Design ED & EAD Class 125-600
7
Table 3. Body-to-Bonnet Bolt Torque Guidelines
Valve Size, Inches
Bolt Torques
(1)
Design ED
Design EAD
SA193-B7
SA193-B8M
(2)
Design ED
Design EAD
N
S
m
Lbf
S
ft
N
S
m
Lbf
S
ft
1-1/4 or less
1
129
95
64
47
1-1/2, 1-1/2 x 1, 2, or 2 x 1
2 or 2 x 1
96
71
45
33
2-1/2 or 2-1/2 x 1-1/2
3 or 3 x 1-1/2
129
95
64
47
3, 3 x 2, or 3 x 2-1/2
4 or 4 x 2
169
125
88
65
4, 4 x 2-1/2, or 4 x 3
6 or 6 x 2-1/2
271
200
156
115
6
- - -
549
405
366
270
8
- - -
746
550
529
390
1. Determined from laboratory tests.
2. SA193-B8M annealed.
Figure 4. PTFE/Composition Packing Arrangements for Plain or Extension Bonnets
UPPER WIPER
(KEY 12)
PACKING
FOLLOWER (KEY 13)
PACKING RING (KEY 7)
PACKING BOX
RING (KEY 11)
LANTERN RING
(KEY 8)
12A8088-A
12A7815-A
12A8173-A
A5904 / IL
9.5 mm
(3/8ĆINCH)
STEM
12.7 mm
(1/2ĆINCH)
STEM
19.1, 25.4, & 31.8 mm
(3/4, 1 & 1Ć1/4 INCH)
STEM
TYPICAL (DOUBLE) ARRANGEMENT
leakage or damage to the new packing. If the surface
condition cannot be improved by light sanding, replace
the damaged parts by following the appropriate steps
in the Trim Maintenance procedure.
9. Remove the cover protecting the valve body cavity
and install a new bonnet gasket (key 10, figure 19
through 21), making sure the gasket seating surfaces
are clean and smooth. Place the valve plug and stem
into the valve body, making sure it is properly centered
on the seat ring. Then slide the bonnet over the stem
and onto the stud bolts (key 16, figure 19, 20, or 21) or
onto the valve body cavity if cap screws (not shown)
will be used instead.
Note
Proper performance of the bolting
procedures in step 10 compresses the
spiral wound gasket (key 12, figure 19 or
20) or load ring (key 26, figure 21)
enough to both load and seal the seat
ring gasket (key 13, figure 19, 20, or 21).
It also compresses the outer edge of the
bonnet gasket (key 10, figure 19 through
21) enough to seal the body-to-bonnet
joint.
The bolting procedures in step 10
include—but are not limited
to—ensuring that bolting threads are
clean, and evenly tightening the cap
screws, or the nuts onto the studs, in a
crisscross pattern. Tightening one cap
screw or nut may loosen an adjacent cap
screw or nut. Repeat the crisscross
tightening pattern several times until
each cap screw or nut is tight and the
body-to-bonnet seal is made. When the
operating temperature has been
reached, perform the torquing procedure
once again.
10. Install bolting, using accepted bolting procedures
during tightening, so that the body-to-bonnet joint will
withstand test pressures and application service
conditions. Use the bolt torques in table 3 as
guidelines.