Cov kav dej tooj liab tau siv txij li thaum xyoo 1960s thiab muaj kev ntseeg siab heev. Cov kav dej tooj liab yog cov tiv taus corrosion, kub thiab to. Copper tubing tuaj nyob rau hauv peb qhov ntau thiab tsawg: M (nyias-walled), L (nruab nrab-thickness), thiab K (thickest-walled.) Hom M thiab L feem ntau yog siv rau hauv cov khoom kub thiab txias, thaum hom K yog siv. rau cov kev pabcuam hauv av.
Txawm koj xav taucov kav dej tooj liab, tooj liab ,tooj liab daim hlau, peb muaj cov khoom thiab kev txawj ntse kom tau raws li koj xav tau.
