1、Designation: F3149 15Standard Practice forDetermining the Maintenance Factor (m) and Yield Factor (y)Loading Constants Applicable to Gasket Materials andDesigns1This standard is issued under the fixed designation F3149; the number immediately following the designation indicates the year oforiginal a
2、doption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice will establish criteria for determiningloading constant
3、s that are referenced in the American Societyof Mechanical Engineers (ASME) pressure vessel design(Boiler and Pressure Vessel Code, Section VIII, Divs. 1 and 2).These constants are specific to this design criterion formetallic, semi-metallic, and nonmetallic gaskets.1.2 UnitsThe values stated in inc
4、h-pound units are to beregarded as the standard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
5、is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2000 Classification System for Rubber Products in Auto-motive ApplicationsF104 C
6、lassification System for Nonmetallic Gasket Materi-alsF868 Classification for Laminated Composite Gasket Mate-rials2.2 ASME Standards:3B16.5 Pipe Flanges and Flanged Fittings: NPS 1/2 throughNPS 24 Metric/Inch Standard Boiler and Pressure VesselCode Section VIII, Divs. 1 and 2PCC-1 Guidelines for Pr
7、essure Boundary Bolted FlangeJoint Assembly2.3 DIN Standard:DIN 3535 Gaskets for Gas Supply42.4 FSA Standard:FSA G 605:11 Standard Test Method for Determining (m)and (y) Loading Constants Applicable to Gasket Materialsand Designs53. Terminology3.1 Definitions:3.1.1 gasket contact area, A1,ngasket ar
8、ea in contact withthe flange surfaces and under load.3.1.1.1 DiscussionThe gasket contact area described inthis practice can deviate from the effective area described in theASME pressure vessel design.3.1.2 leak rate, nvolumetric leak rate per inch gasketoutside diameter.3.1.3 maintenance factor, m,
9、 nfactor that is required tocalculate the additional flange fastener preload needed tomaintain a seal after internal pressure is applied to a joint.3.1.4 surface stress, nstress applied to the gasket contactarea and equal to the applied load divided by gasket contactarea.3.1.5 yield factor, y, nfact
10、or that provides the gasketminimum design seating stress required to seal a joint uponassembly.3.1.5.1 DiscussionThis assumes no pressure and,therefore, a lack of hydrostatic end load effect on the assembly.Reported in psi.4. Significance and Use4.1 The gasket factors are a function of leak rate; th
11、erefore,this practice generates curves. Constants for use in the ASMEBoiler and Pressure Vessel Code, Section VIII, Appendix 21This practice is under the jurisdiction ofASTM Committee F03 on Gaskets andis the direct responsibility of Subcommittee F03.40 on Chemical Test Methods.Current edition appro
12、ved June 1, 2015. Published August 2015. DOI: 10.1520/F3149-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM websit
13、e.3Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from
14、 the Fluid Sealing Association, 994 Old Eagle School Rd.,#1019, Wayne, PA 19087-1866.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1code calculations are selected from these data. Specific m andy values can be selected based on a max
15、imum desired leak rateor derived from these data as described in this procedure. Thispractice addresses the influence of leak rate and gasketthickness on a gaskets ability to provide a seal initially and inoperation. This practice is performed at room temperature;therefore, this practice does not ac
16、count for all conditions, suchas high temperature or thermal cycling or both, that boltedflange connections may be subject to in field application.4.2 This practice determines two general characteristics thatare specific to the ASME design criteria. Caution should beexercised when comparing yield an
17、d maintenance factorsbetween gasket materials, and it is recommended that the mand y curves be compared. Selecting a gasket material for usein an application should not be based exclusively on these twogeneral characteristics. Gasket material selection for a givenapplication should consider addition
18、al information not de-scribed in this practice, which includes, but is not limited to,chemical resistance, thermal resistance, creep relaxation,compressibility, and accommodation of thermal cycling.4.3 This practice builds upon work conducted in the FluidSealing Association (FSA G 605:11). The assoc
19、iated roundrobin data is provided for reference in Tables 1-4.5. Apparatus5.1 The test apparatus is composed of three elements: testfixture, loading technique, and leak measurement.5.2 The test fixture may use a flange or platen press. Thesurface finish of the sealing area shall meet rules stated in
20、ASME B16.5 for acceptable surface finish with a roughness of125 to 250 in. (3.2 to 6.6 m).5.3 Hydraulically loaded flanges or platen presses are ac-ceptable. (The use of manual loading platens is not acceptable.)If a bolted flange fixture is selected, then loading of thefasteners shall be bolt stret
21、ch controlled. (The use of torquecontrolled loading is not acceptable.) Examples of bolt-stretch-controlled loading include the use of calibrated bolts andultrasonic devices. In addition, bolted flange fixtures shall beassembled per ASME PCC-1 guidance to minimize variabilityof test results. Such va
22、riables include flange parallelism, boltloading pattern, and multi-stage tightening levels.5.4 A leak measurement system is required. Leak measure-ment methods include differential pressure gage, manometer,flowmeter, and mass spectrometry. The test fixture shall have acontainment system to capture l
23、eakage outside the gasket,except when flow is measured upstream of the fixture.NOTE 1If leak rate is measured with a mass spectrometer, themeasured leak rate will be higher because of the higher pressuredifferential across the gasket, especially in the y value portion of the test.This is due to the
24、vacuum created at the gasket outside diameter by themass spectrometer.6. Test Specimen6.1 The test specimen should have a gasket width of 0.5 in.(12.7 mm) or greater. The inside and outside diameter of thegasket should be agreed upon between the producer and user.6.2 The recommended specimen thickne
25、sses are116 and18in. (1.6 and 3.2 mm).7. Conditioning7.1 Condition the gasket in accordance with ClassificationSystem F104, Classification F868, or as agreed upon betweenthe producer and user.7.2 Ensure the flange face is clean and free of defects,scratches, or foreign material, or a combination the
26、reof.8. Procedure8.1 Determining Yield Factor, y:8.1.1 Measure and record the initial gasket thickness ininches per the procedure described in Classification F104.8.1.2 Record the surface finish of the flanges or platens (seeSection 5).8.1.3 Center the gasket on the flange face or platen.8.1.4 Load
27、the gasket to 500 psi (3.45 MPa) surface stress.8.1.5 Pressurize the fixture to 2 psig (0.14 bar) and recordthe media.8.1.6 Hold for 15 min and record the leak rate. If the leakrate cannot be controlled or is in excess of measurementdevice, proceed to 8.1.7.TABLE 1 Fluid Sealing Association (FSA) Ro
28、und Robin Testing of Polytetrafluorethylene (PTFE), Yield FactorYield Factor, y(psi)F104 Type 45 Glass-Filled PTFELaboratory 1 Laboratory 2 Laboratory 3Test Specimen 1 Test Specimen 2 Test Specimen 1 Test Specimen 2 Test Specimen 3 Test Specimen 1 Test Specimen 2 Test Specimen 3500 1.14E-04 5.14E-04
29、 9.52E-03 4.30E-03 1.32E-02 1.27E-02 4.09E-03 1.46E-021000 5.14E-06 6.29E-05 1.10E-03 6.83E-04 3.20E-04 9.21E-04 1.41E-03 1.28E-031500 1.71E-07 9.86E-06 6.79E-04 6.95E-04 6.30E-042000 1.63E-07 9.69E-06 5.49E-04 7.59E-04 3.55E-042500 1.51E-07 9.54E-06 1.78E-04 1.62E-04 1.62E-043000 1.49E-07 8.86E-06
30、1.62E-04 1.62E-04 1.62E-043500 1.46E-07 9.31E-06 1.62E-04 1.62E-044000 1.42E-07 7.71E-064500 1.41E-07 8.69E-065000 1.37E-07 8.66E-065500 1.37E-07 5.43E-066000 1.34E-07 4.57E-06Selection of yieldfactor, y, basedon 0.00085 cm3/min per inch OD500 500 1000 1000 1000 1500 1500 1500F3149 1528.1.7 Increase
31、 the load in an incremental step of 500 psi(3.44 MPa) surface stress. Larger increments can be used withmaterials known to require higher seating loads.8.1.8 Hold for 15 min and record the leak rate.8.1.9 Repeat 8.1.7 and 8.1.8 until either the leak rate cannotbe detected or the desired maximum leak
32、 rate is obtained.8.1.10 Depressurize and disassemble the fixture.8.1.11 Measure and record the final gasket thickness ininches.8.1.12 Calculate the yield factor, y, for each stress incre-ment:y 5 W A1(1)where:W = total compressive force (lbs force) andA1= gasket contact area (in.2).8.1.13 Plot the
33、leak rate versus the yield factor, y.8.1.14 Select a yield factor based on the maximum desiredleak rate (Fig. 1) or the point of diminishing improvements inleak rate (the lowest yield factor at which higher surfacestresses do not result in significant leak rate reduction) (Fig. 2).It is acceptable t
34、o interpolate between load steps.8.2 Determining the Maintenance Factor, m:8.2.1 A new gasket shall be used for this section of testing.TABLE 2 Fluid Sealing Association (FSA) Round Robin Testing of Compressed Non-Asbestos (CNA), Yield FactorYield Factor, y(psi)F104 Type 71 CNALaboratory 1 Laborator
35、y 2 Laboratory 3Test Specimen 1 Test Specimen 2 Test Specimen 1 Test Specimen 2 Test Specimen 1 Test Specimen 2 Test Specimen 3500 2.23E-01 2.38E-01 2.50E-02 1.19E-01 8.45E-02 1.41E-01 1.30E-011000 7.06E-02 7.03E-02 1.41E-02 1.87E-02 3.02E-02 4.60E-02 4.72E-021500 2.95E-02 2.97E-02 5.62E-03 8.35E-03
36、 2.02E-02 2.52E-02 2.97E-022000 1.26E-02 1.26E-02 2.33E-03 3.61E-03 4.28E-03 2.94E-03 3.68E-032500 4.82E-03 4.80E-03 1.33E-03 1.55E-03 1.52E-03 1.95E-03 1.36E-033000 2.11E-03 2.11E-03 1.22E-03 6.48E-04 1.31E-03 7.92E-04 6.62E-043500 9.57E-04 9.43E-04 8.17E-04 5.98E-04 4.69E-04 4.36E-044000 4.25E-04
37、4.29E-044500 1.90E-04 1.91E-045000 7.71E-05 7.71E-055500 2.91E-05 2.86E-056000 1.54E-05 1.63E-05Selection of yieldfactor, y, based on0.00085 cm3/minper inch-OD4000 4000 3500 3000 3500 3000 3000TABLE 3 Fluid Sealing Association (FSA) Round Robin Testing of PTFE, Maintenance FactorNOTE 1Laboratory 2 i
38、ncreased the surface stress by the hydrostatic end load.NOTE 2Per 8.2.16, maintenance factors less than 2.0 are typically reported as 2.0 for use in ASME design calculations for non-elastomeric gaskets.F104 Type 45 Glass-Filled PTFELab 1 Lab 2 Lab 3SurfaceStress(psi)Mainte-nanceFactor, mTestSpecimen
39、1TestSpecimen2SurfaceStress(psi)Mainte-nanceFactor, mTestSpecimen1TestSpecimen2TestSpecimen3SurfaceStress(psi)Mainte-nanceFactor, mTestSpecimen1TestSpecimen2TestSpecimen36770 21.5 4.29E-07 6.00E-06 7072 22.6 BDLABDL BDL 6770 21.4 BDL BDL BDL6270 19.9 1.77E-06 9.43E-06 6572 20.9 BDL BDL BDL 6270 19.8
40、 BDL BDL BDL5770 18.2 1.97E-05 4.86E-05 6072 19.2 BDL BDL BDL 5770 18.1 BDL BDL BDL5270 16.5 6.57E-05 1.51E-04 5572 17.6 2.17E-03 6.67E-04 8.00E-03 5270 16.4 2.42E-05 2.91E-04 4.04E-044770 14.9 1.43E-04 2.79E-04 5072 15.9 1.33E-03 8.33E-04 9.17E-03 4770 14.8 2.08E-04 7.30E-04 6.30E-044270 13.2 2.34E
41、-04 4.30E-04 4572 14.2 1.33E-03 1.17E-03 5.00E-03 4270 13.1 4.36E-04 1.05E-03 7.27E-043770 11.5 3.43E-04 6.02E-04 4072 12.6 1.67E-03 6.67E-04 4.67E-03 3770 11.4 3.23E-04 1.32E-03 1.45E-033270 9.9 4.57E-04 8.16E-04 3572 10.9 1.83E-03 1.00E-03 7.00E-03 3270 9.8 5.49E-04 1.45E-03 1.63E-032770 8.2 6.29E
42、-04 1.08E-03 3072 9.2 1.67E-03 8.33E-04 7.50E-03 2770 8.1 7.75E-04 2.00E-03 2.99E-032270 6.5 9.14E-04 1.46E-03 2572 7.6 2.33E-03 1.00E-03 1.12E-02 2270 6.4 1.41E-03 2.55E-03 6.12E-031770 4.9 1.49E-03 2.42E-03 2072 5.9 2.67E-03 1.67E-03 1.37E-02 1770 4.8 2.89E-03 4.20E-03 9.53E-031270 3.2 1.48E-02 1.
43、83E-03 1572 4.2 3.50E-03 2.67E-03 2.27E-02 1270 3.1 4.12E-03 5.88E-03 1.31E-02770 1.5 2.23E-02 9.26E-01 1072 2.6 7.50E-03 6.17E-03 5.93E-02 770 1.4 1.49E-02 1.24E-02 1.53E-02Selection of mbased on maxi-mum leak rateof 0.085 cc/min-in OD1.5 3.2 2.6 2.6 2.6 1.4 1.4 1.4ABDL = below detection limit.F314
44、9 1538.2.2 Measure and record initial gasket thickness in inches.8.2.3 Record the surface finish of the flanges or platens (seeSection 5).8.2.4 Ensure flange facing is clean and free of contaminantsand debris from the previous section of testing.8.2.5 Center the gasket on the flange face or platen.8
45、.2.6 Load the gasket to 6770 psi (46.7 MPa) surface stress.8.2.7 Pressurize the fixture to 300 psig (20.7 bar) and recordthe media.8.2.8 Hold for 15 min and record the leak rate. If the leakrate exceeds maximum measurable leak rate or is above themaximum desired leak rate, increase the stress to 10
46、000 psi(68.9 MPa), then hold for 15 min, and record the leak rate.8.2.9 Decrease the load in an incremental step of 500 psi(3.44 MPa) surface stress. Increments can be varied based onmaterial characteristics and performance in previous tests.8.2.10 Hold for 15 min and record the leak rate.TABLE 4 Fl
47、uid Sealing Association (FSA) Round Robin Testing of CNA, Maintenance FactorNOTE 1Laboratory 2 increased the surface stress by the hydrostatic end load.F104 Type 71 Compressed Non-AsbestosLab 1 Lab 2 Lab 3SurfaceStress(psi)Mainte-nanceFactor, mTestSpecimen1TestSpecimen2SurfaceStress(psi)Mainte-nance
48、Factor, mTestSpecimen1TestSpecimen2SurfaceStress(psi)Mainte-nanceFactor, mTestSpecimen1TestSpecimen2TestSpecimen36770 21.5 5.71E-04 1.66E-02 7072 22.6 2.05E-02 BDLA6770 21.4 6.62E-04 1.00E-03 2.91E-046270 19.9 5.71E-04 1.71E-02 6572 20.9 2.15E-02 1.00E-03 6270 19.8 1.31E-03 1.42E-03 3.23E-045770 18.
49、2 5.71E-04 1.83E-02 6072 19.2 2.23E-02 1.17E-03 5770 18.1 1.32E-03 1.60E-03 4.68E-045270 16.5 5.71E-04 2.00E-02 5572 17.6 2.35E-02 8.33E-04 5270 16.4 3.13E-03 2.91E-03 5.75E-034770 14.9 5.71E-04 2.11E-02 5072 15.9 2.38E-02 1.33E-03 4770 14.8 9.24E-03 3.17E-03 1.44E-024270 13.2 5.71E-04 2.26E-02 4572 14.2 2.45E-02 1.33E-03 4270 13.1 1.38E-02 5.86E-03 2.97E-023770 11.5 5.71E-04 2.46E-02 4072 12.6 2.48E-02 8.33E-04 3770 11.4 6.16E-02 2.67E-02 6.19E-023270 9.9 5.71E-04 2.63E-02 3572 10.9 2.75E-02 1.17E-03 3270 9.8 8.38E-02 7.24E-02 7.91E-022770 8.2 5.71E-04 2
