Method 3 at a temperature of 40 C, no cracking shall be observed wh
35、en viewed under 2 magnification. 9.8 Permeability to gas (class B only) When tested in accordance with BS EN ISO 4080:1995 Method 2, Clause 13 (when the determination is to be carried out on hose) or Method 3 (when the determination is to be carried out on a hose assembly) using a test gas of 95 % p
36、ropene at cylinder pressure (approximately six bar) and standard temperature (see BS 903-A35), the gas permeance for all bore sizes shall be no greater than 25 cm 3 /m/h. 9.9 Resistance to kinking When tested in accordance with Annex E using a hose test length of 100 times the nominal hose bore, the
37、 gas pressure shown on the manometer shall fall by no more than 10 mbar. BS 8451:2004 BSI 1 March 2004 5 10 Marking The following information shall be marked at least once every 0.5 m along the length of the hose: a) the manufacturers name or identification; b) the number and date of this British st
38、andard, i.e. BS 8451:2004 2) ; c) the class and type; d) the month and year of manufacture; e) the nominal bore. EXAMPLE MN/BS XXXX: 1997/A-H/12-96/6.3 2)Marking BS 8451:2004 on or in relation to a product is a claim by the manufacturer that the product has been manufactured to the requirements of t
39、he standard. The accuracy of such a claim is therefore solely the manufacturers responsibility. Enquiries as to the availability of third party certification should be addressed to the appropriate certification body. Users of this British Standard are advised to consider the desirability of third-pa
40、rty certification of product conformity with this British Standard. Users seeking assistance in identifying appropriate conformity assessment bodies or schemes may ask BSI to forward their enquiries to the relevant association.BS 8451:2004 6 BSI 1 March 2004 Annex A (normative) Method of test for no
41、n-ignition A.1 Apparatus A.1.1 Ignition test apparatus, as shown in Figure A.1, having ground glass joints in accordance with BS 572:1985. A.1.2 Heating furnace, 350 W, with internal dimensions 150 mm deep by 50 mm in diameter. A.1.3 Tubular sliding resistance, 190 W to 200 W with screw movement or
42、an auto-transformer with continuously variable output voltage. A.1.4 Calibrated flowmeter for oxygen, 0 to 5 l/min at atmospheric pressure and 150 C. A.1.5 Nitrogen-filled mercury-in-glass thermometer, suitable for use at 150 mm immersion, graduated from approximately 300 C to 400 C in intervals of
43、not more than 5 C, the graduations starting not less than 200 mm above the bulb. A.2 Procedure Insert the ignition test apparatus in its aluminium foil wrapping into the electric furnace. NOTE 1 The purpose of the aluminium foil is to minimize radiant heat and to obtain more uniform temperature dist
44、ribution. Adjust the energy supply to the electric furnace with the variable resistance or autotransformer so that a constant temperature of 360 C to 365 C is maintained with the oxygen flowing at (2 0.1) l/min. After cleaning by buffing, cut the sample of lining rubber for test into blocks of 8 mm
45、3to 10 mm 3in which no side is less than 1.3 mm nor greater than 2.5 mm. When the furnace is at constant temperature, quickly remove the holder, impale a sample block of the lining rubber under test on the tungsten point and replace the sample holder in the apparatus. NOTE 2 It is necessary for this
46、 operation to be carried out quickly so that cooling is reduced to a minimum. Retain the sample in the apparatus for at least two minutes and observe it carefully during this period for evidence of ignition. NOTE 3 Fumes can be observed but this does not constitute evidence of ignition, which is nor
47、mally accompanied by a flash, and sometimes by a small explosion. Test three samples consecutively. If ignition of a sample does occur, ensure that the temperature of the apparatus falls back to the value specified above before testing the next sample. Ensure that the tungsten point is kept clean and sharp.
