The
necessary steps for installing all expansion joints shall be
pre-planned. The installers shall be made aware of these steps as well
as the installation instructions furnished by the manufacturer. The most
critical phases of the expansion joint installation are as follows.
Care shall be exercised to prevent any damage to the thin bellows section, such as dents, scores, arc strikes and weld spatter.
No
movement of the expansion joint (compression, extension, offset,
rotation and especially torsion) due to piping misalignment, for
example, shall be imposed which has not been anticipated and designed
into the movement capability of the expansion joint. If such movements
are imposed, they can result in system malfunction, damage to the
bellows or other components in the system. Specifically, cycle life can
be substantially reduced, forces imposed on adjacent equipment may
exceed their design limits, internal sleeve clearances may be adversely
affected, and the pressure capacity and stability of the bellows may be
reduced.
Any
field pre-positioning shall be performed in accordance with specific
instructions which include both the direction and magnitude of the
movement.
Anchors,
guides and pipe supports shall be installed in strict accordance with
the piping system drawings. Any field variances from planned
installation may affect proper functioning of the expansion joint and
must be brought to the attention of a competent design authority for
resolution.
The
expansion joint, if provided with internal sleeves, shall be installed
with the proper orientation with respect to flow direction.
After
the anchors or other fixed points are in place and the piping is
properly supported and guided, the expansion joint shipping devices
should normally be removed in order to allow the expansion joint to
compensate for changes in ambient temperature during the remainder of
the construction phase.