CHECK VALVES - SWING, TILTING DISC & PISTON - API594/API6D/BS1868/B16.34
Australian Pipeline Valve - Installation, Operation and Maintenance Manual
14
A P P E N D I X A
INDICATIVE BONNET BOLTING (BOLTED BONNET*) TORQUE NM
TABLE A
STUD SIZE
inch-TPI
Bolting Material
B7/B7M/B16/L7/L7M/
L43/660 Cl.A/UNS
N07718/UNS 09925
B8 Cl.2/B8C Cl.2/B8M
Cl.2/B8T Cl.2/XM-19
UNS N06625 Gr 1
1/4-20 UNC
7
7
5
5/16-18 UNC
15
15
10
3/8-16 UNC
25
25
15
7/16-14 UNC
40
40
25
1/2-13 UNC
60
60
40
9/16-12 UNC
90
90
60
5/8-11 UNC
120
120
80
3/4-10 UNC
215
215
145
7/8-9 UNC
345
315
230
1-8 UNC
520
475
345
1.1/8-8 UN
725
625
510
1.1/4-8 UN
1000
880
715
1.3/8-8 UN
1460
975
975
1.1/2-8 UN
1925
1285
1285
1.5/8-8 UN
2480
1655
1655
1.3/4-8 UN
3140
2090
2090
* Consult APV for pressure seal bonnet
Note:
(1) Torque tolerance ±10%.
(2) For temperatures above 750°F (400°C) use 75% of the torque values. In high temperature services, there is a possibility of creep in the
bonnet studs. Regular checking of the bonnet - studs for tightness, would help prevent leakage through the bonnet gasket.
(3) Above torque values are with the bolts lubricated.
(4) Values above are based on 30,000 psi (206.85 Mpa) bolting stress and lubricated with heavy graphite and oil mixture or a copper based
anti-seize grease.
(5) Do not exceed by more than 25% of values stated when emergency torquing is required.
(6) All bolts shall be torqued in the pattern as shown in Figure 2 on next page to ensure uniform gasket loading.
(7) Optimum torque can vary depending on type of body gasket but do not increase torque more than 10% above those shown.
(8) Consult us for other bolt material.
(9) Most B8M and B8 bolts are class 1 so do not assume class 2 unless you are sure.
Note
For ‘pressure seal’ bonnet consult APV for torques (where bolting is applicable). Bolt
tensions shown must be decreased by 25% when other or no lubrication used. Non
lubricated bolts can have an efficiency of less than 50% the torque of values stated.
Indicative torques are shown only, different body gasket systems, different sizes &
classes, etc., will have different torque requirements. Furthermore, other stud
grades can have much lower torques depending if class 1 or class 2 and or above
variables.
