Does Your Veterinary Clinic/Hospital Pass the Smell Test?

When it comes to providing optimum air quality in your clinic (you know the place you spend most of your time and greet new clients often, hoping to put your best foot forward) an ounce of prevention is worth a pound of cure. In researching this blog, I “googled” smells in veterinary clinics and came across a long string of posts of former clients bashing a vet for her smelly clinic and saying how they stopped using her and would never go back and still had the foul smell in their nose, etc..They inferred that her smelly clinic meant she was not a competent Veterinarian and they couldn’t trust her with their pets. Maybe she was an excellent doctor who made the unfortunate mistake of trusting her veterinary clinic to an engineer who does not specialize in animal facility design.

There are six key components to a properly designed mechanical system for any animal sheltering facility (and very few people get this right)

Zoning – physical & biological separations: there should be many smaller zones. Proper configuration creates individual mechanical, architectural, fire & noise control areas. These isolated spaces promote better odor and disease control and better environmental control. Zoning should be defined your engineer with your architect at the beginning of the project. It should not be defined by the architect.

Controls & dehumidification: dehumidification is necessary in nearly ALL climates. DO NOT use evaporative cooling or setback controls. USE simple thermostats for each zone. Use a separate humidistat for each zone @ 50% (fans should run continuously) and equipment should be accessible for maintenance.

Flow rates: How air flows makes or breaks the system. Flow paths and velocities are OPPOSITE to typical “human” medical facilities so an experienced animal care facility engineer is critical. Air distribution design must be for animals (which populate the bottom three feet of the room). In an animal care facility the total air flow is 2 to 3 times what’s required in typical human facility design. (Air changes per hour is an extremely poor method. Air flow should be specifically designed for the area, animal density, disease and air system being used.)

Fresh air – is key for dilution of pathogens. So how much is too little? How much is too much? Not 10% and not 100%. It’s important to note that fresh air varies from room to room. Denser population dictates more air. Larger building volume dictates less air. Balancing exhaust with fresh air is imperative. Exhaust should match or be slightly less than the fresh air in the ENTIRE building. Exhaust should have a normal level and a purge level. Your primary exhaust points should be catteries, bathing, isolation, therapy and kenneling.

Filtration and treatment – Why filter at all? Why not just use 100% fresh air? Even at merely 30% fresh air, 70%-80% of HVAC utility costs will be in heating and cooling the fresh air and you can achieve highly effective odor control by utilizing other available methods. Carbon filtration, ionization & ozone are highly effective odor controllers. Ionization, hydroxyl radicals & ozone are effective in killing airborne bacteria. Filtration removes dander, hair, spores & pollens and UV is effective at killing viruses. Be sure your engineer understands the product effectiveness. All methods of air treatment have benefits & detriments.

In addition to adequate air flow, adequate fresh air, dehumidification, and air treatment, proper air distribution is critical.  Without proper air distribution, the other features of the HVAC system will perform poorly or not at all.  Where possible, air should be delivered vertically to the floor surfaces at moderate velocity.  Exhaust should be as low and close to sources of moisture, odor and disease as possible, including direct exhaust from cages, rather than in the middle of the ceiling as shown below.  Returns should be located in intermediate locations from the perspective of odor and moisture.  All of the air distribution features work with the caging and plumbing systems to create a clean environment.  In this manner, the direction of the vertical air distribution pushes clean, treated, dehumidified air in the same direction as the washing and cleaning, ideally toward the drains, which is only really possible with a complete renovation or new construction.  Typical diffusers should not be used.  Improper air flow is the one area where we see the most errors in design and installation for existing buildings.

Designing a new vet clinic can be challenging and rewarding.  If you are in the midst of selecting an architect for this purpose, find out who their engineer is and speak to that person directly. Better yet, hire the engineer independently of the architect. Get specific answers from them on their firm’s odor control game plan. An engineer who has experience in animal care can make a world of difference in the outcome. Our firm partners with architects throughout the US and Canada and it’s our mission to help create safe, sustainable and practical design solutions.

About the author


C. Scott Learned, MS, MBA, PE, LEED AP


Scott Learned is president of Design Learned, Inc., supervising the engineering of mechanical, electrical, plumbing, fire protection, and air and noise control aspects of animal care facilities. In addition, he provides consultation, floor planning recommendations, and the specification of animal caging, animal equipment, and finishes. Scott possesses a vast knowledge of animal facility requirements — inspired and informed by his extensive experience caring for pets and rescued animals.

Scott Learned is Board Certified, both as a Licensed Professional Mechanical Engineer (PE) and a Licensed Professional Electrical Engineer (PE) and is a Leadership in Energy and Environmental Design Accredited Professional (LEED AP). He is registered with the NCEES and holds Professional Engineering registrations throughout most of the United States. Scott is a frequent speaker on animal care facility engineering at national conferences and has published a range of articles addressing the challenges of engineering for animal care facilities in Pet Services Journal, Animal Sheltering magazine, and the proceedings of several veterinary organizations.

Mr. Learned attended the University of Connecticut earning his Master of Business Administration, Master of Science in Mechanical Engineering, Bachelor of Science in Psychology, and Bachelor of Science in Engineering, Mechanical Engineering.