API Spec 5B

API 5B, Specification for Threading, Gauging and Thread Inspection of Casing, Tubing, and Line Pipe Threads.This Specification covers dimensions, tolerances and marking requirements for API threads and the gauges that control the acceptance criteria for the threads. Thread element gauges, instruments and requirements for the inspection of threads for line pipe, round thread casing, and buttress casing connections are included.

BUTTRESS CASING (BCSG)

SIZE

T.P.I.

T.P.F.

PITCH DIAMETER

STANDOFF TOLERANCE

4-1/2

5

1:16

113.132

2.540±0.381

5

125.832

5.080±0.381

5-1/2

138.532

6-5/8

167.107

7

176.632

7-5/8

192.507

8-5/8

217.907

9-5/8

243.307

10-3/4

271.882

11-3/4

297.282

13-3/8

338.557

16

1:12

404.825

4.445±0.381

18-5/8

471.500

20

506.425