Size DN20

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FLANGE DIMENSIONS TABLE SIZE (DN) 20 (3/4″)

Class/Table Flange O.D. PCD Bolts Bolt Size Hole Size Minimum Flange Thickness*
Cast Iron Copper Alloy Ductile Iron Steel
ASME Class 125 B16.1 3 7/8″ / 98mm 2 3/4″ / 69.9mm 4 1/2″ 5/8″ / 16mm 11/32″ / 9mm 9/16″ / 14mm
ASME Class 150 B16.24/B16.5 3 7/8″ / 98mm 2 3/4″ / 69.9mm 4 1/2″ 5/8″ / 16mm 11/32″ / 9mm 9/16″ / 14mm
ASME Class 300 B16.24/B16.5 4 5/8″ / 117mm 3 1/4″ / 82.6mm 4 5/8″ 3/4″ / 19mm 17/32″ / 13mm 5/8″ / 16mm
ASME Class 600 B16.5 4 5/8″ / 117mm 3 1/4″ / 82.6mm 4 5/8″ 3/4″ / 19mm 5/8″ / 16mm
ASME Class 900 B16.5 5 1/8″ / 130mm 3 1/2″ / 88.9mm 4 3/4″ 7/8″ / 22mm 1″ / 25mm
ASME Class 1500 B16.5 5 1/8″ / 130mm 3 1/2″ / 88.9mm 4 3/4″ 7/8″ / 22mm 1″ / 25mm
ASME Class 2500 B16.5 5 1/2″ / 140mm 3 3/4″ / 95.2mm 4 3/4″ 7/8″ / 22mm 1 1/4″ / 32mm
ISO7005-1/AS4331.1 ⑤ PN20 (ANSI 150) 100mm 70mm 4 M14 16mm 13mm
ISO7005-1/AS4331.1 ⑤ PN50 (ANSI 300) 120mm 82mm 4 M16 18mm 16mm
ISO7005-1/AS4331.1 ⑤ PN110 (ANSI 600) 120mm 82mm 4 M16 18mm 16mm
ISO7005-1/AS4331.1 ⑤ PN150 (ANSI 900) 130mm 89mm 4 M20 22mm 25mm
ISO7005-1/AS4331.1 ⑤ PN260 (ANSI 1500) 130mm 89mm 4 M20 22mm 25mm
ISO7005-1/AS4331.1 ⑤ PN420 (ANSI 2500) 140mm 95mm 4 M20 22mm 32mm
AS2129① Table C 100mm 73mm 4 13mm 14mm 13mm 13mm 10mm
AS2129① Table D 100mm 73mm 4 13mm 14mm 13mm 6mm 13mm 10mm
AS2129① Table E 100mm 73mm 4 13mm 14mm 13mm 6mm 13mm 10mm
AS2129① Table F 100mm 73mm 4 13mm 14mm 13mm 8mm 13mm 10mm
AS2129① Table H 115mm 83mm 4 16mm 18mm 16mm 10mm 13mm
AS2129① Table J 115mm 83mm 4 16mm 18mm 16mm 16mm
AS4087① PN14 100mm 73mm 4 M12 14mm 6mm
AS4087① PN16
AS4087① PN21
AS4087① PN35
BS10 Table D 4″/ 102mm 2 7/8″ / 73mm 4 1/2″ 9/16″ / 14mm 1/2″ / 13mm 1/4″ / 6mm 3/8″ / 10mm
BS10 Table E 4″ / 102mm 2 7/8″ / 73mm 4 1/2″ 9/16″ / 14mm 1/2″ / 13mm 1/4″ / 6mm 3/8″ / 10mm
BS10 Table F 4″ / 102mm 2 7/8″ / 73mm 4 1/2″ 9/16″ / 14mm 1/2″ / 13mm 5/16″ / 8mm 3/8″ / 10mm
BS10 Table H 4 1/2″ / 114mm 3 1/4″ / 83mm 4 5/8″ 11/16″ / 17mm 5/8″ / 16mm 3/8″ / 10mm 1/2″ / 13mm
BS10 Table J 4 1/2″ / 114mm 3 1/4″ / 83mm 4 5/8″ 11/16″ / 17mm 5/8″ / 16mm 5/8″ / 16mm
BS10 Table K 4 1/2″ / 114mm 3 1/4″ / 83mm 4 5/8″ 11/16″ / 17mm 3/4″ / 19mm 3/4″ / 19mm
ISO7005-1/2AS4331.1⑤ PN6 90mm 65mm 4 M10 11mm 14mm 14mm
ISO7005-1/2AS4331.1⑤ PN10 105mm 75mm 4 M12 14mm 16mm 16mm 18mm
ISO7005-1/2AS4331.1⑤ PN16 105mm 75mm 4 M12 14mm 16mm 16mm 18mm
ISO7005-1/2AS4331.1⑤ PN25 105mm 75mm 4 M12 14mm 18mm 16mm 18mm
ISO7005-1/2AS4331.1⑤PN40 105mm 75mm 4 M12 14mm 18mm
BS4504② PN6 90mm 65mm 4 M10 11mm 14mm
BS4504② PN10 105mm 75mm 4 M12 14mm 16mm
BS4504② PN16 105mm 75mm 4 M12 14mm 16mm 6mm 18mm
BS4504② PN25 105mm 75mm 4 M12 14mm 18mm 8mm 18mm
BS4504② PN40 105mm 75mm 4 M12 14mm 9mm 18mm
BS4504② PN64 130mm 90mm 4 M16 18mm 22mm
BS4504② PN100 130mm 90mm 4 M16 18mm 22mm
EN1092-1/2/3③ PN6 90mm 65mm 4 M10 11mm 14mm 14mm
EN1092-1/2/3③ PN10 105mm 75mm 4 M12 14mm 16mm 16mm 18mm
EN1092-1/2/3③ PN16 105mm 75mm 4 M12 14mm 16mm 16mm 18mm
EN1092-1/2/3③ PN25 105mm 75mm 4 M12 14mm 18mm 16mm 18mm
EN1092-1/2/3③ PN40 105mm 75mm 4 M12 14mm 18mm
EN1092-1/2/3③ PN63 130mm 90mm 4 M16 18mm 22mm
EN1092-1/2/3③ PN100 130mm 90mm 4 M16 18mm 22mm

AS2129 still in use but now only covers Table D to H. Table C now obsolete, Table J to T now replaced by AS4331.1 which is a replication of ISO7005-1 which in turn is equivalent to ASME 150-2500 class ANSI B16.5. AS4331.1 and ISO 7005-1 also incorporates previous DIN PN rated flanging. AS4087 is the new standard covering Table D to H. The same drilling is specified but the PN rating system is used (PN14 to PN35) and in some cases flange thickness varies slightly. AS4087 PN14 & PN16 are the same drilling as AS2129 Table D. AS4087 PN21 is the same drilling and rating as AS2129 Table F. AS4087. AS4087 PN14 & PN16 is the same drilling as AS2129 Table D. AS4087 PN21 is the same rating and drilling as AS2129 Table F and PN35 is the same drilling as Table H. AS4087 specifies raised face in Ductile Iron PN16 & PN35 and flat face in Grey Cast Iron PN14, PN21, PN35. Click here to view full AS4087 flanging dimensions.

② British metric standard BS4504 is now obsolete and replaced by EN1092-1 edition 09-2008 for steel flanges which also incorporates DIN2501 standard. EN1092-1 is also published in the British standards as BS-EN1092-1. Flange drillings in EN1092-1 are generally the same as BS4504 but EN1092-1 covers a wider range.

EN1092-1 is for steel flanges, EN1092-2 is for Iron flanges, EN1092-3 is for Copper Alloy flanges, EN1092-4 is for Aluminium flanges. Regarding EN1092-2 Iron flanges, these figures are for integral flanges on valves, etc. Cast (Grey) Iron thicknesses are shown in Cast Iron column. EN1092-2 specifies a thinner flange thickness for Ductile Iron in larger sizes which is shown in the Ductile Iron column. For full EN1092-1 table Click here EN1092-1 is for steel flanges.

Refer EN1092-3 copper alloy, EN1092-4 aluminium alloy.

ISO7005-1 & ISO7005-2 (which AS4331.1/2 mirrors) replaces DIN 2501 & DIN 2533 and BS4504 PN6 to 40. ISO7005-1 & 7005-2 PN6 to 40 is the same as EN1092-1/2 (note some flanges thicknesses vary slightly) but also incorporates ANSI flanging redesignated as PN20, PN50, PN110, PN150, PN260, PN420. ISO7005-1/AS4331.1 is steel flanges (ISO7005-1 refers to EN1092-1 for steel flange sizes), ISO7005-2/AS4331.2 is iron flanges, ISO7005-3/AS4331.3 is copper alloy flanges. AS4331.1 is a reproduction of ISO7005-1, AS4331.2 is a reproduction of ISO7005-2, AS4331.3 is a reproduction of ISO7005-3. Note where we combine ISO/AS/EN above, some standards do not publish some flange materials, so do not assume CI/DI/Steel/Copper Alloy is published in all three standards. The thicknesses for integral flanges are not the same as for welding & blind flanges. Furthermore ISO7005-1 PN ratings refer to EN 1092-1 which are also published below. EN 1092-2 ratings are generally also aligned with ISO7005-2 which once again are also published below.

* Varies according to flange type (thickness usually includes raised face height where applicable) refer to standard. Some standards publish integral flange thicknesses used for valves which are often different than blind or welding flange thicknesses hence refer to standard for clarification. Refer links to flange standards in the technical screen of our website.

This above table is a rough ready reckoner only to understand standards, differences & commonality and to assess interchangeability. Refer to the standard required itself before manufacture.

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