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Animal Arts – How to Ventilate a Cat Cage

Posted on Thu, Feb 09, 2012 @ 02:48 PM

Brought to you by Contributing Editor Vicki Pollard of Animal Arts.

Cats are susceptible to all manner of disease as a result of inadequate housing. The animal care industry is responding to this issue by promoting an increase in the size of individual cages and by enriching the cages with hiding boxes, resting ledges, and separated eating and litter areas.  However, we also need to address how to properly ventilate feline environments. In this article, we will explore practical solutions for getting fresh air into a cat cage and moving dirty air out.

Research from the UC Davis Koret Shelter Medicine Program indicates that airborne transmission is only the fourth most important cause of disease among cats in shelters behind fomite transmission, environmental contamination, and direct contact. In fact, studies show that cats do not have the lung capacity to project airborne pathogens across a room.

It is still important to a cat’s health and wellbeing to have the benefit of fresh, uncontaminated air.  Yet, most typical designs do not accomplish this simple goal. For example, even when one supplies 25 air changes per hour to a typical cat ward, the air exchange rate inside a cat cage can be almost negligible. This is because the cage is a dead air space outside of the primary air exchange pattern in the room.

The practice of aggressively ventilating an entire room does accomplish odor control, but it is not necessarily bringing much benefit to each cat. If we exchange air through the cat cage instead of around it, it is possible to achieve room odor control while reducing overall room air exchange rates and increasing the effective air exchange rates in the cats’ breathing zone.

Your cages don’t have to be built in to be ventilated. A rolling cage is a very practical home for a cat in a facility and has many advantages. It can be cleaned easily, it can be reconfigured based on need, and it can be rolled from room to room with its occupant inside to reduce unnecessary handling of cats, which is a significant source of stress. But how does one ventilate a rolling cage? We originally considered a solution that involved plugging a return flex duct into the back of a cage, similar to a dryer duct. However, this has proven to be clumsy, unsightly, and not very practical.  

The low-tech solution illustrated below accomplishes the same goal without the disadvantages.  The wall behind the cage is designed to accommodate the exhaust ductwork, while the supply is located in the ceiling in front of the cage. The cage must then be outfitted with a grille in the back. Most caging suppliers will work with their clients to have this grille installed in the cage while it is manufactured.

How to Ventilate a Cat Cage Insert Image

The cage is backed up to the wall, and air is naturally sucked through the cage on its way to the exhaust grille. In order to prevent air from rushing around the cage, we recommend placing a rubber bumper or neoprene gasket at the top and bottom and both sides of the cage along the wall to provide a better seal.

A mechanical engineer should be able to use volume measurements to calculate the CFM (cubic feet per minute) that will flow through the cage and adjust the overall volume of room air exchange accordingly. Our office uses 30 CFM per cage (depending on the size of the cage) as a guideline, because this volume of air exchange provides sufficient odor control without creating a feeling of air rushing through the cage. Even if you use less than this amount, the result will still be more satisfactory than in a typical ceiling-ventilated room, because the air is flowing in the direction that most benefits the occupants.

If the cage is built in, then the solutions depend on the cage configuration. Two-sided configurations are typical in cat adoption areas. Typically, the purpose of this design is to provide a front viewing area and a staff zone behind the cage.  The simplest solution for ventilating these cages is to supply the air in the public viewing aisle, pull the air through the cage, and exhaust on the staff side of the enclosure. This involves nothing more than providing a ventilation slot at the top of the cage on the front side. Your mechanical engineer should calculate the size of this slot. Our office typically uses a continuous slot of one inch. We locate the slot at the top of the cage to prevent the cat from being stressed by potential adopters.

  • For built-in cages that are against a wall, our favorite solution is to use a cage that has a built-in litter ventilation chase. This is a nice feature because it prevents litter odors from contaminating the rest of the cage.  It is important to remember that your design team should work with you and the caging manufacturer to ensure that the following problems are solved:
  • The cage should not have an all-glass front or there will be no way to pull the air into the cage. The ventilation chase must be accessible and cleanable to prevent litter dust from accumulating.
  • The chase and duct attachments must be sized properly to achieve the air exchange that is desired. Do not assume that the manufacturer has worked this out in a way that is satisfactory for your project. For a recent project, we worked with a manufacturer to create a custom duct attachment piece.

The ventilation chase solution can also be used in two-sided cat cage configurations if you wish to prevent litter odors and contaminated air from flowing into the staff zone behind the cages.

The solutions presented in this article are only some that are available to you. The purpose of discussing these possible solutions is primarily to raise awareness and create a dialog about this important issue. If we shift the paradigm from thinking about what is best for the room to what is best for the cat, then we are working together to dramatically improve the quality of life for cats in individual housing.

Tags: Animal Care, Contributing Editors, Animal Arts Editors