Effect of water flow rate on decontamination efficiency of emergency safety showers

Standards for overhead emergency safety showers used for decontamination in laboratories and production sites specify the spray pattern and the water flow rate. Up to now, there has not been a scientific basis for these requirements. The decontamination of water-soluble contaminants has been investigated using 15 customary shower heads at different water flow rates. A general relationship between water flow rate and decontamination effectiveness could not be established: At a low flow rate, the wash-off time in general did not exceed the time observed at considerably higher flow rates. The shortest decontamination time has been found with a spray pattern that does not fulfil current standards.