1、 STD-EEMUA PUB NO L72-ENGL 1998 D 57bb734 0001570 298 1. THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION GUIDE FOR THE PROCUREMENT OF VALVES FOR LOW TEMPERATURE (NON-CRYOGENIC) SERVICE PUBLICATION No 192 : 1998 I EEMUA I COPYRIGHT Engineering Equipment and Materials Users AssociationLicens
2、ed by Information Handling Services STD-EEMUA PUB NO 192-ENGL 1998 = 57bb734 0001571 124 7 * THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION GUIDE FOR THE PROCUREMENT OF VALVES FOR LOW TEMPERATURE (NON-CRYOGENIC) SERVICE PUBLICATION No 192 : 1998 Copyright 1998 The Engineering Equipment an
3、d Materials Users Association ISBN O 85931 086 8 45 Beech Street LONDON EC2Y 8AD I EEMUAI Telephone: 0171-628 7878 Fax: O 17 1-628 7862 COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling Services STD.MUA PUB i40 392-ENGL 1998 E 57bb73ri 0003592 Ob0 .I 1 T
4、HE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION The Engineering Equipment and Materials Users Association-EEMUA-was formed in 1983 by the Amalgamation of the Oil Companies Materials Association (OCMA) and the Engineering Equipment Users Association (EEUA). It is an organisation of substanti
5、al purchasers and users of engineering products, whose members include leading national and multi-national companies in the petroleum, gas; chemical and energy industries. A list of Full and Associate Members (the latter being limited to membership of three technical committees) is given below. EEMU
6、A is concerned with the design, installation, operation and maintenance of the engineering plant used by members in pursuing their business activities. The Association aims to reduce members costs by providing the opportunity for them to share resources and expertise in order to keep abreast of tech
7、nological developments and improve the effectiveness and efficiency of their engineering activities. EEMUA supports the British Standards Institution, works with other institutions, associations, government departments, regulatory authorities and the Confederation of British Industry, and is also ac
8、tively involved with other standards-making bodies, both national and international, such as the American Petroleum Institute. Work, which is carried out in-house by members alone or with the help of other organisations, may lead to the production of Association publications. These are prepared prim
9、arily for members use, but are usually offered for sale and thus for more general use. Such publications may also be submitted, normally through the British Standards Institution, as bases for appropriate national, European or international standards. A list of current EEMUA Publications which may b
10、e purchased from the Association is given at the end of this document. Full Members Associate Members Associated Octel BG BP Ammo Caltex Petroleum Conoco Dow Corning Eastern Generation Esso/ExxonMobil Eutech Foster Wheeler Energy Lindsey Oil Refinery National Power PowerGen Shell AstraZeneca BASF D
11、external pressure relief valves) will be required. Such thermal relief valves should clear any insulation. They should be bench set and demonstrated to relieve at a pressure between 1.1 times and 1.3 times the rated pressure of the protected valve. Material selection should be appropriate to the int
12、ended duty. 5.6 Thermal Effects Proposed materials should be reviewed for potentially undesirable effects when subjected to temperature changes. Combinations of materials having significantly different coeftcients of expansion should be given particular attention. This is especially important in the
13、 case of bolted joints. Bolted joints incorporating long bolts should be avoided where possible, especially where temperature changes are likely to be applied unequally throughout the joint. In this regard, double flanged butterfly and check valves may be preferred to standard wafer types. Additiona
14、lly, valves which rely on mechanical loading to effect a seal (e.g. wedge gate and globe valves) may be vulnerable to leakage during temperature changes. 5.7 Pressure Boundary Penetrations The number of penetrations (drain points etc.) of the pressure retaining boundary should be minimised. In corro
15、sive service or where significant temperature variations are expected the use of screwed plugs and fittings should be avoided where possible. Where the use of such fittings is unavoidable, seal welding may need to be considered. 12 COPYRIGHT Engineering Equipment and Materials Users AssociationLicen
16、sed by Information Handling ServicesI 6 MATERIALS 6.1 General Materials should be shown to be suitable for the maximum and minimum operating temperatures. and be compatible with the working fluid(s). 6.2 Metallic Materials Certain materials (e.g. austenitic steels and many non-ferrous alloys) are no
17、t susceptible to brittle fracture and are therefore inherently suitable for use down to -50C but for others specific evidence of adequate low temperature toughness will be required. In the case of ferrous materials this is usually provided by requiring Charpy impact tests to be conducted on a sample
18、 of the material/ heat treatment batch at a temperature which qualifies the material for the lowest operating temperature. (Note that depending on location of thermocouples, material mass, etc., local temperatures during a low temperature test may fall below the measured test temperature and this sh
19、ould be taken into account when determining impact test temperatures for test valve materials.) Material specifications or (piping etc.) design codes usually provide guidance on the suitability of materials for use at low temperatures, e.g. ASME B3 1.3 permits use of a number of steels and weldments
20、 down to -29“ C for certain duties without impact tests additional to those required by the material specification. However EEMUA recommends that the requirements of its Publication 153 be followed. That publication is based on the philosophy of Appendix D of BS 5500 applied to piping components. EE
21、MUA Pub. 153 Appendix SA indicates the temperature at which impact tests should be conducted on ferrous steels to permit continuous operation at a given minimum temperature. This is related to wall thickness: the thicker the material the more closely the required test temperature approaches the mini
22、mum operating temperature. Where impact test results exist for temperatures higher than the minimum design temperature, EEMUA Pub. 153 will indicate whether or not additional low temperature testing is required. Spheroidal graphite cast irons should not be used at temperatures below -29C. Grey cast
23、irons should not be used below -10C or where thermal shock is expected. It is important that material certification and traceability are adequate to demonstrate suitability for the operating temperatures (e.g. BS EN 10204, 3.1.b). Minimum required impact energy values may vary depending on the appli
24、cation. The material standard or applicable piping etc. design code will usually indicate minimum required values. Materials in sliding or rubbing contact should be reviewed to ensure the avoidance of galling, which is more likely at low temperatures where efficient lubrication may not be present. 6
25、.3 Non-metallic Materials Non-metallic materials are widely used in valves for such items as seals, seat rings, linings and gaskets. The properties of many non-metallic materials vary considerably with temperature, and this is particularly true of elastomers. In general, the hardness of elastomers 1
26、3 COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling ServicesSTD*EEMUA PUB NO 192-ENGL 1798 D 57bb73Li 000Lb03 77b I 1 increases with decreasing temperature whilst their resilience decreases. In many cases of both polymers and elastomers, coefficient of f
27、riction increases with decreasing temperatures below 0C. Appendix A gives typical, useful low temperature limits for a number of commonly encountered elastomers and polymers. it is important to realise, however, that much depends on the way in which the material is employed, loads applied etc. When
28、in doubt, the advice of the manufacturer should be sought. 14 COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling ServicesSTD-EEHUA PUB NO 172-ENGL 1978 S7bb734 0001b04 602 I I 7 MARKING Marking should be generally in accordance with the valve product stan
29、dard. In addition. all valve nameplates should indicate the low temperature limit of operation. Where valves have been made unidirectional (e.g. by the arrangements included to avoid cavity overpressure) valve bodies or flanges should be clearly and permanently marked to indicate direction of flow,
30、hy casting, forging, stamping etc. All nameplates and their method of attachment should be such as to be unaffected by exposure to the minimum operating temperature. 15 COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling Services8 TESTING 8.1 General Valve
31、s in the fully assembled condition should be subjected to the hydrostatic body and seat tests appropriate to the valve type as a minimum requirement (EEMUA Pubs 170 to 173 provide valuable guidance on appropriate test practice and acceptance standards). In addition, it is recommended that, where pos
32、sible, all valves intended for low temperature service be subjected to body and seat leak testing using air or nitrogen at a pressure of at least 5 bar (again, EEMUA Pubs 170 to 173 provide guidance). Such tests are more searching than tests using liquid, and provide an indication that build quality
33、, set up etc. are generally acceptable. They are a better guide to performance at low temperatures. There may be other tests (high pressure gas, electrical continuity, etc.) which it is appropriate to conduct. Valves intended for flammable service may need to be covered by fire type-test certificate
34、s, particularly where polymer or elastomeric seals are incorporated. After testing with water, valves should be dried to a high standard. Alternatively, consideration should be given to testing using air, gas or a non-aqueous liquid (e.g. kerosene). 8.2 Type Qualification Test The purpose of this te
35、st is to confirm valve operability and the adequacy of sealing at low temperatures. Valves should be qualified by tests on a representative sample at or below the minimum operating temperature. It is recommended that a single test should qualify valves of the same type no more than two nominal sizes
36、 larger and two nominal sizes smaller than the tested valve and having identical or lower pressure ratings, identical materials and identical design features (e.g. sealing mechanisms, body joints, gaskets). Where there are significant differences between component sizes (e.g. seal section sizes) sep
37、arate qualification tests are recommended. Changes to materials or design should be reviewed to confirm the validity of the qualification. Test valves should be certified to have material properties (impact strength etc.) appropriate to the test temperature. Tests may be conducted by the manufacture
38、r or by an independent test laboratory. In the former case, test results should be fully documented and witnessed by competent personnel. Testing should be carried out on unpainted valves and should be conducted in accordance with a properly prepared test procedure which addresses the following: saf
39、ety measures method of cooling siting of thermocouples calibration of gauges, pressure transducers, thermocouples etc. test pressures and durations 17 Previous page is blank COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling Servicestest sequence acceptan
40、ce standards recording of results requirements for witnessing. A suitable outline test procedure is provided in Appendix B. Through-body leakage should be measured using a mass spectrometer with the sniffing technique. Through-seat leakage should normally be measured by liquid displacement in a meas
41、uring tubekylinder or by flow measurement techniques. A mass spectrometer may be used for critical services. Acceptance standards may vary depending on the intended application and/or valve type (e.g. less stringent seat leakage rates may be appropriate to metal seated valves-see EEMUA Pubs 170 to 1
42、73 for guidance). Suggested acceptance standards for general application of soft seated valves are provided in Appendix C. Alternatively, there may be sufficient experience of application in similar conditions to those proposed to make testing unnecessary. In such cases it is important to establish
43、the actual operating conditions experienced by the valve(s) rather than those which could theoretically occur. A type test may also he dispensed with where low temperature testing has already heen undertaken by a manufacturer, in which case the valve design, materials. test procedure, test condition
44、s and results should be reviewed for appropriateness, completeness etc. 18 COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling ServicesSTD-EEMUA PUB NO 172-ENGL 1778 57bb734 OOO1b07 311 FKM (viton) rubber HNBR (hydrogenated nitrile) rubber CR (neoprene) ru
45、bber APPENDIX A: LOW TEMPERATURE LIMITS OF NON-METALLIC MATERIALS -5 to -35 depending on grade -20 - 25 The table below provides guidance on low temperature application of some commonly encountered elastomers and plastics. This assumes continuous exposure, but it should be noted that most materials
46、will withstand brief excursions to 5C lower without detriment. The figures for elastomers include a 10C margin over the glass transition temperature. For many polymers actual values are very grade dependent and the low-temperature limit may be also be affected by the mechanical design and loading em
47、ployed. Where doubt exists the valve manufacturer and/or material manufacturer should be consulted. PPS (Ryton) polymer PEEK (Victrex) polymer Nylon II Material * * -60, but grade dependent Minimum Temperature (OC) 1) NBR (nitrile) rubber -30 II FFKM (chemrazlkalrez) rubber II EPDM rubber O (L.T. gr
48、ades only) -40 II PTFE polymer - 190 * Grade dependent-consult manufacturer. 19 COPYRIGHT Engineering Equipment and Materials Users AssociationLicensed by Information Handling ServicesAPPENDIX B: SUGGESTED TYPE TEST PROCEDURE A suggested type test procedure is set out in sequential order below. 1 3
49、3 4 5 6 7 8 9 10 Perform the standard hydrostatic body and seat tests. Open the valve against rated differential pressure, measuring break-out and running torque. Dry and degrease the valve. Note. For low temperature testing the valve should be fitted with end closures which allow the valve body to experience loads in the direction of the pipe axis. Supports should be such as to ensure this. The sealing integrity of end closures should be such as to enable the required body etc. leak rates to be met without masking effects. Conduct a body and seat
