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ASME B1.20.1 - 2013: Pipe Threads, General Purpose, Inch - Reaffirmed 2018, 2013
- CONTENTS
- FOREWORD
- COMMITTEE ROSTER
- CORRESPONDENCE WITH THE B1 COMMITTEE
- 1 INTRODUCTION [Go to Page]
- 1.1 Scope
- 1.2 Related Standard
- 1.3 Thread Designations [Go to Page]
- 1.3.1
- 1.3.2
- 1.4 Sealing NPT and NPSC Only [Go to Page]
- 1.4.1 Mating Threads.
- 1.4.2 Sealant.
- 1.4.3 Tightening Torque.
- 1.4.4 Other Considerations.
- 1.4.5 Pressure-Tight Threads Without Sealant.
- 1.5 Appendices
- 1.6 Referenced Standards
- 1.7 Terminology
- 2 AMERICAN NATIONAL STANDARD PIPE THREAD FORM [Go to Page]
- 2.1 Thread Form
- 2.2 Angle of Thread
- 2.3 Thread Height
- 2.4 Thread Truncation
- 3 SPECIFICATION FOR TAPER PIPE THREADS, NPT [Go to Page]
- 3.1 General [Go to Page]
- 3.1.1 Notation.
- 3.1.2 Symbols.
- 3.1.3 Handling Considerations.
- 3.1.4 Form of Thread.
- 3.1.5 Taper of Thread.
- 3.1.6 Pitch Diameters of Thread.
- 3.1.7 Length of Effective Thread.
- 3.1.8 Hand-Tight Engagement Between External and Internal Taper Threads.
- 3.1.9 Wrench-Tight Engagement Between External and Internal Taper Threads. [Go to Page]
- 3.1.9.1 Thread Engagement Considerations.
- 3.1.9.2 Special Applications.
- 3.1.10 Tolerances on Product Taper, Lead, and Angle.
- 3.1.11 Basic Dimensions.
- 3.2 Gaging NPT Threads [Go to Page]
- 3.2.1 External Thread Gaging [Go to Page]
- 3.2.1.1 L1 Ring Gage.
- 3.2.1.2 External L1-Indicating Gage.
- 3.2.2 Internal Thread Gaging [Go to Page]
- 3.2.2.1 L1 Plug Gage.
- 3.2.2.2 Internal L1-Indicating Gage.
- 3.2.3 Nicked Threads.
- 3.2.4 Treatment of Chamfers, Recesses, Counterbores. [Go to Page]
- 3.2.4.1
- 3.2.4.2
- 3.2.4.3
- 3.2.4.4
- 3.2.4.5
- 3.2.5 Acceptance of Product Made Prior to This Revision.
- 3.2.6 Coated Threads. [Go to Page]
- 3.2.6.1 Coating Buildup.
- 3.2.6.2 Precoating Gaging Standoff Compensation, Internal Thread.
- 3.2.6.3 Precoating Gaging Standoff Compensation, External Thread.
- 3.2.6.4 Precoating Gages.
- 3.2.7 Supplemental Gaging
- 3.3 Acceptability
- 4 SPECIFICATIONS FOR INTERNAL STRAIGHT THREADS IN PIPE COUPLINGS, NPSC [Go to Page]
- 4.1 Pressure-Tight Internal Straight Pipe Threads [Go to Page]
- 4.1.1 Thread Designation.
- 4.1.2 Dimensions and Limits of Size.
- 4.2 Gaging NPSC Internal Threads [Go to Page]
- 4.2.1 L1 Plug Gage.
- 4.2.2 L1 Internal Indicating Gage.
- 5 SPECIFICATIONS FOR RAILING JOINT TAPER PIPE THREADS, NPTR [Go to Page]
- 5.1 Railing Joints [Go to Page]
- 5.1.1 Thread Designation.
- 5.1.2 Form of Thread.
- 5.2 Gaging and Tolerances, NPTR
- 6 SPECIFICATIONS FOR STRAIGHT PIPE THREADS FOR MECHANICAL JOINTS; NPSM, NPSL [Go to Page]
- 6.1 Straight Pipe Threads for Mechanical Joints [Go to Page]
- 6.1.1 Thread Designations.
- 6.1.2 Pitch and Flank Angle.
- 6.1.3 Diameter of Thread.
- 6.2 Free-Fitting Mechanical Joints for Fixtures, NPSM
- 6.3 Loose-Fitting Mechanical Joints With Locknuts, NPSL
- 6.4 Gaging for NPSM and NPSL Threads [Go to Page]
- 6.4.1 GO Gaging.
- 6.4.2 NOT GO Gaging.
- 6.4.3 Indicating Gages.
- 6.4.4 Gage Dimensions.
- 7 GAGES AND GAGE TOLERANCES FOR AMERICAN NATIONAL STANDARD TAPER PIPE THREADS, NPT [Go to Page]
- 7.1 Gage Design [Go to Page]
- 7.1.1 Gages for External Threads.
- 7.1.2 Gages for Internal Threads.
- 7.1.3 Partial End Threads.
- 7.1.4 Marking of Gages.
- 7.2 Master Gages [Go to Page]
- 7.2.1 Master Gage Tolerances.
- 7.3 Working Gages [Go to Page]
- 7.3.1 Working Gage Tolerances.
- 7.4 Relation of Lead and Angle Variations to Pitch Diameter Tolerances of Gages
- Figures [Go to Page]
- Fig. 1 Root, Crest, and Flank Engagement, NPT
- Fig. 2 Basic Form of American National Standard Taper Pipe Thread, NPT
- Fig. 3 American National Standard Taper Pipe Thread Notation
- Fig. 4 Gaging External Taper Threads With L1 Ring Gage
- Fig. 5 Gaging of Chamfered Threads
- Fig. 6 Gaging Internal Taper Threads With L1 Plug Gage
- Fig. 7 NPT Standard Taper Pipe Thread Plug and Ring Gages
- Fig. 8 Suggested Form of Gage Thread
- Tables [Go to Page]
- Table 1 Limits on Crest and Root Truncation of American National Standard External and Internal Taper Pipe Threads, NPT
- Table 2 Basic Dimensions of American National Standard Taper Pipe Thread, NPT
- Table 3 Tolerances on Taper, Lead, and Angle of Pipe Threads, NPT
- Table 4 Dimensions, Internal Straight Threads in Pipe Coupling, NPSC
- Table 5 Dimensions of External and Internal Taper Pipe Threads for Railing Joints, NPTR
- Table 6 Dimensions of External and Internal Straight Pipe Threads for Fixtures, NPSM
- Table 7 Dimensions, External and Internal Straight Pipe Thread for Locknut Connections, NPSL
- Table 8 Basic Dimensions of Threaded Gages for American National Standard Taper Pipe Threads, NPT
- Table 9 Working Gage Tolerances for American National Standard Taper Pipe Thread, NPT
- Table 10 Diameter Equivalent of Variation in Half Included Angle of Thread for Tools and Gages
- Table 11 Diameter Equivalent of Variation in Lead for Tools and Gages
- NONMANDATORY APPENDIX A THE TURNS OF ENGAGEMENT METHOD OF GAGING PRODUCT THREADS [Go to Page]
- A-1 METHOD OF GAGING
- A-2 TOLERANCE
- NONMANDATORY APPENDIX B TAP DRILL SIZES
- NONMANDATORY APPENDIX C THREAD TYPES AND CORRESPONDING GAGES AND GAGING [Go to Page]
