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Flange Bolting Torque Values Recommended by API-6A 20th Edition1
Stud Threads Yield Strength = 80 ksi Bolt Stress = 40 ksi Yield Strength = 105 ksi Bolt Stress = 52.5 ksi Yield Strength = 95 ksi Bolt Stress = 47.5 ksi
Dia. per inch Tension F (lbf) Torque Cof = .07 (ft-lbf) Torque Cof = 0.13 (ft-lbf) Tension F (lbf) Torque Cof = .07 (ft-lbf) Torque Cof = 0.13 (ft-lbf) Tension F (lbf) Torque Cof = .07 (ft-lbf) Torque Cof = 0.13 (ft-lbf)
(Inch) TPI ── ── ── ── ── ── ── ── ──
0.500 13 5,676 27 45 7,450 35 59 ── ── ──
0.625 11 9,040 52 88 11,865 68 115 ── ── ──
0.750 10 13,378 90 153 17,559 118 200 ── ── ──
0.875 9 18,469 143 243 24,241 188 319 ── ── ──
1.000 8 24,230 213 361 31,802 279 474 ── ── ──
1.125 8 31,618 305 523 41,499 401 686 ── ── ──
1.250 8 39,988 421 726 52,484 553 953 ── ── ──
1.375 8 49,340 563 976 64,759 739 1,281 ── ── ──
1.500 8 59,674 733 1,278 78,322 962 1,677 ── ── ──
1.625 8 70,989 934 1,635 93,173 1,226 2,146 ── ── ──
1.750 8 83,286 1,169 2,054 109,313 1,534 2,696 ── ── ──
1.875 8 96,565 1,440 2,539 126,741 1,890 3,332 ── ── ──
2.000 8 110,825 1,750 3,094 145,458 2,297 4,061 ── ── ──
2.250 8 142,292 2,496 4,436 186,758 3,276 5,822 ── ── ──
2.500 8 177,685 3,429 6,118 233,212 4,500 8,030 ── ── ──
2.625 8 ── ── ── ── ── ── 233,765 4,716 8,430
2.750 8 ── ── ── ── ── ── 257,694 5,424 9,712
3.000 8 ── ── ── ── ── ── 309,050 7,047 12,654
3.250 8 ── ── ── ── ── ── 365,070 8,965 16,136
3.750 8 ── ── ── ── ── ── 491,099 13,782 24,905
3.875 8 ── ── ── ── ── ── 525,521 15,208 27,506
4.000 8 ── ── ── ── ── ── 561,108 16,730 30,282

The torque values reprinted in this table are guidelines only and are the exclusive property of API.

Note: Cof = Coefficient of Friction. Cof of 0.07 is for PTFE (Teflon/Xylan) coatings. Cof of 0.13 is for commonly available anti-seize lubricants. All values are approximate. No assumption of liability by API is implied or assumed for the use of this information.