ES-1 Internal Machining and Solid Machined Backing Rings for Circumferencial Butt Welds

CHARTER MEMBERS

ACCO ENGINEERED SYSTEMS Glendale, California

ACCORD PIPE FABRICATORS, INC. Jamaica, New York

ARMISTEAD MECHANICAL, INC. Mahwah, New Jersey

BASSETT MECHANICAL, INC. Kaukauna, Wisconsin

BUCHANAN INDUSTRIES LLC Fargo, North Dakota

FLO-RITE, INC. Riviera Beach, Florida

GEM INDUSTRIAL, INC. Walbridge, Ohio

HPI CONSTRUCTION CO., INC. Huntington, West Virginia

HUXTABLE & ASSOCIATES, INC. Lawrence, Kansas

IDEAL WELDERS, LTD. Delta, British Columbia (Canada)

INDUSTRIAL POWER SYSTEMS, INC. Toledo, Ohio

J. F. AHERN CO. Fond du Lac, Wisconsin

J. S. MC KINNEY, INC. Freeport, Texas

JOHN E. GREEN COMPANY Highland Park, Michigan

KINETIC SYSTEMS, INC. Santa Clara, California

MARELICH MECHANICAL CO. INC. Hayward, California

MC ABEE CONSTRUCTION, INC. Tuscaloosa, Alabama

MC CARL’S, INC. Beaver Falls, Pennsylvania

MECHANICAL INCORPORATED Freeport, Illinois

MID STATES PIPE FABRICATING, INC. El Dorado, Arkansas

MURPHY COMPANY St. Louis, Missouri

NARDEI FABRICATORS, LTD. Calgary, Alberta (Canada)

NEWMECH COMPANIES, INC. St. Paul, Minnesota

PIONEER PIPE, INC. Marietta, Ohio

PIPING SYSTEMS, INC. New London, Wisconsin

S & D / OSTERFELD MECHANICAL CONTRACTORS Dayton, Ohio

S. A. COMUNALE COMPANY, INC. Barberton, Ohio

SCHECK MECHANICAL WI CORP. Kaukauna, Wisconsin

TEAM INDUSTRIES, INC. Kaukauna, Wisconsin

UNIVERSITY MECHANICAL & ENGINEERING CO. San Diego, California

W. J. O'NEIL COMPANY Livonia, Michigan A current index of the latest revised ES Standards, Technical Bulletins and Safety Training Guideline is available from the Pipe Fabrication Institute. PFI Safety Training Guideline, Standards and Technical Bulletins are published to serve proven needs of the pipe fabricating industry at the design level and in actual shop operations. Hence, such needs are continually considered and reviewed by the Engineering Committee of the Pipe Fabrication Institute to provide recommended procedures, which have been demonstrated by collective experiences to fulfill requirements in a manner for Code compliance. However, as the PFI Standards are for minimum requirements the designer or fabricator always has the option of specifying supplementary conditions in the form of requirements beyond the scope of the PFI publications.

PFI Standard ES-1 (Revised September 2004)

INTERNAL MACHINING AND SOLID MACHINED BACKING RINGS FOR CIRCUMFERENTIAL BUTT WELDS

Prepared by

Pipe Fabrication Institute Engineering Committee

All PFI Standards are advisory only. There is no agreement to adhere to any PFI Standard and their use by anyone is entirely voluntary.

Copyright by

PIPE FABRICATION INSTITUTE Dedicated to Technical Advancements and Standardization in

the Pipe Fabrication Industry Since 1913

USA 666 Fifth Ave., #325 New York, NY 10103

CANADA 655, 32nd Ave., suite 201 Lachine, QC H8T 3G6

WEB SITE www.pfi-institute.org

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2


INTERNAL MACHINING AND SOLID MACHINED BACKING RINGS FOR CIRCUMFERENTIAL

BUTT WELDS

METRIC CONVERSIONS

The conversion of quantities between systems of units involves a determination of the number of significant digits to be retained. All conversions depend upon the intended precision of the original quantity and are rounded to the appropriate accuracy.

Pipe sizes together with applicable wall thicknesses are not shown with metric equivalents.

The SI (metric) values where included with the customary U.S. values in this Standard are the rounded equivalents of the U.S. values and are for reference only.

Metric units were derived utilizing the following conversion factor:

Conversion Factor inches to 25.4 millimeter

1. Scope 1.1 This Standard covers the dimensioning of solid

machined backing rings and the internal machining of seamless and welded piping components for use with these rings.

1.2 Piping components must be internally machined to a close tolerance to accept solid machined backing rings. For this reason, solid machined backing rings are not recommended for use with piping components with wall thickness less than 0.562" (14mm).

2. Backing Rings 2.1 Solid machined backing rings may be of either flat

or tapered design. Refer to Figures l, 2, 3, and 4 for backing ring dimensions and design.

2.2 The nominal diameter of a tapered solid machined backing ring shall be 0.010" (0.3mm) larger than the corresponding nominal internal counterbore of the piping component. The nominal diameter of a flat solid machined backing ring shall be equal to the corresponding nominal internal counterbore of the piping component. The diametrical tolerance on either a flat or tapered solid machined backing ring shall be +.000" –.010" (+0.0mm – 0.3mm).

3. End Preparation 3.1 Typical end preparations for different wall

thicknesses are shown in Figures 1 through 4. Those dimensions which are marked with an

asterisk (*) may be modified as appropriate for the applicable welding process and variables associated with that process. These specific dimensions shall be defined in the Welding Procedure Specification.

4. Internal Machining 4.1 The following terms define the various dimensions

and tolerances required to compute the internal machining dimensions ("C" dimension) for different types of piping components.

A = specified outside pipe diameter B = nominal inside pipe diameter C = I.D. machining dimension d = specified minimum inside diameter Mo = over tolerance on C-bore Mu = under tolerance on C-bore Ru = under tolerance on outside diameter So = over tolerance on inside diameter Su = under tolerance on inside diameter T = minimum ordered wall thickness t = nominal wall thickness tm = minimum wall required by design

4.2 To assure proper fit-up of adjoining components, and to assure proper fit-up of the backing ring it is recommended that "Mo" be set at +.010" (0.3mm) and "Mu" at –.000" ( –.000mm).

NOTE: It must be recognized that large diameter pipe with a relatively thin wall, has a tendency to spring back after removal from the machining fixture, so the

11

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3


tolerance (Mu or Mo) on the internal machining dimension "C" is therefore applicable to pipe ends measured in the restrained condition. This should be considered when checking the "C" dimension after removal from the machining fixture.

4.3 Pipe and companion components specified by outside diameter.

4.3.1 For pipe and companion components specified by outside diameter and minimum wall, the I. D. machining dimension is determined as:

C = A – Ru – Mo – 2tm , +Mo – Mu

4.3.2 For seamless and hollow forged pipe to ASTM A106, A312, A335, A376, or A405, "Ru = 0.031 in. Using the recommended values of "Mo" and "Mu" in paragraph 4.2 Formula 4.3.1 becomes:

C = A – 0.041 – 2tm +.010" –.000"

4.3.3 For pipe specified by outside diameter and nominal wall (or schedule) where the ASTM 12 1/2% nominal to minimum wall thickness tolerance applies, Formula 4.3.1 becomes

C = A – 0.041 – 1.75 t +.010" –.000"

"C" dimensions and corresponding backing ring dimensions for standard ANSI B36.10 pipe sizes, 24" and under with wall thickness 0.562" (14mm) and heavier, are published in Table 1. These dimensions have been calculated in accordance with Formula 4.3.3.

4.4 Pipe and companion components specified by inside diameter.

4.4.1 The formulas below may be used as a guide to determine the internal machining dimension for pipe and companion components specified by inside diameter:

a) for use of flat solid backing rings.

C = d+So+Su – Mo +Mo – Mu

b) for use of tapered solid backing rings where the possibility of weld buildup is to be minimized or eliminated.

C = d+So+Mo +Mo – Mu

NOTES:

1. Where "d" is specified as nominal instead of minimum I.D., "Su" should be dropped from the expression.

2. When using welded plate pipe, permissible variationsin out-of-roundness and diameter may make procurement of pipe with sized ends desirable. In this case "So" should be set equal to the plus sizing tolerance and "Su" the minus sizing tolerance.

4.5 Where the outside and/or inside diameters of the adjacent components differ from each other by more than the nominal tolerances, the heavier component shall be tapered in accordance with ANSI B16.25, Figure l.

5. Material Ordering 5.1 In some cases selection of internal machining

dimensions may affect ordered wall thicknesses of pipe and mating components.

5.2 Seamless pipe ordered by outside diameter: Formulas 4.3.1, 4.3.2 and 4.3.3 are intended to permit minimum wall to be maintained without purchase of material having wall thickness in excess of that required to satisfy "tm", or "T" as applicable.

When pipe and adjoining components are received with the O.D. larger than dimension "A" but within the permitted O.D. tolerance, or when internal machining for solid machined backing rings is performed, it may be necessary to perform an additional operation of depositing weld metal on the I.D. or O.D. surface at the welding end (weld buildup) to assure satisfactory contact between the internal machined surface of the piping component and the backing ring and to maintain tm.

Industry experience indicates that use of Formulas 4.3.1, 4.3.2 and 4.3.3 to determine the internal machining dimension will result in a satisfactory seat contact 7/32" (6mm) minimum (approximately 75% minimum length of contact) between pipe and 10° tapered backing rings. Occasionally it will be necessary to perform a weld buildup to provide sufficient material for machining for satisfactory seating.

5.3 Pipe ordered to inside diameter:

When the formulas listed in 4.4.1 are used for computing internal machining dimensions, and pipe is received with the I.D. at the minimum of the

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4

3/16"* (5mm)

30°*

7/32" MIN.(6mm)

±10°

3/4" (19mm)

3/16

"

1/16

"*(2

mm

)

(5m

m)

DTC (RING O.D.)(BORE)A B

t

BREAK CORNERS

TAPERED BACKING RING FOR NOMINAL WALLTHICKNESS (t) 9/16" TO 1" (14-25mm) INCLUSIVE

FIG. 1

FLAT BACKING RINGS FOR NOMINAL WALLTHICKNESS (t) 9/16" TO 1" (14-25mm) INCLUSIVE

FIG. 2

3/4" (19mm)DFC (RING O.D.)(BORE)

t

B

BREAK CORNERS

3/16"* (5mm)

1/2"(13mm)

1/8" R. MIN (3mm)

1/16

"*(2

mm

)

3/16

"(5

mm

)30°*

30° MAX.

A

permitted tolerance range, the possibility exists that machining will encroach “tm”

To minimize this problem, one of the following options may be utilized:

a) The ordered pipe wall thickness must be increased to provide additional stock for machining by use of the following formula

T = So+Su+tm +Mo

b) The "C" dimension and the minimum wall (tm ) that must be maintained at the "C" dimension should be specified on the purchase order for the pipe.

Note regarding rolled and welded pipe:

Due to the greater tolerances permitted for this material regarding out of roundness and variation in diameter, use of the options listed in 5.3 above may not necessarily eliminate the need for weld buildups in these materials.


9


TABLE 1 MACHINING DIMENSIONS (Metric) (continued) Nominal Pipe Size

(mm)

Schedule Number or Wall

Nominal O. D. Nominal I. D.

Nominal Wall

Thickness

Machined I. D. of Pipe "C"

O.D. of Backing Ring

"A" "B" "t" Tapered Ring “DT” Straight Ring “DS” 0.25 0.25 0.25 Tolerance

-1.00

Tolerance-1.00

Tolerance-1.00

60 406.40 373.08 16.66 376.20 376.45 376.2080 " 363.52 21.44 367.89 368.15 367.89100 " 354.03 26.19 359.54 359.79 359.54120 " 344.47 30.96 351.21 351.46 351.21140 " 333.35 36.53 341.43 341.68 341.43

16 O. D. (406)

160 " 325.42 40.49 334.54 334.80 334.54 40 457.20 428.65 14.27 431.17 431.42 431.17 60 " 419.10 19.05 422.81 423.06 422.81 80 " 409.55 23.83 414.50 414.76 414.50

18 O. D. 100 " 398.48 29.36 404.77 405.03 404.77(457) 120 " 387.35 34.93 395.05 395.30 395.05

140 " 377.85 39.67 386.72 386.97 386.72 160 " 366.73 45.24 376.99 377.24 376.99

40 508.00 477.82 15.09 480.59 480.85 480.59 60 " 466.75 20.62 470.87 471.12 470.87 80 " 455.63 26.19 461.14 461.39 461.14

20 O. D. 100 " 442.93 32.54 450.01 450.27 450.01(508) 120 " 431.80 38.10 440.28 440.54 440.28

140 " 419.10 44.45 429.16 429.41 429.16 160 " 407.97 50.01 419.48 419.74 419.48

--- 558.80 527.05 15.88 529.97 530.23 529.97 60 " 514.35 22.23 518.87 519.13 518.87 80 " 501.65 28.58 507.75 508.00 507.75

22 O. D. 100 " 488.95 34.93 496.65 496.90 496.65(559) 120 " 476.25 41.28 485.52 485.78 485.52

140 " 463.55 47.63 474.42 474.68 474.42 160 " 450.85 53.98 463.30 463.55 463.30

30 609.60 581.05 14.27 583.57 583.82 583.5740 " 574.65 17.48 578.03 578.28 578.0360 " 560.37 24.61 565.53 565.79 565.5380 " 547.67 30.96 554.41 554.66 554.41100 " 531.83 38.89 540.51 540.77 540.51120 " 517.55 46.02 528.02 528.27 528.02140 " 504.85 52.37 516.89 517.14 516.89

24 O. D. (610)

160 " 490.52 59.54 504.42 504.67 504.42

All dimensions are in millimeters.

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8


TABLE 1 MACHINING DIMENSIONS (Metric) Nominal Pipe Size

(mm)

Schedule Number or Wall

Nominal O. D. Nominal I. D.

Nominal Wall

Thickness

Machined I. D. of Pipe "C" O.D. of Backing Ring

"A" "B" "t" Tapered Ring “DT” Straight Ring “DS” 0.25 0.25 0.25 Tolerance

-1.00

Tolerance -1.00

Tolerance-1.00

3 (76) XXS 88.90 58.42 15.24 61.19 61.44 61.194 (102) XXS 114.30 80.06 17.12 83.29 83.54 83.29

160 141.30 109.55 15.88 112.47 112.73 112.475 (127) XXS " 103.20 19.05 106.91 107.16 106.91

120 168.28 139.73 14.27 142.24 142.49 142.246 (152) 160 “ 131.75 18.26 135.31 135.56 135.31

XXS “ 124.38 21.95 128.83 129.08 128.83 100 219.08 188.90 15.09 191.67 191.92 191.67 120 “ 182.55 18.26 186.11 186.36 186.11

8 (203) 140 “ 177.83 20.62 181.94 182.19 181.94 XXS “ 174.63 22.23 179.15 179.40 179.15 160 “ 173.05 23.01 177.75 178.00 177.75

80 273.05 242.87 15.09 245.64 245.90 245.64 100 “ 236.52 18.26 240.08 240.33 240.08

10 (254) 120 “ 230.17 21.44 234.54 234.80 234.54 140 “ 222.25 25.40 227.56 227.81 227.56 160 “ 215.90 28.58 222.00 222.25 222.00

60 323.85 295.30 14.27 297.82 298.07 297.8280 “ 288.90 17.48 292.28 292.53 292.28

100 “ 280.97 21.44 285.34 285.60 285.34120 “ 273.05 25.40 278.36 278.61 278.36140 “ 266.70 28.58 272.80 273.05 272.80

12 (305)

160 “ 257.20 33.32 264.49 264.74 264.4960 355.60 325.42 15.09 328.19 328.45 328.1980 “ 317.50 19.05 321.21 321.46 321.21

100 “ 307.95 23.83 312.90 313.16 312.90120 “ 300.02 27.79 305.97 306.22 305.97140 “ 292.10 31.75 298.98 299.24 298.98

14 O. D. (356)

160 “ 284.18 35.71 292.05 292.30 292.05

All dimensions are in millimeters.

5

BREAK CORNERS

ROUNDED

TAPERED RINGS FOR NOMINAL WALLTHICKNESS (t) GREATER THAN 1" (25mm)

FIG. 3

3/4" (19mm)

7/32" MIN(6mm)3/

4"*

(19m

m)

DTC(RING O.D.)(BORE)

t

B

3/16"* (5mm)

1/16

"*(2

mm

)

3/16

"(5

mm

)

30°*

±10°*

±10°

A

1/ 2"

(13 mm)

DS(R ING O.D.)

(BO RE)

1/16"*

(2mm)

3/16"

(5mm)

3 0° M AX.

F LAT BAC KIN G R ING S F OR N OM INA L W ALLTHI CKN ESS (t) GRE AT ER T HAN 1" (25m m)

FI G. 4

3/4" (19m m)

3/4" (19mm

)

CB

BRE AK C ORN ERS

1/8 " R. M IN (3mm )A

R OUN DED

3/16" * (5m m)3 0°*

10° *

t


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TABLE 1 MACHINING DIMENSIONS

Nominal Pipe Size

Schedule Number or

Wall

Nominal O. D. Nominal I. D. Nominal Wall Thickness



"A" "B" "t" Tapered Ring “DT” Straight Ring “DS”

Tolerance + 0.010 - 0.040 Tolerance + 0.010

- 0.040 Tolerance + 0.010 - 0.040

3 XXS 3.500 2.300 .600 2.409 2.419 2.409

4 XXS 4.500 3.152 .674 3.279 3.289 3.279

5 160 XXS

5.563 “

4.313 4.063

.625

.750 4.428 4.209

4.438 4.219

4.428 4.209

6

120 160 XXS

6.625 “ “

5.501 5.187 4.897

.562

.719

.864

5.600 5.327 5.072

5.610 5.337 5.082

5.600 5.327 5.072

8

100 120 140 XXS 160

8.625 “ “ “ “

7.437 7.187 7.001 6.875 6.813

.594

.719

.812

.875

.906

7.546 7.327 7.163 7.053 6.998

7.556 7.337 7.173 7.063 7.008

7.546 7.327 7.163 7.053 6.998

10

80 100 120 140 160

10.750 “ “ “ “

9.562 9.312 9.062 8.750 8.500

.594

.719

.844 1.000 1.125

9.671 9.452 9.234 8.959 8.740

9.681 9.462 9.244 8.969 8.750

9.671 9.452 9.234 8.959 8.740

12

60 80

100 120 140 160

12.750 “ “ “ “ “

11.626 11.374 11.062 10.750 10.500 10.126

.562

.688

.844 1.000 1.125 1.312

11.725 11.507 11.234 10.959 10.740 10.413

11.735 11.517 11.244 10.969 10.750 10.423

11.725 11.507 11.234 10.959 10.740 10.413

14 O. D.

60 80

100 120 140 160

14.000 “ “ “ “ “

12.812 12.500 12.124 11.812 11.500 11.188

.594

.750

.938 1.094 1.250 1.406

12.921 12.646 12.319 12.046 11.771 11.498

12.931 12.656 12.329 12.056 11.781 11.508

12.921 12.646 12.319 12.046 11.771 11.498

All dimensions are in inches.

7


TABLE 1 MACHINING DIMENSIONS (continued)

Nominal Pipe Size

Schedule Number or

Wall

Nominal O. D. Nominal I. D. Nominal Wall Thickness



"A" "B" "t" Tapered Ring “DT” Straight Ring “DS”

Tolerance + 0.010 - 0.040 Tolerance + 0.010

- 0.040 Tolerance + 0.010 - 0.040

16 O. D.

60 80

100 120 140 160

16.000 “ “ “ “ “

14.688 14.312 13.938 13.562 13.124 12.812

.656

.844 1.031 1.219 1.438 1.594

14.811 14.484 14.155 13.827 13.442 13.171

14.821 14.494 14.165 13.837 13.452 13.181

14.811 14.484 14.155 13.827 13.442 13.171

18 O. D.

40 60 80

100 120 140 160

18.000 “ “ “ “ “ “

16.876 16.500 16.124 15.688 15.250 14.876 14.438

.562

.750

.938 1.156 1.375 1.562 1.781

16.975 16.646 16.319 15.936 15.553 15.225 14.842

16.985 16.656 16.329 15.946 15.563 15.235 14.852

16.975 16.646 16.319 15.936 15.553 15.225 14.842

20 O. D.

40 60 80

100 120 140 160

20.000 “ “ “ “ “ “

18.812 18.376 17.938 17.438 17.000 16.500 16.062

.594

.812 1.031 1.281 1.500 1.750 1.969

18.921 18.538 18.155 17.717 17.334 16.896 16.515

18.931 18.548 18.165 17.727 17.344 16.906 16.525

18.921 18.538 18.155 17.717 17.334 16.896 16.515

22 O. D.

--- 60 80

100 120 140 160

22.000 “ “ “ “ “ “

20.750 20.250 19.750 19.250 18.750 18.250 17.750

.625

.875 1.125 1.375 1.625 1.875 2.125

20.865 20.428 19.990 19.553 19.115 18.678 18.240

20.875 20.438 20.000 19.563 19.125 18.688 18.250

20.865 20.428 19.990 19.553 19.115 18.678 18.240

24 O. D.

30 40 60 80

100 120 140 160

24.000 “ “ “ “ “ “ “

22.876 22.624 22.062 21.562 20.938 20.376 19.876 19.312

.562

.688

.969 1.219 1.531 1.812 2.062 2.344

22.975 22.757 22.265 21.827 21.280 20.788 20.350 19.859

22.985 22.767 22.275 21.837 21.290 20.798 20.360 19.869

22.975 22.757 22.265 21.827 21.280 20.788 20.350 19.859

All dimensions are in inches.

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Documents

ES-1 Internal Machining and Solid Machined Backing Rings for Circumferencial Butt Welds