1. 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, – 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; and
Describe methods and tools used to confirm the system is functioning as designed

3. 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

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 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

5. 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

6. Presumes perfect air mixing
From the CDC Guidelines for Environmental Infection Control In Healthcare Facilities, June 2003
If reintroducing new contaminant (dust) then the calculations are not applicable but the concept of dilution/reduction still applies
Presumes no new contaminant being introduced
Presumes perfect air mixing

7. 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

8. 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

9. Microenvironments

10. Why Bother? Required by Code Written Policy/Management Plans
ANSI/ASHRAE/ASHE Standard (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

11. 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

12. Recommendations become Requirements

13. Requirements (2013 California Mechanical Code)

14. Requirements (2013 California Mechanical Code)

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 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

17. Impact of Temporary Changes

18. Impact of Temporary Changes
+ +
+ +

19. 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 = ??

20. Rotating Vane Anemometer
How do we know it’s working?
Tools to Test
Test and Balance
Pressure Differentials
Micromanometer
Balometer
Rotating 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; and
We can use a variety of tools and specialty vendors to test how well our permanent and temporary ventilation systems are working.

22. Questions?