ASME B1.20.1 pdf free download

ASME B1.20.1 pdf free download Pipe Threads, General Purpose (Inch)
1.4 Sealing (NPT and NPSC Only)
1.4.1 Mating Threads. Mating threads shouldalways contact on the thread flanks.The design toler-ances are such that mating crests and roots may clear,contact, or interfere (see Fig.1). This joint may not neces-sarily seal, unless a sealant is used.
1.4.2 Sealant. Where pressure-tight, leak-free jointsare required, it is intended that threads conforming tothis Standard be made up wrench-tight with a sealant.To prevent galling during installation, the sealant mayhave lubricating properties.
1.4.3 Tightening Torque. Due to application-specificvariables such as materials, wall thickness,operatingpressures,etc., no guidance is given in this Standardregarding joint-tightening torque. However, jointsshould be tightened beyond the hand-tight engagementposition. Advancing the joint past hand-tight createsinterference between external and internal thread flanks,produces a seal (with the use of a sealant), and helpsprevent loosening of the joint.Overtightening may bedetrimental to the sealing function of the joint.
1.4.4 Other Considerations. Out-of-roundness ofmating parts can negatively affect their ability to sealwhen made up wrench tight. The product’s elasticityand ductility will also affect sealing-
1.4.5 Pressure-Tight Threads Without Sealant. Pipethreads designed for pressure-tight joints that may beused without sealing compounds (Dryseal Threads) arecovered in ASME B1.20.3.
1.5 Appendices
Useful and supplementary information that is not apart of this Standard is presented in a nonmandatoryappendix. Specifically,the nonmandatory appendicescover the turns of engagement method of gaging, sug-gested prethreading hole diameters, and an explanatorygaging matrix.
1.6 Referenced Standards The latest issues of the following documents form a part of this Standard to the extent specified herein. ASME B1.2, Gages and Gaging for Unified Screw Threads ASME B1.7, Screw Threads: Nomenclature, Definitions, and Letter Symbols ASME B1.20.3, Dryseal Pipe Threads (Inch) ASME B1.20.7, Hose Coupling Screw Threads (Inch) ASME B1.30, Screw Threads: Standard Practice for Calculating and Rounding Dimensions ASME B47.1, Gage Blanks Publisher: The American Society of Mechanical Engineers (ASME), Two Park Avenue, New York, NY 10016-5990; Order Department: 22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007-2900 (www.asme.org)
1.7 Terminology Definitions of terms and symbols for thread dimen- sions are given in ASME B1.7.