Which standard governs the design of heating, ventilation, and process systems serving spaces in healthcare facilities?

• A. NFPA 99
• B. NFPA 55
• C. ASHRAE 170
• D. ASSE 6000

Answer: (C)

Ventilation design criteria for healthcare spaces are set by a standard that specifically addresses health care facility airflow. This standard, ASHRAE 170, defines minimum outdoor-air requirements, ventilation rates (air changes per hour) by space type, filtration, humidity ranges, and pressure relationships for areas such as patient rooms, operating rooms, isolation rooms, and other care spaces. It guides how HVAC and process systems are sized and operated to support infection control and patient safety. The other standards focus on different topics—NFPA 99 covers life-safety and medical gas/vacuum considerations, NFPA 55 deals with storage and handling of compressed gases and cryogenic fluids, and ASSE 6000 covers medical gas and vacuum piping and installation.