1、BRITISH STANDARD BS5244:1986 Recommendations for Application, storage and life expiry of hydraulic rubber hoses and hose assemblies UDC 621.643.3-036.43:678.43-462.029.46BS5244:1986 This British Standard, having been prepared under the directionof the Rubber StandardsCommittee, waspublished under th
2、e authorityof the Board of BSI andcomes into effect on 28 November1986 BSI 07-1999 First published February 1976 First revision November 1986 The following BSI references relate to the work on this standard: Committee reference RUM/9 Draft for comment 85/36439 DC ISBN 0 580 15462 9 Committees respon
3、sible for this British Standard The preparation of this British Standard was entrusted by the Rubber Standards Committee (RUM/-) to Technical Committee RUM/9, upon which the following bodies were represented: British Coal British Gas Corporation British Rubber Manufacturers Association Chief and Ass
4、istant Chief Fire Officers Association Department of the Environment (The Crown Suppliers) Fire Extinguishing Trades Association Health and Safety Executive Home Office Institution of Fire Engineers London Fire Brigade London Transport Executive Malaysian Rubber Producers Research Association Minist
5、ry of Defence Society of Motor Manufacturers and Traders Limited Water Authorities Association The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Association of Hydraulic Equipment Manufacturers British Railways Board Energy Industries Counc
6、il Engineering Equipment and Materials Users Association Amendments issued since publication Amd. No. Date of issue CommentsBS5244:1986 BSI 07-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Applications 1 3 Storage 2 4 Life expiry 5 Figure 1 Recommended schema
7、tic assembly layout 3 Table 1 Test recommendations for hoses 6 Table 2 Test recommendations for hose assemblies 6 Table 3 Test recommendations for stored equipment 6 Publications referred to Inside back coverBS5244:1986 ii BSI 07-1999 Foreword This revision of this British Standard, prepared under t
8、he direction of the Rubber Standards Committee, supersedes BS5244:1976 which is withdrawn. This revision reflects current practice in the industry and, in particular, the recommendations for life expiry of hydraulic hoses and hose assemblies have been updated. These recommendations are not applicabl
9、e to automobile hydraulic brake hose assemblies which may often be exposed to unusual installation conditions due to restriction of the available space when the assembly is fitted to a vehicle. Also, they do not apply to wire reinforced hoses for water jetting since this type of hose has a lower saf
10、ety factor between the working pressure and the burst pressure. Storage and handling procedures for large hoses are described in BS1435. Attention is also drawn to the realted British Standards: BS3558,BS3574 and British Standard 3F68. A British Standard does not purport to include all the necessary
11、 provisions of a contract. Users of British Standards are responsible for their 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, pagesi andii, pages1 to6,
12、an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS5244:1986 BSI 07-1999 1 1 Scope This British Standard gives recommendations for hydraulic hos
13、es relating to: a) the layout of fluid systems incorporating rubber hose assemblies and to the application of these assemblies; b) the procedure to be adopted for the storage of rubber hoses and hose assemblies, whether held as single items or as part of an equipment assembly or subassembly; c) a li
14、fe expiry policy to be adopted in respect of stored rubber hoses and hose assemblies in order to ensure adequate safety with reasonable economy. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Applications 2.1 Selection of hose assemblies When s
15、electing hose assemblies for any particular purpose, full consideration should be given to the working pressure of the system, including any surge pressures which are likely to be generated. Care should also be taken to ensure that the materials used in the hose and its end fittings are compatible w
16、ith the fluid to be used in the system and with the external environmental conditions. Particular attention should be paid to the fluid and ambient temperatures of the hose environment since temperatures in excess of those for which the hose assembly is designed will considerably shorten its life. N
17、OTEInformation of this nature should normally be obtained from the specification governing the hose. 2.2 Design of layout 2.2.1 The primary application of rubber hose assemblies in fluid systems is to ensure a satisfactory fluid flow where flexible connections are required. In addition to being inst
18、alled in the straight condition, hose assemblies are used in a number of configurations. Figure 1 shows some of these with, in each case, ways of employing hose assemblies which are recommended and those which are not recommended. The free lengths of each leg of these configurations should be suffic
19、ient to accommodate the most severe movements expected. Very short straight runs should be avoided. NOTEThe schematic diagrams shown in Figure 1 refer to hose assemblies installed under actual operating conditions. Some test methods may require configurations which contravene these recommendations:
20、it is emphasized that such configurations are applicable to the specific test conditions only and do not authorize the use of such configurations for general service applications. 2.2.2 Sufficient flexibility and clearance should be provided to permit deflections of the equipment under vibration and
21、 shock, and the layout of the system should be such that the hose is not liable to be damaged or chafed during any deflections which might take place. The length of flexible hose used should be limited to that necessary to provide the required flexibility but should be of such a length that the inst
22、alled assembly is at no time under tension. 2.2.3 Systems should be so arranged that the radius of any bend in the hose is as large as possible. At no time should the hose be bent below its specified minimum bend radius which is normally stated in the hose specification. It is important to take into
23、 consideration any additional bending of the hose which may occur during its normal working cycle. To ensure that shock or any other movement does not reduce the bend radius of the hose below its specified minimum, the length of the hose should be such that when it takes up a natural position, it al
24、lows a length of straight hose at least six times the outside diameter where it enters the end fittings. Sufficient support should be provided to prevent the weight of the hose causing excessive stress or bending at the connection. 2.2.4 In order to reduce vibration stresses, rigid pipes to which th
25、e hoses are attached should be firmly supported in suitable pipe clips as close as possible to the hose. All pipe hangers and clips should be attached to a substantial part of the structure. 2.2.5 It is important to ensure that no tensile load is transmitted to the hose due to thermal expansion of t
26、he structure between the attachment points, or from any other cause. Locations which would subject hoses to excessive heating should be avoided, e.g.proximity to exhaust systems. Heat shielding or insulation by cladding should be considered, where applications permit, for certain heat-environmental
27、situations. 2.2.6 In no circumstances should the hose be used as a means of traction. 2.2.7 Hose assemblies, joints and couplings should be located at easily accessible points. 2.3 Installation 2.3.1 Before attempting to connect a hose assembly, it is essential to ensure that the jointing surfaces a
28、re completely free from foreign matter and from burrs, flash or fins. Damage to these surfaces, especially where cone connections are concerned, may cause leakage.BS5244:1986 2 BSI 07-1999 Union nuts should be hand-tightened at both ends and the hose allowed to adopt a natural position. A longitudin
29、al line is normally marked on rubber hose assemblies for guidance during assembly and on no account should this line be twisted during the final tightening of the end connections (see Figure 1). Excessive force should not be used when tightening end connections, and long-handled spanners or wrenches
30、 should never be used for this purpose. Particular care should be taken to comply with torque tightening figures where specified. 2.3.2 Rubber hoses should not be painted without reference to the manufacturer as many paints contain substances deleterious to the rubber. 3 Storage NOTEThe storage cond
31、itions recommended in this clause are particularly relevant to the requirements of the Ministry of Defence. Where a faster turnover of hose occurs, as in industry, simpler methods of storage would be adequate. 3.1 General Rubbers change in physical properties during storage and ultimately may become
32、 unserviceable because of excessive hardening, softening, cracking, crazing or other degradation. These changes may be the result of one particular factor or a combination of factors, such as the action of oxygen, ozone, light, heat, humidity, or oils and solvents. Reinforcement materials are also a
33、dversely affected by unsuitable conditions of storage. The object of the recommendations in this clause is to advise how these effects may be minimized by a careful choice of storage conditions. 3.2 Cleansing prior to storage When the bore of a hose has become contaminated with foreign matter it sho
34、uld be cleaned and dried prior to storage. This should be done in accordance with the requirements of the specification to which the item was manufactured. In the absence of any instruction, cleansing should be carried out with soap and water followed by a clean water rinse. Water should not be perm
35、itted to come into contact with any fabric or metal reinforcement. Organic liquids, e.g.petrol, paraffin, etc., or detergent solutions should not be used. After cleansing, the hose or hose assembly should be dried with clean warm air before being placed into storage. 3.3 Temperature The storage temp
36、erature should preferably be below15 C, and every effort should be made to keep below25 C as higher temperatures cause the rubber materials to deteriorate more rapidly. Hoses should not be stored close to sources of heat which might raise their temperatures above25 C. The effects of low temperature
37、are not permanent, but hoses may become stiffer if stored at low temperatures and care should be taken to avoid distorting them during handling at those temperatures. When hoses are taken from low temperature storage for immediate use, their temperatures should be allowed to reach15 C to25 C through
38、out to eliminate any low temperature effects in the rubber before they are put into service. NOTEAlthough it is desirable to observe these conditions, it is appreciated that when hoses form part of large mechanical equipment, it may be necessary, because of the size of the equipment, to store them i
39、n less than ideal conditions. Every effort should, however, be made to ensure that the temperatures to which the hoses are subjected are kept as low as possible. The hoses should also not be exposed to light, extremes of humidity or be placed near equipment capable of generating ozone (see3.4, 3.5 a
40、nd3.6). 3.4 Humidity Very moist or very dry conditions should be avoided.65% r.h. is recommended. 3.5 Light Hoses should at all times be protected from light, particularly direct sunlight and strong artificial light. Unless the hoses are packed in opaque containers it is advisable to cover any windo
41、ws in storage rooms with a red or orange coating, or screen. Equipment incorporating hoses should, wherever possible, be covered to ensure that the hoses are not subjected to direct sunlight. 3.6 Oxygen and ozone 3.6.1 Wherever possible, hoses should be protected from circulating air by wrapping (se
42、e 3.9.6), or by storage in airtight containers. 3.6.2 As ozone is particularly injurious to most rubbers, storage rooms should not contain any equipment that is capable of generating ozone, such as mercury vapour lamps, high voltage electrical equipment, electric motors, or other equipment which may
43、 give rise to electric sparks or silent electrical discharges.BS5244:1986 BSI 07-1999 3 NOTEHigh pressure applied to a twisted hose may cause failure of the hose or loosen the end connection. Figure 1 Recommended schematic assembly layoutBS5244:1986 4 BSI 07-1999 Figure 1 Recommended schematic assem
44、bly layout (concluded)BS5244:1986 BSI 07-1999 5 3.7 Deformation Hoses should, wherever possible, be stored in a relaxed condition free from tension, compression, or other deformation. Wherever possible, large bore hoses should not be stacked. If it is impossible to avoid deformation due to the lengt
45、h of the hose, it should be coiled as large as possible and not less than the minimum size recommended by the manufacturer. 3.8 Contact with other materials 3.8.1 Contamination by organic liquids, solvents, oils, greases, or other similar materials at any time during storage should be avoided. 3.8.2
46、 Direct contact with some metals (e.g.manganese, iron and particularly copper and its alloys) and their compounds, can, under certain conditions, have deleterious effects on some rubbers. Hoses should therefore not be stored in contact with such metals or materials impregnated with their compounds,
47、e.g.wrapping or wood impregnated with copper naphthenate. 3.8.3 Because of the possible transfer of plasticizers or other ingredients, rubber hoses should not be stored in contact with polyvinyl chloride (PVC). 3.8.4 Contact with creosote-impregnated timber or fabrics should be avoided. 3.9 Packagin
48、g and protection 3.9.1 Although this is, to some extent, governed by the size and type of hose, the basic principles given in 3.9.2 to 3.9.6 should be observed. 3.9.2 The open ends of the hose assemblies should be sealed with plugs or caps of metal, or a suitable plastics material, so designed as to
49、 prevent the fitting of the hose assembly without their prior removal. The end fittings of hose assemblies should then be wrapped in mouldable waxed wrap as described in BS1133-7.1 secured to the hose with a pressure-sensitive adhesive tape as described in BS1133-14. The purpose of sealing the ends of hoses and hose assemblies is to prevent the ingress of dirt and other contaminants and to minimize the effects of weathering. 3.9.3 Hose assemblies which are stored as part of an assembly with only one end secured should have the free end suitably protected ag
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