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BRITISH STANDARDBS 6755-1:1986Testing of valves Part 1:Specification for production pressure testing requirementsUDC 621.646:620.1:532.11Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:1986This British Standard,having been prepared under the direction of the Piping Systems Components Standards Committee,was published under the authority of the Board of BSI and comes into effect on 31 December 1986 BSI 12-1998The following BSI references relate to the work on this standard:Committee reference PSE/7 Draft for comment 85/75573 DCISBN 0 580 15479 3Committees responsible for this British StandardThe preparation of this British Standard was entrusted by the Piping Systems Components Standards Committee(PSE/-)to Technical Committee PSE/7,upon which the following bodies were represented:Amalgamated Union of Engineering WorkersAssociated Offices Technical CommitteeAssociation of Bronze and Brass FoundersAssociation of Hydraulic Equipment ManufacturersBritish Chemical Engineering Contractors AssociationBritish Compressed Gases AssociationBritish Foundry AssociationBritish Gas CorporationBritish Maritime TechnologyBritish ShipbuildersBritish Valve Manufacturers Association Ltd.Copper Development AssociationCopper Tube Fittings Manufacturers AssociationElectricity Supply Industry in England and WalesEnergy Industries CouncilEngineering Equipment and Materials Users AssociationGAMBICA(BEAMA Ltd.)General Council of British ShippingHealth and Safety ExecutiveInstitute of British FoundrymenInstitution of Chemical EngineersInstitution of Gas EngineersInstitution of Mechanical EngineersInstitution of Water Engineers and ScientistsSociety of British Gas IndustriesSteel Casting Research and Trade AssociationWater Authorities AssociationWater Companies AssociationAmendments issued since publicationAmd.No.Date of issueCommentsLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:1986 BSI 12-1998iContentsPageCommittees responsibleInside front coverForeword iiSection 1.General1Scope 12Definitions 1Section 2.Performance3General 24Pressure-containing capability of valve shell 25Butterfly valve disk strength 26Seat leakage 27Back seat leakage 28Test certificate 2Appendix A Equivalent leakage rates 4Appendix B Test durations 4Appendix C Equivalent sizes of valves having flanged ends,threaded ends,weld ends and capillary or compression ends 5Appendix D Pressure tests 5Table 1 Maximum permissible seat test leakage rates 3Table 2 Maximum permissible back seat test leakage rates 3Table 3 Equivalent leakage rates 4Table 4 Test durations 4Table 5 Equivalent sizes of valves 5Publications referred to Inside back coverLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:1986ii BSI 12-1998ForewordThis Part of BS 6755 has been prepared under the direction of the Piping Systems Components Standards Committee.BS 6755 is published in two Parts:Part 1:Specification for production pressure testing requirements;Part 2:1)Specification for fire type-testing requirements.This Part of BS 6755 will supersede BS 5146-1 and BS 5146-2 and is related to ISO 5208-1982,published by the International Organization for Standardization(ISO),but is not equivalent in technical content.The main differences are as follows.a)Pressure test requirements specified in BS 5146-1 have been included in this Part of BS 6755 which are not specified in ISO 5208.b)More details of the test methods are given in this Part of BS 6755.c)Maximum allowable leakage rates for the seat and back seat tests are designated differently to ISO 5208 and BS 5146-2 and therefore a table of equivalent leakage rates is given in appendix A.d)The minimum durations for pressure tests do not necessarily comply with ISO 5208;the actual test durations are given in the valve product standards.e)For guidance,a table of test durations is given in appendix B and may be used where an appropriate valve product standard does not exist or where test times are not specified in a standard.f)For comparison and information,a table of equivalent sizes of valves having different ends is given in appendix C.This Part of BS 6755 establishes the basic requirements and methods for the production pressure testing of valves.It revises the production pressure testing requirements specified in BS 5146-1:1974 and BS 5146-2:1984 both of which will eventually be superseded by this Part of BS 6755 and will be withdrawn.In the meantime valves should be tested,as appropriate,in accordance with either:It is the intention to refer to this Part of BS 6755 for production pressure testing in all the valve product standards listed in this foreword and this will be achieved either by revisions to existing standards or by amendments published to existing standards.It is expected that all valves will be required to be production pressure tested in accordance with this Part of BS 6755 within a date of 2 years of publication of this standard.Within this period BS 5146-2:1984 will be withdrawn and the production pressure testing requirements specified in BS 5146-1:1974 will be deleted together with clauses covering inspection requirements.1)In preparation1)i)BS 5146-1:1974;ii)BS 5146-2:1984;iii)the requirements in the relevant valve product standard;or2)this Part of BS 6755.Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:1986 BSI 12-1998iiiIt is intended that this Part of BS 6755 be used in conjunction with the appropriate valve product standard when specified wholly or in part only by the valve product standard or with a valve application standard,e.g.BS 759-1,when applicable.In particular,it applies when specified by any one of the following valve product standards:This Part of BS 6755 gives general test requirements:specific test requirements,such as test durations and permissible leakage rates,are or will be included in the valve product standards.In addition,it may be used for the pressure testing of valves not covered by product standards.Throughout this standard all pressures specified are gauge pressures(in bar2).It has been assumed in the drafting of this Part of BS 6755 that the execution of its provisions is entrusted to appropriately qualified and experienced people because it calls for 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 refers,in particular,to pneumatic testing(see D.2 and D.5)and attention is drawn to Guidance Note GS4,“Safety in pressure testing”,produced by the Health and Safety Executive and published by HMSO.A British Standard does not purport to include all the necessary 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 pagesThis document comprises a front cover,an inside front cover,pages i to iv,pages 1 to 10,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.BS 1414BS 5153BS 5159BS 6364BS 1868BS 5154BS 5160BS 1873BS 5155BS 5163BS 5150BS 5156BS 5351BS 5151BS 5157BS 5352BS 5152BS 5158BS 53532)1 bar=105 N/m2=105 Pa.Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIivblankLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:1986 BSI 12-19981Section 1.General1 ScopeThis Part of BS 6755 specifies production pressure testing requirements and describes in appendix D tests to confirm the pressure-containing capability of the shell of a valve under pressure,and tests verifying the degree of tightness and pressure-retaining capability of the valve seat(s)and/or closure mechanism.Where requirements in a valve product standard differ from those given in this standard then the requirements of the product standard apply.NOTEThe titles of the publications referred to in this standard are listed on the inside back cover.2 DefinitionsFor the purposes of this Part of BS 6755 the following definitions apply.2.1 test pressurethe internal pressure to which the valve under test is subjected2.2 nominal size(DN)a numerical designation of size which is common to all components in a piping system other than components designated by outside diameters or by thread size.It is a convenient round number for reference purposes and is only loosely related to manufacturing dimensionsNOTE 1Nominal size is designated by the letters DN followed by the appropriate reference number.NOTE 2This definition is identical to that given in ISO 6708.NOTE 3A table of equivalent sizes for valves having flanged ends,threaded ends,weld ends and capillary or compression ends is given in appendix C.2.3 nominal pressure(PN)a numerical designation which is a convenient rounded number for reference purposesall equipment of the same nominal size(DN)designated by the same PN number shall have compatible mating dimensionsNOTE 1The maximum permissible working pressure depends on materials,design and working temperatures,and should be selected from the tables of pressure/temperature ratings given in the appropriate standards.NOTE 2Nominal pressure is designated by the letters PN followed by the appropriate reference number.NOTE 3This definition is identical to that given in ISO 7268.2.4 seat ratingthe maximum permissible differential pressure(in bar)at 20 C,across the seatLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:19862 BSI 12-1998Section 2Section 2.Performance3 GeneralWhen tested in accordance with appendix D,the valve shall comply with clauses 4 to 7,as appropriate.4 Pressure-containing capability of valve shell4.1 When tested in accordance with D.6,the valve shall comply with 4.2 or 4.3,as appropriate,and 4.4,where applicable.4.2 When the test fluid is a liquid there shall be no visually detectable leakage.Unless otherwise specified in the appropriate valve product standard,seepage from stuffing boxes and other stem sealing mechanisms is permissible at the shell test pressure provided that there is no visually detectable leakage when the pressure is reduced to the seat test pressure.CAUTION.Attention is drawn to the fact that if the gland of a valve is tightened whilst the pressure in the valve is higher than the seat test pressure,this practice could lead to unsafe conditions.4.3 When the test fluid is a gas:a)if the valve is immersed in clean water,the upper surface of the valve shell shall not be more than 50 mm below the surface of the water and there shall be no bubbles breaking the surface of the water;b)if the valve is coated with a leak detection fluid,there shall be no continuous formation of bubbles.4.4 When tested in accordance with D.6.3,diaphragm valves with sealed bonnets shall show no visually detectable leakage.5 Butterfly valve disk strengthWhen tested in accordance with D.7,there shall be no visible evidence of structural damage to the disk or of leakage through the disk during the test duration.NOTELeakage past the disk edge is not a cause for deeming that the valve does not comply with this Part of BS 6755.6 Seat leakageWhen tested in accordance with D.8,the maximum permissible seat test leakage rate shall be one of the rates given in Table 1,the particular leakage rate(s)being given in the valve product standard.7 Back seat leakageWhen tested in accordance with D.9,the maximum permissible back seat test leakage rate shall be one of the rates given in Table 2,the particular leakage rate(s)being specified in the valve product standard(see also note 3 to Table 2).8 Test certificateWhere a test certificate is issued it shall:a)contain a statement by the manufacturer confirming that the valves have been tested in accordance with this Part of BS 6755 and as required by the product standard and comply with this Part of BS 6755;b)state the actual pressures and fluid used in the tests.NOTEWhen a test certificate is required this should be requested on the enquiry and/or order for the valves.Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:1986 BSI 12-19983Section 2Table 1 Maximum permissible seat test leakage ratesTable 2 Maximum permissible back seat test leakage ratesTestRate ARate BRate CRate Dmm3/smm3/smm3/sHydrostatic testNo visually detectable leakage for the duration of the test time as given in the appropriate valve product standard or appendix B,as appropriate0.01 DN0.03 DN0.1 DNPneumatic testNo visually detectable leakage for the duration of the test time as given in the appropriate valve product standard or appendix B,as appropriate0.3 DN3.00 DN30 DNNOTE 1Equivalent leakage rates for ISO 5208 and BS 5146-2 are given in appendix A.NOTE 2No visually detectable leakage may be demonstrated during a pneumatic test in accordance with 4.3.NOTE 3The leakage rates only apply when discharging to ambient conditions.NOTE 4No visual leakage is accepted as being within the requirements of rates A,B,C and D.NOTE 5See note to Table 5 for large size Class rated valves.TestRate ARate BRate CRate Dmm3/smm3/smm3/smm3/sHydrostatic test0.03 DN0.03 DN0.03 DN0.1 DNPneumatic test3.00 DN3.00 DN3.00 DN30 DNNOTE 1The rate or rates of each test leakage for each valve type are specified in the appropriate valve product standard.NOTE 2The leakage rates only apply when discharging to ambient conditions.NOTE 3No visual leakage is accepted as being within the requirements of rates A,B,C and D.NOTE 4See note to Table 5 for large size Class rated valves.Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Sun Jul 15 09:08:15 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS 6755-1:19864 BSI 12-1998Appendix A Equivalent leakage ratesEquivalent leakage rates for this Part of BS 6755,BS 5146-2 and ISO 5208 are given in Table 3.Appendix B Test durationsTable 4,which is for guidance only,may be used where an appropriate valve product standard does not exist or where test times are not specified in a standard.In those cases where the appropriate valve product standard specifies different minimum test durations than those given in Table 4,the requirement of that valve product standard applies.Table 3 Equivalent leakage ratesTable 4 Test durationsThis Part of BS 6755aBS 5146-2ISO 5208A33B22C1AD11a See Table 1.Minimum te