FAC and TBR represent something significant to the Medical Department Representative (MDR). What is it?

• A. Total Flow Rate and Biochemical Residual
• B. Flow and Turbidity Readings
• C. Amount of halogen present in potable water after disinfection
• D. Chlorine taste and odor thresholds

Answer: (C)

FAC and TBR focus on the disinfectant left in drinking water after treatment. Free Available Chlorine (FAC) is the portion of chlorine that remains active to kill microbes, while Total Bromine Residual (TBR) tracks the bromine-based disinfectant still present. Together, they quantify the amount of halogen disinfectant in the potable water supply. For the Medical Department Representative, these values are key indicators that the ship’s water system remains adequately disinfected and safe for consumption. The other options describe physical or sensory properties (flow, turbidity, taste/odor) rather than the chemical disinfectant residuals that FAC and TBR measure.