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HVAC Systems and Their Role in Infection Control and Prevention. Presented by: John Martinelli Corporate Director of Healthcare Services Forensic Analytical Consulting Services. Inc. November 14, 2013 – CSHE Orange County Chapter In-Service Webcast. Presentation Objectives.
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HVAC Systems and Their Role in Infection Control and Prevention Presented by: John Martinelli Corporate Director of Healthcare Services Forensic Analytical Consulting Services. Inc. November 14, 2013 – CSHE Orange County Chapter In-Service Webcast
Presentation Objectives Upon completion of this session you will be able to: : • Discuss the impact of HVAC system on infection control and prevention in hospital settings; • Describe the importance of pressure relationships established by the HVAC systems; • Explain how air exchange rates and pressure differentials work together to control and remove airborne contaminants; • List resources available to assist in determining how a room’s HVAC system should perform based on the room use; • Describe the impact of temporary or unplanned changes to the HVAC system’s function can impact the environment; and • Describe methods and tools used to confirm the system is functioning as designed
Major Functions of HVAC • Provide fresh air • Control temperature and humidity • Filter air coming in to the building • Control air flow • By creating pressure differentials • Directional supply (laminar flow) • Alignment of supply and exhaust/return • Quickly relocate, dilute and remove airborne contaminants
Teamwork Required • Air Exchanges • Calculations based on space volume and total air supplied to the space • (20’ x 20’ x 10’ = 400 cubic foot space, with 100 CFM supplied gets one room volume of air exchange every 4 minutes or 15 ACH) • Pressure differentials • Barriers required (walls and doors, ceilings and floors) • Open doors can defeat the design • Amount of air supplied and air removed must be different
Air Exchanges What it does • Supplies filtered, fresh air to the space • In with the good • Dilutes and replaces • Out with the bad • CO2, airborne contaminants
From the CDC Guidelines for Environmental Infection Control In Healthcare Facilities, June 2003 Presumes no new contaminant being introduced Presumes perfect air mixing
Pressure Differential (ΔP) • Positive pressure • More air supplied to space than removed • Examples • Protective Environment (PE) Rooms • Patients at high risk of acquiring infection • Operating Rooms • Wrap and Pack (Clean side) of Sterile Processing
Pressure Differential (ΔP) • Negative pressure • More air removed from space than is supplied • Examples • Airborne Infection Isolation Rooms (AIIR’s) • Restrooms • Scope Wash • Decontamination (Dirty side) of Sterile Processing
Why Bother? • Required by Code • ANSI/ASHRAE/ASHE Standard 170-2008 (Table 7.1) • AIA Guidelines, 2001 • FGI Guidelines, 2010 – TJC (EOC Standard) • Cal Mechanical Code (Table 4A) - OSHPD • Written Policy/Management Plans • And It Works! • Reduces HAI’s • Provides defensibility
Why Bother? • Stepped up enforcement • Joint Commission looking at pressure differentials more closely than ever • OR’s, Endoscopy, SPD/CSP • Findings can be for EOC and Leadership
But it was compliant when it was built (So do I have to bring it up to current code?) • Can remain as installed unless: • Change in Room Function (per paragraph 104.3) • Remodel (per paragraph 104.1, minor remodel OK) • Deemed necessary by building official for the general safety and welfare of the occupants and the public (per paragraph 102.6) • Per OSHPD Code Application Notice,
Can Minor Adjustment = Major Changes • IAQ Complaints • Staff restricting flow, changes things everywhere • Outdoor intakes require inspection and maintenance • Filter replacements • Clogged filters impact air supply (Quantity) • Impact of Construction Projects • Temporary Negative Pressure Areas Impact other Areas
Impact of Temporary Changes + + + +
How do we know it’s working? • Test and Balance Reports • Measure supply (and exhaust/return) volumes from all registers in all critical spaces • Check Pressure Differentials at all doors and windows • Open windows and doors? • SPD doors open for work flow • Roll up doors at Materials Receiving and doors to hall propped open = ??
How do we know it’s working? Tools to Test • Pressure Differentials • Test and Balance Micromanometer Balometer Rotating Vane Anemometer
Summary : • The HVAC system can have a significant positive impact on infection control and prevention in hospital settings; • In addition to making the indoor environment comfortable air exchange rates and pressure differentials work together to control and remove airborne contaminants; • The California Mechanical Code provides tables to show how the HVAC system should perform based on space use; • Temporary or unplanned changes to the HVAC system’s function can impact the environment; and • We can use a variety of tools and specialty vendors to test how well our permanent and temporary ventilation systems are working.