Izifudumezi ezijikelezayo zifakwe ngaphakathi kwenqanawa efakwe kwi-thermally insulated apho ulwelo okanye igesi idlula.Imixholo ifudunyezwa njengoko ihamba idlula into yokufudumeza, yenza izifudumezi zokujikeleza zilungele ukufudumeza kwamanzi, ukhuseleko lomkhenkce, ukufudumeza ubushushu beoli, kunye nokunye.
Izifudumezi ezijikelezayo zinamandla, izifudumezi zombane zangaphakathi ezenziwe ngeplagi ejijwayo okanye indibano yesifudumezi esenziwe ngeflange efakwe kwitanki yokukhwelana okanye inqanawa.Ulwelo olungagxininisi okanye olucinezelekileyo lunokufudunyezwa ngokufanelekileyo kusetyenziswa ukufudumeza okujikelezayo ngokuthe ngqo.