HVAC Design for Veterinary Clinics

What You Need to Know

Veterinary clinics are one of the hardest building types to ventilate. You have surgery rooms that need clean filtered air. Kennels that produce constant odour. Isolation rooms that must stop pathogens from spreading. Reception areas where pet owners expect a fresh, clean environment. Each zone has different temperature, pressure, and air quality needs.

AS 1668.2:2024 requires 5 L/s per square metre of exhaust air for animal enclosures, kennels, and veterinary centres. That is one of the highest exhaust rates in the standard. On top of that, surgery rooms need 10 to 15 air changes per hour with filtered supply air. Isolation rooms need 12 or more air changes per hour at negative pressure with 100% exhaust.

For a typical small animal vet clinic (200 to 500 sqm), mechanical engineering design fees range from $5,000 to $12,000. Larger veterinary hospitals with multiple surgery suites, imaging rooms, and boarding facilities range from $12,000 to $25,000+.

• AS 1668.2:2024, Table 4.3 sets the exhaust rate for animal enclosures, pet shops, veterinary centres, and kennels at 5 L/s per sqm. This is a contaminant-based exhaust rate, not a per-person outdoor air rate.
• AS 1668.2:2024, outdoor air requires a minimum of 10 L/s per person for clinic consultation and treatment areas. Higher rates apply where anaesthetic gases or chemical disinfectants are used.
• NCC Part F6 references AS 1668.2 for mechanical ventilation. Veterinary clinics with animal housing areas require mechanical ventilation. Natural ventilation alone does not satisfy the standard for animal enclosures.
• NCC Part J6 covers energy efficiency of HVAC systems. All mechanical systems must comply with fan power limits and controls requirements. Applies to supply, return, and exhaust fans.
• Australian boarding codes require temperatures between 15 and 27 degrees Celsius in enclosed animal housing areas with forced ventilation. NSW Animal Welfare Code of Practice No. 5 and Victorian Code of Practice for Boarding Establishments.
• Air change rates for kennels: 8 to 12 ACH to control odour build-up and maintain air quality. Required by Australian boarding establishment codes. Ventilation must avoid draughts and distribute air evenly.
• Humidity control: relative humidity should be maintained between 30% and 70% in animal housing areas. High humidity promotes bacterial growth and worsens odour. Low humidity causes respiratory irritation in animals.

The biggest challenge in vet clinic HVAC is zone separation. A well-designed system creates three pressure zones. Reception and waiting areas run at positive pressure. Clinical areas (consult rooms, treatment, surgery) run at neutral pressure. Kennels, wet areas, and isolation rooms run at negative pressure. Air flows from clean to dirty. Odour migrates away from clients, not toward them.

Surgery rooms need filtered supply air at 10 to 15 ACH. A minimum filter rating of MERV 14 is standard for veterinary surgery. The room should be positive relative to adjacent corridors. This prevents corridor contaminants from entering the sterile field. Anaesthetic gas scavenging is separate from the general HVAC system.

Kennel areas are the primary odour source. At 5 L/s per sqm, a 40 sqm kennel ward needs 200 L/s of exhaust. That is a significant volume of conditioned air being thrown away. Makeup air must be supplied to replace it, and that makeup air needs heating or cooling. This is why kennel areas drive a large portion of the energy bill.

Isolation rooms are critical for clinics that treat infectious cases. The room must be at negative pressure relative to the corridor. Air change rates must reach 12 ACH or higher. All air from the isolation room must be exhausted directly outside. None of it returns to the general HVAC system. A pressure monitor at the door confirms the room is working correctly.

Imaging rooms (X-ray, CT) have their own requirements. Temperature control matters because equipment generates heat and animals under sedation cannot regulate body temperature well. These rooms typically need dedicated split systems or fan coil units.