PQ for purified water system @ different conditions!

We have installed a new purified water system generation and distribution @ ambient temperature. We have different climate condition’s here like during winter raw water temp stays 10-15°C and summer its 25-35°C so we have heat exchangers for the seasonal conditions and these heat exchangers are connected to main plant utilities boiler and chiller for their operations. The pw usage requirements are for day shift only 5 days a week typically and no usage in the night time. As the entire plant is running 1 daytime shift we want to shut down the utilities. But would want the entire water system running (recirculation only) without the utilities and resume normal generation of PW with utilities running the next day morning. So during winter/summer the raw water and pw water temperature may vary to the extremes during the night time. If I am to validate the system how would I proceed as there are different temperature maintained during daytime and at the night ?. Should I do all the 3 phases of PQ for day and night conditions !!! Please help me.

That’s a tricky one. Normally, I do a one year PQ to account for seasonal variations and it sounds like you’re already planning for that. However, your company’s plan to shut down utilities during the night definitely add an extra challenge into your system. Since it sounds like you’re concerned, I would suggest a reduced level of monitoring during the night conditions or maybe first thing in the morning before the utilities come back on line. Your primary objective should be to show that the water you’re using in your process is of appropriate quality. That said, I would think that you would also want to know how the turning on and off of the utilities affects your water system.

Without knowing the design of your system, that’s probably the best advice I can give you right now. Whatever you decide, just make sure that it is spelled out in your validation plan/protocol with your rationale as to why you picked the testing.

HI shulerkl,
thanks for your comments !
how about this- if I sample and test during day and nighttime without concerning about utilities or temperature been maintained in the system it would arrive at some results. as my concern is microbial growth only and all other chemical parameters remaining within the limit, I would need to have a more shorter sanitization frequency ie more no of sanitization cycles
and I keep doing the testing for over 12 months. would that be justifiable becos at this stage I cant access the system functionality without testing it,
your thoughts on this !!
do also mail me ur mail id so that I can send details of my water system