Informative Annex 1

May 20, 2004 1 of 11

Informative Annex 1

Flanges

These Informative Annexes are for the use of the Task Force and are not to be included in the API Standards

Introduction: This Annex provides background on the Flange Section (6.4.11) of the SP. Normally discussion paragraphs are placed after each paragraph in order to provide background on the preceding SP. During the development of these discussion paragraphs for the flange section, considerable investigation was carried out to determine the differences between the referenced ISO 7005-1 & 2 standards and the customary US ASME references. It was felt that the results of this investigation were better presented in an Annex rater that imbedded in the body of the SP due to the length and tables associated with these Discussion paragraphs.

6.4.11 FLANGES

• 6.4.11.1 Flanges shall conform to ISO 7005-1 Series 1, including Annex D & E or 7005-2 Series 1 or ASME B16.1, B16.5, B16.42 or B16.47 (Series A or Series B), as specified, except as specified in 6.4.11.1 through 6.4.11.7 (617).

Note 1: ISO 7005-1 (steel flanges) PN 20, 50, 110, 150, 260, 420 are designed to be interchangeable with ASME B16.5 and MSS SP-44 flanges - ISO 7005-1 flanges are not identical to ASME B 16.5 and MSS SP 44 flanges but are deemed to comply with the dimensions specified in the ASME B 16.5 and MSS SP 44.

ISO 7005-2 (cast iron) flanges PN 20, 50 are designed to be interchangeable with ANSI/ASME B16.1 (gray cast iron) and B 16.42 (ductile cast iron)but they are not identical. They are deemed to comply with dimensions specified in ASME B16.1 (grey cast iron) and B 16.42 (ductile cast iron).

Note 2: ISO PN 2.5, 6 do not have a corresponding ASME class and ASME Class 75, 400 & 800 do not have corresponding ISO PN designation. The use of these PN and Class flange ratings are therefore not recommended.

Discussion Note1: ISO 7005-1 (Steel) and 7005-2 (Cast Iron) are dimensional standards.

7005-1 does not mandate materials or corresponding Pressure / Temperature ratings, although various Informative Annexes list commonly used materials and corresponding Pressure / Temperature ratings. By including the Annexes D & E in 6.4.11 these annexes now become normative and part of this specification.

7005-2 includes as part of the standard, tables specifying materials and pressure temperature ratings and therefore these do not have to be added after the reference to 7005-2 in paragraph 6.4.11.

In contrast, the ASME flange standards include, as part of the specification, ASME materials and the corresponding pressure temperature limitations and therefore materials and pressure temperature references do not have to be added after ASME standards in paragraph 6.4.11.

Discussion Note 2 ISO 7005-1 and 7005-2 have flange rating (PN) divided into Series 1 and Series 2. Series 1 flanges are the basic ratings. Series 2 flanges are on a list for possible deletion. We have defaulted to Series 1 flanges thereforein 6.4.11.

Note to TF Chairmen: When equipment has cast flange nozzles the TF should confirm that the flange ratings for the material as outlined in these ISO and ASTM flange specifications are sufficient for the casing rating.

6.4.11.2 When ISO 7005-1 has been specified, materials shall be in accordance with Annex D-1 (DIN) or Annex D-2 (ASTM) as specified. The Pressure Temperature ratings in Annex E shall correspond to the materials specified.

Note: Annex E Table 1-4 covers D-1 materials and Table 5-21 covers D-2 materials.

•6.4.11.3If specified, ASME B 16.47 Series A flanges shall be provided.

Discussion Note 1: The ASME B 16.47 Series A flange dimensions are based on MSS SP 44 flanges which have larger bolt circle than the ASME B16.47 Series B flanges which are dimensionally based on API 605 flanges. Since the Series B are based on an API document (API 605), the SP’s were written to default to an API document, API 605 section of ASME B 16.14 was used in 6.4.11.

Discussion Note 2: 6.4.11.2 was added to allow a user to choose the ASME B 16.47 Series A flanges which are based on the larger MSS SP 44 flanges.

Discussion Note 3: Series A ( API 605) and B (MSS SP 44) do not mate with each other . For example:

Class 300#, 26” diameter Series A flange bolt circle is 34.5” Dia. (MSS Base)

Class 300#, 26” diameter Series B flange bolt circle is 31.62” Dia.(API Based)

Discussion Note 4: Table 1 has been developed outlining the scope of the various Flange reference standards.

Table 1 - Scope of Standards
Standard Number / Scope / Annex
ISO 7005-1 / Steel Flanges Dimensions only. Need to specify Materials and P/T Ratings. See Annex D & E / D covers materials
D1 covers DIN Material.
D2 covers ASTM Material.
E covers P/T Ratings for materials covered in D1 and D2
Table E 1-4 Cover D1 materials
Table E 5-21 Cover D2 Materials. The P/T ratings in tables E5-21 agree with flanged and butt welded flanges in ASTM B-16.5
ISO 7005-2 / Cast Iron Flanges / Gray (GI)
Ductile (DI
Malleable (MI)
ASME B 16.1 / Cast Iron Flanges Class 25( 4”- 96” Dia.),125 ( 1”- 96”Dia.), 250 (1”-30”Dia., 800 (2”-12”Dia.)_
ASME B 16.42 / Ductile Iron Flanges Class 150 & 300 (1“-24”Dia.)
ASME B 16.47 Series A (General use flanges) / Large Diameter Steel Flanges (26”- 60” Dia.) Class 75,150,300,600,900
Adopted MSS SP-44 dimensions.
Materials are divided into 22 groupings with corresponding P/T limitations for each group of materials. For example, depending on the material a 300 class flange at 400 F can be rated from 495psi (Table 2-2.1 Group 2.1 Material) to 705 psi (Table 2-1.14 Group 1.14 material)
ASME B 16.47 Series B (Compact flanges which generally have smaller bolt circle dia. than Series A) / Large Diameter Steel Flanges (26”- 60”Dia.). Class 150,300,600,900 .
Incorporated API 605 flanges which previously covered these size flanges. API therefore has been withdrawn in preference of ASME 16.47)
ASME B 16.5 / Pipe flanges & Flanged Fittings-Steel. Class 150, 300 ,400, 600, 900,1500, all (1/2-24” Dia.),2500 (1/2-12”)
MSS SP-44 / Steel PIPELINE Flanges Class 150 (12”-60” Dia), 300(12-60”Dia.), 400(12”-60” Dia), 600(12”-60” Dia) ,900 (12”-48”Dia)
Dimensions:
There is only one P/T limitation table as opposed to the 22 in ASME B 16.47 series A flanges. A 300 class flange at 400 F is rated at 665 PSI (Table3) this compares to rating between 495 and 705 PSI for ASME B 16.47 Series A flanges
Steel Pipeline flanges - Has been incorporated into and superseded by ASME 16.47 Series A
API 605 / API 605 has been withdrawn and replaced with ASME 16.47Series B
API 607 / Fire Test for soft seated quarter turn valves (Title from API catalog) This does not look correct
MSS SP-7 / According to MSS a standard using this number was never issued

MSS = Is the Manufacturers Standardization Society of the valves and fitting industry. There web page is

Discussion Note 5: In the American system (ASME) the flanges are designated by a class rating. These have been changed in the ISO system to nominal pressure (PN) designations. The equivalent PN designations are as follows:

Table 2 - Class Rating vs. PN
ASME / European
System / ISO in 7005-1 and -2
Steel
(ST)
ASME B 16.5 / Cast Iron
(CI)
ASME
B-16.1 / Ductile Iron (DI)
ASME
B-16.42 / Steel
(ST)
ASME
B-16.47A / Steel
(ST)
ASME
B-16.47B
PN 2.5 / PN 2.5(2)
PN 6 / PN 6(2)
PN 10 / PN 10(1)
PN 16 / PN 16(1)
Class 25
Class 75
Class 125 / PN 20(1)
Class 150 / Class 150 / Class 150 / Class 150 / PN 20(1)
PN 25 / PN 25(2)
PN 40 / PN 40(2)
Class 250 / PN 50(1)
Class 300 / Class 300 / Class 300 / Class 300 / PN 50(1)
Class 400 / Class 400 / Class 400
Class 600 / Class 600 / Class 600 / PN 110 ISO 7267 indicates this as PN 100. there is no PN designation of 110.
Class 800
Class 900 / Class 900 / Class 900 / PN 150(1)
Class 1500 / PN 260??ISO 7267 indicates this as PN 250. There Is no PN designation of 260.
Class 2500 / PN 420(1)

Note 1: (1) Per ISO 7267-1983 (e) “ Piping components – Definition of nominal pressure” These designations are referred to as Series 1 and are the basic rating.

(2) Per ISO 7267-1983 (e) “ Piping components – Definition of nominal pressure” These designations are referred to as Series 2 ratings which will be constantly monitored for possible deletion, with PN 40 having a limited application.

Therefore in 6.4.11 Series 1 basic ratings are specified.

The following notes have been inserted after 6.4.11.

Note 2: ISO 7005-1 (steel flanges) PN 20, 50, 110, 150, 260, 420 are designed to be interchangeable with ASME B16.5 and MSS SP-44 flanges - ISO 7005-1 flanges are not identical to ASME B 16.5 and MSS SP 44 flanges but are deemed to comply with the dimensions specified in the ASME B 16.5 and MSS SP 44.

6.4.11.4Cast, Ductile and Maluable iron flanges shall be flat faced and conform to the dimensional requirements of ISO 7005-2 or ASME B16.1 or l6.42 as specified. PN 20 (Class 125) flanges shall have a minimum thickness equal to PN50 (Class 250) for sizes DN 200 (8 NPS 8) and smaller.

Discussion: Ductile and Maluable were added for clarity since the title of ASME B 16.42 refers to Ductile Iron and ISO 7005-2 covers Ductile Iron. ASME B 16.1 refers to Cast Iron in its title.

Discussion: ISO 7005-2 paragraph 2.4.1 & 2.4.2 I summarized in Table 3 below. The tabke is correct in that PN 20 flanges made of Gray CI are required to be FF.

Table 3 – Flange Face Configuration
PN / Material /Face Configuration
PN 2.5.
PN 6.0.
PN 10
PN 16
PN 25
PN 40 / Gray CI RF
Ductile CI RF
Maluable CI RF or FF
PN 20 / Gray CI FF
Ductile CI RF
Maluable CI RF or FF
PN 50 / Gray CI RF

Ductile CI RF

Maluable CI RF or FF

[NOTE to TF Chairmen: If your standard addresses flange finishes note that ISO 7005-1 & 2 include flange finish requirements that are similar to, but not the same as, ASME B16.1, B 16.5, B16.42or 16.47 You may wish to address this issue if flange finish has been a substantial enough issue to include in the present published standard.

6.4.11.5Flanges other than those covered in 7005-2 cast iron shall conform to the dimensional requirements of the flanges specified in 6.4.11.1

Discussion: This requires machines which may be made of materials other than steel such as Ni resist or Bronze for example to have the flange dimensions equal to those of steel (ISO 7005-1). ISO 7005-2 covers nodular and ductile iron in addition to gray cast iron. The term Cast iron was not inclusive enough in 6.4.11.4 and therefore was removed and reference made to ISO 7005-2.

6.4.11.6Flat face flanges with full raised face thickness are acceptable on casings (or cylinders) of all materials. Flanges in all materials that are thicker or have a larger outside diameter than required by ISO or ASME are acceptable. Non-standard (oversized) flanges shall be completely dimensioned on the arrangement drawing. If oversized flanges require studs or bolts of non-standard length, this requirement shall be identified on the arrangement drawing. (610)

6.4.11.7Flanges shall be full faced or spot faced on the back and shall be designed for through bolting.

6.4.11.8 The flange gasket contact surface shall not have mechanical damage which penetrates the root of the grooves for a radial length of more than 30% of the gasket contact width.

For all steel flanges, imperfections in the flange facing finish shall not exceed that permitted in ASME B 16.5 or ASME 16.47 as applicable.

Discussion : Section 6.4.5 in ASME B 16.5 and Section 6.1.5 in ASME B 16.47 address in detail this subject. Each standard has two tables one addresses imperfections which penetrate the root and the other table addresses imperfections which do not penetrate the root of the flange finish.

6.4.11.8 as written, ie. “For all steel flanges” is ment to have this requirement also apply to ISO 7005-1. There is no similar allowable imperfection requirement in ISO 7005-1 and no such imperfection considerations are found in the flange standards ASME B 16.1, 16.42 or ISO 7005-2 covering CI, DI, or NI.

This paragraph was modified since the requirements of the ASME standards are more stringent than the 30% criteria. Table 4 compares the SP 30% criteria and a frequently used 2” 300 lb flange.

Table 4 Flange finish imperfections
SP / Standard / Size & Class / Gasket face Length
OD – ID/2 = Face Width / ASME B 16.5 allowable inperfection (radial projection in inches) / 30% Radial Face width
No root penetration / Root penetration
ASME B 16.5 / 2” 300lb / 3.62 - 2.07 /2 = .775 / .12 / .06 / .775 X .3 = .232 vs ASME allowable of .06

(ASME B 16.5 Steel Flanges)

6.4.4 Flange Facing Finish. The finish of contact faces of pipe flanges and connecting end flanges of fittings shall be judged by visual comparison with Ra standards (see ASME B46.1) and not by instruments having stylus tracers and electronic amplification.

6.4.4.1 Tongue and Groove and small Male and Female. The gasket contact surface shail not exceed 125 µin. roughness.

6.4.4.2 Ring Joint. The side wall surface of gasket groove shall not exceed 63 µin. roughness.

6.4.4.3 Other Flange Facings. Either a serrated concentric or serrated spiral finish having a resultant surface finish from 125 µin. to 250µin. average roughness shall be furnished. The cutting tool employed should have an approximate 0.06 in. or larger radius, diameter, thickness, and facing

and there should be from 45grooves/in. through 55of the standard flange of the size from which the grooves /in.

(ASME 16.47 Steel Flanges)

6.1.4 Flange Facing Finish. The finish of contact faces of pipe flanges shall be judged by visual comparison with Ra Standards (see ANSI/ASME B46.1) and not by instruments having stylus tracers and electronic amplification. The finishes required are given below. Other finishes may be furnished by agreement between user and manufacturer.

6.1.4.1 Ring-Joint. The side wall surface to gasket groove shall not exceed 63 µin. roughness.

6.1.4.2 Other Flange Facings. Either a serrated concentric or serrated spiral finish having a resultant surface finish from 125 µin. to 250 µin. Average roughness shall be furnished. The cutting tool employed should have an approximate 0.06 in. or larger radius, and there should be from 45 grooves/in. through 55 grooves/in.

(ASME B 16.1 CI fanges)

6.2 Facing

6.2.1 Classes 25 and 125 cast iron flanges and flanged fittings shall be flat faced (i.e., without projection

or raised face) and finished in accordance with MSS SP-6.

6.2.2 Class 250 flanges and flanged fittings shall have a raised face 0.06 in. high of the diameters given

in Table 6 and finished in accordance with MSS SP- 6. The raised face is included in the minimum flange thickness and center-to-face dimension.

(ASME B 16.42 Ductile Iron flanges)

6.2.3 Flange Facing Finish. Contact faces shall be finished in accordance with MSS SP-6.

MSS SP-6

(ISO 7005-1 Steel Flanges)

2.5.5 Surface finish of flanges

2.5.5.1 All flange jointing faces shall be finished in accordance with table I or table 2, as appropriate. The surface finishes shall be compared by visual or tactile means with reference specimens which conform to the Ra and Rz values given in tables 1 and 2.

NOTES

1 It is not intended that instrument measurements are taken on the flange faces, and the R, and R, values as defined in IS0 468 relate to the reference specimens.

2 Other finishes may be agreed between the manufacturer and purchaser.

2.5.5.2 The dimensions given for facings (particularly tongue and groove types) in this part of IS0 7005 apply to flanges in the condition as delivered.

When special coatings or finishes are required this should be stated in the order so that an appropriate allowance may be incorporated in the machining of any relevant mating dimensions.

2.5.5.3 Flat face, raised face and large spigot/recess facings [i.e. types A, B and E/F (large)] shall be turned. Turning shall be carried out with a round-nosed tool in accordance with

table 1.

2.5.5.4 For tongue/groove, small spigot/recess, “0’‘-ring recess/groove and ring-joint facings [i.e. types C/D, E/F

(small), G/H and J] the gasket surfaces shall be machined in accordance with the values shown in table 2.

(ISO 7005-2 CI)

2.4.3 Surface finish of flanges

All flange jointing faces shall be finished in accordance with table 1. The faces shall be compared by visual or tactile means with reference specimens which conform with the Ra and Rz values given in table 1.

NOTES

1 It is not intended that instrument measurements are taken on the flange faces, and the Ra and Rzvalues as defined in IS0 468 : 1982,

Surface roughness - Parameters, their values and general rules for specifying requirements, relate to the reference specimens.

2 Other finishes may be agreed between the manufacturer and purchaser.

11/4/2018