Butterfly Valves: Double-flanged, Lug- and Wafer-type, and Butt-welding Ends

API STANDARD 609

NINTH EDITION, APRIL 2021

API MONOGRAM PROGRAM EFFECTIVE DATE: OCTOBER 2021

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms and Definitions 2

4. Pressure-temperature Ratings 3

   1. Valve Rating 3

   2. Shell Rating 3

   3. Seat Rating 3

   4. Differential Pressure Rating 4

5. Design 4

   1. General 4

   2. Body 5

   3. Face-to-face Dimensions 5

   4. Valve Body Flange Facings 8

   5. Disc Clearance 8

   6. Shaft and Shaft Seals 8

   7. Piping Connection External Bolt Holes 9

   8. Valve Body Seat Retainer—Category B Valves Only 9

   9. Operating Mechanisms 11

   10. Antistatic Design (Electrical Continuity Between Disc, Shaft, and Body) 11

   11. Packing Gland Bolting—Category B Valves Only 12

6. Materials 12

   1. Body 12

   2. Pressure Boundary Elements 12

   3. Process Wetted Parts 12

   4. Packing or Shaft Seal Materials 12

   5. Gland Bolting 12

   6. Operating Mechanisms—Category B Valves Only 12

7. Testing, Inspection, and Examination 12

   1. Inspection and Examination 12

   2. Pressure Tests 13

   3. Electrical Continuity Test 13

   4. Repair of Defects 13

8. Markings 13

9. Packaging and Shipping 14

   1. Coatings 14

   2. Shaft Packing 14

   3. Packaging 14

   4. Spare Parts 14

10. Purchase Order Information 14

Annex A 15

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Contents

Page

Annex B (informative) Information to be Specified by Purchaser 16

Annex C (informative) Typical Butterfly Valve Construction and Nomenclature 18

Annex D (normative) Disc-to-pipe Clearances 21

Bibliography 25

Figures

1. External Bolting Options for Lug- and Wafer-type Valves 10

2. Limitations for Flange Face Interruptions That Fall Within the Gasket Seating Area 11

1. Typical Part Nomenclature for Category A Concentric Disc Type 18

2. Typical Part Nomenclature for Category B Offset Disc Type 19

3. Typical Offset-type Constructions 20

1. Disc-to-pipe Clearance for Category A Concentric Disc Type 22

2. Disc-to-pipe Clearance for Category B Offset Disc Type 23

Tables

1. Minimum Seat Pressure-temperature Ratings for Category B Valves 3

2. Face-to-face Dimensions for Category A Valves (Lug- and Wafer-type) 6

3a Face-to-face Dimensions for Category B Valves (Lug- and Wafer-type) 6

3b Face-to-face Dimensions for Category B Valves (Double-flanged Long Pattern) 7

3c Face-to-face Dimensions for Category B Valves (Double-flanged Short Pattern) 7

1. Nominal Radial Clearances 21

2. Relationship of Unlined Steel Pipe Schedule to Valve Category, Size, and ASME class 24

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Butterfly Valves: Double-flanged, Lug- and Wafer-type, and Butt-welding Ends

1. Scope

   
   

   1. This standard covers design, materials, face-to-face dimensions, pressure-temperature ratings, and examination, inspection, and test requirements for gray iron, ductile iron, bronze, steel, nickel-based alloy, or special alloy butterfly valves.

      
      

   2. The following two categories of butterfly valves are included:

      
      

      1. Category A—Manufacturer’s rated cold working pressure (CWP) butterfly valves, usually with a concentric disc and seat configuration. Sizes covered are NPS 2 to NPS 60 for valves having ASME class 125 or class 150 flange bolting patterns.

         
         

      2. Category B—ASME class and pressure-temperature-rated butterfly valves that have an offset seat and either an eccentric or a concentric disc configuration. Sizes covered are listed below:

         
         

         • for lug and wafer, class 150 and 300: NPS 2 to NPS 60;

           
           

         • for lug and wafer, class 600: NPS 3 to NPS 60;

      
      

      — for double-flanged short and long pattern, class 150, 300, and 600: NPS 3 to NPS 60;

      
      

      — for butt-welding ends, class 150, 300 and 600: NPS 3 to 60;

      
      

      Information to be specified by the purchaser is shown in Annex B.

      
      

   3. Valve configurations include double-flanged, lug- and wafer-type with facings that permit installation between ASME and MSS flanges and butt-welding ends. Configurations conform to the standards and specifications listed in Section 2. Typical valve construction and nomenclature for valve parts are shown in Annex C.

      
      

2. Normative References

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any addenda) applies.

API Standard 598, Valve Inspection and Testing

API Standard 607, Fire Test for Quarter-turn Valves and Valves Equipped with Nonmetallic Seats

API Standard 641, Type Testing of Quarter-turn Valves for Fugitive Emissions

ASME B1.11 , Unified Inch Screw Threads (UN, UNR, and UNJ Thread Forms)

ASME B16.5, Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24, Metric/Inch Standard

ASME B16.24, Cast Copper Alloy Pipe Flanges, Flanged Fittings, and Valves: Classes 150, 300, 600, 900, 1500 and 2500

ASME B16.25, Buttwelding Ends

ASME B16.34, Valves—Flanged, Threaded, and Welding End

1 ASME International, Two Park Avenue, New York, New York 10016-5990, www.asme.org.

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