Aeroseal Newsletter Jan 2015

Posted by on 22 June 2015

IAQ Considerations For Hospitals

CDC Guidelines For Healthcare Facilities

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Indoor air quality is a concern in any commercial environment but it is particularly significant in hospitals and other healthcare facilities where the spread of environmental and airborne pathogens can have particularly serious consequences. According to reports from the Center for Disease Control (CDC) and others, nosocomial infections (also known as Healthcare Acquired Infections – or HAI) in U.S. hospitals are on the rise.

More than 2 million people each year enter U.S. healthcare facilities and contract infections unrelated to their initial healthcare concern. These infections increase a patient’s average hospital stay from 4.5 days to 21.1 days and kills 90,000 U.S. patients each year – more than AIDS, breast cancer and auto accidents combined.

The cost of treatment is also staggering. Healthcare Acquired Infections add an average of $57,000 to a patient’s hospital bill – that’s an additional $28 billion to $30 billion to the nation’s health costs each year.

While airborne pathogens represent a fraction of the total instances of HAI, the detrimental effect that such an outbreak can have on both patients and healthcare workers can not be underestimated. The CDC, therefore, has developed guidelines for minimizing healthcare-associated infections that include ventilation standards for specialized care environments such as isolation rooms, protective environments and operating rooms. The original report,Guidelines for Environmental Infection Control in Health-Care Facilities , includes recommendations for reducing the spread of contaminants via water, services and other environmental factors and comes in two parts.

Given the recent attention being paid to these concerns, we thought a review of some of the most applicable recommendations was in order. A quick review of the following report highlights will provide a good overview of the types of recommendations contained in the report and allow you to identify areas that may call for further attention.

General considerations:

  • Use AIA guidelines as minimum standards where state or local regulations are not in place for design and construction of ventilation systems in new or renovated health-care facilities. Ensure that existing structures continue to meet the specifications in effect at the time of construction.
  • Ensure that heating, ventilation, air conditioning (HVAC) filters are properly installed and maintained to prevent air leakages and dust overloads.
  • Engineer humidity controls into the HVAC system and monitor the controls to ensure adequate moisture removal.
  • Locate duct humidifiers upstream from the final filters. Incorporate a water-removal mechanism into the system and locate all duct takeoffs sufficiently downstream from the humidifier so that moisture is completely absorbed.
  • Incorporate steam humidifiers, if possible, to reduce potential for microbial proliferation within the system, and avoid use of cool-mist humidifiers.
  • Locate exhaust outlets >25 ft from air-intake systems. Locate outdoor air intakes >6 ft above ground or >3 ft above roof level. Locate exhaust outlets from contaminated areas above roof level to minimize recirculation of exhausted air.
  • Use portable, industrial-grade HEPA filter units capable of filtration rates in the range of 300–800 ft3/min to augment removal of respirable particles as needed.
  • Select portable HEPA filters that can recirculate all or nearly all of the room air and provide the equivalent of >12 ACH.
  • When ultraviolet germicidal irradiation (UVGI) is used as a supplemental engineering control, install fixtures 1) on the wall near the ceiling or suspended from the ceiling as an upper air unit; 2) in the air-return duct of an AII area; or 3) in designated enclosed areas or booths for sputum induction.
  • Seal windows in buildings with centralized HVAC systems, including PE areas.
  • Emphasize restoration of appropriate air quality and ventilation conditions in AII rooms, PE rooms, operating rooms, emergency departments, and intensive care units.
  • Provide backup emergency power and air-handling and pressurization systems to maintain filtration, constant ACH, and pressure differentials in PE rooms, AII rooms, operating rooms, and other critical-care areas.
  • HVAC systems serving offices and administrative areas may be shut down for energy conservation purposes, but the shutdown must not alter or adversely affect pressure differentials maintained in laboratories or critical-care areas with specific ventilation requirements (i.e., PE rooms, AII rooms, operating rooms).
  • Whenever feasible, design and install fixed backup ventilation systems for new or renovated construction of PE rooms, AII rooms, operating rooms, and other critical-care areas identified by ICRA .

During Construction And Remediation

  • Establish a multidisciplinary team that includes infection-control staff to coordinate demolition, construction, and renovation projects and consider proactive preventive measures at the inception; produce and maintain summary statements of the team’s activities.
  • Incorporate mandatory adherence agreements for infection control into construction contracts, with penalties for noncompliance and mechanisms to ensure timely correction of problems.
  • Establish and maintain surveillance for airborne environmental disease (e.g., aspergillosis) as appropriate during construction, renovation, repair, and demolition activities to ensure the health and safety of immunocompromised patients.
  • Before the project gets under way, perform an ICRA to define the scope of the activity and the need for barrier measures.
  • Determine if the facility can operate temporarily on recirculated air; if feasible, seal off adjacent air intakes. If this is not possible or practical, check the low-efficiency (roughing) filter banks frequently and replace as needed to avoid buildup of particulates.
  • Seal windows and reduce wherever possible other sources of outside air intrusion (e.g., open doors in stairwells and corridors), especially in PE areas.
  • Seal off and block return air vents if rigid barriers are used for containment.
  • Ensure proper operation of the air-handling system in the affected area after erection of barriers and before the room or area is set to negative pressure.
  • Create and maintain negative air pressure in work zones adjacent to patient-care areas and ensure that required engineering controls are maintained.
  • Provide construction crews with 1) designated entrances, corridors, and elevators wherever practical; 2) essential services (e.g., toilet facilities) and convenience services (e.g., vending machines); 3) protective clothing (e.g., coveralls, footgear, and headgear) for travel to patient-care areas; and 4) a space or anteroom for changing clothing and storing equipment.
  • Clean work zones and their entrances daily by 1) wet-wiping tools and tool carts before their removal from the work zone; 2) placing mats with tacky surfaces inside the entrance; and 3) covering debris and securing this covering before removing debris from the work zone.
  • In patient-care areas, for major repairs that include removal of ceiling tiles and disruption of the space above the false ceiling, use plastic sheets or prefabricated plastic units to contain dust; use a negative pressure system within this enclosure to remove dust; and either pass air through an industrial-grade, portable HEPA filter capable of filtration rates of 300–800 ft3/min., or exhaust air directly to the outside.
  • Commission the HVAC system for newly constructed health-care facilities and renovated spaces before occupancy and use, with emphasis on ensuring proper ventilation for operating rooms, AII rooms, and PE areas.

Some highlighted recommendations for ventilating protective environment (PE) rooms.

  • Incorporate ventilation engineering specifications and dust-controlling processes into the planning and construction of new PE units (Figure 1).


  • Install central or point-of-use HEPA filters for supply (incoming) air.
  • Ensure that rooms are well-sealed by 1) properly constructing windows, doors, and intake and exhaust ports; 2) maintaining ceilings that are smooth and free of fissures, open joints, and crevices; 3) sealing walls above and below the ceiling; and 4) monitoring for leakage and making any necessary repairs.
  • Ventilate the room to maintain >12 ACH.
  • Locate air supply and exhaust grilles so that clean, filtered air enters from one side of the room, flows across the patient’s bed, and exits from the opposite side of the room.
  • Maintain positive room air pressure (>5 Pa [0.01-inch water gauge]) in relation to the corridor.
  • Maintain airflow patterns and monitor these on a daily basis by using permanently installed visual means of detecting airflow in new or renovated construction, or by using other visual methods (e.g., flutter strips or smoke tubes) in existing PE units. Document the monitoring results.
  • Install self-closing devices on all room exit doors in PE rooms.
  • Do not use laminar air flow systems in newly constructed PE rooms.
  • Ensure that the patient’s room is designed to maintain positive pressure.
  • Use an anteroom to ensure appropriate air-balance relationships and provide independent exhaust of contaminated air to the outside, or place a HEPA filter in the exhaust duct if the return air must be recirculated (Figure 2).


Infection-Control and Ventilation Requirements for AII Rooms

  • Incorporate certain specifications into the planning and construction or renovation of AII units. (Figure 3).


  • Maintain continuous negative air pressure (2.5 Pa [0.01 inch water gauge]) in relation to the air pressure in the corridor; monitor air pressure periodically, preferably daily, with audible manometers or smoke tubes at the door (for existing AII rooms), or with a permanently installed visual monitoring mechanism. Document the results of monitoring
  • Ensure that rooms are well-sealed by properly constructing windows, doors, and air-intake and exhaust ports; when monitoring indicates air leakage, locate the leak and make necessary repairs.
  • Install self-closing devices on all AII room exit doors.
  • Provide ventilation to ensure >12 ACH for renovated rooms and new rooms, and >6 ACH for existing AII rooms.
  • Direct exhaust air to the outside, away from air-intake and populated areas. If this is not practical, air from the room can be recirculated after passing through a HEPA filter.
  • Where supplemental engineering controls for air cleaning are indicated from a risk assessment of the AII area, install UVGI units in the exhaust air ducts of the HVAC system to supplement HEPA filtration or install UVGI fixtures on or near the ceiling to irradiate upper room air.

Hopefully this review of the report highlights proves of value as you prepare for your next healthcare-related project. You can view bothPart I and Part II of the report by visiting the CDC website or clicking on the provided links.