Working safely in abiosafety cabinet

Per Staugaard

NBN symposium 2012

In this Symposium:

• mentioned in the guidelines

• validated protection against aerosols

• if properly used

Importance of Biosfetycabinets

Aerosol → ContainmentAerodynamicsHEPA filtrationLAF cabinets vs BSC[do’s & don’ts]

laboratory infectionscaused by

• puncture/spraying with hypodermic 22%

• spillage / spraying in general 22%

• cut by broken glass 20%

• swallowing during pipetting 17%

• bite or scratch by infected animals 11%

• other known causes 1%

• unknown 7%

reference : Pike (1976)

containment & procedures & personnelprotection

secondary containment

fermenter/culture bottle

down streamprocessing

biosafetycabinet

primary containment

HEPA filter

Restricted entrancetraining/informationmedical control

personel protection

Aerodynamics basics

1µm0,1µm 10µm 1mm1nm 0,1mm0,1nm 10nm

gasses

atoms

prionsvirusses

falling particlesaerosol [floating particles]

Human hair

pollen

bacteria

High Efficiency Particulate Air Filter [HEPA]

mamalian cells

HEPA filter [1]

• Sieve-effect

Sieve effect

HEPA filter

• Inertia

HEPA filter

• Interception

Inertia & collision

HEPA filter

• Diffusion [Brownian movement]

Brownian movement

HEPA-filterfilter-efficiency and particle size

HEPA-filterfilter-efficiency and particle size

‘Making sense of HEPA filtration’Anderson et al.March 1988

Factors influencing the effectivity

mechanism Air velocity Particle size Fiber diameter Filter densitydiffusion(BrownianMovement)

- - - +

Collision /Impaction(inertia)

+ + - +

interception 0 + - 0

- = Negative correlation

+ = Positive correlation

0 = No influence

From: De Rudder& Remon: Aanbevelingen bij de productie van Parenteralia

HEPA-filter

HEPA-filter

Anderson 1988

1µm0,1µm 10µm 1mm1nm 0,1mm0,1nm 10nm

virusses

falling partioclesaerosol [floating particles]

bacteria

most penetrating size

fine filtration

ULPA HEPA pre filter

sizes of particles

Depth Filter

99,99…% removed

HEPA filter construction

Anderson 1988

LAF cabinetsproduct protection

Downflow Crossflow

Beware of the difference !

LAF cabinetproduct protection

BSC [dutch BVK]Biosafety cabinet [workbench]product + worker protection

Three types

Biosafety Workbench

Class II:worker protectionAND product protection

Class I:worker protection

Biosafety cabinet

Single filterDouble filter

Recirculation inthe room

Exhaust airducted

Class IIrecirculation vs

extraction

Prevention of leakageby neg pressure

-

- -+

Class II

Total exhaust

Use [indicative !]

How Biological Safety Cabinets Are Classified

Classification is an important consideration in the selection of any biological safety cabinet. Over the years,the scientific community has adopted commonly accepted classification criteria to differentiate containmentcapabilities and performance attributes. Biological safety cabinets are divided into three classifications.Baker designs and manufactures all of these types of biosafety containment cabinets.

Classification Biosafety Level Application

Class I 1,2,3 low to moderate risk biological agents

Class II 1,2,3 low to moderate risk biological agents

Class III 4 high risk biological agents

Baker Company

Classification[mainly USA]

75 FPM = 0,4 m/s100 FPM = 0,5 m/s

Baker Company

New NSF

Classification,

Adopted 2002

Previous NSF

ClassificationGeneral Description

A1Class II,

Type A

70% air recirculated; 30% exhausted from a common

plenum to the room;

75FPM intake;

may have biologically contaminated positive pressure

plenum

A2Class II,

Type A/B3

70% air recirculated; 30% exhausted from a common

plenum to the room;

100FPM intake;

biologically contaminated plenum under negative

pressure or surrounded by negative pressure

A2Class II,

Type B3

70% air recirculated; 30% exhausted from a common

plenum to a facility exhaust system;

100FPM intake;

biologically contaminated plenum under negative

pressure or surrounded by negative pressure

B1Class II,

Type B1

40% air recirculated; 60% exhausted from cabinet;

exhaust air pulled through dedicated exhaust duct into

facility exhaust system;

100FPM intake

all biologically contaminated plenums are negative to

the room or surrounded by negative pressure plenums

B2Class, II

Type B2

0% air recirculated; 100% exhausted from cabinet

exhaust air pulled through dedicated exhaust duct into

facility exhaust system;

100FPM intake

all ducts and plenums are under negative pressure

all contaminated ducts are under negative pressure or

surrounded by directly exhausted negative pressure

ducts or plenums

NEN-EN 12469

• Class I >0,7-1,0 m/s

• Class II > 0,4 m/s

• Class III> 0,7 m/s [“lost glove”]

Airflow & crosscontamination

Opening of the window

Combination with room ventilation

Thimble connection

BSC

1000 mm

B 5726 (1992)British Standard - recomandations for installation

minimal distances

Location in the Lab.

BSC

300 mm

Location in the Lab.

BSC

1000 mm

1500 mm

Location in the Lab.

BSC2000 mm

Location in the Lab.

BSC

Movements in the Lab.

BSC

1500 mm

Location in the Lab.

BSC

3000 mm

BSC

Location in the Lab.

Video examples

From Video by TNO[1989]

From Video Precieszoals het hoort

[1997]

checklistClothinggloves

cleaningswitch on in time

moving in materialssitting position

surroundigsorganization work area

doing the work

cleaning

filling in logbook[maintenance]

sleeves

discarding waste

disinfection

[sterile]

disinfection

references

• W.L. Anderson, [1988]Making Sense of HEPA filtrationtechnical presentation ITCFS, march 1988

•