Free residual chlorine means that swimming pool water is disinfected by adding chlorine. After contact for a period of time, there is still a proper amount of chlorine in the water to ensure the continuous sterilization ability. Free residual chlorine in swimming pool water should not be too high or too low. If it is too low, it will lose its sterilization ability. If the chlorine content is too high, it means that too much chlorine will have certain toxicity to human body.
Detection of Residual Chlorine in Swimming Pool GB/T5750. 1 1-2006 "Disinfection Index" in Standard Test Method for Drinking Water, the measured value of free residual chlorine is less than the limit specified in GB 17324-2003 "Hygienic Standard for Drinking Water", that is, 0.005 mg/.
Used for disinfection of swimming pools.
Scientists set the residual chlorine index of swimming pool water at 0.4 ~ 0.6 mg/L (0.4~0.6ppm).
The public health bureau of the United States and FINA stipulates that it is 0.2 mg/L. According to the national conditions of China, the personnel are complicated, and some people have bad hygiene habits. In order to better ensure the health of swimmers, the lower limit of 0.4 mg/L is relatively safe. If it can reach the national standard, some diseases that are easy to spread in water, such as pink eye, trachoma and otitis media, can be basically prevented.
Refer to the above content: Baidu Encyclopedia-No residual chlorine