Case Study: Case Study: Using Particle Using Particle Assessment to Determine Assessment to Determine
Ventilation (HVAC) PerformanceVentilation (HVAC) Performance
Harry L. SkalskyHarry L. Skalsky PhD DABT PhD DABT
Skalsky & AssociatesSkalsky & Associates27356 Becedas27356 Becedas
Mission Viejo, CaliforniaMission Viejo, California(949) 855-2363(949) 855-2363
HISTORYHISTORY
Industry - Industry - Aluminum Powders & Alumina Aluminum Powders & Alumina Abrasives (NIOSH/OSHA)Abrasives (NIOSH/OSHA)
Indoor Air Indoor Air – Allergens and Irritant Dusts (Air-O-Cell – Allergens and Irritant Dusts (Air-O-Cell etc.)etc.)
Hazardous Waste Site Hazardous Waste Site – Dust Excursions – Dust Excursions (Direct Reading Dust Monitors etc.)(Direct Reading Dust Monitors etc.)
Exposure Assessment - Exposure Assessment - Particle Counter, Air-Particle Counter, Air-O-Cell, and NIOSH procedures.O-Cell, and NIOSH procedures.
Exposure Assessment Exposure Assessment (November (November 2001)2001)
Respirable DustTotal DustParticle CounterAir-O-Cellmg/m3mg/m3Particules/m3Structures/m3
<0.09<.0538667825499Location 2
<0.09<.053424739391Location 3
<0.09<.053378279670Location 6
HVAC System EvaluationHVAC System Evaluation((100% Ambient Air appeared to eliminate a 100% Ambient Air appeared to eliminate a
airborne fungal spore problem)airborne fungal spore problem)
Was HVAC System delivering excess Was HVAC System delivering excess fungal spores to the interior ?fungal spores to the interior ?
OrOr
Was the “cure”, a fortuitous occurrence Was the “cure”, a fortuitous occurrence ? ?
HVAC – Primary FilterHVAC – Primary Filter85% in 3 to 10 micron85% in 3 to 10 micron
HVAC – Final Filter HVAC – Final Filter 95% down to 0.3 micron95% down to 0.3 micron
Collection EquipmentCollection Equipment
Particle Counter HHPC-6 Particle Counter HHPC-6 Laser Particle Counter Laser Particle Counter (six (six channels 0.3 to >10channels 0.3 to >10m)m)
Two Air-O-Cells at 15 lpm. Two Air-O-Cells at 15 lpm. (5 minutes - outside and 10 (5 minutes - outside and 10 minutes - indoor hallway)minutes - indoor hallway)
Supply Duct MonitoringSupply Duct Monitoring
Balometer – Balometer – to measure, record to measure, record and monitor air flow throughout the and monitor air flow throughout the 30 minute30 minute collection time. collection time.
Plastic Shroud – Plastic Shroud – to prevent to prevent mixing with hallway air.mixing with hallway air.
Collection delay - Collection delay - to allow to allow “flushing” of bag prior to sampling. “flushing” of bag prior to sampling.
Particle/Structure CountsParticle/Structure Counts20% versus 100% Outside20% versus 100% Outside
Air-o-cellParticles/M3Particle Counts/ft3lessGreaterGreaterTotalthanthanthan
2 microns2 microns2 microns
61,69613,92814,8303,630,646Intake Air146,2616,61328,6711,193,123Intake Air
10,5192,749Hallway81,29827,928Hallway
2,536370220765,824Supply Air1,702272410268,466Supply Air
4%3%1%21%1%4%1%23%
Particle EfficiencyParticle Efficiency((System Average by Particle size)System Average by Particle size)
Supply/Intake Airborne Particulate
>10.0um5.0-10.0um2.0-5.0um1.0-2.0um0.7-1.0um0.3-0.7um
99.2%97.9%98.5%91.6%93.4%77.9%Recirculated(AM&PM)
100.0%99.2%98.8%94.3%94.8%71.4%Ambient (AM)
AOC Structure EfficiencyAOC Structure Efficiency((System Average by AOC Category)System Average by AOC Category)
98%96%99%78%90%99%99%98%
OTHERMINERALSBIOLOGICALAir-O-CellUnidentifiedMoldSkinStructures/
Fragmentsm3
97303787744338Intake Air2706237013841043Intake Air
146051765528Hallway25319545361345Hallway
216140774Supply Air26517716Supply Air
1E3
1E4
1E5
1E6
1E7
Str
uctu
res o
r C
ou
nts
/M3 o
f A
ir
1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930313233343536
Number of data pairs
Particles >2um Structures >2um(A)Structures >2um(B)
Particle Counter vs Air-O-CellParticles/ Structures Greater Than 2um
Intake LocationIntake Location (day1&2)(day1&2)
1E1
1E2
1E3
1E4
1E5
1E6
1E7
1E8
1E9
Str
uctu
res o
r C
ou
nts
/M3 o
f A
ir
1 2 3 4 5 6 7 8 9101112131415161718192021222324252627282930313233343536
Number of Data Pairs
Particles <2um Structures <2um(A)Structures <2um(B)
Particle Counter vs. Air-O-CellParticles/Structures Less than 2 um
Intake LocationIntake Location (day1&2)(day1&2)
0
5000
10000
15000
20000
25000
30000
35000
Str
uctu
res/M
3 o
f A
ir
1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930313233343536
Number of Data Pairs (Outside Intake)
Structures >2um(A)Structures >2um(B)
"Duplicate" Air-O-Cell - Particle DataAvg Count-12409 Avg Dif.- 3340 (27%)
Intake LocationIntake Location (day1&2) AOC > 2(day1&2) AOC > 2mm
0
10000
20000
30000
40000
50000
60000
70000
80000
Str
uctu
res/M
3 o
f A
ir
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Number of Data Pairs (Hallway)
Structures >2um(A)Structures >2um(B)
"Duplicate" Air-O-Cell - Particle DataAvg Count=11142 Avg Dif.=3838 (34%)
HallwayHallway Locations Locations (day1) AOC > 2(day1) AOC > 2mm
SupplySupply Locations Locations (day1) AOC > 2(day1) AOC > 2mm
0
20
40
60
80
100
120
140
160
180
200
Str
uctu
res/M
3 o
f A
ir
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Number of Data Pairs
Structures/M3 (A)Structures/M3 (B)
"Duplicate" Air-O-Cell - Particle DataAvg. Count = 34 Avg. Diff = 23 (68%)
SupplySupply Locations Locations (day1) AOC > 2(day1) AOC > 2mm
0
20
40
60
80
100
120
140
160
180
200
Str
uctu
res/M
3 o
f A
ir
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Number of Data Pairs
Structures/M3 (A)Structures/M3 (B)
"Duplicate" Air-O-Cell - Particle DataAvg. Count = 34 Avg. Diff = 23 (68%)
0
1000
2000
3000
4000
Sp
ores/M
3 o
f A
ir
1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930313233343536
Number of Data Pairs (Outside Intake)
Spores/M3 (A)Spores/M3 (B)
"Duplicate" Air-O-Cell - Spore DataAvg. S/M3 = 948 Avg Diff =528 (55%)
Intake LocationIntake Location (day1&2) AOC – Spores(day1&2) AOC – Spores[5 Minute][5 Minute]
Hallway LocationsHallway Locations (day1&2) AOC – Spores(day1&2) AOC – Spores[10 minute][10 minute]
0
20
40
60
80
100
120
140
160
180
Sp
ores/M
3 o
f A
ir
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Data Pairs
Spores/M3(A)Spores/M3(B)
"Duplicate" AOC Hallway Spore DataAvg=34 S/M3 Avg. Diff= 24 S/M3 (68%)
Supply LocationsSupply Locations (day1&2) AOC – Spores(day1&2) AOC – Spores[30 minute][30 minute]
0 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15
Sp
ores/M
3 o
f A
ir
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Number of Data Pairs
Spores/M3(A)Spores/M3(B)
"Duplicate" AOC Balometer Spore DataAvg = 6.1S/M3 Avg Diff=0.2 S/M3 (3%)
ConclusionsConclusions
HVAC Filtration Efficiency HVAC Filtration Efficiency cancan be be measured by a variety of different factorsmeasured by a variety of different factors
Particle Counters and Air-O-Cells yield Particle Counters and Air-O-Cells yield veryvery different results in the field. different results in the field.
Paired Air-O-Cell samples yield a Paired Air-O-Cell samples yield a high high degree of variabilitydegree of variability both in spore count both in spore count (3-68%) and particle count (27-68%).(3-68%) and particle count (27-68%).