Boiler with a chemical feed is equipped with what kind of back flow device?

Boiler with a chemical feed is equipped with what kind of back flow device?

• A. Backflow preventer with check valve
• B. air gap/ reduced pressure principal
• C. Vacuum breaker only
• D. Double check valve with relief

Answer: (B)

When a chemical feed is connected to a boiler, backflow prevention is needed to stop any contaminated boiler water or chemicals from flowing back into the potable water supply. For this high-hazard cross-connection, the recommended protection is either an air gap or a reduced pressure principle backflow preventer. An air gap creates a physical separation between the potable line and the chemical line, so even if pressure changes occur, there’s no path for backflow into the drinking water. A reduced pressure principle device maintains a lower pressure zone and vents if reverse flow starts, providing robust protection against backflow and back-siphonage. The other options don’t meet the required level of protection here: a vacuum breaker alone isn’t reliable for boiler chemical feeds and can be overcome by backpressure; a double-check valve with relief protects against some backflow but is typically used for lower-hazard connections and may not satisfy code for chemical feeds into boilers.

When a chemical feed is connected to a boiler, backflow prevention is needed to stop any contaminated boiler water or chemicals from flowing back into the potable water supply. For this high-hazard cross-connection, the recommended protection is either an air gap or a reduced pressure principle backflow preventer. An air gap creates a physical separation between the potable line and the chemical line, so even if pressure changes occur, there’s no path for backflow into the drinking water. A reduced pressure principle device maintains a lower pressure zone and vents if reverse flow starts, providing robust protection against backflow and back-siphonage. The other options don’t meet the required level of protection here: a vacuum breaker alone isn’t reliable for boiler chemical feeds and can be overcome by backpressure; a double-check valve with relief protects against some backflow but is typically used for lower-hazard connections and may not satisfy code for chemical feeds into boilers.