• Peter van ’t Erve

• Project Manager

• International Service

Particle Measurement& Validation bv

Erkenningsnummer 3445-00

Particle Measurement & Validation bv

Introduction Basic stuff HEPA-filtration Types of cabinets Maintenance Criteria Disinfection HEPA-filter change Miscellaneous

Erkenningsnummer 3445-00

Basic stuffBasically a cabinet consists of :

The Body : Stainless Steel Epoxy coated steel

Prefilter : Eff. 80 – 90% acc. EN 779 HEPA-filters : Eff. 99,99% acc. EN 12469 Fan : To create the velocity Electronics : To control the velocity and the alarm features

Accessories : on customer requirement

Basic stuff Pre-filters

Cheap glassfiber filter-material, to protect the expensive HEPA-filters To be changed every year

Low cost exchange

Lifetime of a HEPA: without Prefilter appr. 6 yearswith Prefilter : appr. 12 years

Filter classification according EN 779

Filter type Pre-filters & Fine-filters

Filter class G1 G2 G3 G4 F5 F6 F7 F8 F9

Am % >65 65<80 80<90 90 - - - - -

Em % - - - - 40<60 60<80 80<90 90<95 95

Basic stuff H.E.P.A. filters

HEPA = High Efficiency Particulate Air ULPA = Ultra Low Particulate Air

The purpose of a HEPA-filter is to catch small particles.

Construction of a HEPA-filter: Filter media (Glass fiber or

similar)

The media is pleated to a package of a certain size.

The pleated media is glued together in a frame

HEPA-Filtration: Efficiency

The efficiency of a HEPA-filter according EN 12469:99,99% when tested by means of a photometer.

100.000particles 10 Particles

HEPA-FiltrationSieve operation of a HEPA

HEPA-FiltrationInterception/impaction

Product Protection

Personal protection

Product and personal protection

Types of cabinets: General

Downflow unit

Crossflow

Types of cabinets: Product protection

Laminar Downflow

Class II A (Double exhaust)

Class II BClass II A

HEPA-Filter

Pre-filter

Types of cabinets: Biological safety cabinets

InflowRecirculationPressure plenumDownflowExhaust

Flow pattern

70%

30%

Types of cabinets: Biological safety cabinets

Check on Pre-filterAirflow velocity’s

downflow & inflowFilter efficiency test by means of a photometer

or particle counterCheck on alarmsettings

Maintenance: General

Product Protection

Personal protection

Product and personal protection

When do we need to change it?

Turn over one edge of the pre-filter,

If the down side is becoming grey, replace it.

Take care of contaminated areas !!

Maintenance: Control of Pre-filter

Test Retention at frontaperture

Leaktightnessof carcass

Filters Product protection Crosscontamination

Routinemaintenancetesting

Check thatmanufacturer’sspecification is met;

Measuring air velocity(Annex G en H)

Check airflow patterns

Not applicable Filter efficiency testwith the help of a testaërosol(Annex D)

Check thatmanufacturer’sspecification is met;

Measuring air velocity(Annex G en H)

Check airflow patterns

Check thatmanufacturer’sspecification is met;

Measuring air velocity(Annex G en H)

Check airflow patterns

Maintenance: Control of air flow and velocity

Airflow velocity measurements

Downflow

Measurements have to be taken at- 8 positions minimum, - 50 to 100 mm above the top edge of the front aperture.

1/8 l 1/8 l3/8 l 3/8 l

1/4 d

1/4 d

Criteria:- All values have to be >0,25 and < 0,50m/s;

- According manufacturer’s specifications;

- No individual measurement should deviate more than 20% from the mean.

Maintenance: Airflow measurements (EN 12469)

InflowAccording Annex G you have to measure the velocity in the exhaust duct and calculate the volumetric rate of discharged exhaust air. With this air volume you can calculate the mean inflow velocity.

In practice it is much more easier to measure the inflow velocity in the front aperture.

Criteria:Mean inflow velocity > 0,40 m/s and,

according manufacturer’s specifications.

a

bc

Window

Workingspace

H

L

abc

1 2 3

1/8 L 4/8 L 7/8 LFront view

Side view

Maintenance: Airflow measurements (EN 12469)

Airflow velocity measurements

Flow pattern

Inflow:

The direction of the inflow should be inward over the whole area of the front aperture.

Downflow:

The direction of the flow should be downwards without turbulence as a result of options or other obstructions in the working area.

Maintenance: Airflow measurements (EN 12469)

Tested using smoke

Procedure:

Option 1.

Filtertest with a Particle Counter and a test aërosol.

Option 2.

Efficiency test with a Photometer and a test aerosol.

Criteria:

Tested with a Photometer a local penetration should be not more than 0,01%.

Related Standards:

• IES-RP-CC006.2• ISO/CD 14644-3• EUROVENT 4/8

Maintenance: Control of HEPA filter efficiency

Referential measurement

(80-120 µgr / L)

100% measurement

Photometer

Generating the test aerosol

(DOP, Emery 3004 , DEHS)

Scanning probe

Downflow / Crossflow unit

Maintenance: Control of HEPA filter efficiency

++

+ ++

_

_

_

_

_ _

+

_

+

+

+

Generating the test aerosol

(DOP, Emery 3004 , DEHS)

100%

100% measurement

(80-120 µgr / L)

Photometer

Probe

Scanningprobe

Maintenance: Control of HEPA filter efficiency

Photometer

Generating the test aerosol

(DOP, Emery 3004 , DEHS)

100% measurement

(80-120 µgr / L)

100%Probe

Scanningprobe

Maintenance: Control of HEPA filter efficiency

Inflow High Alarm

Create a high alarm by increasing the voltage of the fan and check whether there is a high alarm.

Low Alarm Create a low alarm by de-creasing the

voltage of the fan and check whether there is a high alarm.

Downflow High Alarm

Create a high alarm by increasing the voltage of the fan and check whether there is a high alarm.

Low Alarm Create a low alarm by de-creasing the

voltage of the fan and check whether there is a high alarm.

Window Alarm (If applicable)Check whether there is an alarm if the window is not in a calibrated position.

Other alarmpoints Check all other alarmpoints

Maintenance: Alarm Settings (EN 12469)

• Adjust alarmwindow to calculated alarmsettings

• Make your alarm

window as big as possible

Maintenance: Setting the alarms

High alarm

• Determine High alarm

(Vav + 20%)

• Adjust alarmwindow to calculated alarmsettings

• First High alarm

• Adjust alarmwindow to calculated alarmsettings

• First High alarm

• Then Low alarm

Vav

• Adjust velocity

Low alarm

• Determine Low alarm

(Vav - 20%)

Maintenance: Testpoints CA(B) / x and EF(B) / x cabinets

A: Aerosol supply

B: 100% measuring point (and test point for overall efficiency test 1st HEPA-filters on a CB and EFB) This point might also be on top of the cabinet for a CA(B)

C: Scanning downflow HEPA-filter

D: Scanning exhaust HEPA-filter (overall efficiency test on a CA(B)

There are three ways to connect a safety cabinet to a duct!

1. Direct connection!2. Direct connection with a by-pass!3. Connection via a thimble!

Ducting: Ways of ducting

• Both cabinet and the external ventilator have to be switched on at the same time, this is done by a potential free contact (optional accessory) coming from the cabinet!

• The anti blow-back-valve assures that no contaminated air can travel back into the cabinet!

• The room pressure will fluctuate depending if the cabinet is switched on or off. However it is possible to have the air inflow adjusted to the amount of air that is extracted from the room!

• Advantage: Higher level of safety!

Externalfan

Anti Blow Back Valve

Airsupply

Ducting: Direct connection

Externalfan

Anti Blow Back Valve

Airsupply

By-pass valve

• The external ventilator works 24hrs a day!• When the cabinet is switched on the by-pass

valve in the duct will open in order to extract the exhausted air from the cabinet.

• When the cabinet is switched off the valve will close and will extract the same amount of air from the room!

• The valve is also controlled by a potential free contact coming from the cabinet.

• The anti blow-back-valve assures that no contaminated air can travel back into the cabinet!

• Advantage: Higher level of safety and the room pressure will be constant at all time!

Ducting: Bypass connection

Effects on the roompressure:• When the cabinet is switched on the

exhausted air will be extracted from the cabinet!

• When the cabinet is switched off the exhausted air will be extracted from the room!

• Advantage: No adjustments have to be made to the cabinet and the pressure in the room will be constant!

Externalfan

Airsupply

Ducting: Via a Thimble

There are three possibilities:

There is no extra fan in the exhaust system.

There is an extra fan in the exhaust system, but there is no link between the status (Day- or Stand-by position) of the cabinet and extra exhaust fan.

There is an extra fan in the exhaust system, with a link between the status (Day- or Stand-by position) of the cabinet and extra exhaust fan.

Adjusting the alarms can be done by increasing or decreasing the downflow and inflow air velocity by means of the fan of the cabinet.

What will be the effect on the alarm settings if the cabinet is connected on an exhaust duct work?

Why desinfection:

- Microbiological Safety Cabinet is a Biohazard.

- All parts in the cabinet are a possible risk for

both personnel and environment when opened.

When desinfection:

- If repair needs to be done inside the cabinet.

With what can we desinfect a cabinet

Air mixed with fresh air and product

HEPA-filtered air mixed with product

Contaminated air

HEPA-filtered air

- That depends on the product which was handled in the cabinet,

responsible for desinfection is the head of the laboratory.

Disinfection

Air mixed with fresh air and product

HEPA-filtered air mixed with product

Contaminated air

HEPA-filtered air

Clean Air techniek offers a so called FAS 2000 which

is using Formalin for desinfection and Ammonia to

neutralize the Formalin afterwards.

FAS 2000

DisinfectionUsing Formalin

Depending on the size (volume) of the cabinet, Formalin is put in the can with the red cap and Ammonia is put in the can with the blue cap.

FAS 2000

DisinfectionUsing Formalin

In order to prevent Formaldehyde of getting into the

laboratory, the cabinet has to be sealed off.

You can do this by sealing the cabinet with a plastic bag.

Make sure that the bag is sealed to the floor.

DisinfectionUsing Formalin

First HEPA-filter on a Class IIB cabinet:

HEPA-filter change1st HEPA

Take of the pressurebar.

(On older models you have to cut the silicon along the outer edge of the filter.)

HEPA-filter change1st HEPA

Seal the opening of the HEPA-filter in order

to prevent parts to come out of the HEPA-filter

HEPA-filter change1st HEPA

Replace the HEPA by a new one and put the pressure

bar back in it’s place.

HEPA-filter change1st HEPA

Take of the backpanel

Disconnect the fan and take it out

HEPA-filter changeDownflow HEPA

Unloosen the pressure bars of the downflow plenum and the exhaust HEPA and take them out.

Lift the pressure plenum and take it out.

Take out the HEPA-filter.

Pressure bars

Plenum

HEPA-filter

HEPA-filter changeDownflow HEPA

Put in a new HEPA-filter with the seal downwards and put everything back in it’s place.

HEPA-filter changeDownflow HEPA

Put in a new HEPA-filter with an extra seal on one end.

Put everything back in it’s place

Lift the exhaustduct

Unloosen the pressurebars

and take them out

Lift the pressure plenum

and take it out

Take out the HEPA-filter

HEPA-filter changeExhaust HEPA

Criteria

Criteria Cabinet type EF / x (EN 12469)

- HEPA-filter efficiency downflow > 99,99%

- HEPA-filter efficiency exhaust > 99,99%

- Vaverage downflow velocity: 0,35 m/s.

-Alarm for downflow velocity: Vaverage +/- 20% as where all individual measurements should be

> 0,25m/s and < 0,50m/s.

- Vaverage inflow velocity : > 0,30 m/s at the top of the working opening.

- Alarm for inflow velocity: < 0,28 m/s at the top of the working opening.

- HEPA-filter efficiency downflow > 99,99%

- HEPA-filter efficiency exhaust > 99,99%

- Vaverage downflow velocity: 0,35 m/s.

-Alarm for downflow velocity: Vaverage +/- 20% as where all individual measurements should be

> 0,25m/s and > 0,50m/s.

- Vaverage inflow velocity : > 0,30 m/s at the top of the working opening.

- Alarm for inflow velocity: < 0,28 m/s at the top of the working opening.

- HEPA-filter efficiency 1st HEPA > 99,99%

Criteria Cabinet type EFB/ x (EN 12469)

Criteria CLF x and DLF x

- According Federal Standard 209B

- HEPA-filter efficiency > 99,99%

- Vaverage downflow velocity: 0,35 m/s.

- Alarm : Vaverage - 20% and Vaverage +20% if applicable.

- Vaverage horizontal velocity: 0,45 m/s.

Downflow unit

Crossflow

Criteria Standards

BS 5726 DIN 12950 DIN 12980 EN 12469HEPA-filter efficiencyDownflow HEPA > 99,997% > 99,997% > 99,997% > 99,99%HEPA-filter efficiencyExhaust HEPA > 99,997% > 99,997% > 99,997% > 99,99%HEPA-filter efficiencyFirst HEPA - - > 99,99% > 99,99%Downflow velocity Vaverage should be defined by the

manufacturer and should be > 0,25 - < 0,50 m/s.Additionally no individual measurement should differ more than 20% of Vaverage and be > 0,25 - < 0,50 m/s.

Vaverage= 0,40m/sAdditionally no individual measurement should differ more than 20% of Vaverage as where all individual measurements should be > 0,32m/s and < 0,48 m/s.

Vaverage should be defined by the manufacturer and should be > 0,32 - < 0,48 m/s.Additionally no individual measurement should differ more than 20% of Vaverage and be > 0,32 - < 0,48 m/s.

Vaverage should be defined by the manufacturer and should be > 0,25 - < 0,50 m/s.Additionally no individual measurement should differ more than 20% of Vaverage and be > 0,25 - < 0,50 m/s.

DLF / BSS x : Vaverage = 0,35 m/sDLF / REC x : Vaverage = 0,35 m/s

CA / x : Vaverage =0,40 m/s CB / x : Vaverage =0,35 m/s. EF / x : Vaverage =0,38 m/sEFB / x : Vaverage =0,38 m/s

Inflow velocity Vaverage should be > 0,70 m/s. Vaverage should be > 0,40 m/s. Vaverage should be > 0,40 m/s. Vaverage should be > 0,40 m/s.

DLF / BSS x :Vaverage on top of working opening should be > 0,22m/s.Alarmsituation : Vaverage < 0,19m/s.DLF / REC x :Vaverage on top of working opening should be > 0,22m/s.Alarmsituation : Vaverage < 0,19m/s.

CA / x :Vaverage on top of working opening should be > 0,28m/s.Alarmsituation : Vaverage < 0,26m/s.

CB / x :Vaverage on top of working opening should be > 0,28m/s.Alarmsituation : Vaverage < 0,26m/s.

EF / x :Vaverage on top of working opening should be > 0,28m/s.Alarmsituation : Vaverage < 0,26m/s.EFB / x :Vaverage on top of working opening should be > 0,28m/s.Alarmsituation : Vaverage < 0,26m/s.

Video

Test equipment

VACUUMUP

STREAMDOWN

STREAMFILTER

3 WAY VALVE

LIGHT STOPCONE OF LIGHT

CONE OF DARKNESS

LIGHT SOURCEPHOTO-MULTIPLIERTUBE

Test equipmentPhotometer

Test equipmentAerosolgenerator, generating a testaerosol DOP, EMERY 3004 or DEHS

2NOZZLES

5NOZZLES

SIGHTGLASS

AEROSOLSOLUTION

PRESSUREREGULATOR

ADJUSTINGKNOB

AIRINLET

FILTER

DRAIN

SIGHTGLASS

AEROSOLRESERVOIR

PRESSUREREGULATOR

ADJUSTINGKNOB

NITROGENINLET

FILTER

ORIFICE AND

VALVE

HEATER BLOCK