NFPA 22.4. Tank Materials (4.4):
Water tank materials are limited to steel, wood, concrete, coated fabrics, and fiberglass-reinforced plastic tanks.
Pioneer Water Tanks are manufactured with ZINCALUME® Steel. ZINCALUME® steel Pioneer Water Tanks are third-party tested and proven to withstand fire immersion. This enables Pioneer Water Tanks to provide a consistent water supply, even during a fire emergency.