IVC FAQ™ – 5


IVC FAQ™ is a series of questions and answers related to IVC systems and the modern technologies used for laboratory rodent housing systems.


5. What are the benefits of a cage filter top having a large filter area compared to a cage filter top that has a small filter area?

The larger the (exposed) filter media area of a cage filter top is, the more freely gas exchanges through the filter. The smaller the filter area, the more restricted the airflow becomes. Smaller cage filters fill with particulate faster, …

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requiring more air pressure and more energy to maintain the same air exchange rate as the filter loads, while reducing the useful life of; Filter top filters, cage filters, blower Pre-filters and HEPA filters.

Cages with molded transparent plastic tops with filter paper inserts on the top were first developed by Robert Sedlachek in the mid 1970s and commercially mass produced by Lab Products, llc. starting in the early 1980s (Jack R. Hessler, DVM, MS, The History of Environmental Improvements in Laboratory Animal Science: November, 2008).

The Micro-Isolator® is a housing system used to maintain rodents free of airborne pathogens. The housing was developed as a means to protect valuable research animals from infectious agents carried on particulate matter, such as dust particles. The effectiveness of providing barrier protection for animals at the cage level has been well document in countless scientific articles for almost 40 years.

Micro-Isolator® brand product lines support wide acceptance and use by researchers since its inception in the early 1980’s. The Micro-Isolator® can be used for housing laboratory animals in two ways; either housing animals on a ventilated housing system or can be used as a “Static” cage (non- forced air) housing system.

When used on a Lab Products, llc. ventilated housing system, the full filter helps to prevent cage bedding and feed dust, animal dander, moisture and allergens from exiting the cage/rack (and entering the room environment), while helping prevent particulate build up inside of the exhaust duct-work on the ventilated rack. Used as a static cage, the full filter in the Lab Products, llc. cage filter top allows for natural downward filtered air convection between the room and inside of the cage, to help maintain the well being of the animals and cage-level micro-isolation integrity.

Should the power be disrupted to a rack causing the fans to cease operating, the Micro-Isolator® reverts to a static cage condition. Thus, the welfare of the animals and the integrity of micro-isolation at cage level is maintained, while the window of opportunity for cage intervention is extended as the animals can still breathe thanks to natural air convection of the static cage.  In contrast, in other manufacturer’s cage tops that contain a small filter area or have no filter at all, undesirable or unsafe levels of carbon dioxide may develop very quickly inside of the (static) cage and end up being harmful to the animals or negatively impact the interpretation of research results.

Lab Products, llc. has found that some facilities may wash the filter tops with media monthly. Some may wash every six months and others may wash once a year or even longer. The filters last a long time, filter replacement cost is minimal and filter change out is made easy with a Lab Products, llc. Filter Change device that rests on a tabletop or Workbench.

Additional questions or comments related to this posting? Please contact us and we’ll be happy to respond.

© 2015 Bio Medic Corporation. Micro-Isolator is a registered trademark and IVC FAQ is a trademark of Lab Products, llc.


Our next question:

6. Does Lab Products, llc. offer a positive or negative pressure ventilated cage housing system for rodents?

We offer a combination of both positive and negative pressure airflow at the same time for protecting your rodents, personnel and research with technologies proven over decades of field use. Switching back and forth to one pressure or the other is simply unnecessary…

Come back for the answer to this question.

© 2015 Bio Medic Corporation

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