• 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