Hospital Microbiome ProjectOverview of building science measurements

January 15, 2013Dr. Brent Stephens and Tiffanie Ramos, Illinois Institute of TechnologyDr. Jeffrey Siegel, University of Toronto

Dr. Brent Stephens, Ph.D.Assistant Professor

Department of Civil, Architectural and Environmental EngineeringIllinois Institute of Technology

brent@iit.edu

Built Environment Research Groupwww.built-envi.comAdvancing energy, environmental, and

sustainability research within the built environment

Overview

• We are tasked with characterizing the hospital in mostly non-biological ways during the yearlong study– Outdoor air ventilation rates– Human occupancy– Temperature + relative humidity + light intensity– Room pressurization– Surface characteristics

• We will assess by measuring a variety of parameters in:– Patient rooms (x 10)– Mechanical rooms (x 2)

• Experimental plan development– Initial plan by Jeffrey Siegel (University of Toronto)– Three hospital visits by IIT– Feedback from UC oversight committee, facilities, and engineers

Building science experimental plan

• We have two main priorities with our measurements:1. Get the measurements done accurately

2. Do so in the least invasive way possible

• Our current plan will require some minor room modifications– Purpose is to limit in-room interactions and retrieve data from hallway– Mostly small penetrations in ducts and walls

• We are working on these

• Patient rooms– 5 rooms on each of the 9th and 10th floors

• West wing– 9th floor

• Rooms 09014-09018– 10th floor

• Rooms 10014-10018

Patient room measurements

• Four measurement locations in each patient room– Measuring at 5-15 minute intervals

1. HVAC return grille

• CO2

• Pressure (flow)• Temperature and RH• HVAC filter-based microbial sampler

2. HVAC supply diffuser• Temperature• Pressure (flow)

3. Near patient• Temperature, RH, and light intensity

4. Doorway• Beam break occupancy sensor

Patient room measurements

AlcoveCabinets

HV

AC

Sup

ply

Diff

user

HVACReturn Grille

Bathroom

Fire

wal

l

Win

dow

Hal

lway

Ent

ry

Beam-breakOccupancy Sensors

• Most sensors will be installed in the ceiling plenum

TAirflow

T/RHLight

T/RH/CO2/Airflow

Absorber column

HVAC filter based microbial sampler

HVAC filter bioaerosol ‘sampler’

Magnetic filter frame

Patient room instrument enclosures

CO2

Pressure

Patient rooms: Surface characterization

• Still a point of discussion• Where bio samples are taken on surfaces

– Temperature: Point and shoot infrared thermometer– Water activity

• Basically RH at surface

– Discussions of additional characterization of chemical compounds on surfaces (e.g., chem wipes) and/or surface roughness (e.g,. force microscopy)

Mechanical rooms

• Three measurement locations in each of 2 sets of mechanical systems– AHU 6 (located on the 11th floor)

• Serves 10th floor– AHU 11, 12, 13, and 14 (located on 11th and 12th floors)

• All connected to serve 8th and 9th floors

8th floor(patient rooms)

9th floor (patient rooms)

10th floor (oncology)

11th floor (mechanical room)

12th floor (mechanical room)

AHU 11-14 (all connected)

9th floor (patient rooms)

10th floor (oncology)

11th floor (mechanical room)

AHU 6 (alone)

Mechanical rooms

• Temperature, RH, and CO2 in each of:– Outdoor air– Return air– Supply air (mixed OA + RA)

• Measurement of CO2 provides outdoor air ventilation rates– Fraction of outdoor air supplied

CO2 Sensor

CO2 Sensor

CO2 Sensor

Temp. Probe

Temp. Probe

Temp. Probe

Data Logger (w/USB)

Data Logger (w/USB)

Data Logger (w/USB)

PATIENT ROOMSRoom survey

Return Air

Supply Air

Return Air

Return Air Grille

-Pressure Sensor (w/ power)-CO2 Sensor (w/ power)-Datalogger (T/RH)-HVAC filter bio sampler

Supply Air

Supply Diffuser

-Pressure Sensor (w/ power)-2 temperature probes-Datalogger

Supply Duct

Alcove(from inside patient room)

Alcove

4 USB cables2 absorber columns

Firewall between patient rooms and hallway

Drop ceiling space

Power Outlet

Beam-break occupancy Sensor

MECHANICAL ROOMSRoom survey

Outside Air

Supply Air

Relief Air

Return Air

AHU

AHU

AHU

Current status

• Still building and calibrating equipment in laboratory at IIT– T/RH, CO2 and pressure

– Filter media installed at hospital for validation– Filter magnetic frame being constructed

• Meeting with construction/safety/electrical teams at hospital – Today– Finalizing room penetration and power plan

• Intensive setup and on-site calibration period– By end of January– Testing mixing assumptions, flow calibration, sensitivity testing

• Trial run– By first of February

Questions/comments

brent@iit.edu

Required “construction” and aesthetic/code issues

• USB cables through fire wall• USB cable output at nurse stations• HVAC filter media installation

– Magnetic filter frame

• Loose cables in the plenum (and potentially in sight)– Return air and supply air

• Exact location of portable HOBO logger– Magnetic

• Occupancy sensor– Likely magnetic

• Power requirements– Low voltage DC, hopefully from extension cord in plenum

• CO2 absorber column just outside in the hallway plenum

• Pressure taps in return and supply ductwork

Longer term setup and sampling plan at the hospital

• Immediate– HVAC filter on 1-2 sample return grilles– Can we collect enough aerosols to detect microbial communities?– If so, we will proceed with media and frame order

• Mid to late January– Install an entire setup as a prototype in one patient room– Verify our equipment plan and order additional supplies– Test our “intensive” calibration procedures– Also explore mechanical room installations (much less invasive)

• Late January to early February– Replicate successful prototype in patient rooms

Particle removal efficiency of HVAC filter media

.

Alcove

Cabinets

Supp

ly D

iffus

er

Return Grille

Bathroom

Power

USB

Tubing

Voltage Output

Firewall

Occupancy Sensors

2” conduit through firewall

AC power strip or multi-outlet extension cord (need 3) from outlet behind TV: 120 V

12 VDC, 1000 mA

From the AC power strip, 2-3 12V DC, 1A power supplies will connect to our equipment. Very low power. UL Listed.

Two adjacent rooms can feed one alcove, supplying:4 USB cables for data retrieval, and2 0.25 inch outer diameter tubes for absorber column (for CO2) All through a 2 inch conduit through firewall (exact location TBD)

Patient Room Building Science Equipment Layout

Hal

lway

Fire

wal

l

Note on voltages:DC power to instruments (red) is 12VDC, 1A

Voltage output is for data output (purple) is maximum 0-2.5 VDC

Pressure Sensor

Temp. Probe (x2)

Pressure Sensor

CO2 Sensor

Data Logger (w/USB)

Data Logger (w/USB)

Patient Rooms

+ Filter

Data Logger (w/USB)