Which backflow prevention device is specifically designed to protect against backflow caused by back pressure?

The correct choice is a Reduced Pressure Zone (RPZ) device, which is specifically designed to protect against backflow caused by back pressure. The RPZ functions by using two independently acting check valves, along with a relief valve located between them. This configuration helps ensure that any backflow resulting from back pressure is effectively contained and will not contaminate the potable water supply.

In situations where water pressure within a system can exceed that of the supply line, contaminants may be pushed back into the drinkable water system. RPZ devices are particularly effective in applications where there is a potential for such an incident, making them a critical component in safeguarding public health.

Other devices, while they do provide backflow protection, may not be as effective or are designed for different backflow scenarios. An air gap, for instance, is a physical separation that prevents backflow but is not specifically tailored to handle back pressure situations. Similarly, a double check valve provides protection against backflow but is typically more suited for low hazard situations and may not manage back pressure effectively as an RPZ would. The pressure vacuum breaker is designed to protect against back siphonage rather than back pressure.