1. PURPOSE
1.1 This fabrication and erection specification defines the minimum requirements for installation of expansion joints.
2. scope
2.1 This specification applies to the installation of all expansion joints in cold boxes and cans.
2.2 This installation procedure may be used as the basis for other expansion joint installations at the discretion of the appropriate technical expert.
3. related documents
3.1 Air Products Engineering Documents 4WPI-SW70003 Oxygen Clean (Class AA) Inspection and Acceptance Requirements
4. GENERAL
4.1 An expansion joint is constructed of relatively thin gage material to provide the flexibility needed to absorb the expected thermal movements. This requires handling, installation, and inspection procedures to prevent damage to the thin section, and to ensure that unaccounted movements as a result of piping misalignments, for example, are not imposed.
5. PRE-INSTALLATION INSPECTION
5.1 Inspect the expansion joint for overall cleanliness, expansion joints used in cold boxes/cans shall have been Class AA cleaned to 4WPI-SW70003 (oxygen clean).
5.2 Verify that there is no freight damage (for example, dents, broken hardware, or loose shipping bars). Any damage shall be reported immediately to the Air Products representative.
5.3 Check the opening into which the expansion joint will be installed to verify that it is within the tolerances indicated on the drawings. If drawings specify an offset, check the direction and magnitude of the offset provided by the opening.
5.3.1 Verify that he offset magnitude shown on the isometric drawings corresponds to the offset of the opening before the joint installation.
5.4 Verify that the shipping bars installed on the joint are maintaining the correct length and any offset of the expansion joint.
5.5 Verify that the shipping bars can provide stability during installation.
Note: Do not remove the shipping bars until the installation is complete.
5.6 The attachment edges of the pipe shall be smooth, clean, and parallel to each other.
5.7 The area around the expansion joint shall be cleared of any sharp objects or protrusions. If not removable, they shall be noted so they can be avoided.
5.8 Remove any protective covering from the ends of the expansion joint. Plywood covers might have been used to protect the flanges and weld ends.
5.9 Inspect tie-rods. Expansion joint tie-rod assemblies consist of lugs, tie-plates, or flanges welded to the joint. One set of nuts is tack welded to the rod on the outside face of the tie-plate to restrain the pressure thrust. If the expansion joint is designed for vacuum service, an additional set of nuts is tack-welded to the rod on the inside face of the tie-plate to restrain the system to keep the bellows from collapsing under extreme vacuum. The nuts are tack welded to the tie-rods by the manufacturer for reasons pertaining to safety. They must not be loosened, removed, or tampered with by anyone during installation, pressure test, or operation.
6. INSTALLATION
6.1 Check the expansion joint tag plate to verify that the proper expansion joint is installed in the correct location.
6.2 Expansion joints provided with lifting lugs shall be lifted only by the designated lifting lugs. Expansion joints not provided with lifting lugs may be lifted by grabbing two tie rods as close to the tie rod lugs as possible.
6.3 Shipping bars (painted yellow) shall not be used as lifting devices.
6.4 Chains or other lifting devices shall not be used directly on the bellows element or bellows cover.
6.5 With the flow arrow oriented in the direction indicated on the piping isometric, the expansion joint shall be lifted and positioned into the opening.
6.5.1 Weld end expansion joints: Before welding, the bellows element shall be covered with a fire-retardant cloth to prevent arc strikes or weld splatter from damaging the bellows.
6.5.2 Flanged end expansion joints: Orient expansion joint flanges so that the bolt holes are aligned with the mating flanges. Do not force the bolt holes to match the mating flange. This will severely reduce the expansion joint capability during operation and might cause premature failure of the joint. It is a good practice to leave one pipe flange loose until the expansion joint is installed.
6.6 Expansion joints shall not be used to correct for misalignment of the piping.
6.7 Install gaskets and bolts.
6.8 Remove all temporary shipping rods and covers following final installation in the piping system but before the pressure test. Temporary rods and covers (if any) are painted yellow.
7. POST-INSTALLATION INSPECTION BEFORE THE SYSTEM PRESSURE TEST
7.1 Verify that the expansion joint has not been damaged during handling and installation.
7.2 Check the flow arrow shown on the tag plate to verify that the expansion joint has been installed in the correct orientation/direction.
7.3 Verify that the shipping bars have been removed.
7.4 Verify that the expansion joint is not misaligned beyond any offset that was preset by the manufacturer.
7.5 Verify that the tie rods are free to move and are not binding.
7.6 Verify direction and magnitude of the offset. The offset shown on the drawings is prior to joint installation and might have changed because of the weight of the expansion joint. Deviation within 13 mm (1/2 in) is acceptable. An Air Products representative must be immediately notified if the installed offset deviates more than 13 mm (1/2 in) from the drawings.
8. INSPECTION DURING AND IMMEDIATELY AFTER SYSTEM PRESSURE TEST
8.1 A visual inspection of the system shall be performed to check for all the following items: Evidence of leakage or loss of pressure Distortion or yielding of supports in the near vicinity of the expansion joint and the hardware Any unanticipated movement of the piping caused by the pressure Evidence of instability (squirm) in the bellows
8.2 Immediately after the pressure test, verify that the expansion joint installed offset has not changed from that measured in paragraph 7.6.
8.3 Any evidence of abnormality or damage shall be reported immediately to an Air Products representative.