Part 1 General

Part 2 Outpatient Facility Types

ANSI/ASHRAE/ASHE Standard 170-2017 Ventilation of Health Care Facilities

Heads up: There are no amended sections in this chapter.
absorption distance: the distance downstream of a humidifier required for all moisture to be absorbed into the airstream.
addition: an extension or increase in floor area or height of a building, building system, or equipment.
airborne infection isolation (AII): the isolation of patients infected with organisms spread by airborne droplet nuclei less than 5 pm in diameter. For the purposes of this standard, the abbreviation "AII" refers to the room that provides isolation.
Informative Note: See FGI (2014), CDC (2003), and CDC (2005) in Appendix B.
airborne infection isolation room: a room that is designed according to the requirements of this standard and that is intended to provide airborne infection isolation.
alteration: a significant change in the function or size of a space, in the use of its systems, or in the use of its equipment, either through rearrangement, replacement, or addition. Routine maintenance and service shall not constitute an alteration.
authority having jurisdiction (AHJ): the agent or agency responsible for enforcing this standard.
average velocity: the volumetric flow rate obtained by dividing the air quantity issuing from an air distribution device by the nominal face area of the device.
building: a structure that is wholly or partially enclosed within exterior walls and a roof, or within exterior and party walls and a roof, and that affords shelter to persons, animals, or property. In this standard, a building is a structure intended for use as a hospital or health care facility.
equipment: devices for heating, ventilating, and/or air conditioning, including but not limited to furnaces, boilers, air conditioners, heat pumps, chillers, and heat exchangers.
essential accessories: those components of a system, required to allow proper operation of that system, that are reasonably subject to mechanical failure (e.g., pumps, fans, control air compressors). Humidifiers, controls, and tanks are not included in this definition.
high-risk immunocompromised patients: patients who have the greatest risk of infection caused by airborne or waterborne microorganisms. These patients include but are not limited to allogeneic stem-cell transplant patients and intensive chemotherapy patients.
immunocompromised patients: patients whose immune mechanisms are deficient because of immunologic disorders, chronic diseases, or immunosuppressive therapy.
Informative Notes:
  1. Examples of immunologic disorders include human immunodeficiency virus (HIV) infection or congenital immune deficiency syndrome.
  2. Examples of chronic diseases include diabetes, cancer, emphysema, or cardiac failure.
  3. Examples of immunosuppressive therapy include radiation, cytotoxic chemotherapy, antirejection medication, or steroids.
  4. For more information, see CDC (2003) in Appendix B.
infection control risk assessment (ICRA): a determination of the potential risk of transmission of various infectious agents in the facility, a classification of those risks, and a list of required practices for mitigating those risks during construction or renovation.
inpatient: a patient whose stay at the health care facility is anticipated to require twenty-four hours or more of patient care.
invasive procedure*: a procedure that
  1. penetrates the protective surfaces of a patient's body (e.g., skin, mucous membranes, cornea);
  2. is performed in an aseptic surgical field (i.e., a procedure site);
  3. generally requires entry into a body cavity; and
  4. may involve insertion of an indwelling foreign body.
Informative Note: Invasive procedures are performed in locations suitable to the technical requirements of the procedure with consideration of infection control and anesthetic risks and goals. Accepted standards of patient care are used to determine where an invasive procedure is performed. "Invasive procedure" is a broad term commonly used to describe procedures ranging from a simple injection to a major surgical procedure. For the purposes of this document, the term is limited to the above description. The intent is to differentiate those procedures that carry a high risk of infection, either by exposure of a usually sterile body cavity to the external environment or by implantation of a foreign object into a normally sterile site. Procedures performed through orifices normally colonized with bacteria, and percutaneous procedures that do not involve an incision deeper than skin, would not be included in this definition.
invasive imaging procedure room: a room in which radiographic imaging is used and in which instruments or devices are inserted into patients through the skin or body orifice under sterile conditions for diagnosis and/or treatment.
nonaspirating diffuser: a diffuser that has unidirectional downward airflow from the ceiling with minimum entrainment of room air. Classified as ASHRAE Group E, these diffusers generally have very low average velocity. For the purposes of this standard, the performance of these diffusers is to be measured in terms of average velocity.
nursing facility: a facility that provides resident care, treatment, and services areas (including skilled nursing, subacute care, and Alzheimer's and other dementia facilities).
operating room (OR)*: a room in the surgical suite that meets the requirements of a restricted area and is designated and equipped for performing surgical or other invasive procedures. An aseptic field is required for all procedures performed in an OR. Any form of anesthesia may be administered in an OR if proper anesthesia gas administration devices are present and waste anesthesia gas disposal systems are provided.
patient care area: an area used primarily for the provision of clinical care to patients. Such care includes monitoring, evaluation, and treatment services.
procedure room*: a room designated for the performance of procedures that do not meet the definition of "invasive procedure" and may be performed outside the restricted area of a surgical suite and may require the use of sterile instruments or supplies. Local anesthesia and minimal and moderate sedation may be administered in a procedure room as long as special ventilation or waste-anesthesia gas-disposal systems are not required for anesthetic agents used in these rooms.
protective environment (PE) room: a patient room that is designed according to this standard and intended to protect a high-risk immunocompromised patient from human and environmental airborne pathogens.
restricted area*: a designated space in the semi-restricted area of the surgical suite that can only be accessed through a semi-restricted area. The restricted access is primarily intended to support a high level of asepsis control, not necessarily for security purposes. Traffic in the restricted area is limited to authorized personnel and patients. Personnel in restricted areas are required to wear surgical attire and cover head and facial hair. Masks are required where open sterile supplies or scrubbed persons may be located.
triage: the process of determining the severity of the illness of or injury to patients so that those who have the most emergent illnesses/injuries can be treated immediately and those less severely injured can be treated later or in another area.
*  Informative Note: Definition is adapted from the FGI Guidelines; see FGI (2014) in Appendix B.
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