Fitilar da ke hana fashewa ba lallai ba ne mai hana ruwa.
Ka'idar hana wuta (kewaye) fitilu masu hana fashewa shine ware tushen kunnawa daga iskar gas masu fashewa. Ba a rufe rumfunan su gaba ɗaya kuma suna da ƙananan gibi. Wadannan gibin suna taka muhimmiyar rawa wajen rigakafin fashewa; kamar yadda harshen wuta ya ratsa ta wadannan kunkuntar wurare, yana gamuwa da juriya da bacewar zafi, rage zafi zuwa matakan da bai isa ya kunna fashewar ba. Don buƙatun da ke buƙatar tabbatar da fashewa da kuma hana ruwa iyawa, Tabbatar an ƙayyade ƙimar kariya ta casing azaman IP65 ko IP66.