Post on 09-Aug-2020
Important Role Filters Play
in Industrial Hygiene
National Association of Air Filtration Conference
David W. Bearg, PE, CIH
September 21, 2006
Focus:
• Understanding the role of filtration in achieving a healthy and productive indoor environment
Achieving a Healthy & Productive Indoor Environment:
• Delivery of clean supply air
• Delivery of intended quantities of outdoor air for ventilation
• Moisture Management
• Access to daylight
WARNING:
• The Delivery of clean supply air does NOT guarantee the achievement of a clean indoor environment.
• Supply air is only one potential source of particulate matter in the indoor environment.
Particle Generation per minute:
Motionless Standing - 100,000 particles 0.3 micron or larger
Walking at 2 mph –
5,000,000 particles
Montana State University
Commissioning, Asking the Right Question:
• Not just, “Is the HVAC system working as intended?”, but
• “How is the HVAC system performing to provide a healthy and productive indoor environment for the smallest energy cost?”
Universal Truth:
• As it is with energy, if the performance of the HVAC system is not being monitored and reviewed, it cannot be managed well !!!
Monitoring Goals for HVAC System:
• Particulate levels,
• Moisture levels, and
• Carbon Dioxide concentrations
Monitoring Approaches for Assessing Effectiveness of Particulate Control:
• Visual assessment,
• Particle counting, and
• Gravimetric measurements
• Pressure drops across filters
Monitoring Approach for Assessing Effectiveness of Particulate Control:
• Measure the Pressure Drop across filter bank, either at the AHU or remotely (data-log).
Energy saving while achieving Effective Particulate Control:
• Reduce unnecessary resistance to air flow (i.e., pressure drop) by increasing surface area of filters to reduce media velocities: lower media velocities, lower pressure drop for the fan energy to overcome, and lower labor costs achieved by longer intervals between filter changes.
Interdependence of outdoor, indoor and HVAC conditions:
Whether by design or not, the components of a building and its HVAC interact -> Use Integrated Design to achieve the highest Effective Operation of a building’s systems
Interdependence of outdoor, indoor and HVAC conditions:
Since the occupant is exposed to how all of the components of a building and its HVAC interact -> The assessment of building and HVAC performance should consider how all these components are potentially interacting:
Solution:
IPA
Integrated
Performance
Assessment
Integrated Performance Assessment:
Just as with Integrated Design, IPA focuses on the end result by considering how all the various components of the HVAC system work together to achieve their intended results.
Integrated Performance Assessment:
FILTRATION
Measurements to assess the particle loading of the air delivered to the occupants, and not just after it leaves the filter bank.
IPA – Filtration: Comparison between OA and SA for fine particulate
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
10.5 11 11.5 12 12.5 13
Outdoor Air - FineSupply Air - Fine
Particulate counts / minute: 0.5 micron and larger diameter
Time, Hours
Capture Effectiveness = 90%
E-1: 0.3 to 1.0 microns
IPA – Filtration: Comparison between OA and SA for coarse particulate
0
50
100
150
10.5 11 11.5 12 12.5 13
Outdoor Air CoarseSupply Air - Coarse
Time, Hours
Particle Counts per Minute: 5 micron and larger diameter
18 particles/min
66 particles/min
Capture Effectiveness = 73%
E-3: 3.0 to 10 microns
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
6-Jan0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
High traffic - fineExterior wall - fineHigh Traffic - CoarseExterior wall - coarse
| |
7-Jan 12-Jan9-Jan8-Jan 10-Jan 11-Jan||
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CoarseParticles perCubic
Fine Particles per Cubic Foot
Figure 3. Comparison of fine andCoarse Particles per Cubic Foot between High and Low traffic areas
IPA Filtration: Particle Generation Activities Within the Space
Effectiveness of Particulate Control:
• Intimately tied to the effectiveness of ventilation effectiveness, or how the geometry of how the air moves through the occupied spaces
RECOMMENDATIONS: 1. Harvest wasted energy in HVAC system by
increasing area of filtration.
2. Periodically compare particulate counts for the outdoor air, the supply air, and the room air to assess and document performance.
3. Also monitor HVAC performance with respect to moisture management and ventilation performance.
Integrated Performance Assessment:
MOISTURE MANAGEMENT
Measurements to assess the indoor humidity levels associated with: humidification, dehumidification, interior moisture leaks, and moisture intrusions through the building envelope.
Stratus Computer, June 19, 1995
48
53
58
63
68
0 2 4 6 8 10 12 14 16 18 20 22 0TIME OF DAY
DEWPOINT TEMPERATURE
DEG. F
O/A - Roof
O/A - Ground
RTU-1 Supply
RTU-1 Return
RTU-2 Supply
RTU-2 Return
R-2003
MS Lab
R-2498
R-2568
R-2600
R-2359
R-2122
R-2223
R-2077
R-2238
R-2639
R-1006
LAB # 5
Lab #3
Lab #8
DOCK
Lab #7
Supply Air
Dock
Outdoors
Lab #5
BIDMC Shapiro Center
20
25
30
35
40
45
50
0 2 4 6 8 10 12 14 16 18 20 22 0Time of Day
Dew Point Temperature Degrees
F
Outside Air1001 Board1002 Conf.701 B703 D7F3 Waiting747705 A707760 Conf.736 Conf.713 D721 D720724731 B7357F1 B7F2 Waiting601 B601 F603 D649605 A607610 A Conf.6F3 B613 D621 C620 Conf.6406F1 B639629 A631 G501 D5035605F3505
Sunday, December 18, 2005
1001 BoardRoom
Room 649 ( AHU 4 )
Outdoor Air
731B ( AHU 1 )
BIDMC Shapiro Center
20
25
30
35
40
45
50
0 2 4 6 8 10 12 14 16 18 20 22 0Time of Day
Dew Point Temperature Degrees
F
Outside Air AHU A SA
AHU B SA AHU C SA
AHU D SA
December 18, 2005
AHU D SA
AHU A SA
Outdoor Air
BIDMC Shapiro Center
45
50
55
60
0 2 4 6 8 10 12 14 16 18 20 22 0Time of Day
Dew Point Temperature Degrees
F
Outside AirAHU A SAAHU B SAAHU C SAAHU D SAAHU A RAAHU B RAAHU C RAAHU D RA1001 Board1002 Conf.507 D568 A513747705 A515 C521 B522713 D539531 C724731 B5F1 Waiting550 A Teach.550 B Conf.601 B601 F603 D649605 A607610 A Conf.6F3 B613 D621 C620 Conf.6406F1 B639629 A631 G501 D5035605F3505
September 23, 2005
AHU A SA
Outside Air
HVAC Monitoring, Accuracy & Confidence: Shared-Sensor Approach
DEHUMIDIFICATION
Integrated Performance Assessment:
MOISTURE MANAGEMENT
Measurements to assess the indoor humidity levels associated with: humidification, dehumidification, indoor sources of moisture, and moisture intrusions through the building envelope.
THE NEW ENGLANDApril 4, 1996
0
5
10
15
20
25
30
0 2 4 6 8 10 12 14 16 18 20 22 0
TIME OF DAY
DEWPOINT TEMPERATURE DEG. F
Outside Air
7 West (S-15)
6 South (S-16)
6 East (S-19)
9 East (S-21)
2 North (S-23)
Cafeteria
4 South (S-16)
10 West (S-15)
9 West (S-15)
8 West (S-15)
6 West (S-15)
5 West (S-15)
4 West (S-15)
Return (R-15)
3 East (S-19)
Return (R-19)
7 Core (S-21)
4 East (S-21)
3 West (S-3)
13-V (R-3-S)
SB-Loading Dock
SB-W Garage
IPA – Moisture: Identification of interior source
Newly Constructed Middle School
20
25
30
35
40
45
0 2 4 6 8 10 12 14 16 18 20 22 0Time of Day
Dew Point Temperature Degrees
F
Outdoor
Auditorium
Roof Special 1
Roof Special 2
Roof Special 3
Roof Special 4
April 5, 2005
Elevated humidity where the auditorium roof meets the vertical wall of the main school building
Outdoor humidity
Moisture Management & IAQ: Water Intrusion Evaluation
BENEFITS from MOISTURE MONITORING:
• Commissioning: Verification of Integrity of Building Envelope with respect to water entry,
• Early detection of water intrusion, as this provides an
Early Warning of potential MOLD growth !
• Improved management of indoor water features by knowing their impact on indoor humidities,
• Balancing energy and IAQ by optimizing the use of cold dry winter air for ventilation and cooling.
Integrated Performance Assessment:
VENTILATION
Measurements to assess the amount of ventilation provided, both during peak occupancies and the completeness of the overnight flushout.
300
500
700
900
1100
1300
1500
1700
1900
2100
0 2 4 6 8 10 12 14 16 18 20 22 0
Outdoor Air
Return Air
Room 112
Room 108
Room 115
Room 111
Room 107
Room 178
Room 105
CO2 ppm
TIME of DAY
IAQ DATAGRAPH MONITORED OFFICE BUILDING "CS" Locations served by AHU #2, July 2, 1997
IPA – Ventilation: Determination of Localized Ventilation Deficiencies
300
400
500
600
700
800
900
1000
1100
6-Jan 7-Jan 8-Jan 9-Jan 10-Jan 11-Jan 12-Jan 13-Jan
Pantry (3)
12 - South Area (3)
Outdoor Air
12 - NW Area (3)
Pantry (1)
Conference 11-1 (1)
12 - NW Area (1)
Pantry (2)
Conference 12-1 (2)
12 - NW Area (2)
Pantry (4)
Living Room (4)
12 - NW Area (4)
Conference 1101
Outdoor Air
Carbon dioxide, ppm
Time
780 ppm
1,010 ppm
IPA – Ventilation: Incomplete Overnight Flushout of Bio-Effluents & VOCs
BIDMCShapiro Center
300
400
500
600
700
800
900
1000
1100
1200
0 2 4 6 8 10 12 14 16 18 20 22 0
Time of Day
CO2 ppm
Outside Air
601 B
601 F
603 D
649
605 A
607
610 A Conf.
6F3 B
613 D
621 C
620 Conf.
640
6F1 B
639
629 A
631 G
September 23, 2005
Outdoor Air
610 A Conference
613 D
HVAC Monitoring should include occupied locations as well as at the AHUs to identify actual ventilation performance
BIDMC Shapiro Center
45
50
55
60
0 2 4 6 8 10 12 14 16 18 20 22 0Time of Day
Dew Point Temperature Degrees
F
Outside AirAHU A SAAHU B SAAHU C SAAHU D SAAHU A RAAHU B RAAHU C RAAHU D RA1001 Board1002 Conf.507 D568 A513747705 A515 C521 B522713 D539531 C724731 B5F1 Waiting550 A Teach.550 B Conf.601 B601 F603 D649605 A607610 A Conf.6F3 B613 D621 C620 Conf.6406F1 B639629 A631 G501 D5035605F3505
September 23, 2005
AHU A SA
Outside Air
HVAC Monitoring, Accuracy & Confidence: Shared-Sensor Approach
DEHUMIDIFICATION
Interaction of HVAC parameters?:
• Is the reduced dehumidification occurring at AHU A due to its needing to condition a larger percentage of Outdoor Air ?
BIDMC Shapiro Center
300
400
500
600
700
800
0 2 4 6 8 10 12 14 16 18 20 22 0
Time of Day
CO2 ppmOutside Air AHU A SA
AHU B SA AHU C SA
AHU D SA AHU A RA
AHU B RA AHU C RA
AHU D RASeptember 23, 2005
Outdoor Air
AHU - A SA
Comparison of Supply Air, Return Air and Outdoor Air for AHUs
Percentage of OA in SA Calculation:
% OA = Return Air – Mixed (Supply) Air
Return Air – Outdoor Air
AHU 1, between 11:17 and 11:20
%OA = (602-536)/(602-448) = (66/154)
= 43% OA
% of Outdoor Air for the AHUs can vary significantly through the day
AHU A
Percentage of Outdoor Air BIDMC Sharpiro Center
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0:00 0:00 0:00 0:00 0:00 0:00 0:00
Time, Hours
AHU-A
AHU-B
AHU-C
AHU-D
September 23, 2005
`
12:00 6:00 8:00 10:00 2:00 4:00 6:00
IPA : Combined MOISTURE and VENTILATION MANAGEMENT
Measurements to assess both absolute humidity levels and ventilation rates for
very high quality HVAC performance (Balancing IAQ and Energy Use):
• Optimizing the Delivery of wintertime dry cold outdoor air for ventilation & cooling
IPA : Integrated absolute humidity
and ventilation monitoring:
Critical Combination for IAQ
1) Diagnostic feedback on ventilation rates, critical for achieving good, or even superior, IAQ
2) Diagnostic feedback on moisture management for both comfort and preventing mold growth
Monitoring of end points: Addition of carbon dioxide to dew point monitoring to assess ventilation performance as well as moisture management performance:
Synergy yielding more robust feedback on building & HVAC performance
IPA –Integrated monitoring:
Other gaseous parameters to consider:
• Carbon monoxide
• Hydrogen sulfide
• VOCs ? ? ?
Universal Truth:
If it isn’t being effectively monitored,
how can it be effectively managed?
This applies to not only energy use, but also HVAC systems for moisture management and ventilation management
Monitoring can provide not only diagnostic feedback, but also HVAC control: DCV
1) Appropriate after it has been determined that the HVAC system is performing as intended,
2) Appropriate in areas where potential occupancies are both high and variable, and
3) Recommend logging and review of monitoring data.
BENEFITS from Verifying HVAC Performance:
Improved building operation and reduced risk in the areas of:
More optimum ventilation performance,
Moisture management.
Balancing IAQ and Energy Use
Improved management of building:
“Monitoring end points provides specific feedback that can help building owners and managers maintain the efficient performance of systems over time and remedy any problems that arise.”
Rachel Reiss
Improving the Energy Performance of Green Buildings
E Source, ER-0511, July 2005
RECOMMENDATIONS: 1. Install monitoring system that data logs both
absolute humidity (dew point) and carbon dioxide every half hour at key locations in the building.
2. Designate individual or firm to review the monitoring data in a timely fashion.
3. Periodically compare particulate counts for the outdoor air, the supply air, and the room air.
IPA –Integrated monitoring:
Achieve a healthier and more productive indoor environment for the smallest expenditure of energy
Thank you,
David Bearg, sagefarm@comcast.net