Maintaining a high level of indoor air quality has become an increasing challenge for health care facilities. It is said that 5% of all patients who enter an inpatient health care facility for treatment will develop an infection during the visit (nosocomial infections). The complex hospital environment requires special attention to ensure healthy IAQ to protect patients and health care staff against nosocomial infection and occupational diseases. The risks to patients and other occupants of health care facilities are varied and are dependent on several factors. These are the most critical pair:
HVAC system design and operation. Airborne contaminants are the main culprit for infections in health care facilities. It is therefore imperative for design engineers not only to control air movement in the space, but also to ensure that the delivered air is of the cleanliness criteria to prevent the growth of infection-causing micro-organisms. Health care facilities are designed to better manage IAQ by improving particulate control, moisture control, and pressurization. Hospital maintenance staffs also need to ensure that their maintenance regimes are in line with the design intent in order to minimize the occurrence of airborne infectious disease.
Construction procedures. The risks are mostly derived from demolition using inadequate barriers, exterior wall removal, and core drilling during renovation projects. Proper construction techniques and design mitigation needs to be implemented during the design and construction of health care facilities to ensure that IAQ is not compromised. To address IAQ issues, the design and construction team must implement an Infection Control Risk Assessment (ICRA) plan for all health care renovation projects.
This article will identify the health care standards for IAQ, their implementation during design and operation, and the importance of creating an ICRA plan for health care renovation projects. 


Fungal Spores. These are either unicellular or multicellular, reproductive or distributional cells, which are an essential element of the various phases of the complex life cycles of the fungi. Fungal spores consist of many hundreds of different micro-organisms that assist in the decay of plants. When fungal spores are reproducing, airborne spores are emitted into the air. These airborne fungal spores cause serious infections in humans and can lead to sickness and even death.
Fungi differ significantly from most airborne pathogens in that only the person inhaling the fungi is at risk. It can enter buildings through improper design ventilation systems. Though they are normally harmless and non-parasitic, fungi are a common cause of respiratory and allergic reactions.
Bacteria. These are single-celled microorganisms that can exist either as independent, free-living organisms or as parasites. Bacterial infections in the hospital environment can vary from strains that cause minor sickness to strains that result in incurable disease and ultimately death. Despite the fact that operating, trauma, and procedure rooms may appear to be clean, they often contain many different strains of bacteria. The bacteria concentration in these areas is the differential between the rate of bacteria released by occupants and the rate of removal by an air filtration system. In a recirculation air system (which is permitted for most areas in a health care facility), filters must remove these dangerous bacteria before they re-enter in the health care environment. It is very important to note that some bacteria, typically those less than 5 microns, cannot be removed by filtration systems because of their very small size, and they remain in the air indefinitely.
Examples of common diseases caused from bacterial infection are Legionnaire’s Disease (caused by Legionella pneumophila bacteria), Tuberculosis (caused by Mycobacterium tuberculosis bacteria), lobar pneumonia (cased by Streptococcus pneumonia) and Cystic Fibrosis (caused by Pseudomonas aeruginosa).
Viruses. A virus is a small infectious agent that can replicate only inside the living cells of organisms. Most viruses are too small to be seen directly with a light microscope. Viruses infect all types of organisms, from animals and plants to bacteria. The spread of viruses in hospitals can lead to several types of nosocomial infections such as common cold, flu, gastroenteritis, and chicken pox.
Pollens. This is a fine powdery substance, typically yellow, consisting of microscopic grains discharged from the male part of a flower or from a male cone. Pollens are not pathogenic, but they are a common cause of allergic rhinitis (sinus inflammation and eye irritation) and asthma. Pollen particles are generally much larger than the contaminants discussed above and are easily removed by high-quality filter media.


There are several guidelines that govern indoor air quality requirements for licensed health care facilities. Licensed health care facilities are required to comply with the Joint Commission on Accreditation of Health care Organizations (JCAHO). Regarding filtration requirements for healthcare facilities, JCAHO references the Facility Guidelines Institute (FGI) Guidelines for Design and Construction of Health Care Facilities, the 2010 Edition (which, in turn, references the ANSI/ASHRAE/ASHE Standard 170 - 2008, Ventilation of Health Care Facilities for the requirements governing ventilation for all areas within a health care environment). 
For military health care facilities (Army, Navy, Air Force, Marines and Coast Guard), the Unified Facilities Criteria (UFC) 4-510-01, Design for Medical Facilities, February 18, 2009, Change 1 April 2009, Appendix A, contains a table of ventilation requirements that list the HVAC IAQ requirements for all health care facilities.
For Veteran Affairs (VA) health care facilities, the HVAC Design for Manual for New, Replacement, Addition and Renovation of Exiting VA Facilities, March, 2011, Chapter 6 – room data sheets, contains tables of ventilation requirements that list the HVAC requirements for IAQ for all health care facilities. This standard also references ASHRAE 170-2008 and ASHRAE 62.1 – 2007 for minimum ventilation rates.
For health care projects pursuing a U.S. Green Building Council LEED rating, there is a minimum IAQ performance required as part of the prerequisite. LEED guidelines reference ASHRAE 62.1-2007 for new construction and major renovation in its current 2009 version. The guideline also tackles the requirement of pollutant source control in Prerequisite 2, which prohibits smoking in buildings. Points available for:
  • Implementing IAQ measures such as outdoor air delivery monitoring, which ensures that the facility achieves prescribed outside ventilation rates during its operation.
  • Increasing outside air ventilation rates by 30% above ASHRAE 62.1-2007, which allows for further dilution of the indoor pollutants.
  • Developing and implementing a construction IAQ management plan before building occupancy, which is used to evacuate the air-borne contaminants that were collected in the building during construction; and the reduction in the use of contaminants that are odorous, harmful, irritating and/or harmful such as VOC and urea-formaldehyde by documenting the use of construction and furnishing materials with low or no levels of certain chemicals known to cause harm.   
These code-required and voluntary standards apply to ventilation requirements for new buildings, additions to existing buildings, and alterations to existing health care facilities. These standards do not cover the ventilation requirements for existing health care facilities that are not being modified. For this reason, there are many existing health care facilities with spaces and departments with poor air quality simply due to the fact that they were constructed before the current standard and codes were created. 
These standards govern pollutant source control and stipulate the filtration requirement of areas within a health care facility. The standards also govern the air change requirements for most areas in a health care facility. The designer should be aware that some areas may not be specifically defined in the standards.
Therefore, experience and judgment should be used to assign the appropriate ventilation rates and requirements to these spaces by applying the code or standard that governs defined spaces which are most similar in function.


The ventilation system for health care facilities needs to address the following criteria in order to achieve good indoor air quality.
  1. Outdoor air minimum ventilation requirements and air change requirements for each space. These design criteria address the dilution and removal of contamination such as fungal spores, bacteria, viruses, pollens, and other hazardous chemicals.
  2. Pollutant source control inside and outside of the hospital. These requirements will be met by proper filtration specification and the design of the exhaust system to remove contaminants from within the facility.
  3. The system’s ability to restrict air movement between certain rooms and departments. This will be addressed by the pressure rela-tionship requirements to limit the movement of contaminated air from one area to the other. 
  4. Specification of means to ensure that the system is functioning as designed.
The first step in designing the HVAC system for a hospital is to define the ventilation requirements for each space. If a ventilation standard is not prescribed by the owner or the authority having jurisdiction (AHJ), the first place to start is ANSI/ASHRAE 170 - 2008. This standard provides guidelines to ensure that the HVAC equipment and distribution system meet minimum standards for the criteria listed above, as well as relative humidity, and temperature requirements for all health care spaces. 
When multiple standards apply, the most stringent in each category should be selected. SmithGroupJJR provides engineering de-sign services for both private and government agencies; the health care engineering department has developed a proprietary tool in REVIT MEP. This automated tool compares different ventilation standards and facilitates the selection of the most stringent of the applicable standards. This has been used on several projects, including but not limited to, the National Intrepid Center of Excellence (NICOE) satellite building in Fort Belvoir, VA; the National Intrepid Center of Excellence (NICOE) satellite building in Camp Lejeune, NC; the Hattiesburg Clinic Heart and Vascular Center; and the VA San Antonio Polytrauma Center – Building 1 Renovation. 
These projects compare up to three ventilation standards. For example, the NICOE projects will need to meet UFC-4510-01 because they are located on military bases, ASHRAE 62.1-2007 because they are design to achieve LEED silver rating (Version 2009), and ASHRAE 170 – 2008 because they may be JCAHO accredited health care facilities.
The second step is to design, install, and calibrate monitoring devices to continuously monitor the important criteria required for acceptable indoor air quality, and thus prove ongoing compliance. This design strategy should include, but not be limited to, the following.
  1. Ensure that an accurate airflow monitoring station is installed in the outside air intake; specify accuracy of plus or minus two percent (+/- 2%) of reading at plus or minus a quarter percent repeatability (+/- 0.25%). In my experience, the Ebtron Gold series is one of the best available in the industry because of its accuracy and ease of installation in locations where most traditional technologies cannot be applied. The control specification should include analogue input points with maintenance alarm, DDC control point, setpoint adjustment, alarm limits, and trending.
  2. Ensure than an accurate magnehelic pressure gauge is specified. Dwyer series 2000 is a very accurate one that is used by most air-handling unit manufacturers. The control specification should include an analogue input point with maintenance alarm at the BAS workstation.
  3. Room pressure monitors should be specified for specialized areas such as operating rooms, procedure rooms, isolation rooms, and pharmacy IV preparatory rooms. These rooms should be designed to maintain a differential of 0.0015 in of water between adjacent communicating spaces. These pressure monitors should include an audible alarm as well as a maintenance alarm at the BAS when the rooms are not maintaining the design pressure differential. Upper and lower limits of pressure should be specified in order to avoid nuisance alarms. 
These design principles, coupled with monitors to ensure that the designed system is operating as intended, will maintain acceptable IAQ in the spaces during HVAC system operation. The next step is ensuring that indoor air quality is maintained. This can be done by developing an IAQ operation plan and developing a method to continuously monitor the IAQ performance for the facility. 


Of all the code required and voluntary standards available, LEED is the only one that goes beyond ventilation and filtration requirements. LEED tackles other important contaminants that are often found in materials used in buildings. It is important to note that LEED is not a standard and is not enforceable, and therefore there is no current standard that handles VOC, formaldehyde, particulate matter (PM10), carbon monoxide, and urea-formaldehyde. Reducing the concentration of these pollutants will further improve the IAQ in health care facilities. 
It is imperative for health care facilities to develop their own means of measuring IAQ; develop an Indoor Air Quality Management Plan (IAQMP) and the means to continually monitor and track IAQ performance. This can be done by identifying all sources of pollu-tants, defining a maximum concentration that is allowable indoors, and providing a means of ensuring that these concentrations are not exceeded. Mitigation should be included in the IAQMP in order to provide means and methods of reducing the IAQ to an acceptable level during operation if the concentrations are exceeded. This can be handled by ongoing building flush-out. A design engineer and a control specialist will jointly develop a flush-out procedure. This should be added as a control sequence to the BAS; there should also be an option to enable and disable the function at the BAS. This flush-out will be similar to the LEED requirement for flushing out buildings during operation.


It is very important that the operation of a hospital is not compromised during the renovation of an existing space. To address renovation work, the FGI Guidelines for Design and Construction of Health Care Facilities, (2010 edition), recommends the development of an Infection Control Risk Assessment (ICRA) plan during renovation. It is particularly important to ensure a safe environment for patients, visitors, and staff within an occupied facility, which is focused on the delivery of ongoing health care. The design team must create and maintain work areas that support the facility’s infection control protocols to ensure a safe environment for patients, visitors, and staff.  
Infection Control Risk Assessment (ICRA) is best understood as a strategic plan to protect patients, staff, and visitors during con-struction, demolition, renovation, testing, and maintenance. The plan is developed as early as facility planning and design, and refined and implemented through completion of the activity or project. It identifies, assesses, and provides the contingencies appropriate as it relates to IAQ by identifying the following.
  1. The project’s impact on the health care environment 
  2. The highest-risk patients and areas
  3. The need for and placement of barriers for airborne contaminants, as well as specialized ventilation and/or filtering
  4. Entry and exit for workers and materials
  5. Work schedules and the time of day appropriate for construction
  6. The need for humidity and temperature control, noise suppression, and vibration dampening and personal protective equipment (PPE), as well as the type of PPE needed
  7. Air handling and ventilation in specially designed areas, the potential need for additional isolation rooms and limiting of waterborne pathogens in the water system
  8. Depressurizing the renovation work area in relation to the adjacent spaces to prevent the exfiltration of construction dust to adjacent spaces
  9. Ensuring that negative pressure is maintained in the renovation areas by using pressure monitors
In addition to the IRCA plan, regular meetings should be held to update the plans as necessary to ensure that any changes are incorporated before implementation.