Kev txiav txim siab yog tias cov kab hluav taws xob overhead muaj hnub nyoog yuav tsum muaj kev ntsuam xyuas dav dav ntawm peb yam: zoo li, kev ua haujlwm zoo, thiab kev sim ua haujlwm. Nov yog cov txheej txheem tshwj xeeb:
Kev tshuaj xyuas qhov tshwm sim: Qhov Kev Ntsuas Ncaj Ncees Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij tau raug tshav ntuj, los nag, thiab qhov kub thiab txias hloov mus rau lub sijhawm ntev. Qhov no tuaj yeem ua rau pom cov cim ntawm kev laus hauv cov rwb thaiv tsev thiab cov ntaub qhwv:
Xim Hloov: Cov txheej rwb thaiv tsev hloov los ntawm nws cov xim qub (xws li, dawb, lub teeb grey) mus rau daj, xim av, lossis txawm dub, ib qho kev kos npe ntawm PVC khoom oxidation thiab decomposition.
Deg Cracks: Cov txheej rwb thaiv tsev tsim ib lub network ntawm cov kab nrib pleb lossis nplua fissures. Nyob rau hauv cov xwm txheej hnyav, lub plhaub sab nraud tawm, nthuav tawm cov khoom siv hlau sab hauv.
Hardness txawv txav: maj mam nyem cov hlau (tom qab fais fab tuag lawm). Yog tias nws xav tias tawv thiab nkig, tawg yooj yim thaum khoov, lossis hloov pauv, yog tias nws hnov mob thiab nplaum, tawm hauv cov ntiv tes, nws qhia tau tias txheej txheej rwb thaiv tsev tau deteriorated.
Kev sib txuas taw tes corrosion: Saib seb puas muaj verdigris (tooj liab oxide) los yog hmoov dawb (aluminium oxide) ntawm cov hlau pob qij txha thiab cov terminals. Cov no yuav ua rau kom muaj kev sib cuag thiab ua rau muaj cua sov hauv zos.