IM-PP 724607 0815
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At no point in the piping system should a fitting
be the sole means of support. For example, when
installing a tee, both the branch and the trunk must
be properly supported. Piping systems should
be isolated from shock and vibration through the
proper use of hangers, supports and vibration-
eliminating devices.
Figure 3.2 Spacing for sliding pipe hanger
3.5.9 Pressure surges
The maximum operating pressure in a ProPress
system is 200 psi; this is a working limit and applies
to general operation as well as pressure transients.
Good engineering practices should be utilized to
design the system in a way that minimizes sharp
pressure surges. Pressure surges or transients from
fast acting valves, pump surges and other sources
that result in water hammer effects can cause
damage to many system components, including
press fittings. When fast acting valves and/or
pumps are incorporated into any system, the
designer and installer should isolate press fittings
from the effects of sharp pressure surges. ProPress
fittings should be isolated or separated by sufficient
distance from pumps, fast acting valves and other
sources of pressure transients.
3.6
Viega ProPress installation requirements
The following are special requirements to consider
when installing the Viega ProPress fitting system.
3.6.1 Rotating a pressed fitting
Once a Viega ProPress fitting has been pressed, it
can be rotated (not by hand), but once rotated more
than five degrees, the fitting must be re-pressed
to restore resistance to rotational movement. If the
fitting is re-pressed, care should be taken to align
the flats on the jaw and fitting.
3.6.2 Deflection
When pressing Viega ProPress fittings in a system,
the deformation of the fitting is constant. This
allows for a consistent leak-free joint every time
and is a result of the pressing technique.
The pressing process can cause deflection
(angular misalignment) to occur. Deflection
while pressing can be corrected by alternating
the position of the press tool on each fitting
connection. An example would be placing the
press tool on the right side of the first press
connection and alternating to the left side of the
press fitting on the second connection.
While deflection cannot be completely eliminated,
it can be minimized using this method.
3.7 Identification
All Viega ProPress piping systems should be
continuously marked in accordance with ANSI
A13.1 or as required by the local Authority
Having Jurisdiction.
Figure 3.1 Spacing for sliding pipe hanger
4
"
All parts of the support equipment need to be
designed and installed to not disengage due
to movement of the supported piping. Sliding
hangers must be positioned so that they cannot
unintentionally become rigid hangers when the
system is in use. See Figure 3.1. Figure 3.2 shows
a sliding pipe hanger that becomes a rigid hanger
with spacing in excess of 10".
Summary of Contents for Megapress
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