Code
Vomit-contaminated water shall have the FREE CHLORINE RESIDUAL checked and the FREE CHLORINE RESIDUAL raised to 2.0 mg/L (if less than 2.0 mg/L) and maintained for at least 25 minutes (or an equivalent time and concentration to reach the CT VALUE) before reopening the AQUATIC VENUE.
Annex
For vomit contamination, the CT VALUE for norovirus is thought to be in the same range as Giardia, so the same CT VALUES are used as for a formed stool contamination.502
Table 6.5.3.3: Giardia Inactivation Time for Vomit Contamination
Chlorine Levels (mg/L)
Disinfection Time*
1.0
45 minutes
2.0
25 minutes
3.0
19 minutes
*These closure times are based on a 99.9% inactivation of Giardia cysts by chlorine, pH 7.5, 77°F (25°C). The closure times were derived from the Environmental Protection Agency (EPA) Disinfection Profiling and Benchmarking Guidance Manual. They do not take into account “dead spots” and other areas of poor pool water mixing.