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Article by Paul Gladysz, AIA, NCARB, CSI

Indoor Climate Control

How your hospital performs and how it is perceived by clients and team members is influenced in no small part by the quality of the indoor environment. Your building's heating, ventilation and air conditioning (HVAC) system plays a major role. A good system not only provides comfort but also mitigates foul smells and keeps loud dog barking from resonating into every corner.

Comfort Is Subjective

The fact is, comfort is subjective. It's not possible to make everyone comfortable all the time. Achieving a middle range so that most people are comfortable almost all of the time is the more affordable goal.

Beyond comfort considerations, veterinary hospitals present unusual challenges to HVAC designers. You want experienced mechanical engineers involved. Ultimately, the engineer is the one who must select properly sized equipment and assemble it into an integrated, whole-building solution.

Cost Versus Expectations

Veterinary hospitals have many unique and varied spaces and systems that cannot modulate based on occupancy load often do not support ideal conditions. How much are you willing or able to spend on a high-end system? Some perform exceptionally well, but there is a point of diminishing returns. Meeting with your design team and especially the mechanical engineer is an essential first step.

Humidity and Temperature

Condensation, mold and comfort are a function of humidity. In general, the damper a space is, the less comfortable it is. The fact that dry heat is better than humid heat holds true for cooling, too. Ideally, you want to maintain a 50% indoor relative humidity to support comfort, reduce condensation and control the growth of mold and pathogens.

Limit Pathogens

While humidity control is an important feature for preventing the spread of pathogens, more can be done. Aerosolized droplets and viruses travel on air currents and have no problem hitching a ride through the HVAC system.

Ways to combat this include:

• Segment the building to segregate which spaces share air.
• Filter the air.
• Sanitize the airstream using devices such as a UV-C (ultraviolet germicidal irradiation).
• Block recycled air from entering from high-risk areas.

Limit Odors

Veterinary hospitals play host to many odor sources: animal waste, electrocauterization, laser surgery, dentals, built-up residue in runs and wards, and even employee food. (I’m looking at you, you reheated fish lover!) How can your clinic be kept from smelling like the hospitals of old?

• Clean the odor source as soon as you can — no source, no odor.
• To prevent contamination of client areas, the building can be segmented, or zoned into three major zones: the front client area, the center clinical areas, and the rear housing and utility areas. If the front zone is designed with positive pressure relative to other areas, the air will move from the front to back. The central zone would be negative relative to the front zone. The intent is to keep odors in the source room or move them toward the rear until cleaning occurs.

The Noise Problem

One issue with air supply systems is that they can transmit noise. Air ducts are commonly constructed of sheet metal. These long tubes of reflective surfaces easily carry sounds like barking dogs a long way.

Again, zoning is a strategy to mitigate sound leaks, so the proper routing of ducts and the strategic use of acoustical linings and flex ducts will go a long way in eliminating the problem.

Don’t Forget Maintenance

It's no secret that veterinary hospitals produce considerable amounts of fur and dander that constantly clog filters, grilles and diffusers.

Maintenance considerations should include:

• Ease of access to HVAC systems.
• A service contract that calls for frequent filter changes — usually every three months.
• Inspection of the surgery HEPA filter at least twice a year.

Other Considerations

Here are some rooms that need special attention when an HVAC system is installed.

• Exam: Make exam rooms as comfortable as your budget permits. Client perception of your entire business can be made or broken in this room.
• Surgery: A sterile operating field needs to be maintained and temperature can be an issue. Introducing HEPA-filtered air in a downward flow directly over the operating table and using low wall return grilles for Laminar flow (minimal turbulence) ensures only filtered air touches the surgical field. Ideally, the air temperature should be adjustable independent of other rooms in the zone. One way is to use a supplementary mini split air conditioner as long as it does not blow across the sterile field.
• ICU and treatment: The strategic use of exhaust fans is key, much like a hood over a kitchen stove. At least one exhaust fan near a treatment table or cage bank is typical.
• Isolation: This high-risk room should not return any air to the HVAC system. All the air should be exhausted when the room is occupied.
• Pack and prep: Pack sterilization usually happens with a steam autoclave and is a source of humidity. Consider using a ceiling exhaust fan that can be switched on when necessary. I suggest installing a timer switch so that the fan isn’t left on inadvertently.
• Bathing and grooming: Major sources of humidity, these services are typically performed in a separate room. The equipment type and size will depend on the frequency of use. An exhaust fan might be enough, while separate heat and humidity mitigation might be needed at other hospitals.
• Feline wards and boarding: These are major odor producers, so an exhaust fan and minimal or no air returned to the HVAC system are the norms. Some cat condos permit litter compartments to be exhausted directly.
• Dog wards and boarding: If possible, don’t return the air to the HVAC system. Constant cleanup protocols are important here with non-absorbing surface finishes to help. Another issue is humidity. For indoor-outdoor runs separated by flaps or guillotine doors consider them as an outdoor space and strive to temper rather than fully condition the air.

This article was originally published in 'Today's Veterinary Business'. Read the full text here.

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