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Glossary
Healthcare

What is ASHRAE 170?

Definition

ASHRAE Standard 170 sets the minimum ventilation requirements that hospitals and other health care facilities must meet, space type by space type, for designers and operators alike.

Who it applies to

ASHRAE and the American Society for Health Care Engineering (ASHE) publish it jointly for health care designers and operators. ASHE notes that authorities having jurisdiction enforce different editions, so each facility must confirm with its AHJ which one governs.

What the 2025 edition changed

ASHE lists these among the significant updates:

  • Optional use of natural ventilation
  • Total outdoor air calculated at system level when one system serves both Standard 170 and Standard 62.1 spaces
  • Updated rules for Class 2 and Class 3 imaging rooms
  • Added behavioral health space types and space types aligned with the Facility Guidelines Institute 2026
  • A reorganized Section 10 on ventilation during construction

Tracking rooms between rebalancing visits

Commissioning proves design airflow once. Aqueduct logs temperature, humidity and CO2 by zone, and the AHU and RTU twins record damper position, fan status and supply air temperature over time, so drift in a sensitive space can be traced to the unit that serves it.

Questions

ASHRAE 170: common questions

ASHRAE 170 is the ventilation standard written specifically for health care facilities. It sets air change rates, outdoor air, pressure relationships, filtration, temperature and humidity for spaces such as operating rooms, isolation rooms and pharmacies. Aqueduct's view is on the ASHRAE 170 compliance page.

ASHRAE 62.1 covers ventilation in most other occupied buildings, while 170 governs health care spaces. The 2025 edition clarifies outdoor air totals when one system serves both, which matters in hospitals where offices and clinical rooms share air handlers.

Not automatically. The edition that applies is the one the AHJ has adopted, which often lags the newest publication. Facilities usually adopt newer provisions during renovation projects, when design teams have to confirm the governing edition anyway.

By logging temperature, humidity and pressure in critical rooms and the status of the air handlers serving them. Aqueduct records zone conditions and air handler states over time and raises alerts on excursions, which supports the utility management evidence surveyors ask for under the Joint Commission.

See Aqueduct on your own facility.

Bring a site, a utility bill or a question. We will show you where the loss is.

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