Owner manual
Resilient Seated Butterfly Valves – Flange Bolt Tensioning Data
All information herein is proprietary and condential and may not be copied or reproduced without the expressed written consent of BRAY INTERNATIONAL, Inc.
The technical data herein is for general information only. Product suitability should be based solely upon customer’s detailed knowledge and experience with their application.
Mounting : 21
5. When all bolts are snug-tight, each bolt in the joint then
shall be tightened additionally by the applicable amount
of nut rotation given in Note 1. During tightening there
shall be no rotation of the valve or flange.
Note 1
For bolt lengths not exceeding 8 diameters
or 8 inches (203.2 mm) = 1/4 turn
For bolt lengths exceeding 8 diameters
or 8 inches (203.2 mm) = 1/2 turn
Disclaimer:
Bray Controls is issuing these recommendations only
as a guide to installation. This recommendation is
based on the full compliance of all materials supplied
to their appropriate specifications. Since many of the
components are not manufactured by Bray we can
take no responsibility for any damage caused during
installation.
Series 20/21 and 30/31 - Flange Bolt Torque Chart
Valve Size Normal Torque Range Normal Torque Range
In mm Ft-lbs N-m
2 50 30 40
2.5 65 30 40
3 80 35 50
4 100 35 - 40 50 - 55
5 125 35 - 45 50 - 60
6 150 35 - 50 50 - 65
8 200 45 - 55 60 - 75
10 250 55 - 75 75 - 100
12 300 65 - 110 90 - 150
14 350 75 - 120 100 - 165
16 400 75 - 120 100 - 165
18 450 85 - 130 115 - 175
20 500 85 - 130 115 - 175
Please note that the N-m and Ft-lbs values are based
on bolt size in respective metric and ANSI flanges, i.e.
these values are not a direct conversion between N-m
and Ft-lbs.
The values represent average torques needed to ensure
full compression of the resilient valves’ seats into the
valves’ bodies when installed in pipeline flanges. The
face of both flanges must come into full contact with
the valves’ metal bodies.
No additional torque is required for proper functioning
of the Bray resilient seated valves.
The torque values are based on using new, coarse-
threaded, lubricated fasteners. Up to 25% may be
added to the Normal Torque Range values when using
non-lubricated fasteners.
Torque Values specified by flange manufacturers must
not be exceeded.