An overview of ASHRAE/ASHE Guideline 43, Operations Guideline for the Ventilation of Health Care Facilities

Tip #39

Dino Coliano, MBA, SASHE, Director of Healthcare Solutions, VERGENT

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What is ASHRAE/ASHE Guideline 43?

Guideline 43, developed by ASHRAE in collaboration with ASHE, provides operational guidance and recommendations to help hospital facilities managers address heating, ventilation and air-conditioning (HVAC) systems as a comprehensive whole.

The guideline was purposely written as a guideline and not a standard. A guideline is a set of recommendations or best practices providing general advice on how to perform activities or tasks, while a standard is a mandatory set of rules that, when adopted, must be followed to be in compliance. Guidelines are advisory and have the tone of “should” whereas standards are enforceable rules and have the tone of “shall.” The creators of Guideline 43 never intended it to be adopted as a standard; rather, it was developed to provide guidance on how to properly operate and maintain ventilation systems within health care facilities.

Why is the guideline needed?

First, it's needed because ANSI/ASHRAE/ASHE Standard 170, Ventilation of Health Care Facilities, is not an operations guide. While 170 is the adopted design standard for new construction, there truly was not an operational guideline available. standard 170 establishes a set of minimum design requirements for new construction and substantial changes to HVAC systems in existing hospitals. The standard seeks to ensure ventilation systems provide health care facilities with a comfortable environment and with ventilation to dilute and assist in controlling odor and asepsis. Guideline 43, on the other hand, is an operations guide created to work in collaboration with Standard 170, not in conflict. Secondly, the guideline is needed to help health care facilities consistently address the compliance challenges stemming from failing to properly control ventilation systems to provide appropriate temperature, humidity, pressure relationships, air-exchange rates and filtration efficiencies in care areas (as frequently cited higher-risk accreditation requirements as reported by both The Joint Commission and DNV Healthcare over the last five years).

Guideline 43 also clarifies the difference between design requirements and allowable operating conditions. A common example identified is the design requirement in the 2008 edition of Standard 170 for operating room (OR) temperature is 68 F to 75 F. However, even the 2008 edition acknowledges that this temperature range may not be sufficient and provides a footnote (footnote O in Table 7.1) to the requirement for ORs that allows the requirements to be exceeded if surgeons or surgical procedures indicate that the range is insufficient.

The guideline encourages the optimization of HVAC systems and the resources they use through the application of a ventilation management program, along with the appropriate application of alternative equipment and patient-centered maintenance practices.

One of the most important aspects of the guideline is to establish monitored, ventilated spaces throughout the health care facility using their functional space listing as the base document. The guideline recommends that ventilated spaces be categorized based on risk of harm. Section 5 of the guideline provides guidance on differentiating “critically” and “generally ventilated” spaces. Additionally, operational functionality of spaces should be periodically monitored and verified. The guideline also recommends the continued application of the building management systems (BMS) and computerized maintenance management systems (CMMS) for advanced monitoring and verification of established condition indicators throughout the health care facility.

The guideline introduces and advocates the development of a “Ventilation Management Program” (VMP) as the deliverable and provides a framework in Guideline 43’s Appendix F on implementing a “nine step process” that includes Step 1) forming a multi-disciplinary group of leaders from across the organization, as referenced to as the Ventilation Management Committee (VMC), to provide guidance and buy-in of the VMP, Step 2) developing sources of truth as the governing, referenced documents to include ASHRAE/ASHE Standard 170, Guideline 43, any State or local documents, and equally important, the facilities functional space inventory, Step 3) developing risk rankings of spaces and the HVAC systems and equipment supporting those spaces to prioritize testing, excursion responses, and work orders, Step 4) establishing the condition indicators or key performance metrics in the VMP, Step 5) establishing excursion response plans to help address when environmental parameters (temperature, humidity, and pressure relationships) inevitably fall out of range at some point, Step 6) actually creating the VMP as it will need to be defined and published as the “program” to be referenced by hospital employees, Step 7) approval of the VMP by the VMC and executive leadership of the hospital, Step 8) educating the hospital staff to include clinical, non-clinical, and facilities employees on the VMP, and Step 9) creating a process to periodically review and maintain the VMP.

What’s next for Guideline 43?

ASHRAE published and released the guideline on June 15, 2025. It is available for purchase on the ASHE website; https://www.ashe.org/ashrae-ashe-guideline-43. The next step for the broader ASHE community is awareness and education of Guideline 43. ASHE highly encourages members and non-members to purchase and read the document to become familiar with it. In addition to articles like this one, there are two other published articles noted below that provide additional guidance and perspectives on Guideline 43 and creating a VMP.

1. Health Facilities Management – July 8, 2025 – “Operating and maintaining ventilation infrastructure” by Jonathan Flannery, ASHE
2. Health Facilities Management – March 31, 2021 – “Nine steps to developing a ventilation management plan” by Taylor Vaughn, Brooke Bohme, and Clayton Smith of Children’s Health Dallas

In addition, ASHE and several Guideline 43 committee members have been speaking at the recent Healthcare Facilities Innovation Conferences, and at local ASHE Chapter conferences and meetings nationally to further educate the broader community. As more members and non-members become aware of Guideline 43, the next steps continue to be education, acceptance, and implementation by Hospitals and Health Systems nationally. It is expected this phase will be the longest and will remain active over the next few years as acceptance and implementation by the community increases.

Finally, as noted, Guideline 43 is a guideline and not a standard. ASHE has positioned the guideline in a comparable way to the recently released Water Management Program and advocates for its acceptance by CMS and the AOs as a guidance document of ventilation systems operations and maintenance best practices to support Hospitals and Health Systems in meeting physical environment ventilation compliance requirements .

 

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