What device is required on hoses when filling tanks for termiticides?

The correct choice is the requirement for anti-backflow devices on hoses when filling tanks for termiticides. This device is crucial in preventing contamination of the water supply by ensuring that no backflow occurs. During the filling process, if a disturbance creates a pressure change, the anti-backflow device acts as a barrier, keeping chemicals and hazardous substances from flowing backward into the potable water source. This is particularly important in pest control operations, where termiticides are used, as they can be toxic and harmful if they enter drinking water systems.

Other options, while important in their own contexts, do not directly address the critical issue of preventing backflow contamination during the filling of tanks. For instance, pressure gauges are useful for monitoring system pressure but do not prevent contamination. Suction strainers help to filter out debris when transferring liquids but do not safeguard against backflow. Flow meters measure the volume of liquid being transferred, which is important for careful application but does not address safety concerns regarding contamination. Thus, the need for anti-backflow devices is specifically focused on protecting the integrity of water supplies during the management of termiticides.