CDHF-SVX01N-EN
31
Table 10.
Installation data for 150 psig (1034.2 kPaG) flange adapters (Style 741)
Nominal Pipe Size
Assembly
Screw Size
(a)
Number of Assembly
Screws Required
Screw Pattern Diameter
Weight
in.
mm
in.
in.
mm
lb
kg
4
114.3
5/8 x 3
8
7.5
191
7.7
3.5
5
141.3
3/4 x 3-1/2
8
8.5
216
9.3
4.2
6
168.3
3/4 x 3-1/2
8
9.5
241
10.3
4.7
8
219.1
3/4 x 3-1/2
8
11.75
298
16.6
7.5
10
273.0
7/8 x 1/44
12
14.25
362
24.2
11.0
12
323.9
7/8 x 1/4
12
17
432
46.8
21.2
14
355.6
1 x 4-1/2
12
18.75
476
75
34.0
16
406.4
1 x 4-1/2
16
21.25
540
90
40.8
18
457
1.13 x 4.75
16
22.75
578
100
45.4
20
508
1.13 x 5.25
20
25.00
635
120
54.4
(a)
Screw size for conventional flange-to-flange connection. Longer screws are required when flange washer must be used.
Screw-Tightening Sequence for
Water Piping Connections
This section describes a screw-tightening sequence for
flanges with flat gaskets or O-rings. Remember that
improperly tightened flanges may leak.
N
No
otte
e:: Before tightening any of the screws, align the
flanges. Flange screw torque requirements are
provided in the following table.
Table 11.
Flange screw torque recommendations for
O-ring and flat-gasket piping connections
Screw Size
Gasket Type
O-Ring
Flat
in.
mm
ft·lb
N·m
ft·lb
N·m
3/8
9.5
25
34
12–18
16–24
1/2
13
70
95
33–50
45–68
5/8
16
150
203
70–90
95–122
3/4
19
250
339
105–155
142–210
Note:
Screw size is determined by the diameter of the screw shank.
Flanges with 4, 8, or 12 Screws
Tighten all screws to a snug tightness, following the
numerical sequence for the appropriate pattern as
shown in the following figure. Repeat this sequence to
apply the final torque to each screw.
Figure 20.
Flange screw tightening sequence (4, 8, or
12 screws)
1
3
4
2
1
3
4
5
7
8
2
6
1
3
4
10
11
9
5
7
8
12
2
6
4 screws
8 screws
12 screws
Flanges with 16, 20, or 24 Screws
Tighten only the first half of the total number of screws
to a snug tightness, following the numerical sequence
for the appropriate pattern as shown in the following
figure. Next, sequentially tighten the remaining half of
the screws in numerical order.
