1. Lub vojvoog khoov yuav tsum tsis pub tsawg tshaj qhov muab khoov lub vojvoog kom tiv thaiv kev puas tsuaj rau lub cev pob txha los yog kev puas tsuaj thaum ntxov vim yog ncab ntau dhau.
2. Raws li qhov xwm txheej ntawm kev siv, qhov raug xaiv ntawm hom dej hose, qhov tshwj xeeb, tsis txhob siv qhov tsis raug lossis hloov pauv.
3. Thaum siv lub hose, lub siab yuav tsum tau hloov kho kom haum thiab qeeb kom tsis txhob muaj kev nce siab sai thiab ua rau lub cev puas tsuaj.
4. Thaum qhov chaw ua haujlwm hloov pauv, nws yuav tsum tau nqa tawm hauv av, tsis txhob rub hauv av, kom tsis txhob khawb cov roj hmab sab nrauv thiab xeb cov pob txha txheej.
5. Thaum thauj cov kua uas muaj corrosive, sab hauv yuav tsum tau ntxuav tom qab siv los tiv thaiv qhov seem los ntawm corroding lub raj lub cev ntev ntev lossis xaiv cov khoom sib xws.
