ASME B16.5 History Rev Page 1 of 9

Transcription

1 Page 1 of 9 Presented here is a history of the development of ASME B16.5, Pipe Flanges and Flanged Fittings prepared by Guy Jolly and Don Frikken. Topics included in separate sections are: 1. General History 2. Ratings History 3. Flange Facing Finish History 1. General History This section is a summary of changes in the B16.5 standard over the years. While this section has some descriptions regarding ratings, you can find a more extensive discussion in the Ratings History Section. Originally, flanges always were made integral with fittings or valves. Threaded, lopped, and various welding types of flanges came into being because of the development of threading and tapping machinery, the development of flanging or VanStoning processes, and later the development of the art of welding. Year Summary of Changes Materials 1920 B16 committee formed by the American Engineering Standards Committee to unify and further develop standards for pipe flanges and fittings Subcommittee 3 was organized to develop flange standards for pressures in the 250 psi to 3200 psi range and for elevated temperatures. Active work began in October, including steel flanged fittings B16e, STEEL PIPE FLANGES AND FLANGED FITTINGS, published as American Tentative Standard with requirements for 250, 400, 600, 900 and 1350 lb flanges. Integral flanges, i.e. flanges cast or forged as part of the fitting, were covered in all series; threaded and blind companion flanges were covered only in the 250 lb series. The dimensions of the 250 lb Cast 1ron Standard were accepted directly for the 250 lb series and, with increased bolting and a thickening of the flanges, for the 400 lb series. The 800 lb, 1200 lb, and 3000 lb Hydraulic Standards, with modifications, served as the basis for the 600 lb, 900 lb, and 1350 lb series. Flanges A95 26T A105 26T Bolting A96 26 Classes A, B, & C

2 Page 2 of 9 Year Summary of Changes Materials 1932 ASA B16e published with addition of 100 lb flanges based on 125 lb cast iron flange dimensions; and rerating of 250 lb to 300 lb and 1350 lb to 1500 lb. The addition of the 100 lb flanges was motivated by the needs of the oil refineries where the use of cast iron had been found to constitute a hazard in case of fire. The uprating of the 1350 lb series resulted from demands of the power industry which was reaching for higher pressures and temperatures. Following an investigation into the factors determining stiffness of flanges and flange hubs, screwed and lapped flange dimensions were added in all pressure classes. The hub lengths and, in sizes 14" through 20", the hub diameters of the 300 lb pressure class were made somewhat greater The 1930s witnessed increased pressures, increased temperatures, the introduction of a new gasket called the ring type joint and advances in the art of welding. A revision was published that extended the size range in all classes down to the ½ inch size added slip on flanges in the 150 and 300 lb classes added blind and welding neck flanges in all pressure classes added 1500 lb flanges in the 14 in. through 24 in. size range added 2500 lb flanges and flanged fittings in the 1 2 in. through 12 in. size range added dimensions for a full line of ring joint flanges with higher ratings taken from API 5 G 3 flange ratings were established for materials other than carbon steel The dominant consideration for determining the hub length on welding neck flanges was to provide sufficient length to prevent the heat of welding from warping the flange face American War Standard B16e5 was published with increased pressure temperature ratings for all materials and all pressure classes as a measure to conserve vital materials in piping components. Slip on flanges were added for pressure classes above 300 lb. This document also added flanged end valves to the scope ASA B16e6 was published adopting the higher wartime ratings. The supplement updated material specification references and added a table of metal wall thicknesses for welding end valves. Slip on flanges were removed for pressure classes above 300 lb. Flanges A A Grade C1 A Class I and II A Class I and II A Grade F1 Bolting A96 33 A193 37T A194 38T Flanges A27 39 Gr B & B2 A216 42T Gr WCA & WCB A Gr 1 & II A Cl I & II A Gr C1 A217 42T Gr WC! & WC2 A Gr F1

3 Page 3 of 9 Year Summary of Changes Materials 1953 Changed from ASA B16e designation to ASA B16.5 and published with new materials a clearly defined rating basis that was permitted to be used for unlisted materials ratings extended to all commonly used alloy steels addition of socket welding flanges the reinstatement of slip on flanges of the 400 lb, 600 lb, and 900 lb pressure classes 1957 ASA B16.5 published with deletion of Class B ratings (for raised face flanges) making Class A ratings (for ring joint flanges) the standard for all types of flanges; limiting dimensions for gaskets, other than ring joint, which would merit the Class A ratings; and the addition of pressure temperature ratings for several new materials. This edition added The regular flange bolting is based on a stress not to exceed 7000 psi assuming the primary service pressure to act upon an area circumscribed by the outside diameter of raised face The primary service pressure is equal to the flange designation in psi; e.g. for a 300 lb flange = 300 psi ASA B16.5 addenda published with ratings for nickel, low carbon nickel, Monel, Inconel, Hastelloy B, Hastelloy C, aluminum alloys, and aluminum bronze. Flanges A105 57T Gr I & II A181 57T Gr 1 & II A335 55T P2, P3b, P21, P5b A182 57T F11, F22, F12, F5a, F9, F304, F310, F347, F321 & F316, A350 57T LF1, LF3 A216 57T WCB A217 57T WC1, WC4, WC5, WC7, C5, C12, A351 57T CF8, CF8C, CF8M A352 57T LC1, LC2, LC3 B160, B164, B166, Code Case 1173, Code Case 1194, B247 alloys , 6061 T6, B148 9A, 1961 ASA B16.5 published with clarifications. The number of steels expanded significantly ASA B16.5 published with clarifications. This edition was referenced in ASME Boiler and Pressure Vessel Codes until B was published ANSI B16.31, Non Ferrous Pipe Flanges, published with ratings from 1960 addenda. Same as ASA B addenda ANSI B16.5 published with a revised rating procedure, including a rating basis for Class 150 (150 lb) flanges; and new product forms, bar and plate, for special applications, including fabricated flanged valves and fittings. This Edition continued to cover rules for flanged valves but butt welding valves were moved to the new B16.34 standard.

4 Page 4 of 9 Year Summary of Changes Materials 1977 ANSI B16.5 published with a further revised rating basis for Class 150 flanges; the revision of ratings for stainless steel and certain alloy steel flanges; and removal of all references to valves (moved to B16.34) ANSI B16.5 published with the addition of nickel and nickel alloys; and the addition of metric dimensions for information only. ANSI B16.31 was withdrawn to avoid the conflict in nickel and nickel alloy ratings with B16.5. These ratings were similar but not identical ASME/ANSI B16.5 published with nickel alloy ratings extended to higher temperatures; and the deletion of metric bolt hole sizes ASME B16.47, Large Diameter Steel Flanges, introduced that extended coverage for construction of flanges in the NPS 26 to NPS 60 size range. Flange dimensions and ratings were based on MSS SP 44 for Series A flanges and based on API 605 for Series B flanges ASME B16.5 published with permission for dual marking; revised flange facing finish requirements; and revised pressure temperature ratings ASME B16.5 published with metric units as primary and allowing US customary units as alternate; revised pressure temperature ratings; altered flange thickness dimensional reference planes for Class 150 and 300 flanges; and the addition of straight hub welding flanges ASME B16.5 published with clarifications and some updates to pressure temperature ratings ASME B16.5 published with clarifications B16 Case 4 published to cover the construction details and ratings for 13 Cr flanges from A182 F6a Class 1 and Class 2 and A217 CA15 materials ASME B16.5 published with the addition of NPS 22 and clarifications.

5 Page 5 of 9 2. Ratings History This section describes in more detail the rating history of B16.5 flanges, including the introduction of ceiling pressure values. Year Summary of Changes 1927 B16e, STEEL PIPE FLANGES AND FLANGED FITTINGS, published with requirements for 250, 400, 600, 900 and 1350 lb flanges. The ratings were based on working steam pressures in psi at 750 o F. Higher pressures were allowed for non shock hydraulic ratings for fluids such as boiler feed water to 450 o F. The highest pressures were allowed for non shock hydraulic ratings for fluids such as air at or near ambient temperature. Ratings in psi Series Air Temp 450 o F 750 o F ASA B16e published with addition of 100 lb flanges; rerating of 250 lb to 300 lb and 1350 lb to 1500 lb flanges. The addition of the 100 lb flanges was motivated by the needs of the oil refineries where the use of cast iron had been found to constitute a hazard in case of fire. The uprating of the 1350 lb series resulted from demands of the power industry which was reaching for higher pressures and temperatures. In some sizes, notably the 2½ and 3 inch sizes (largest 4 bolt flanges), difficulties in producing tightness with certain gaskets were reported. This was thought to be related to their wide bolt spacing in relation to the flange thickness. Ratings in psi Series Air Temp 300 o F 450 o F 500 o F 750 o F A single sheet addendum issued under the designation ASA B16e This dealt entirely with pressure temperature ratings. The primary ratings were unchanged, but made two improvements: 1. The ratings below 750 o F were made more uniform. 2. Flanges had been limited to 750 o F. New ratings were added for higher temperatures based on newly revealed creep properties of medium steel. Service pressure, % rating at 750 o F Temperature ( o F) Steam Service Oil Service

6 Page 6 of 9 Year Summary of Changes 1939 A revision was published that added pressure temperature ratings for carbon molybdenum steels. Pressure temperature ratings were 20% higher for ring joint gaskets (Class A) than for other types of gaskets (Class B). 100 lb flanges were re designated as 150 lb without a change to the pressuretemperature ratings nor any changes in critical dimensions except that 3 1/2 inch and smaller flanges had an increase in flange thickness. Standard faced carbon molybdenum and equivalent alloy steel flanges were given the ratings established for 5% chromium molybdenum alloy steel flanges in Section 3 of the Code for Pressure Piping, ASA B Their primary rating temperature was 900 o F; above this value, the ratings paralleled the decrease in creep strength of the material. The secondary rating pressure, of 100 o F was estab1ished 20% higher than that for carbon steel, presumably based on the higher yield strength of 5% chromium molybdenum; ratings between 100 o F and 900 o F were interpolated. Ring joint carbon molybdenum flange ratings were made to follow the cast or forged alloy steel flange ratings established by the oil industry in the 1937 issue of API Standard S G 3. The ring joint ratings were set at six fifths of the ratings established for standard faced flanges During World War II (WWII), the USA War Production Board brought together a group of Stress Analyst and flange experts to review the B16e 1939 flange standard pressure temperature ratings that existed at that time. This was a full time job for this team and action was at a premium. Their goal was to make carbon steel flanges more acceptable for the defense industry projects during WWII without relying on alloy steel flanges. With exception of the 150 lb flanges, they increased all the flange ratings and published an American War Standard (B16e5 1943) for flanges that was used during WWII for defense contracts. The American War Standard history indicates that they did not change the 150 1b ratings with the reason, the Class 150 series is not sufficiently strong to warrant any improvement in its present rating. Fluid service ratings were removed but gasket specific ratings were retained. The flanged valve ratings were made to be the same as the flange class ratings ASA B16e6 was published. Following WWII, the Flange Committee adopted the American War Standard pressure temperature ratings and those ratings are close to what are in B16.5 today Added a general rating method that was permitted to be used for unlisted materials ASA B16.5 published with deletion of Class B ratings (for raised face flanges) making Class A ratings (for ring joint flanges) the standard for all types of flanges; limiting dimensions for gaskets, other than ring joint, which would merit the ratings; and the addition of pressure temperature ratings for several new materials. The revised pressure temperature rating method required that all ratings not exceed the carbon steel ratings up to 650 o F. Because of its low yield strength A182 F304 had lower ratings than carbon steel from 20 o F to 650 o F. This was the first use of the ceiling pressure values ASA B16.5 addenda published with ratings for nickel, low carbon nickel, Monel, Inconel, Hastelloy B, Hastelloy C, aluminum alloys, and aluminum bronze ASA B16.5 published with clarifications.

7 Page 7 of 9 Year Summary of Changes 1968 ASA B16.5 published with clarifications. This edition was referenced in ASME Boiler and Pressure Vessel Codes until B was published ANSI B16.31, Non Ferrous Pipe Flanges, published with ratings from the ASA B addenda An effort was made to develop a modern rational method for determining ratings for flanges made from new materials. Extensive successful experience had validated the ratings established in 1943, but how to translate that experience to new materials wasn t firmly established. The rating method developed resulted in flange ratings that were similar to the 1943 ratings for Class 300 and higher flanges as shown in Figure 1. Applying the same rules to Class 150 flange ratings resulted in a significant bump in the ratings at higher temperatures as shown in Figure 2. ANSI B16.5 was published with the revised rating procedure. The revised rating procedure included a ceiling pressure temperature table with values that could not be exceeded even for those flanges having specified strength properties significantly greater than the ceiling materials. The ceiling pressures below creep was based on the ratings for A216 WCC. The ceiling pressures in the creep range were based on the higher of the ratings of A216 WCC and A182 F The new ratings published in 1973, were not accepted by the referencing Boiler and Pressure Codes nor by the piping codes. Organized opposition to the increase in ratings for Class 150 flanges led by petroleum refiners prevented the adoption of the ratings in the 1973 edition of B16.5. The reasoning was that experience has shown that the existing Class 150 ratings, while generally acceptable, were marginal, so any significant increase in ratings for these flanges should not be permitted. The rating method was modified so that the Class 150 flanges had ratings similar to the historically proven ratings, and ANSI B was published with ratings similar to the 1968 edition. This edition included revision of ratings for stainless steel and certain alloy steel flanges. The ceiling pressures and ceiling materials were changed. Except for Class 150 flanges ceiling pressures below creep temperature were based on the A216 WCC material group ratings for 500 o F and lower temperatures. Over 500 o F into the creep temperature the ceiling pressure was based on the higher of the ratings of A182 F11 and A182 F316 material groups. An empirical method was introduced for ceiling pressures for Class 150 ratings ANSI B16.5 published with the addition of nickel and nickel alloys. ANSI B16.31 was withdrawn to avoid the conflict in nickel and nickel alloy ratings with B16.5. The ratings were similar but not identical ASME/ANSI B16.5 published with nickel alloy ratings extended to higher temperatures ASME B16.5 published with permission for dual marking; revised flange facing finish requirements; and revised pressure temperature ratings. Changes in tensile, yield or allowable stresses in ASME Section II, Part D led to B16.5 pressure temperature rating changes ASME B16.5 published with revised pressure temperature ratings.

8 Page 8 of 9 Year Summary of Changes 2009 ASME B16.5 published with clarifications and some updates to pressure temperature ratings No substantive rating changes No substantive rating changes. Figure 1. Class 300 Carbon Steel Ratings Pressure, psi Temperature, F Thru thru Figure 2. Class 150 Carbon Steel Flange Ratings Pressre, psi Temperature, F Thru thru 2013 Since the 1977 edition was published, the ratings have been adjusted when more accurate material properties were published in Section II of the ASME Boiler and Pressure Vessel Code, resulting in modest changes.

9 Page 9 of 9 3. Flange Facing Finish History Year Flange Facing Finish Requirements 1957 ASA B16.5 had no requirements for flange facing finish (FFF) ASA B16.5 required FFF meet the requirements of MSS SP ANSI B16.5 added specific requirements for FFF. For raised face and large male and female: 24 to 40 grooves per inch using a tool with an approximate 0.06 in. or greater radius 500 microinch maximum roughness for Class 150 & microinch maximum roughness for Class 400 and higher 1977 ANSI B16.5 changed the maximum roughness requirement for Class 400 and higher to 500 microinch ANSI B16.5 changed the roughness requirement to a range of 125 to 500 microinch ASME B16.5 revised the FFF requirements for FFF of other facings to: 45 to 55 grooves per inch 125 to 250 microinch roughness During the 1970 s and 1980 s, the flange facing finish discussions lasted for about an hour at each of the B16 subcommittee meetings. The reason for the discussions was the perceived needed FFF for the various types of gaskets used with the flanges. For sheet gaskets, like the popular compressed asbestos gaskets used at the time, a rougher finish is desirable to lower the probability that the gasket will be blown out of the flanged joint. For metal gaskets, like the recently introduced spiral wound gasket, a smoother finish is desirable to make it easier to obtain a good seal. At the time, the spiral wound gasket manufacturers were saying the flanges should have a 125 microinch finish for use with their gaskets. As a result, many piping material specifications with spiral wound gaskets specified flanges to B16.5, except with a FFF of 125 microinch. In 1986, Gordon Ruoff of Pennsylvania Process Compressors showed the 20 to 44 grooves/inch using a 0.06 in. radius tool would not produce a finish in the range of 125 to 500 microinch. Gordon used calculations and measured roughness on machined samples to support his position. This presentation led to the changes in the 1996 edition. Subsequently, the requirement for the 125 microinch FFF was dropped in most piping material specification because the finer B16.5 standard FFF was accepted. Sources 1. Guy Jolly and Don Frikken personal files 2. Various editions of the B16 flange standard 3. Piping Engineering published by Tube Turns, 1953 edition