{"operation":"document","citation":"PI-81-0105","title":"Pipeline Safety Interpretation PI-81-0105","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1981-05-01","effective_on":null,"summary":"PI-81-0105 concerning 192.147.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-81-0105.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-81-0105.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-81-0105","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/Pipeline/1981/g81-05-01_Effenberger_192.147-DBx.pdf","body":"<<<PAGE 1>>>\n\nPI-81-0105\nMay 1, 1981\nMr. Leo Effenberger\nNibco Inc.\n500 Simpson Avenue\nP.O. Box 1167\nElkhart, IN 46515\nDear Mr. Effenberger:\nIn regard to your letter of April 14, 1981, it is the policy of this office not to sanction vendors of pipeline\nmaterials. We will be happy, however, to answer any remaining questions you or your clients may have\nregarding compliance with §§192.147 and 195.126.\nSincerely,\nSIGNED\nMelvin A. Judah\nActing Associate Director for\nPipeline safety Regulation\nMaterials Transportation Bureau\n\n<<<PAGE 2>>>\n\nNIBICO INC.\n500 SIMPSON AVENUE\nP.O. BOX 1167\nELKHART, IN 46515\nApril 14, 1981\nMr. Melvin Jadan\nActing Assoc. Director of Pipeline Regulations\nDepartment of Transportation\nMaterials Transportation Bureau\nWashington, DC 20590\nDear Mr. Jadah:\nYour office in September, 1977 issued an opinion to our representative that stress analysis and proof testing\nto VG-101 would be sufficient to qualify our convoluted flange for use under Section 192.147 and 195.126. I\nam enclosing that required documentation and requesting correspondence from your office that we are a\nqualified vendor for flanges under that section. We have several gas companies that will use our product only\nwith this qualification letter from your office.\nSincerely,\nLeo Effenberger, P.E.\nNational Sales Manager\nIndustrial Division\n\n<<<PAGE 3>>>\n\nDEPARTMENT OF TRANSPORTATION\nMATERIALS TRANSPORTATION\nBUREAU WASMNGTON, D.C. 20590\nSeptember 21, 1977\nMr. Gunter Schlicht\nPipetech, Inc.\nOne Northwood Drive #5\nOrinda, California 94563\nDear Mr. Schlicht:\nYour letter of July 7, 1977, requests an interpretation of the applicable requirements of Parts 192 and 195\nrelating to the design and testing of pipeline flanges. Your specific question is: are the requirements of the\nASME Boiler and Pressure Vessel Code, Section VIII, Division 1 (Boiler Code) considered as an equivalent as\nintended in Section 192.147 to the referenced specifications for flanges in Part 192? Also, does the Boiler\nCode meet the requirements for flanges of Section 195.126 in Part 195?\nThe Boiler Code, which is referenced in both Parts 192 and 195, and the ANSI B16.5 and MSS-SP-44\nspecifications that are referenced in Part 192 are intended for the conventional design flanges that would\nbe manufactured by casting or forging rather than the convoluted design that would be folded into\nshape.\nIn Appendix II, Paragraphs UA-45 thru UA-59, inclusive, of the Boiler Code, the procedure for designing\nflanges for manufacture by casting or forging is set forth. It is suggested in this Appendix that if the\nprocedure set forth is not appropriate for the design, then in order to establish allowable working pressures,\nthe flange should be proof tested under the provisions of the Boiler Code, Section UG-101, Proof Tests, to\nestablish maximum allowable working pressure. The testing required by UG-101, that is applicable to all\npressure vessels, is more severe and thorough than that required by any of the other referenced\nspecifications for flanges.\nIt is our opinion that a detailed design and stress analysis supported by a proof test under the provisions of\nUG-101 of the Boiler Code provides the equivalent level of safety intended by Section 192.147.\nSection 195.126 states, with respect to a flange connection, that the \"connection as a unit must be suitable for\nthe service in which it is to be used.\" It does not provide any standard or test method to be used to determine\nthe suitability.\nIt is our opinion that the stress analysis and Boiler Code testing under the provision of UG-101 would be\nsufficient to determine whether flange connections are suitable under Section 195.126.\nSincerely\nCesar DeLeon Acting\nDirector Office of Pipeline\nSafety Operations\n\n<<<PAGE 4>>>\n\nTHOMAS A. SHORT CO.\n3430 Wood Street\nOakland, California 94608\nNovember 8, 1978\nNIBCO Inc.\n500 Simpson Avenue\nElkhart, Indiana\n46514\nAttention: Mr. Bob Russell\nDear Mr. Russell:\nThis letter verifies that the below listed convoluted NIBCO flanges, Class 150, were hydrostatically tested in\nour facility on September 20, 21, 22 and October 27, 1978.\nTEST PURPOSE To establish working pressure ratings for NIBCO convoluted Class 150 flanges in sizes and\ntypes indicated in the tables below in order to satisfy Section VIII, Div. I UG-101 proof test, and Section 1, Div.\n1 PG-100 Proof Test (ASME Pressure Vessel Code).\nTEST SPECIMENS NIBCO convoluted flanges, Class 150, were mounted to conventional ANSI B16.5 blind\nflanges, class 150, raised face with standard serration. Bolting material consisted of A-193 B16 studs\nwith grade 4 nuts, lubricated with anti-seeze lubricant. Gasketing material consisted of 1/16\" thick\nstandard compressed asbestos sheets and/or line backers.\nThe conventional ANSI B16.5 blind flanges were center drilled and tapped with 3/4\" NPT in order to fill\nthe specimen with water through this opening and remove the entrapped air and to connect the\nhydrostatic pressure test system. All flanges were identified per MSS-SP25.\nGENERAL STATEMENT Each pressure test was terminated at point of gasket leakage or gasket blowout and\nnot at the metallic burst pressure level of the component (flange) under evaluation. Three types of flanges\nwere tested. Specific descriptions relating to the flange type preceeds the associated table.\nA) NIBCO Convoluted Weld Neck Flange, Class 150, ASTM A316-60\nThe weld neck flanges were welded to standard wall, black steel pipe on one end while a standard wall\nB16.9 weld end cap was welded to the other end. The pipe length represented a minimum length of two\ntimes the diameter of the nominal flange connection size.\nTest Results: Size Max hydrostatic Pressure PSI Leak Torque Ft.-lb.\n2” 3500 no 100\n2-1/2” 3500 no 110\n3” 2200 yes 125\n1” 2400 yes 150\n5” 2600 yes 190\n6” 1900 yes 200\n8” 2000 yes 270\n10” 2200 yes 500\n\n<<<PAGE 5>>>\n\nB) Convoluted Blind Flanges, Class 150, ASTM A-516-60 The convoluted blind flanges were mounted\ndirectly to convoluted ANSI B16.5 raised face blind flanges.\nTest Results: Size Max hydrostatic Pressure PSI Leak Torque Ft.-lb.\n2” 4200 yes 100\n2-1/2” 3800 yes 110\n3” 2600 yes 125\n4” 2800 yes 150\n5” 2700 yes 190\n6” 2000 yes 200\n8” 2000 yes 330\n12” 1900 yes 600\nC) Convoluted Lap-Joint Flanges, Class 150, ASTM A-36 The convoluted lap-joint flanges were slipped\nover a conventional standard wall stub end type \"A\" to which a piece of standard wall black steel pipe\nwas welded, plus a standard wall B16.7 weld end cap. This entire assembly was mounted to an ANSI\n816.5 raised face standard serration blind flange.\nTest Results: Size Max hydrostatic Pressure PSI Leak Torque Ft.-lb.\n1” 4000 no .35\n1-1/2” 3700 yes 45\n2” 4100 yes 120\n2-1/2” 3950 yes 125\n3” 3500 yes 140\n4” 3000 yes 150\n5” 2800 no 190\n6” 2550 yes 200\nAll welding of the test specimen were performed by Scott Company of Oakland, California. The tests were\nassembled and performed by the THOMAS A. SHORT CO. under the personal supervision of Bill Sutliffe. The\ntests were witnessed by:\nBill Sutliffe\nGerald Horn, Safety Engineer D.I.5 838, N.B. 4663\nPressure Vessel Section\nDivision of Industrial Safety\nDepartment of Industrial Relations\nState of California\nand:\nGunter Schlicht, President\nPipetech, Inc.\nOrinda, California\nVery truly yours,\nR.M. Johnson, Manager Contracting and Repairs\n\n<<<PAGE 6>>>\n\nSTRESS ANALYSIS OF PIPETECH FLANGE\nPROFILE #14\nR.C. Murray\nMay 1976\n\n<<<PAGE 7>>>\n\nINTRODUCTION\nThe purpose of this analysis was to determine stresses and displacements of profile #14 Pipetech\nflange when subjected to both bolt load and hydrostatic pressure.\nThe flange was modeled as a body of revolution with loads applied to simulate the bolt and hydrostatic\npressure. A linear elastic static analysis was conducted.\nThe analysis was conducted with the computer program MARC-CDC. MARC-CDC is a finite element\ncomputer program used for structural analysis. The program is widely used for structural analysis and design\nof nuclear facilities. Westinghouse, General Electric, and Bechtel Corporation are some of the many firms that\nhave used the program. The program is available at all Control data Corporation data centers throughout the\nUnited States. All analysis was conducted on the CDC-6600 computer at the Western Cybernet Center at\nSunnyvale, California.\nDESCRIPTION OF ANALYSIS TECHNIQUE\nThe Finite Element Technique is a numerical procedure which can be used to compute displacements\nand stresses in structures of arbitrary geometry subjected to various loading conditions. Solution is obtained\nby the following steps:\n• Break the structure up into individual elements interconnected by nodal points.\n• Describe the location of the nodal points by specifying the coordinates of each point.\n• Describe the elements by indicating the nodal points connected to them and the material properties\n(E,ѵ) associated with them.\n• Specify the applied loads and indicate which nodal points are not free to move.\nThe finite element program then takes the input geometry, material properties, and load description and\ncalculates displacements at the nodal points and stresses at the center of each element. The mathematical\ntechniques employed in the solution are based on the principles of solid mechanics. Details of the calculations\ncan be found in O.C. Zienkiewicz, The Finite Element Method in Engineering Science.\nMODEL DESCRIPTION\nThe flange was modeled as showing in fig. 1. Four elements were used through the thickness.\nNode and element numbers are shown on the mesh. R and Z components of displacement are\ncalculated at each nodal point in the model, while stresses are calculated at the center of each element.\nRadial, axial, hoop, shear, and von Mises stress are calculated for each element.\nRollers which prevent axial motion (z-direction) were placed at the free end, node 5, and at the gasket,\nnodes 145, 150, and 155. Nodes 226-230 were not constrained. This was felt to be a worst case condition for\nthe flange pipe connection.\nPressures were applied to simulate the bolt load over elements 45, 46, 47, 48, and 49. Pressures were\napplied over elements 116, 117, 133, 134, 135, 136, 137, 153, 154, 155, 156, 157, 158, and 159 to simulate\nhydrostatic pressure. The input load description is shown in Table 1.\nTABLE 1\nInput Loading\nBolt Load = 11,300 lbs/bolt\nTotal Bolts = 12\nContact Area = π(9.942\n– 8.8152) = 66.286 in2\n\n<<<PAGE 8>>>\n\nBolt Pressure = (number of bolts)(bolt load)\nContact area\n= (12)(11,300) = 2045 psi\n66.286\nAlso subjected to a hydrostatic pressure of 285 psi.\nMaterial Properties\nSteel: E = 30 x 106 psi\nѵ=0.3\n\n<<<PAGE 9>>>\n\nRESULTS\nThe contour plot of the von Mises stress is shown in Figure 2. The von Mises stress was calculated by\nthe following formula:\nσvon Mises = √ ½ (σ\nzz -σRR)2 + (σRR -σhoop)2 + (σhoop -σzz)2 + 3σ\n2\nRZ\nFor a ductile material such as steel, the von Mises stress can be compared directly with the allowable\nstress specified for the material. For this loading a maximum von Mises stress of 12, 770 psi occurs in Element\n47. Note that stresses are calculated at the center of the elements and must be extrapolated to get maximum\nvalues at the surface.\nI have also included the stresses computed for each element and the calculated nodal point\ndisplacements.\n\n<<<PAGE 10>>>\n\nMETALLURGICAL AND MECHANICAL\nEVALUATION OF 3\", 4\", AND 6” FLANGES\nHASKELL D. WEISS, P.E.\nMT431\n\n<<<PAGE 11>>>\n\nINTRODUCTION\nThis report presents and evaluation of three flange parts (3\", 4\", and 6\") and a portion of a plate typical\nof starting material prior to cold forming.\nSections were removed from parts by sawing and/or flame cutting and then prepared for study by\npolishing and etching.\nThe analysis was made with the aid of a metallurgical microscope and a microhardness tester.\nThe report sections cover in detail the following:\n1) Metallurgical examination of starting material.\n2) Metallurgical examination of 3”, 4\", and 6” diameter flanges.\n3) Deficiencies that should be corrected.\n4) The effect of welding on flange material.\n5) Product reliability and heat treatment.\nDISCUSSION\n1. The starting material is cross-rolled and has a reported chemical content by weight of:\nC - .18%\nMn - .74%\nP - .006%\nS - .015%\nSi - .22%\nFe - balance\nTo obtain a fine grain it is rare earth treated. It has not as yet been determined if production parts will\nbe pickled, grit blasted or surface treated in some fashion prior to forming. To prevent inbedding of foreign\nmaterials during drawing it is suggested that starting plate be cleaned prior to working.\nA sample was removed from the starting stock as per Fig. 1. Fig. 2 and Fig. 3 show the microstructure in\nboth longitudinal and transverse directions. The grain size and elongation show that rolling was about equal in\neach direction. The dark regions are pearlite and the light regions are ferrite. Reported tensile data:\nYield Strength ------- 45,000 psi\nTensile Strength ----- 66,000 — 72,000 psi\nElongation in 8\" ----- 26.5 — 28.2%\nMicrohardness tests were made on both center and edges of the plate as shown in Fig. 4. The hardness\nnumbers in DPH were converted to Brinell and tensile strength.\nDPH BH Tensile Strength (psi)\nthickness.\nEdge 171 162 79,000\nCenter 150 143 71,000\nThis agrees quite well with the reported data, also it indicated the strength is uniform throughout the\nIt is important that in future purchases of starting stock that this uniformity of microstructure be\nmaintained. Lack of uniformity could lead to differences in springback from one lot of material to another.\nAdditionally lack of uniform texture could cause failure in forming.\n2. There were three flanges examined; a 3\", 4\" and 6\" diameter type. These are formed in\nmultiple draw operations. The tooling concepts may be different between sizes. However, each type is\ntreated as a single population and die design differences are not relevant to the conclusions drawn.\nThe drawing sequences are done at ambient temperature conditions with no anneal, stress relief or\n\n<<<PAGE 12>>>\n\nheat treatment of any type performed on the final formed parts. Thus, the microstructures are representative\nof production parts.\nFig. 5 shows a 3\" blind flange in section and location of microhardness readings and orientation of\ngrain structure examination. Fig. 6 and Fig. 7 shows the variation in cold work areas \"k\" verses \"n\". Areas \"a\"\nand \"c\" are shown in Fig. 8 and Fig. 9. These show laps and heavy deformation resulting from the forming\noperations. Note that in heavily deformed regions the identity of the grain structure is almost lost. Also note\nthe depth of heavy deformation appears to be approximately .010\" to ,015\".\nFrom reference (1) it is noted that steel typical of this composition has a true strain at fracture of\nbetween .9\"/\" to 1.0\"/\". This can be transformed into the cold work capacity which amounts to between 50-\n60%. (Reference 1)\nThe microhardness in the various areas are tabulated and converted into tensile strength and cold\nwork percentage, Table 1. From these numbers and the microstructure and assessment of the part can be\nmade.\nFig. 10 shows a 4\" flange in cross section and location of areas of investigation. Fig. 11 and Fig. 12 of\nareas \"c\" and \"i\" are typical of the microstructure. Note the diamond penetrator mark in Fig. 11, indicating\nmeasurements of cold worked areas within .005\" of the surface. See Table 2 for hardness, cold work and\ntensile strength. The microstructural examination shows no evidence of laps, seams or tears.\nFig. 13 and Fig. 14 shows a 6\" blind flange and the section removed for examination. Fig. 15 and Fig. 16\nshows areas \"a\" and \"c\" where a lap and tear are evident. The hardnesses and cold work are listed by area in\nTable 3.\nComparison of the three flanges by microstructure and cold work would indicate the 4\" to have the\nleast amount of surface deformation. The areas of maximum work, 3\" and 6\", show where metal has been\ncold worked as high as 57%. This heavy amount of cold work however, measures less than .015\".\n3. If the 4” flange were to serve as a standard, then the surface of all parts should be continuous\nwithout tears or laps. From a cosmetic standpoint this would be desirable, however from a reliability\nstandpoint it is not necessary, as will be discussed in section 5. What is needed is reproducibility and quality\ncontrol.\n4. In the upper portion of Fig. 14 is shown an almost straight section. The right edge at the arrow\nindicates a region where the part was flame cut to separate from the balance of the flange. Note the shade\ndifference at the right. This indicates the recrystallized zone due to oxy-acetylene flame cutting. This region\nalso appears during a welding operation. Fig 17 shows two different structures in the heat affected zone\n(HAZ), note Fig. 18 which shows a microstructure typical of the starting material. Working through the regions\nof melt zone and HAZ, the distance involved amounts to .180\". This would indicate that the heat generated by\nan electric arc would not affect the parent material beyond a distance, conservatively with multipass welding,\nof .30\" from the molten edge. Note that the hardnesses are higher in region \"u\", Fig. 17, then in the starting\nmaterial, (Table 3). This results from the rapid cooling of the HAZ allowing for a finer grain structure.\nGenerally, strength increases with decreasing grain size.\nThe above would suggest that welding will not degrade the strength of the worked parent material.\nGenerally, the weld metal is the weakest link in any structure, since it has a cast, course grained\nmicrostructure. This, as a rule, is compensated for by increasing the cross sectional area of the weld metal.\n5. In the absence of long term test data on fully stressed flanges, assumptions and conservative\nestimates are necessary in order to present a credible reliability statement. A review of the stages in the\ndrawing of a 3\" diameter flange indicates that there are three stages involved. The state of stress varies not\nonly throughout the part but through the thickness as well. As indicated earlier the heavy deformation is\n\n<<<PAGE 13>>>\n\nlimited to approximately .015”. Biaxial stresses exist throughout the part and are generally in tension radially\nand in compression circumferentially. A feel for the magnitude of these stresses are indicated by the hardness\nreadings when converted to percentage cold work. The presence of biaxial stresses can be noted by Fig. 19\nwhich is taken in the area between \"a\" and \"c\". Note the elongation of grains perpendicular to the surface, as\nopposed to the grains in Fig. 12 which are parallel to the surface. This would tend to indicate compression at\nthe surface in many locations would inhibit the tendency for fatigue cracking.\nIn my opinion 40% cold work is a tolerable level for parts so long as this amount is kept within .010-\n.020\" of the edge. However, in the 3\" and 6\" flange this is exceeded not in depth but in magnitude. To assess\nthe significance of region \"c\" in Fig. 9, I assumed that a part had a fatigue crack .015\" and cyclic stresses of 10\nKSI (Appendix). This calculates to a part life of 5.5 x 106 cycles. Other stresses, fatigue crack lengths and cyclic\nlife are tabulated in the Appendix. These results show fatigue is not a problem at the selected design loads and\ndefects limited to .015\". I have arbitrarily selected 5.4 x 106 cycles as infinite life. This calculation assumes an\ninfinite thickness of plate. Obviously, this is not true, also the effect of corrosion products on fatigue cracks has\nnot been taken account of in the calculation. For this reason, I have been conservative in my estimates and\nbelieve the above crack limitation and stresses are realistic.\nIt should also be pointed out that high hardness on the surface has a somewhat similar effect relative\nto fatigue resistance as that of shot peening. While, the material below the heavy deformation has an\nextremely high toughness, or fatigue resistance. Therefore, I do not believe it is either necessary to anneal or\nshot peen the flange surfaces. Quality control should be exercised to limit sharp tears to a maximum of .015”\nor approximately 5-10% of the part thickness. Dents as a result of handling are not a problem so long as they\ndo not result in sharp cracks. This is a materials handling problem faced by all users of any structural piece of\nhardware.\nThe inspection techniques can be a combination of \"Magnaflux\" and dye penetrant. The latter can,\nwith experience, be developed to provide a quanitative estimate of the depth of surface flaws. Starting\nmaterial should be randomly (1) mechanically tested; (2) grain size checked; (3) chemically analyzed; (4) and\nhardness tested. All of the above is directed toward the use of a controlled starting material. A lowering of\nreduction of area; increase of grain size; differences between longitudinal and transverse grain structure could\ncause the manufacturing process to become out of control and parts not meet specification.\n\n<<<PAGE 14>>>\n\nREFERENCES\n1. \"Material Properties and Manufacturing Processes\", J. Datsko, John Wiley and Sons, 1967.\n2. \"Linear Elastic Fracture Mechanics and Its Application to Fatigue\", R.I. Stephens, Society of Automotive\nEngineers, 740220, 1974.\n\n<<<PAGE 15>>>\n\nRegion\na (edge)\na (edge)\nc (lap Area)\nc (edge)\nd (edge)\nd (edge)\na x d (center)\ne (edge)\ne (edge)\ne (center)\nf (edge)\nf(edge)\nf (center)\ng (edge)\nh (edge)\ng x h (center)\ng x h (center)\nI (edge)\nI (edge)\nj (center)\nj (center)\nj (outside edge)\nk (inside edge)\nn (outside)\nn(center)\nn (inside)\nn (inside)\nTable 1\nHardness(DPH)\nHardness (BH)\nT.S. (KSI)\nCold Work (%)\n353\n348\n366\n305\n252\n255\n241\n263\n272\n245\n266\n252\n243\n285\n322\n255\n256\n287\n290\n223\n237\n226\n323\n228\n241\n258\n250\n334\n329\n347\n289\n240\n243\n228\n250\n258\n233\n252\n240\n231\n270\n306\n243\n244\n273\n275\n212\n225\n215\n306\n217\n228\n245\n238\n168\n164\n173\n143\n117\n119\n112\n123\n127\n114\n124\n117\n113\n134\n152\n119\n120\n134\n136\n102\n109\n104\n153\n105\n112\n120\n116\n56\n57\n49\n37.5\n39\n35\n41\n42\n36\n41\n37.5\n35\n46\n52\n39\n39\n46\n46\n28\n33\n30\n52\n30\n35\n39\n37\n\n<<<PAGE 16>>>\n\nTable 2\nRegion\nHardness (DPH)\nHardness (BH)\nT.S. (KSI)\na\n221\n210\n101\nc\n225\n214\n103\nd\n252\n240\n117\ne\n232\n221\n107\nf\n223\n212\n102\ng\n254\n242\n119\n116\nh\ni\n250\n277\n238\n262\n130\nj\nj\nk\n247\n255\n235\n243\n115\n119\n265\n252\n124\nm\n263\n250\n123\nCold Work (%)\n28\n29\n37.5\n32\n28\n38\n37\n44\n36\n39\n41\n41\n\n<<<PAGE 17>>>\n\nTABLE 3\nRegion\nCold Work (%)\na (HD)*\n284\n270\n46\na (LHD)*\n287\n273\n135\n46.6\na (NHD)*\n247\n121\n40\na (HD)*\n357\nc (HD)*\n373\nc (LHD)*\n329\nc (LHD)*\n306\n*\n273\ncf\n262\nf\n221\ncf\n221\ne\n204\ne\n247\nee\n242\n256\nn\n306\nn\n243\nn\n275\nnn\n228\ni\n262\nh\n262\ng\n245\ngh\n262\n270\n273\n247\n265\n131\n237\n115\n207\n95\n202\n93\nr\n207\n95\n194\n90\nt\n162\n76\n178\n82\nu\n188\n87\nn\n206\n196\n90\nHD\nHeavily deformed\nLHD\nLess heavily deformed\nNHD\n-\nNot heavily deformed\nWeld Zone + HAZ = 1.3 mm + 3.3mm = 4.6 mm\n=184","truncated":false,"body_characters":22742}