NIBCO Technical Services • Phone: 1.888.446.4226 • Fax: 1.888.336.4226
3
VALVE INSTALLATION GUIDELINES CONTINUED
Butterfly valves should be installed a minimum of six (6) pipe diameters from other line components
and changes in direction in both the upstream and downstream piping. This assures disc clearance
when opening the valve and reduces internal stress on disc by reducing flow turbulence. While not
always practical, it is important to design in as much straight distance on either side of the butterfly
valve as possible.
NIBCO butterfly valves are bi-directional and may be installed with flow in either direction. These
valves can be installed in any horizontal or vertical position. If a choice of stem positions exists, the
valve should be installed with the stem in the horizontal position; this will minimize seat wear by
distributing the stem and disc weight evenly. Also, if the media is abrasive, the horizontal stem
position is highly preferred, which will allow the disc to act as a “scoop” to sweep the line of the
media when operated.
When using a valve with gear operator attached, it may be desirable to have the hand wheel
positioned to allow easy access, or for use of an optional sprocket rim (chain wheel) for remote
operation. It is the responsibility of the installer to determine if a Retaining Harness is needed when
using a chain wheel. Before valve installation, review how to orient the gear operator hand wheel
position in relation to the valve body and piping system. Pre-planning may save from having to
remove a newly installed valve and reinstalling in another orientation.
Open and close the butterfly valve fully before attempting to install it into a piping system to ensure
the gear operator stops are properly set and the valve is fully functional. If the gear operator is
removed from the valve for any reason, prior to or during installation, the gear operator stops must
be properly reset as per Section IV, on page 5.
III. VALVE INSTALLATION PROCEDURE
Always position the connecting pipe flanges accurately in the line, allowing sufficient space between
the flanges for the valve. Make sure the pipe flange faces are clean of any foreign material such as
scale, metal shavings or welding slag. Valves should be installed with the disc in the closed position
to prevent damage to sealing surfaces. Rubber seated butterfly valves have an integral rubber face
that seals to the attaching flanges, therefore
separate gaskets should not be used
.
1. Fully close valve and inspect to assure disc is centered equally in the seat. Adjust gear operator
CLOSE stop if necessary, to center disc in seat. See Section
IV
on page 5.
2. Carefully insert the valve between the pipe flanges. Do not apply any lubricants to the seat faces
as this may damage them.
3. Line up, center & secure the valve between flanges using
customer supplied
desired bolts as
listed in
TABLE 2
on next page. Do not tighten bolts at this time, hand tighten then “snug-up”.
4. Carefully open the valve to assure free unobstructed disc movement. Disc interference may
result when valves are installed in pipelines having smaller than normal inside diameters, such
as heavy wall pipe, plastic-lined pipe, as-cast flanges, or reducing flanges. Interference can also
occur when connecting directly to a swing check or silent check. Suitable corrective measures
must be taken to remove these obstructions, such as taper boring the pipe or installing a spacer
or spool piece.
5. After proper operation is verified, tighten the bolts to the
minimum
recommended bolt torques
listed in
TABLE 3
, next page, using a cross-over pattern as shown in
FIGURE 1
, next page.
6. A multi-stepped process utilizing the cross-over pattern should be used to draw flanges against
the rubber seat from both sides of the valve at the same rate, ensuring even compression. This
should be followed by 2 sets of chase patterns, alternating from one side of the valve to the
other. Refer to
ASME PCC-1 GUIDELINES FOR PRESSURE BOUNDRY BOLTED FLANGE
JOINT ASSEMBLY
for bolt tightening methodology.
7. Pressurize piping to valve and inspect for leakage. If leakage is observed, tighten bolts using
cross-over pattern, increasing torque until leak stops.
DO NOT EXCEED MAXIMUM TORQUES
LISTED IN
TABLE 3
on next page.
8. Recommended torques are made without warranty. Installer must verify proper strength bolts
for application.