Presentation on theme: "HVAC Systems and Their Role in Infection Control and Prevention"— Presentation transcript:
1 HVAC Systems and Their Role in Infection Control and Prevention Presented by:John MartinelliCorporate Director of Healthcare ServicesForensic Analytical Consulting Services. Inc.November 14, – CSHE Orange County Chapter In-Service Webcast
2 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; andDescribe methods and tools used to confirm the system is functioning as designed
3 Major Functions of HVAC Provide fresh airControl temperature and humidityFilter air coming in to the buildingControl air flowBy creating pressure differentialsDirectional supply (laminar flow)Alignment of supply and exhaust/returnQuickly relocate, dilute and remove airborne contaminants
4 Teamwork Required Air Exchanges Pressure differentials 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 differentialsBarriers required (walls and doors, ceilings and floors)Open doors can defeat the designAmount of air supplied and air removed must be different
5 Air Exchanges What it does Supplies filtered, fresh air to the space In with the goodDilutes and replacesOut with the badCO2, airborne contaminants
6 Presumes perfect air mixing From the CDC Guidelines for Environmental Infection Control In Healthcare Facilities, June 2003If reintroducing new contaminant (dust) then the calculations are not applicable but the concept of dilution/reduction still appliesPresumes no new contaminant being introducedPresumes perfect air mixing
7 Pressure Differential (ΔP) Positive pressureMore air supplied to space than removedExamplesProtective Environment (PE) RoomsPatients at high risk of acquiring infectionOperating RoomsWrap and Pack (Clean side) of Sterile Processing
8 Pressure Differential (ΔP) Negative pressureMore air removed from space than is suppliedExamplesAirborne Infection Isolation Rooms (AIIR’s)RestroomsScope WashDecontamination (Dirty side) of Sterile Processing
15 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,
16 Can Minor Adjustment = Major Changes IAQ ComplaintsStaff restricting flow, changes things everywhereOutdoor intakes require inspection and maintenanceFilter replacementsClogged filters impact air supply (Quantity)Impact of Construction ProjectsTemporary Negative Pressure Areas Impact other Areas
19 How do we know it’s working? Test and Balance ReportsMeasure supply (and exhaust/return) volumes from all registers in all critical spacesCheck Pressure Differentials at all doors and windowsOpen windows and doors?SPD doors open for work flowRoll up doors at Materials Receiving and doors to hall propped open = ??
20 Rotating Vane Anemometer How do we know it’s working?Tools to TestTest and BalancePressure DifferentialsMicromanometerBalometerRotating Vane Anemometer
21 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; andWe can use a variety of tools and specialty vendors to test how well our permanent and temporary ventilation systems are working.