VENTILATION

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VENTILATION
Presentation by Pam Fatland Manager, Chemical
Safety Office of Environmental Health
Safety Tulane University [phone] January,
2004
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PROTECT THE WORKER

• Chemical Fume Hoods
• 100 Exhausted to outside
• No recirculation
• Baffles in back should adjust for work with
  chemicals of different volatilities and vapor
  densities
• Designed for work with toxic or hazardous
  chemicals

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PROTECT THE WORKER

• Radiation Fume Hoods
• 100 Exhausted to outside
• May contain HEPA filters (esp. for work with
  Iodine isotopes)
• Usually stainless steel construction
• Usually reinforced for heavy lead shielding
• Designed for work with radioactive materials

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PROTECT THE WORKER

• Perchloric Acid Fume Hoods
• 100 Exhausted to outside
• Special washdown features to prevent perchlorate
  buildup in hood and ductwork
• Not to be used for flammables or other chemicals
  reactive with perchlorates
• Designed for work with perchloric acid

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PROTECT THE WORKER

• Slot Ventilation
• 100 Exhausted to outside
• Draws fumes towards back of work space away from
  workers breathing zone

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PROTECT THE WORKER

• Canopy Ventilation
• May be 100 Exhausted to outside, but not
  recommended for chemical use
• Draws fumes past workers breathing zone
• Best used for heat removal such as in a kitchen

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PROTECT THE WORKER

• Class I Biological Safety Cabinet
• 100 Exhausted through HEPA filter
• Supply air not filtered, so product in cabinet is
  subject to contamination by organisms present in
  the air supply
• May be equipped with arm-length rubber gloves

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PROTECT THE PRODUCT

• Laminar Flow Clean Bench
• Supply air passes through HEPA filter over work
  surface, then is exhausted to the room
• Exhaust air actually blows into operators face
• Never handle toxic or infectious materials in
  Laminar Flow Clean Bench

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PROTECT THE WORKER, THE PRODUCT, AND THE
ENVIRONMENT

• Class IIA Biological Safety Cabinet
• Most commonly used BSC, suitable for procedures
  with clinical specimens or cell cultures
• Some air is recirculated within cabinet through
  HEPA filter, some air is exhausted back into lab
  through another HEPA filter
• Do not use toxic or flammable materials

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PROTECT THE WORKER, THE PRODUCT, AND THE
ENVIRONMENT

• Class IIB1 Biological Safety Cabinet
• Provides containment of infectious aerosols
• Has high energy requirements and operating costs
• Some air is recirculated within cabinet through
  HEPA filter, some air is exhausted back into lab
  through another HEPA filter
• Do not use toxic or flammable materials

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PROTECT THE WORKER, THE PRODUCT, AND THE
ENVIRONMENT

• Class IIB2 Biological Safety Cabinet
• Exhausts 100 of intake air through HEPA filter
• Provides containment of infectious aerosols
• High energy requirements and operating costs
• Some air is drawn in past HEPA filter over work
  area and some air is drawn in through work
  opening and exhausted
• Do not use toxic or flammable materials

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PROTECT THE WORKER, THE PRODUCT, AND THE
ENVIRONMENT

• Class IIB3 Biological Safety Cabinet
• Functionally the same as BSC IIA except air is
  exhausted to the outside through a HEPA filter
  rather than back into the room
• Some air is drawn in through work opening and is
  recirculated within cabinet after passing through
  a HEPA filter
• Can cause buildup of hazardous concentrations if
  toxic or flammable materials are used

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PROTECT THE WORKER, THE PRODUCT, AND THE
ENVIRONMENT

• Class III Biological Safety Cabinet
• Gas tight construction with rubber gloves
• Supply air is drawn through HEPA filter and
  exhaust air is filtered through 2 HEPA filters
  installed in series before discharge to the
  outside
• Provides highest level of worker, product, and
  environmental protection

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FUME HOOD SAFETY TIPS

• Work at least six inches inside hood
• Lower sash to lowest possible position
• Avoid rapid movement into and in front of hood
• Elevate large equipment off work surface
• Keep hood clear of clutter keep amount of
  material in hood to a minimum
• Secure loose lightweight objects such as paper
  towels

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FUME HOOD SAFETY TIPS

• Use an airflow indicator or alarm to make sure
  hood is operating properly. If not, discontinue
  work with hazardous or toxic chemicals.
• Run water in hood drains often
• Ensure adequate illumination in hood
• Wear protective equipment
• Be aware that opening or closing laboratory doors
  can affect performance of hood

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FUME HOOD SAFETY TIPS

• Keep the sash clean and unobstructed
• Place cords and hoses under the airfoil so sash
  can be kept closed
• Clean chemical residues and spills from interior
  hood surfaces to prevent clothing and skin from
  becoming contaminated
• The emptier the hood, the better air currents can
  flow through it

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FUME HOOD SAFETY TIPS

• Do not place absorbent paper under heating
  appliances
• Do not place incompatible chemicals together
• Be sure the hood has an airfoil installed and
  side panels in place

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DUCTLESS HOODS

• The use of ductless fume hoods is discouraged for
  most applications (Problems No indicator to
  tell when filter needs to be changed, multiple
  chemicals can interfere with filtration, small
  spills can overwhelm filtration system, etc.)
• If used, filter must be changed frequently in
  accordance with manufacturers recommendations