Transcript Document

Filtration and
UV disinfection Synergy
By: Normand Brais P.Eng, Ph.D.
National Air Filtration Association
NAFA TECH 2014, Kissimme, FL
April 3 2014
Content
1) UV Fundamentals
2) Cooling Coils Disinfection
3) Filtration Fundamentals
4) Filtration + UV : complementarity
1) Fundamentals of UV light




UV-A
UV-B
UV-C
UV-V
(400-315 nm) Sun glasses
(315-280 nm) Sun tanning
(280-200 nm) Germicidal UV
(200-30 nm) V = Vacuum : O2  O3
DNA : Watson and Crick 1953
Reproduction:
a molecular copying machine
UV Sterilization mechanism:
Dymerisation of Thymines pairs
Fundamental Principle of
UV disinfection
UV Dose = intensity x time
joule/ m2
watt/m2
sec
The larger the Dose,
the more alterations to the DNA,
leading to Sterilization
Direct Mathematical Correlation
N0 = Initial number of micro-organisms
N(t) = Number of micro-organisms surviving at time “t”
I = UV radiation intensity in W/m2
t = exposure time in seconds
Dose = I x t, in Joule/m2
K = susceptibility coefficient in m2/joule
k values:
Susceptibility of microbes to GUV
Most Susceptible
Vegetative bacteria
Organism Group
Member of Group
Vegetative Bacteria
Staphylococcus aureus
Streptococcus pyogenes
Escherichia coli
Pseudomonas aeruginosa
Mycobacteria
Serratia marcescens
Mycobacteria
Mycobacterium tuberculosis
Mycobacterium bovis
Bacterial spores
Mycobacterium leprae
Bacterial Spore
Bacillus anthracis
Bacillus cereus
Fungal Spores
Bacillus subtilis
Fungal Spores
Least Susceptible
Figure 2. General ranking of suceptibility to UVC inactivation of
microorganisms by group.
Aspergillus versicolor
Penicillium chrysogenum
Stachybotrys chartarum
2) Cooling Coils
Surface Disinfection
Coil without adequate Filter
Coil with good Filters: is it clean ?
Samples taken on
Clean Looking Coils
Difference between
virus, bacteria, fungi
and
inert mineral dust ?
inert dust can’t grow
and multiply !
• About multiplication…by 2
2 x 2 x 2 x 2 x….x 2 = ?
10 times = 1,024
20 times = 1 million +
30 times = 1 billion +
What lives on cooling coils ?
A) Mold spores
UV Dose for 90% kill
1.
Aspergillus Niger
D90= 448 mJ/cm2
2.
Cladosporium wemecki
D90= 448 mJ/cm2
3.
Penicillium
D90= 224 mJ/cm2
B) Bacteria
1.
Legionella Pneumophilia
D90= 2.5 mJ/cm2
2.
Pseudomonas Aeruginosa
D90= 2.2 mJ/cm2
UV dose required
against Aspergillus and Cladosporium
UV Dose: 448 mJ/cm2 for 90% kill
= 1 log
UV Dose: 896 mJ/cm2 for 99% kill
= 2 log
UV Dose: 1344 mJ/cm2 for 99.9% kill
= 3 log
UV Dose: 1792 mJ/cm2 for 99.99% kill = 4 log
UV Dose: 2240 mJ/cm2 for 99.999% kill = 5 log
and so on…
How much UV does it take to
keep a coil clean ?
Disinfecting Aspergillus at 99%
within 1 hour
requires a UV intensity of :
Intensity =
896 mJ/cm2/(3600 sec)
= 0.25 mW/cm2
= 250 μW/cm2
Just the tip
of the iceberg…
Coil heat transfer surface –vs- face area

Example :
• coil of 10 ft x 10 ft
• 10 inches thick, 10 fins/inch
Coil face = 100 ft2
Total coil surface = 20,000 ft2
!!
Area ratio = 2 X Fins per inch X Coil thickness
Inter-Fins UV Propagation
Coil FINS
Coil Depth
Move away for better results
Inter-Fins UV Propagation
1 reflection : UV = 80%
2 reflection : UV = 80% x 80%= 64%
3 reflection : UV = 80%x80%x80%= 51%
4 reflection : UV = 80%x80%x80%x80%= 41%
5 reflection : UV = 80%x80%x80%x80%x80%= 33%
6 reflection : UV = 80%x80%x80%x80%x80%x80%= 26%
7 reflection : UV = 80%x80%x80%x80%x80%x80%x80%= 21%
8 reflection : UV = 80%x80%x80%x80% x80% x80% x80% x80%= 17%
9 reflection : UV = 80%x80%x80%x80%x80%x80%x80%x80%x80%=13%
10 reflection : UV = 80%x80%x80%x80%x80%x80%x80%x80%x80%x80%=11%
Aspergillus Niger:
time to reach 99% disinfection
inside a Coil
At Coil face, 250 μW/cm2:
At 2’’ depth, 113 μW/cm2:
At 4’’ depth, 51.4 μW/cm2:
At 6’’ depth, 23.3 μW/cm2:
At 8’’ depth, 10.6 μW/cm2:
At 10’’ depth, 4.8 μW/cm2:
At 12’’ depth, 2.2 μW/cm2:
At 14’’ depth, 1.0 μW/cm2:
At 16’’ depth, 0.45 μW/cm2:
1 hour
2.2 hours
4.9 hours
11 hours
24 hours
52 hours
115 hours
254 hours
561 hours
Aspergillus Niger:
time to reach 99% disinfection
inside a Coil
At Coil face, 500 μW/cm2 :
At 2’’ depth, 227 μW/cm2:
At 4’’ depth, 103 μW/cm2:
At 6’’ depth, 46.6 μW/cm2:
At 8’’ depth, 21.1 μW/cm2:
At 10’’ depth, 9.6 μW/cm2:
At 12’’ depth, 4.3 μW/cm2:
At 14’’ depth, 2.0 μW/cm2:
At 16’’ depth, 0.9 μW/cm2:
0.5 hour
1.1 hours
2.4 hours
5.4 hours
12 hours
26 hours
58 hours
127 hours
281 hours
Aspergillus Niger:
time to reach 99% disinfection
inside a Coil
At Coil face, 1000 μW/cm2 :
At 2’’ depth, 453 μW/cm2:
At 4’’ depth, 205 μW/cm2:
At 6’’ depth, 93.1 μW/cm2:
At 8’’ depth, 42.2 μW/cm2:
At 10’’ depth, 19.1 μW/cm2:
At 12’’ depth, 8.7 μW/cm2:
At 14’’ depth, 3.9 μW/cm2:
At 16’’ depth, 1.8 μW/cm2:
0.25 hour
0.55 hours
1.2 hours
2.7 hours
5.9 hours
13 hours
29 hours
64 hours
140 hours
UV rules of thumb –vs- Coil Thickness

Coil thickness
Avg UV on face
Gross Power

Coil ≤ 12’’
250 μW/cm2
1 Watt/ft2

12’’< Coil ≤ 14’’
500 μW/cm2
2 Watt/ft2

14’’< Coil ≤ 16’’
1 000 μW/cm2
4 Watt/ft2

16’’ < Coil ≤ 18’’
2 000 μW/cm2
8 Watt/ft2
Coil Disinfection
•Elimination of biofilms formation
•Lower pressure drop
•better heat transfer
•energy savings
•Improved occupant’s wellbeing
•UV system design criteria:
• Intensity
• Homogeneity
• Inter-fin penetration
UV COIL DISINFECTION
10 ft x 10 ft Coil
Petri dish samples taken
with UV ON
3) How Filters Work
The MPP Chasm
Most
Penetrating
Particle size
HEPA Filters: MPP Chasm
Filters MERV efficiency (source: NAFA)
4 - Filling the Chasm with UV
4) FILTER+UV SYNERGY
FILTERS: good on small or large microbes
Between 0.02 and 1 micron, filters efficiency drop
HEPA filters:
also a drop of efficiency between 0.1 and 0.4 micron
UV : efficient in this size range
viruses are easy targets for UV.
UV can complete the job
Name
k
SI unit
Parvovirus H-1
0,092 m2/J
Echovirus
0,217 m2/J
Coxsachievirus
0,111 m2/J
Norwalk virus
0,0304 m2/J
VEE
0,0419 m2/J
Reovirus
0,03358 m2/J
Adenovirus
0,039 m2/J
influenza A virus
0,119 m2/J
Coronavirus (SARS)
0,377 m2/J
Mycoplasma pneumoniae
0,2791 m2/J
Neisseria catarrhalis/meningitidis
0,05233 m2/J
Newcastle disease
0,144 m2/J
Coxiella burnetii
0,1535 m2/J
Haemophilus influenza
0,0599 m2/J
Proteus vulgaris/mirabilis
0,07675 m2/J
Vaccinia virus
0,153 m2/J
Measle virus
0,1051 m2/J
Pseudomonas aeruginosa
0,1047 m2/J
E. Coli
0,15611 m2/J
Legionella pneumophila
0,44613 m2/J
Serratia marcescens
0,28653 m2/J
Mycobacterium tuberculosis 0,4721 m2/J
Listeria monocytogenes
0,2303 m2/J
Salmonella
0,221 m2/J
MRSA
0,113 m2/J
D 90%
SIZE
microJ/cm2 Type
2500
1060
2072
7566
5489
6849
5897
1933
610
824
4395
1597
1498
3840
2997
1503
2188
2197
1473
516
803
487
999
1041
2035
virus
virus
virus
virus
virus
virus
virus
virus
virus
bacteria
bacteria
virus
bacteria
bacteria
bacteria
virus
virus
bacteria
bacteria
bacteria
bacteria
bacteria
bacteria
bacteria
bacteria
micron
0,022
0,024
0,027
0,029
0,065
0,075
0,079
0,098
0,113
0,177
0,177
0,212
0,283
0,285
0,291
0,307
0,329
0,494
0,5
0,52
0,632
0,637
0,707
0,800
0,866
Note
UV microJ/cm2 UV microJ/cm2 UV microJ/cm2 UV microJ/cm2 UV microJ/cm2
2500
5000
89,9741%
98,9948%
Meningetis, affects children.
99,5595%
99,9981%
Common cold in fall or summer. Colds,
93,7651%
acute respiratory
99,6113%
disorder.
Gastroenteritis. Airborne transmission.
53,2334%
Common on cruise
78,1288%
ships.
Vancomycin-resistant Enterococcus64,9186%
87,6930%
Colds, fever,
pneumonia
56,8074%
81,3440%
Symptoms
ressemble
common
cold. Can be epidemic in
62,2808%
85,7726%
fever similar to adenovirus.
10000
99,9899%
100,0000%
99,9985%
95,2165%
98,4854%
96,5195%
97,9758%
20000
100,0000%
100,0000%
100,0000%
99,7712%
99,9771%
99,8789%
99,9590%
40000
100,0000%
100,0000%
100,0000%
99,9995%
100,0000%
99,9999%
100,0000%
Causes flu. Can cause epidemia inside
94,8953%
buildings.
99,7394%
99,9993%
100,0000%
100,0000%
Comon colds and lung infections. 99,9919%
100,0000%
100,0000%
100,0000%
100,0000%
Causes pneumonia in 20% of cases.
99,9067%
99,9999%
100,0000%
100,0000%
100,0000%
Second leading cause of Meningitidis,
72,9707%
also causes pharyngitis.
92,6942%
99,4663%
99,9972%
100,0000%
Exposure of humans to infected birds
97,2676%
(for example in 99,9253%
poultry processing plants)
99,9999%
can cause mild
100,0000%
conjunctivitis and
100,0000%
influenza-like
Transmitted from animals to humans.
97,8453%
Q fever: causes99,9536%
chills, headache, fatigue.
100,0000%
100,0000%
100,0000%
Major cause of meningetis. Affects77,6311%
infants, otitis media,
94,9963%
sinusitis.
99,7496%
99,9994%
100,0000%
Pneumonia, ooportunistic infections.
85,3210%
97,8453%
99,9536%
100,0000%
100,0000%
97,8182%
99,9524%
100,0000%
100,0000%
100,0000%
Rubeola,affects children, nosocomial.
92,7741%
Airborne transmission
99,4779%
in schools ventilation
99,9973%
100,0000%
100,0000%
Pneumonia, nosocomial, indoor growth
92,7015%
in dust, water,99,4673%
humififiers. Common
99,9972%
Hospital AI 100,0000%
100,0000%
Source:feces. Found in food, meat and
97,9814%
water. Causes diarrhea,
99,9593%
often deadly.
100,0000%
100,0000%
100,0000%
Legionnaire's disease. Pontiac fever,
99,9986%
pneumonia, deadly
100,0000%
in 15% of cases.100,0000%
100,0000%
100,0000%
99,9225%
99,9999%
100,0000%
100,0000%
Food processing industry pathogen.99,6841%
Causes diarrhea. Elderly
99,9990%
and pregant100,0000%
women
Food processing industry pathogen.99,6014%
Causes diarrhea. Elderly
99,9984%
and pregant100,0000%
women
Methicillin-resistant Staphylococcus
94,0691%
aureus
99,6482%
99,9988%
TB infects 1/3 of world population.Causes
99,9993%
Tuberculosis.
100,0000%
Nosocomial.
100,0000%
100,0000%
100,0000%
100,0000%
100,0000%
100,0000%
100,0000%
100,0000%
100,0000%
100,0000%
Example of Combined efficiency:
MERV 16 Filter + UV ≥ HEPA
Name
SIZE
k
Custom unit
influenza A virus
0,119 m2/J
Coronavirus (SARS)
0,377 m2/J
Mycoplasma pneumoniae
0,2791 m2/J
Neisseria catarrhalis/meningitidis0,05233 m2/J
Newcastle disease
0,144000 m2/J
Coxiella burnetii
0,1535 m2/J
Haemophilus influenza
0,0599 m2/J
Proteus vulgaris/mirabilis
0,07675 m2/J
Vaccinia virus
0,153 m2/J
Measle virus
0,1051 m2/J
Pseudomonas aeruginosa
0,1047 m2/J
E. Coli
0,15611 m2/J
Legionella pneumophila
0,44613 m2/J
Type
micron
virus
virus
bacteria
bacteria
virus
bacteria
bacteria
bacteria
virus
virus
bacteria
bacteria
bacteria
0,098
0,113
0,177
0,177
0,212
0,283
0,285
0,291
0,307
0,329
0,494
0,500
0,520
Note
UV microJ/cm2 Merv 16 Combination
HEPA
Combo Merv 16+UV
15000
FILTER
Filter+UV
alone
Improvement
Causes flu. Can cause
100,0000%
epidemia inside
81,00%
buildings.100,0000% 99,99%
0,01%
Comon colds and lung
100,0000%
infections. 80,00% 100,0000% 99,98%
0,02%
Causes pneumonia 100,0000%
in 20% of cases. 72,00% 100,0000% 99,94%
0,06%
Second leading cause
99,9610%
of Meningitidis,72,00%
also causes 99,9891%
pharyngitis. 99,94%
0,05%
100,0000%
69,00% 100,0000% 99,95%
0,05%
Transmitted from animals
100,0000%
to humans.70,00%
Q fever: causes
100,0000%
chills, headache,
99,97%fatigue. 0,03%
Major cause of meningetis.
99,9875%
Affects infants,
71,00%
otitis media,
99,9964%
sinusitis.99,97%
0,03%
Pneumonia, ooportunistic
99,9990%
infections.71,00%
99,9997% 99,97%
0,03%
100,0000%
72,00% 100,0000% 99,97%
0,03%
Rubeola,affects children,
100,0000%
nosocomial.73,00%
Airborne transmission
100,0000%in schools
99,98%ventilation0,02%
Pneumonia, nosocomial,
100,0000%
indoor growth
89,00%
in dust, water,
100,0000%
humififiers.
99,99%
Common Hospital
0,01%
AI
Source:feces. Found100,0000%
in food, meat and90,00%
water. Causes
100,0000%
diarrhea, often
99,99%
deadly.
0,01%
Legionnaire's disease.
100,0000%
Pontiac fever, pneumonia,
91,00% 100,0000%
deadly in 15% of99,99%
cases.
0,01%
A proof by example :
In-Vitro Fertilization Clinics

IVF clinics with best HEPA filtration
Fertilization success rate stagnated at 20 to 30%

When UV was added to HEPA
Success rate jumped at 70 to 85% ! !
Independent Studies
Published by : THE LANCET Medical Journal
“Impact of Ultraviolet Germicidal Lights Installed
in the Ventilation Systems of Office Buildings on
Workers Health and Well Being”
Richard Menzies MD MSc1,2, Julia Popa BEng MEng1,
James A Hanley PhD2, Thomas Rand PhD3, Don Milton MD Dr. PhD4.
From :
1.Respiratory Epidemiology and Clinical Research Unit, Montreal Chest
Institute,
2.Department of Epidemiology and Biostatistics of McGill University
3.Dep’t of Biology, St. Mary’s University, Halifax, Nova Scotia,
4.Department of Environmental Health, Harvard School of Public Health,
Boston.
The LANCET paper highlights





771 Employees from 3 office buildings participated in the study.
UV ON for 4 weeks
UV OFF for 12 weeks
3 cycles totalling 48 weeks.
Repeated twice, over 2 years.
When UV were ON :
• 40% reduction in respiratory symptoms
• 20% overall reduction in all symptoms
• 30% reduction in mucosal symptoms
These benefits were greatest for those with known allergies.
Conclusions

When properly engineered with adequate
software, UV eliminates coil biofilms and
saves Energy
$$$

UV improves overall performance of filters

Just like for Filtration, UV Fundamentals
are also well defined in ASHRAE Handbook
Working hand in hand with
good filtration practice,
a well engineered
Ultraviolet system
brings a boost to
building hygiene and
energy efficiency.
Thank you !