ANSI/ASHRAE/ASHE Standard 170-2025, Ventilation of Health Care Facilities

ANSI/ASHRAE/ASHE Standard 170 offers guidance, regulation and mandates to designers and operators of health care facilities by providing the minimum requirements for health care facility ventilation. Developed in partnership with ASHRAE, the revised 2025 edition includes the following significant changes: addition of requirements for the optional use of natural ventilation; total outdoor air calculation at the systems level for systems serving both Standard 170 and Standard 62.1 spaces; updated requirements for Class 2 and Class 3 imaging rooms and associated non-imaging spaces and clarification regarding nuclear medicine; clarification of unoccupied turndown requirements in outpatient spaces; clarification of separation distances and stack discharge heights based on complex situations; additional function of space types for behavioral health; updated cooling and heating reserve capacity and fuel on-site requirements; reorganized and updated Section 10 for ventilation during construction; indication of equivalent acceptable alternative filtration testing requirements to allow for easier international use of the standard; updates to have similar requirements for similar space types across the different tables, when appropriate; clarification of bronchoscopy requirements; provision of new space types to coordinate with Facility Guidelines Institute 2026 space types.