Ukubonisa umlingani
1. Indwangu evuselelwe ngokuphelele (100%).
2. Ukusebenza okungangeni amanzi okungaphezu kuka-10,000 mmH2O ngaphansi kwezindinganiso zaseMelika (ASTM).
3. Ukuphefumula okungaphezu kuka-5,000 g/24h m2 ngaphansi kwezindinganiso zaseMelika (ASTM).
4. Yonke imithungo iboshwe ngetheyiphu.
5. Izinga lokungenawo amanzi elingu-4 ukuze kusebenze kangcono emvuleni.