ANSI/ASHRAE/ASHE Standard 170 offers guidance, regulation, and mandates to designers of health care facilities. The revised 2017 edition incorporates 12 addenda to the 2013 standard andincludes the following significant changes:

Addition of adiabatic humidifiers as an acceptable type
Addition of a new type of exam room with lower requirements for less-acute applications
Clarification around the prohibition of controls to change pressure relationships between spaces
Reduction in requirements for electroconvulsive therapy procedure rooms
Reduction in requirements for laboratories when allowed by certain calculations
Higher requirements for higher hazard exhaust airstreams
Coordination of space temperature requirements in the Sterile Processing Department withother industry groups
Clarification of the definition of the primary diffuser array in operating rooms

The standard has also been reorganized into three sections: hospital spaces, outpatient spaces, and nursing home spaces. These changes were made to bring Standard 170 into alignment with the forthcoming 2018 FGI Guidelines.