As many as three regulators in parallel may be required. G. Back Flow Prevention 1. Provide backflow protection at any building water system where there are connections, actual or potential, to a contaminating liquid. Examples include laboratory hose cocks and connection from domestic system to HHW makeup and cooling towers. Backflow may be prevented by installing a backflow prevention device at each individual point of possible contamination, where devices such as vacuum breakers or air gaps may be employed, or at a single point where an industrial water piping system takes off from the domestic water piping.
Industrial water used in labs for experiments is assumed to be non-contaminated.
The industrial system must be protected from HHW, cooling towers, etc., by additional RP devices. Select the type of backflow prevention system appropriate to each individual case. Generally, a separate industrial water system will be justified in buildings having numerous outlets that are susceptible to contamination. A chemistry or laboratory building is a good candidate for a separate industrial system. H. Backflow Prevention Devices Select appropriate backflow prevention devices for the intended service.