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Recommended Air Handling Systems for Food Production

Contact Cee Corp for industrial ventilation solutions


MARCH 28, 2013

Controlled Environment has a significant amount of time spent in food production facilities analyzing ventilation systems. One of the items at the top of the list that needs attention at most facilities is the type of air handling equipment and how it is applied.


A fairly significant design flaw that we encounter in air handling units that supply cooling (DX and/or ammonia systems) are recycling air from the room even when there is process exhaust air being taken out of the room. The result is a negative condition in the room which of course can cause contaminated air, dirt and insects to be drawn in from outside the facility or from contaminated areas inside the facility. A typical example: if there is a requirement for 50 tons of cooling in a production facility and there is 10,000 cfm of exhaust.  Frequently what we see is that the 50 ton air handling unit is recycling air from the room and only bringing in about 10% outside fresh air of the air quantity being handled by the unit; which in this case could be 2,000 cfm. So, in this production room, they are bringing in 8,000 cfm of uncontrolled air from potentially contaminated areas. Most companies that supply air handling units, design their units for recycled air and if one requests a unit that brings in 100% outside air, the prices for these units are significantly higher.

MUA Units


The other significant design flaw we see with air handling units is that the filtration is on the inlet of the unit only.  This approach has pretty much been accepted for years and even today; the new units being installed only have filtration on the inlet. New research going on today highly recommends having filtration on the inlet and the outlet as follows: MERV 12 on the inlet and a MERV 17 on the outlet of filtration systems. This definitely applies to air handling units that recycle air for heating and cooling, however, it is highly recommended for air handling units that bring in 100% of its air from outside.The reason this has become important is that the air handling unit is an enclosure that can contain moisture; and both cooling units and heating units can contain moisture. The moisture is an important part of growing, for example, salmonella.

In a food production area in a facility, cleaning and sterilizing is done consistently and daily. How often, however, have we seen the cleaning crew go inside of an air handling unit? Not often! Contaminants can start to grow inside the air handling units, and be picked up and blown back into the production facility. And just a note, salmonella can be airborne, along with many other types of contaminants. As a summary; a filtration system should be on the inlet and outlet of any air handling system within a food production facility.

MUA Components


Article by:
David Swinehart
Controlled Environment Equipment
North Prairie, Wisconsin 53153

Food safety manufacturing solutions

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