Filtration and - PowerPoint Presentation

Slide1

Filtration and

UV

disinfection

Synergy

By: Normand Brais

P.Eng

,

Ph.D

.

National

Air

Filtration Association

NAFA TECH 2014,

Kissimme

, FL

April 3 2014

Slide2

Content

1) UV Fundamentals

2)

Cooling

C

oils

D

isinfection

3) Filtration

F

undamentals

4) Filtration + UV :

complementaritySlide3

1) Fundamentals of UV light

UV-A

(400-315 nm) Sun glasses

UV-B

(315-280 nm) Sun tanningUV-C (280-200 nm) Germicidal UVUV-V (200-30 nm) V = Vacuum : O2  O3 Slide4

DNA : Watson and Crick 1953Slide5

Reproduction:

a

molecular

copying machineSlide6

UV

Sterilization

mechanism

: Dymerisation of Thymines pairsSlide7
Slide8
Slide9

Fundamental

Principle

of UV disinfectionUV Dose = intensity x time joule/ m

2

watt/m

2

sec

The

larger

the

Dose

,

t

he more

alterations

to the DNA,

leading

to

Sterilization

Slide10

Direct

Mathematical

C

orrelation N0 = Initial number of micro-organisms N(t)

= Number of micro-organisms surviving at time “t”

I

= UV radiation intensity

i

n W/m

2

t

= exposure time in seconds

Dose = I x t

, in Joule/m

2

K = susceptibility coefficient in m2/jouleSlide11
Slide12

k values:

Susceptibility

of microbes to GUV

Figure 2. General ranking of suceptibility to UVC inactivation of microorganisms by group.Slide13

2)

Cooling

Coils

Surface DisinfectionSlide14

Coil

without

adequate

FilterSlide15

Coil

with

good

Filters: is it clean ?Slide16

Samples

taken

on

Clean Looking CoilsSlide17

Difference

between

virus,

bacteria, fungi and inert mineral dust ?Slide18

i

nert

dust

can’t grow and multiply !Slide19

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 +Slide20

What

lives

on

cooling coils ?A) Mold spores UV Dose for 90% killAspergillus Niger D90= 448 mJ/cm2

Cladosporium

wemecki

D90= 448

mJ

/cm

2

Penicillium

D90= 224

mJ

/cm

2

B)

Bacteria

Legionella

Pneumophilia

D90=

2.5

mJ

/cm

2

Pseudomonas

Aeruginosa

D90

= 2.2

mJ

/cm

2Slide21

UV dose

required

against

Aspergillus and Cladosporium UV Dose: 448 mJ/cm2 for 90% kill = 1 log

UV Dose:

896

mJ

/cm

2

for

99%

kill

= 2 log

UV Dose:

1344

mJ

/cm

2

for

99.9%

kill = 3 logUV Dose: 1792 mJ/cm2 for 99.99% kill = 4 logUV Dose: 2240 mJ/cm2 for 99.999% kill

= 5

log

a

nd

so

on…Slide22

How

much

UV

does

it take to keep a coil clean ?Disinfecting

Aspergillus

at

99%

within

1

hour

r

equires

a UV

intensity

of :

Intensity

=

896 mJ/cm2/(3600 sec) = 0.25 mW/cm2 = 250

μ

W/cm

2Slide23

Just the tip

of the iceberg…Slide24

Example

:

coil

of 10 ft x 10 ft

10 inches thick, 10 fins/inchCoil face = 100 ft2 Total coil surface = 20,000 ft2 ! !Coil heat

transfer

surface –vs- face areaSlide25

Area ratio = 2 X

Fins per

inch

X Coil thicknessSlide26

Inter-Fins UV PropagationSlide27

Move away for better resultsSlide28

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%Slide29

Aspergillus Niger:

time to

reach

99%

disinfection inside a CoilAt Coil

face, 250

μ

W/cm2: 1

hour

At 2’’

depth

,

113

μ

W/cm2:

2.2

hours

At

4’’

depth

, 51.4 μW/cm2:

4.9

hours

At

6’’

depth

,

23.3

μ

W/cm2:

11

hours

At

8’’

depth

,

10.6

μ

W/cm2:

24

hours

At

10’’

depth

, 4.8

μ

W/cm2:

52

hours

At 12’’

depth

, 2.2

μ

W/cm2:

115

hours

At

14’’

depth

,

1.0

μ

W/cm2:

254

hours

At

16’’

depth

,

0.45

μ

W/cm2:

561

hoursSlide30

Aspergillus Niger:

time to

reach

99%

disinfection inside a CoilAt Coil face,

500

μ

W/cm2

: 0.5

hour

At 2’’

depth

,

227

μ

W/cm2:

1.1

hours

At

4’’

depth, 103 μ

W/cm2:

2.4

hours

At

6’’

depth

,

46.6

μ

W/cm2:

5.4

hours

At

8’’

depth

,

21.1

μ

W/cm2:

12

hours

At

10’’

depth

, 9.6

μ

W/cm2:

26

hours

At 12’’

depth

, 4.3

μ

W/cm2:

58

hours

At 14’’

depth

,

2.0

μ

W/cm2:

127

hours

At 16’’

depth

,

0.9

μ

W/cm2:

281

hoursSlide31

Aspergillus Niger:

time to

reach

99%

disinfection inside a CoilAt Coil face,

1000

μ

W/cm2

: 0.25

hour

At 2’’

depth

,

453

μ

W/cm2:

0.55

hours

At

4’’

depth, 205 μ

W/cm2:

1.2

hours

At

6’’

depth

,

93.1

μ

W/cm2:

2.7

hours

At

8’’

depth

,

42.2

μ

W/cm2:

5.9

hours

At

10’’

depth

, 19.1

μ

W/cm2:

13

hours

At 12’’

depth

, 8.7

μ

W/cm2:

29

hours

At 14’’

depth

,

3.9

μ

W/cm2:

64

hours

At 16’’

depth

,

1.8

μ

W/cm2:

140

hoursSlide32

UV

rules

of

thumb

–vs- Coil ThicknessCoil thickness Avg UV on face Gross PowerCoil ≤ 12’’ 250 μW/cm

2

1 Watt/ft

2

12’’<

Coil

≤ 14’’

500

μ

W/cm

2

2 Watt/ft

2

14’’<

Coil

≤ 16’’ 1 000 μW/cm2 4 Watt/ft216’’ < Coil ≤ 18’’ 2 000 μW/cm

2

8

Watt/ft

2Slide33

Coil

Disinfection

Elimination

of biofilms formation

Lower

pressure drop

better

heat

transfer

energy

savings

Improved

occupant’s

wellbeing

UV system design

criteria

:

I

ntensity

Homogeneity

Inter-fin

penetrationSlide34

UV COIL DISINFECTIONSlide35

10

ft

x 10

ft

CoilSlide36
Slide37

Petri

dish

samples taken with UV ON Slide38

3) How

Filters

W

orkSlide39
Slide40

The MPP

C

hasm

Most

P

enetrating

Particle

sizeSlide41

HEPA

Filters

: MPP

ChasmSlide42

Filters

MERV

efficiency

(source: NAFA)Slide43

4 -

Filling

the

Chasm

with UV Slide44

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

b

etween

0.1

and

0.4 micron

UV : efficient

in

this

size range

viruses are easy targets for UV.Slide45

UV

can

complete

the job Slide46

Example

of

Combined

efficiency: MERV 16 Filter + UV ≥ HEPASlide47

A proof by

e

xample

:

In-Vitro Fertilization ClinicsIVF clinics with best HEPA filtrationFertilization success rate

stagnated

at

20 to 30%

W

hen

UV

was

added

to HEPA

S

uccess

rate

jumped

at 70 to 85% ! !Slide48

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 MEng

1

,

James A Hanley PhD

2

, Thomas Rand PhD

3

, Don Milton MD Dr. PhD

4

.

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

.Slide49

The LANCET paper highlights

771 Employees

from

3

office buildings participated in the study.UV ON for 4 weeksUV OFF for 12 weeks3

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

.Slide50

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

Slide51

Working

hand in hand

with

good filtration practice, a well engineered Ultraviolet system brings a boost tobuilding hygiene and energy

efficiency

. Slide52

Thank

you

!