HVAC Systems and Their Role in Infection Control

and Prevention

Presented by:

John MartinelliCorporate 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

Microenvironments

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

Recommendations become Requirements

Requirements (2013 California Mechanical Code)

Requirements (2013 California Mechanical Code)

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

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• Test and Balance • Pressure

Differentials

Balometer

Micromanometer

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.

Questions?