H:AWHEM TR9501 filesCover Page for Specification …

1 Issue Date: June 6, 1995. Revision B. June 11, 2010. RECOMMENDATION FOR INTERCHANGEABLE. STUD BOLTS AND TAP END STUDS. FOR API SPEC 6A FLANGES. TECHNICAL REPORT TR9501 . Revision B. AWHEM publications may be used by anyone desiring to do so. Every effort has been made by the Association to assure the accuracy and reliability of the data contained in them; however, the Association makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state or municipal regulation with which this publication may conflict.

2 Association of Well Head Equipment Manufacturers Post Office Box 1166. Bellaire, Texas 77401. AWHEM Recommendation For Stud Bolts and Tap End Studs For API Spec 6A 2. TABLE OF CONTENTS. Section General .. 3. Purpose .. 3. Reference Document .. 3. Definitions .. 3. Application .. 3. Method of calculating stud bolt lengths for type 6B and 6BX flanges .. 4. Stud bolt length table for 6B flange connections with "R" and "RX" gaskets .. 5. Stud bolt length table for 6BX flange connections .. 6. Method of calculating tap end stud lengths for type 6B and 6BX flanges .. 7. Tap end stud length table for 6B studded flange connections with "R" and "RX" gaskets.

3 8. Tap end stud length table for 6BX studded flange connections .. 9. Appendix A - Stud bolt length table for 6B flange connections with "R" gaskets .. 10. Appendix B - Tap end stud length table for 6B studded flange connections with "R" gaskets .. 11. AWHEM Recommendation For Stud Bolts and Tap End Studs For API Spec 6A 3. GENERAL the respective tapped holes. This AWHEM Recommendation compliments and Point - extends but does not conflict with API Spec 6A. End portion of the stud that features incomplete PURPOSE threads to facilitate thread engagement. The maximum length of the point shall equal This AWHEM Recommendation establishes definite times the pitch of the thread.

4 Dimensions for stud bolts and tap end studs for use with API Spec 6A flanges/studded flange Stud Bolts (For Through Bolt Flanges) - connections and provides for dimensionally interchangeable stud bolts and tap end studs for API Studs that have threads over their full length or Spec 6A flanges/studded flange connections. Stud may have an unthreaded portion on the central bolts and tap end studs that may have other lengths area of the body diameter. etc. for special purposes, and comply with the requirements of API Spec 6A, are beyond the scope Tap End Studs (For Studded Flanges) - of this document. Studs threaded on each end with an unthreaded REFERENCE DOCUMENT portion on the body diameter.

5 The thread length dimension on one end controls the depth that API Spec 6A. that end will engage into a tapped hole, and also controls the extension length of the stud beyond Note: This AWHEM Recommendation derives its a studded flange. basis from API Spec 6A and those standards referenced therein. Any subsequent Threads - supplements to API Spec 6A, 17th Edition, or subsequent editions issued, shall require All studs and bolts shall have Class 2A unified review and revision of this AWHEM inch screw threads per ASME Recommendation to assure its application. (Revision of ANSI ) Standard. DEFINITIONS: Size 1" and below shall have UNC threads.

6 Length, (Tap End Stud or Stud Bolt) - Size 1-1/8" and above shall have 8 threads per inch. Measurement end to end, including points. APPLICATION. Length, Nut End Thread - API Spec 6A, "6B" flanges, may use "R" or "RX". 2-1/2 x Diameter = Minimum thread length of gaskets, "RX" gaskets producing greater standoff full threads measured from the end of the stud. between flanges. Tables for "6B" flanges in this document show stud bolt and tap end stud lengths Length, Tap End Thread - that will accommodate both "R" and "RX" gaskets. Some equipment designs provide very little nut and One diameter + maximum point = minimum wrench clearance, so occasions may arise when thread length, measured from the end of the stud manufacturers or users must install shorter stud bolts to the end of thread run out (to the last scratch or tap end studs when using the "R" gaskets.)

7 For this on cut threads, or to the last impression of reason, Appendices A and B follow in this document threads made by other means). to provide lengths for "R" gaskets only. NOTE: The manufacturer shall have and use a means to demonstrate that his threading process produces sufficient full threads on the stud to achieve one (1) diameter of engagement with AWHEM Recommendation For Stud Bolts and Tap End Studs For API Spec 6A 4. METHOD OF CALCULATING STUD BOLT LENGTHS FOR TYPE 6B AND 6BX FLANGES. CALCULATION. The following formula was ROUNDING OFF PROCEDURE. If L is used in establishing stud bolt lengths listed in inch (or more) greater than any 1/4 inch the tables and is included here for the increment, round off upward to the next 1/4 inch convenience of industry.

8 Length shown in increment; if less than inch, round off tables results from rounding as specified in downward to the next 1/4 inch increment. paragraph END POINT-HEIGHT OF STUD BOLTS. The end point is the end portion of a stud bolt L = 2(T + t + d) + S + 2(P) beyond the complete thread; and may be chamfered, rounded, or sheared. The maximum Where: height of each end point shall be x pitch of thread. L = Calculated stud bolt length. T = Total flange thickness. FLANGE FACE STANDOFF VALUES, S. t = Plus tolerance for flange thickness. The approximate distance between faces of d = Heavy hex nut thickness (equals nominal bolt made-up flanges, S is given in API Spec 6A for diameter; see ANSI B : Square and R and RX ring gaskets.)

9 Hex Nuts). S = Flange face standoff. S = 0 for BX. assemblies. See Figure P = Maximum end point height ( x Pitch of thread). Figure L L L. S S NO STANDOFF. API TYPE 6B FLANGE API TYPE 6B FLANGE API TYPE 6BX FLANGE. WITH R GASKET WITH RX GASKET. L. POINT HEIGHT. STUD BOLT WITH NUTS. AWHEM Recommendation For Stud Bolts and Tap End Studs For API Spec 6A 5. STUD BOLT LENGTH TABLE FOR 6B FLANGE CONNECTIONS WITH "R" AND "RX" GASKETS. ACCOMMODATES. "R" AND "RX" TYPE GASKETS. LENGTH LENGTH. DIA. POINT POINT. LENGTH = 2( T + t + d ) + S + 2( P ). T Total flange thickness. t Plus tolerence for flange thickness. d Heavy hex nut thickness.

10 S Flange face standoff. (with "RX" gasket ). P Point Max. ( X Pitch). FLANGE BOLT * FLANGE BOLT *. SIZE DIA. LENGTH SIZE DIA. LENGTH. 2-1/16 2M 7-1/16 2M 2-1/16 3M 7-1/16 3M 2-1/16 5M 7-1/16 5M 2-9/16 2M 9 2M 2-9/16 3M 9 3M 2-9/16 5M 9 5M 3-1/8 2M 11 2M 3-1/8 3M 11 3M 3-1/8 5M 11 5M 4-1/16 2M 13-5/8 2M 4-1/16 3M 13-5/8 3M 4-1/16 5M 16-3/4 2M 5-1/8 2M 16-3/4 3M 5-1/8 3M 21-1/4 2M 5-1/8 5M 20-3/4 3M * tolerance on bolt length: + 1/8 , - 0 inch for lengths up to 12 inches. + 1/4 , - 0 inch for lengths over 12 inches. AWHEM Recommendation For Stud Bolts and Tap End Studs For API Spec 6A 6. STUD BOLT LENGTH TABLE FOR 6BX FLANGE CONNECTIONS.