Tag nrho cov khoom muaj lawv tus kheej lifespan, zoo li lub 80-theem saw hlau. Yog tias cov saw hlau tawg thaum lub sijhawm ua haujlwm, kev puas tsuaj tshwm sim tsis tuaj yeem xav txog. Tom qab tag nrho, cov saw hlau yog siv rau qhov chaw ntawm nqa cov khoom hnyav, thiab kev puas tsuaj los ntawm cov khoom yuav tsis hais, thiab kev nyab xeeb ntawm cov neeg ua haujlwm kuj tseem yuav raug hem. Yog li ntawd, nws yog qhov tseem ceeb kom nrhiav tau thiab hloov cov saw uas siv tsis tau nyob rau lub sijhawm. Thaum 80-theem saw hlau nyob rau hauv cov xwm txheej hauv qab no, nws yog qhov tsim nyog los hloov txoj saw tshiab hauv lub sijhawm. cov ntsiab lus raws li nram no:
1. Thaum txoj kab uas hla ntawm txoj hlua ntawm qib 80-theem mus txog tus qauv kev cai teev tseg, nws yuav tsum nres.
2. Thaum cov theem coj ntawm qhov txaus ntshai ntawm 80-theem saw lub ntsej muag tau ncav cuag 10% ntawm tus nqi nominal qub, nws yuav tsum nres.
3. Yog hais tias lub sib npaug ntawm lub sib zog ntawm cov khoom siv, nqe tauj thiab cov sib txuas ntawm ob hnub kawg ntawm cov saw siab tshaj li 10% ntawm lub tsheb npav, nres siv nws.
4. Tsis txhob siv thaum lub fittings ntawm ob qho kawg ntawm txoj saw hlau tawg pleb los yog tsis xwm yeem.
5, 80 qib saw tsis muaj xeb thiab muaj ntau lub ntsuas uas yuav tsum tau txiav txim los ntawm cov kws tshaj lij txuas ntxiv siv.
Nkag siab txog cov teeb meem uas yuav tsum tau them sai sai rau thaum siv 80-theem saw hlau, thiab nrhiav thiab hloov lawv nyob rau lub sijhawm kom tsis txhob raug xwm txheej thiab ua kom txoj haujlwm zoo. Yog xav paub ntxiv txog cov saw hlau, thov khaws ib lub qhov muag ntawm Qhov saw zoo.
