1. Ductless Hoods
Erik Talley / Matthew Brinton
Environmental Health and Safety
Emerging Trends in Laboratory Ventilation
ACS Fall 2009 National Meeting
Washington DC August 15- 20, 2009

2. What is a “Ductless Hood”?
Enclosure + Fan + Filter =
Ductless Hood
Environmental Health and Safety
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3. No!!!!
Environmental Health and Safety
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4. Design Limitations
 Recirculation of exhaust air is
potentially dangerous.
– Limited Filter Capacity (saturation,
breakthrough, stripping)
 Filter Changes (handling of used
filters, including hazardous waste
disposal as a hidden cost)
 Poor design
 Chemical hoods are used for more
than just chemical containment (e.g.
fire, explosions)
 Not typically maintained by
Facilities
 User Knowledge/Misuse
Environmental Health and Safety
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ehs@med.cornell.edu
212-746-6201

5. Why consider ductless?
(building limitations)
Baker Pavilion Existing External Ducts Centre Georges Pompidou
Environmental Health and Safety
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ehs@med.cornell.edu
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6. Why consider ductless?
(continued)
 Increased safety for benchtop work or
equipment.
 Standard chemical hood design
interferes with needs (e.g. dust
weighing)
 Insufficient need to justify
infrastructure/operational costs of
ducted hood (installation cost, space
needs) .
Environmental Health and Safety
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ehs@med.cornell.edu
212-746-6201

7. Why consider ductless?
(continued)
 Energy efficiency (A
single ducted chemical
hood running 24/7/365
uses as much energy
as a single-family
home.)
 Pollution capture
Environmental Health and Safety
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ehs@med.cornell.edu
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8. Hazard Assessment
 An Industrial Hygienist
must conduct a
comprehensive Hazard
Assessment including:
–Type of Hazards
–Frequency of Use: Dose
–Duration of Use: Dose
–Hazard Generation
Characteristics
–Effluent Characteristics
Environmental Health and Safety
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9. Limited Filter Applications
 HEPA
– Powder weighing,
nanoparticulates, etc.
 Adsorbent Cartridges
– Nuisance odors
– Low toxicity chemicals
– Applications where chemical
usage is:
• limited (volume and time)
• consistent
• controllable
 Dual Filters
– Animal Surgeries
Environmental Health and Safety
www.med.cornell.edu/ehs
ehs@med.cornell.edu
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10. Controls
 Service Contract
 Connect to house
exhaust if possible
(canopy, thimble)
 Minihelic Pressure
Gauge (HEPA), Flow
Monitor, Vapor Sensor
 Signage
 Training
 Inspections
Environmental Health and Safety
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ehs@med.cornell.edu
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11. Case Study - Gross Anatomy
 Plastination
– New Process
– Limited Use
– Single chemical hazard (organotin
compound)
– Very Limited Space
 Hood Selection
– Activated carbon
 Controls
– Air exhausted to outside after
being filtered
– Limited Access
– Training
– Inspection
Environmental Health and Safety
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ehs@med.cornell.edu
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12. Case Study - Clinic
 Urology
– Endoscope disinfection
machine
– Located in interior of building
with no exhaust options
– Gluteraldehyde (5%) Solution
 Hood Selection
– Carbon filter hood designed
specifically for the endoscope
machine
 Controls
– Service Contract
– Labeling
– Training
Environmental Health and Safety
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ehs@med.cornell.edu
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13. Case Study – Laboratory
 Epigenomics Core
Laboratory
– Chemical use limited to sample
preparation
• ~125 ml total chemical usage/month
– Hood use approximately 30-60
minutes a week
 Hood Selection
– Dual Filter
 Controls
– Limited Access
– Labeling
– Service Contract
– Training
Environmental Health and Safety
www.med.cornell.edu/ehs
ehs@med.cornell.edu
212-746-6201

14. Resources
Environmental Health and Safety
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ehs@med.cornell.edu
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