Can some guide me to fix the WFI loop sanitation temperature range with relevant guidelines?
A temperature of 80˚C is very “forgiving” of cooler locations which can still be sanitized even with a 10-15˚C temperature loss as it penetrates throughout the system by convection and conduction, so it is very effective. Cooler temperatures (down to 65˚C) can also be used but is “unforgiving” of yet cooler locations such as outlet valves off of the main loop. So such cooler locations must be flushed with this slightly cooler hot water in order to assure that all surfaces reach sanitizing temperatures greater than 60˚C. Unless systems are specifically designed for this, temperatures hotter than 80˚C can impact the longevity of system materials (e.g. gaskets and diaphragms). A temperature of 80˚C is well hot enough to kill the most heat resistant biofilm organisms that will colonize a water system
In the new USP 1231 the recommended temperature in hot sanitizing has changed. The previous recommendation of at least 80°C has been lowered to 65-80°C.
Since thermal or ozone sanitization of WFI systems is typically no less frequent than weekly, that is not enough time for biofilm (with its endotoxin) to develop in the system and be released by periodic sanitization. If the systems are much less frequently sanitized, there is a chance that developing biofilm could release detectable endotoxin when killed by periodic sanitization.
Ok. But we are running our loop at 81-85 always. Some times in ambient temperature( 2-3 hrs operation) . Then again it will be changed to 81-85. In this case what will be the sanitation temperature and it’s frequency of perform ?
Do weekly sanitization at 65-80°C.