Designed for pressure and drain applications processing ultra pure water and highly corrosive chemicals. The valve is ideal for a wide range of uses, from pharmaceutical to semiconductor in PTFE, Kynar PVDF or Polypro body materials; car washes to chemical plants in the lower-cost Geon PVC body materials, and higher temperatures in those applications with Corzan CPVC bodies. For high purity applications such as deionized water, Series BSDA provides the ultimate in non-leaching, contamination-free sealing. The standard valves are air pressure to open, with "fail safe" spring return to close. Because the diaphragm is attached to the piston, no inlet pressure is required to assist with opening. The BSDA is not designed for vacuum service.