1. I-VNA(indawo ephansi kakhulu) iwumklamo ohlakaniphile wokusebenzisa indawo yokugcina impahla ephezulu ngokwanele.Ingaklanywa ifike ku-15m ukuphakama, kuyilapho ububanzi be-isle bungu-1.6m-2m kuphela, kwandisa umthamo wokugcina kakhulu.
2. I-VNA iphakanyiswa ukuthi ifakwe ujantshi oqondisayo phansi, ukusiza ukufinyelela amaloli ahambayo ngaphakathi kwephasishi ngokuphepha, ukugwema ukulimala kweyunithi yamarakhi.