When we run an SIP of the transfer line during the cool down step we have the line pressurized to 0.3 bar and we have two valves open to the drain to remove the condensate from the line. There is a thermostatic steam trap and check valve between the open valve and the drain. We allow the transfer line to cool for twenty minutes which allows the line to cool to around 50 degrees Celsius. We are getting contamination of our product, one suggestion is to close the valves to drain during cooldown and keep the transfer line pressurized to 0.3 bar. This will allow build up condensate, is this a large problem in keeping sterility.

Vincent typically after SIP we would recommend a clean air blow down of your lines. This keeps the system at positive pressure as you pulse the valves isolating your steam traps leaving your lines and equipment free of condensate. Leaving any pockets moisture in your system after SIP provides a breading ground for microorganisms causing your product to fail. We have seen some clients install air handling units or air heaters which provide hot air to systems to ensure they are dry to prevent a build up of condensate post SIP.

I agree that the system needs to be free of condensate. One way to get rid of condensate after steam is to pull a vacuum. Any hot condensate with instantly boil.

Follow this with an air blow and the system will be clear of water.

John,
Your approach to close the drain valve is a good recommendation, leaving it open is a risk. Make sure you never create a vacuum in the line. If your line is correctly trapped, there should not be much moisture in the line if the line has been held at temperature long enough to heat all the components. If you are concerned with the quantity remaining, you could pulse the drain valve.

If you are getting contaimination, I would recommend you ensure you have an adequate pressure hold test of the system boundary valves before SIP. Ensure you have open pathways beyond the boundary valves to detect valve failure. Even with our best efforts we have missed this on occassion

Hi Vincent, I would agree with the above, any moisture remaining in your system will be uncontrolled and can leave you exposed to potential contamination. You want to ensure your system is free of any condensate/moisture post SIP. Suggestions as above of a (heated) air/nitrogen blow with vacuum will aid just being careful of valving arrangements and integrity of any isolation/boundary valves especially if considering a vacuum step. You may also consider pressurizing post blowdown with nitrogen to maintain an inert positive pressure environment in the line until it is required for use.

Many thanks for the feedback guys. At the moment, we blow the lines down using sterile air. The only thing that we haven't being doing is pulsing the valves, during blow down. We maintain the lines at 0.3 bar pressure, till use. The argument I'm getting back on the condensate is that "but it's sterile condensate". Pulsing the valves during blow down/cool is a good recommendation.