Uninzi lweengcango zomlilo zetsimbi ziphathwa ngepeyinti yomphezulu; iingcango zomlilo zensimbi zinokubonelelwa ngeefestile, ii-shutters, i-ventilation shutters, njl. Iingcango zensimbi zomlilo nazo zikhuselekile kakhulu, kwaye aziyi kuchaphazela imisebenzi yemihla ngemihla yabanye abantu ngenxa yokuvula nokuvala ucango, okunokuphepha ezinye iingozi.