Qhov hnyav uas lub hnab ntim ntau dais thaum siv yog ib lo lus nug uas txhua tus neeg txhawj xeeb txog.
① tuaj yeem txhim kho kev thauj khoom thiab tshem tawm kev ua haujlwm zoo. Nws muaj peev xwm loj, ceev ceev thiab thauj khoom, thiab ntau tshaj kaum npaug ntawm kev ua haujlwm ntau dua li cov ntawv ntim cov hnab ntim khoom.
② Kev thauj mus los yooj yim. Muaj lub nplhaib nqa tshwj xeeb ntawm lub hnab ntim khoom, uas yooj yim rau nqa, thauj khoom thiab tshem tawm cov khoom nqa nqa.
③ Tsawg qhov chaw. Lub hnab khoob yog foldable, me me, thiab lub hnab ntim puv muaj lub peev xwm loj, txuag chaw ntau dua li lub hnab ntim me me.
④ Lub neej ntev, tuaj yeem siv tau ntau zaus. Lub hnab ntim khoom yog ua los ntawm cov ntaub ntawv muaj zog heev uas tuaj yeem siv tau thiab siv tau.
⑤ tuaj yeem tiv thaiv cov khoom zoo. Cov khoom siv ntawm lub hnab ntim khoom yog rainproof thiab impervious, thiab nws kuj tuaj yeem ua kom noo noo-pov thawj tom qab tau ntim thiab muab tso rau sab nraum zoov.
⑥ Muaj ntau yam ntim. Tsuav nws yog hmoov thiab granular cov khoom, cov thawv ntim khoom yuav luag tau ntim.