What is the consensus around air curtains being used for segregation purposes?

Hello,
What is the consensus around air curtains being used for segregation purposes? Outside of air monitoring, how can one verify no cross contamination from line 1 to line 2? Do you need to demonstrate positive air pressure if you are not high risk area? Can the mitigation strategy be similar to the above (air sampling but how for cross contamination?) Additionally, what if the facility infrastructure does not have auto hinge mechanisms on production doors, but train employees only one door can be open at a time and conduct air monitoring? Is that sufficient if standard doors are being used to enter GMP Areas? Thank you everybody. It is certainly a three part question.

Hi Arpagano2,

What are the hazards that you are trying to prevent by using air curtains between line 1 and line 2?

You might want positive pressure depending on the hazard but that is less likely if not high risk products.

IFS Food requires external doors to be self-closing:

4.9.6.2 External doors and gates shall be constructed to prevent the access of pests; they shall be self-closing, unless non-essentiality is justified by risk assessment.

Although it isn’t a requirement I don’t see why you wouldn’t have self-closing mechanisms on your internal doors, it isn’t a large expense to fit a self-closing mechanism.

Kind regards,

Tony

Thank you Tony C. The hazards would be product cross- contamination. I saw this recently in liquid gummy solution blending, but it would be more of a concern with dry powders or powder premix. I also completely misspoke about auto hinge mechanisms. What I meant to inquire about was doors (like roll up doors) that cannot open while another door is open, meaning only one door open at once. Most places I have been do not have this type of capability and just have standard doors but how do you prevent cross contamination outside of training employees to ensure doors are closed when not in use.

My limited experience says air curtains wouldn't be a great solution for separating stationary lines.  You'll end up with more questions about dust control, i.e. where are those curtains blowing the dust around to.  In a couple of spice/dried vegetable milling plants I've worked with, cross contamination was controlled by building physical walls around production lines or sufficiently spacing them out in a processing area.  Hanging plastic curtains have been used at one plant as well, but they end up being difficult to keep clean and you'll get gripes from production about having to keep them washed properly.

One plant had a room in the spice milling area for higher risk milling/packaging of sterols, and we used positive air pressure in that room to keep it safe.  A magnehelic gauge would show the positive pressure was sufficient, and was checked on a separate form hourly.  Whether you determine high risk or low risk for an area, if you've determined positive air pressure is needed to control a hazard, you'll need to monitor the positive air status in some manner.

Training on open doors, specifically exterior doors, is part of the GMP training at all the plants I've worked with.  Some use air curtains for exterior roll up doors where necessary, and also installed ILT's nearby to control possible intrusion.  You'll likely want to document a risk assessment of the door, including paying attention to trend monitoring of ILT's or pheromone traps to demonstrate the air curtains control insect intrusion.

Thank you. Very good information. How about a wash sink in a production room to rinse utensils and tools? Would that be allowed. I’ve never seen this before and toured a site that some washing sinks in the back of the production room with no segregation between the wash are and blending.

Hi Arpagano2,

You are talking about interlocked doors which would be best practice but I would think that there are many facilities that operate without them. Training staff to keep doors is fine but they should be self-closing where practical.

Ideally sinks for washing utensils and tools should be segregated and not used for hand washing, especially if for some reason, you have powders in the area.

As jfrey123 has posted, using air curtains for segregation isn’t the best idea.

I think you need made to make it clear what products you are manufacturing/segregating on those 2 lines if you want sound advice.

Kind regards,

Tony

I would expect an air curtain to cause more problems than it solved if you're trying to prevent small airborne particles from cross contaminating.  Negative local air pressure with extractor venting might serve better that purpose -- you'll of course need to pair that with a filtered intake for the building somewhere nearby.

We do something like this for MAP gasses to control CO2 levels in the package filling areas, but in principle it would work for powders or particulate cross-contamination as well.

Thank you everybody for the great feedback!