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7 .9.2 Expansion joints made of thin-walled bellows shall comply with the<br />
following.<br />
a) <strong>The</strong>y shall be protected from internal damage with a metallic liner<br />
mounted flush with the inside of the shell. <strong>The</strong> liner material shall be<br />
compatible with the base material to which it is attached. Carbon-steel<br />
liners shall be at least 6 mm (1/4 in} thick. liners of stainless steel or<br />
other alloys shall be at least 3 mm (1/8 in) thick. For vertically mounted<br />
bellows, the liner shall be attached at the top and open at the bottom to<br />
allow for free drainage.<br />
b) <strong>The</strong>y shall be protected from external damage with a metallic cover that is<br />
designed to remain intact during shipping, handling and operation.<br />
c) <strong>The</strong>y shall be designed to meet the requirements of the pressure design<br />
code. In no case shall the cycle life, as calculated by EJMA, be less than<br />
1000 normal operating cycles.<br />
d) <strong>The</strong>y shall have the bellows formed from a cylinder that has only<br />
longitudinal weld seams.<br />
e) Bellow welds, including attachment welds, shall be 100% examined by<br />
the liquid-penetrant method. <strong>The</strong> acceptance criteria shall comply with the<br />
pressure design code.<br />
Charlie Chong/ Fion Zhang
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