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The necessary steps for installation of all expansion joints shold be pre-planned. The installers shal be made aware of these steps. It is important that the joints are installed at the correct lengths and should be extended or compressed to make-up deficiencies in pipe length, or offset to accommodate piping which has not been property aligned. Any precompression or pre-extension of the joint should not be neglected if this has been specified.
The most critical phases of the installation are as follows:
a) Carried should be taken to prevent damage to the thin wall bellows section, such as dents, scores, arc strikes and weld spatter
b) No movement of the joint due to pipe misaligment, for example, shal be imposed which has not been anticipated. If souch movements are imposed, this can result in damage to the bellows or other components. Specifically the fatigue life can be substantially reduced, forces imposed on adjacent equipment may exceed their design limits, internal sleeve clearance may be adversely affected, and the pressure capacity and stability of the bellows may be reduced.
c) Anchors, guide and pipe supports shall be installed in strict accordance with the piping system drawings. Any field variations may affect proper functioning of the joint and must be brought to the attention of a competent design authority.
d) The joint, if provided with internal sleeves, shall be installed with the proper orientation with respect to flow direction
e) Once the anchors of other fixed points are installed and piping is properly supported and guided, shipping devices should normally be removed in order to allow the joint to compensate for changes in ambient temperature during the remainder of the construction phase.
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Careful inspection of the entire system shall be made with particular emphasis on the folowing:
a) Are the anchors, guides and supports installed in accordance with the system drawing?
b) Is the proper joint installed in the proper location?
c) Are the joints flow direction and pre-positioning correct?
d) Have all shipping devices been removed?
e) If the system has been desigend for gas, and it is to be tested with water, has provision been made for the support of the additional dead weight load? Some of the water may remain after test. If this is detrimental to the joint or the system, this should be removed before commissioning.
f) Are all guides and supports free to permit pipe movement?
g) Has any joint been damaged during handling or installation?
h) Is any joint misaligned?
i) Is the bellows and other moveable parts of the joint, free from foreign material?
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WARNING: Extreme care must be taken while inspecting any pressurized system or components. A visual inspection ot the system shall include checking the following:
a) Evidence of leakage or loss of pressure
b) Distortion or yielding of anchors, joint hardware, bellows element and other piping components.
c) Any unanticipated movement ao the system due to pressure.
d) Any evidence of instability (squirm) in the bellows.
e) The guides, joints and othermoveable parts shall be inspected for binding.
f) Any evidence of abnormality or damage shall be reviewed and evaluated by competent design authority.
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a) Immediately after placing the system in operation, a visual inspection shall be carried out to ensure that the thermal expansion is being absorbed by the joints in the manner for which they were designed.
b) The bellows shall be inspected for evidence of unanticipated vibration.br>
c) A programme of periodic inspection shall be planned and conducted throughtout the operating life of the system. These inspections shall include examination for evidence of external corrosion, loosening of threaded fastenings and deterioration af anchor guides and supports.
This inspection programme, without other information, cannot give evidence of fatigue, stress corrosion or general internal corrosion.
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A record should be maintained of change of system operating conditions (such as pressure, temperature, cycling, etc.) and piping modifications. Any such change shall be reviewed by a competent design authority to determine its effect on the performance of the joint, anchors, guides and pipework supports.
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