Fume Hood Containment

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• Fume Hood Containment
• Safety Performance

Esco Micro Pte Ltd 21 Changi South Street 1,
Singapore 486777 Tel [phone] Fax 65
6542 6920
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Standard Fume Hood
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Why we use fume hood?

• To contain fumes and hazardous chemicals
• Ensure Safety of laboratory workers

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Face Velocity vs Containment Efficiency

• Fume hood meets face velocity specification but
  are not safe.
• 30-50 of fume hoods meeting face velocity
  requirements fail tracer gas test. (source
  www.safelab.com)

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Existing Standards

• BS 7258 (United Kingdom, Hong Kong)
• DIN 12 924 (Germany)
• EN 14175 (European Union)
• ANSI/ASHRAE 110-1995 (United States)
• NF-X-15-203 (France)
• AS/NZS 82006(Australia New Zealand)

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European StandardEN 14175 2003
EN 14175 2003
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EN 14175 2003

• Group Effort of 11 European Countries
• Combination of BS and DIN standards
• 6 parts- Part 1 Vocabulary- Part 2 Safety
  and performance requirements- Part 3 Type test
  methods- Part 4 On-site test methods- Part 5
  Recommendations for installation and maintenance
  - Part 6 Variable air volume fume cupboards

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Air Flow Test
EN 14175 2003
Probe positions
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Inner Containment Test
EN 14175 2003
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Inner Containment Test
EN 14175 2003
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Inner Containment Test
EN 14175 2003
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Outer Containment Test
EN 14175 2003
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Outer Containment Test
EN 14175 2003
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Robustness of Containment
EN 14175 2003

• Dynamic Testing 'Robustness' of Containment
  Test
• Test equipment as per outer containment test
  equipment
• Flat rectangular plate of 1.9 x 0.4m of thickness
  20mm shall be mounted in front of cupboard.

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Robustness Test of Containment
EN 14175 2003
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US StandardANSI/ASHRAE 110-1995
ANSI/ASHRAE 110-1995
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Introduction
ANSI/ASHRAE 110-1995

• Method of Testing Performance of Laboratory Fume
  Hoods.
• ASHRAE American Heating, Refrigerating and
  Air-Conditioning Engineers, Incorporation.
• Laboratory Fume Hoods, a Performance Test, K.J.
  Caplan and G.W. Kruston, RP-70, ASHRAE
  Transactions, 1978.
• First ASHRAE Standard is published on 1985.

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Test Method
ANSI/ASHRAE 110-1995

• Cross draft face velocity test
• Smoke visualization test
• Tracer gas containment test

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Cross Draft Face Velocity
ANSI/ASHRAE 110-1995

• Cross draft transducer
• Accuracy 3 of reading

• Face velocity transducer
• Accuracy 2 of reading

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Cross draft measurement
ANSI/ASHRAE 110-1995

• Cross draft shall be less than 0.15m/s

H
½ H
5 feet
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Face velocity measurement
ANSI/ASHRAE 110-1995

• 100 sash opening
• Face velocity shall be 0.50m/s 20

x
y
300mm
300mm
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ANSI/ASHRAE 110-1995

• 50 Sash opening
• 25 Sash opening

x
1/2y
300mm
x
1/4y
300mm
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Flow visualization
ANSI/ASHRAE 110-1995

• Enable visual inspection of fume hood air flow
  patterns.
• Consist 2 parts
• Low volume smoke test
• High volume smoke challenge

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Low Volume Smoke Test
ANSI/ASHRAE 110-1995
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High Volume Smoke Challenge
ANSI/ASHRAE 110-1995
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Tracer Gas Containment Test
ANSI/ASHRAE 110-1995
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ANSI/ASHRAE 110-1995
SF6 Gas

• Much heavier than air
• Non-flammable, non-toxic

Tracer gas detector

• To detect and capture leakage of SF6 from hood.
• Detection limit 0.01 PPM

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Mannequin
ANSI/ASHRAE 110-1995

• Mannequin height 1.70m, wearing laboratory cloth.
• Tracer gas detector placed near the mannequin's
  breathing zone.

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Static test
ANSI/ASHRAE 110-1995

• Tracer gas ejector is placed at 150mm behind the
  sash.
• Mannequin placed 75mm in front of sash.
• Mannequin position will change according to the
  ejector location.
• SF6 gas release rate is 4LPM.
• Data acquisition to record detector reading for 5
  mins.

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Static test
ANSI/ASHRAE 110-1995

• Test is conducted at 100, 50 and 25 sash
  opening.
• Every test is carried out with ejector in 3
  positions
• Center
• 300mm from the left
• 300mm from the right
• Spillage shall not exceed 0.1ppm, in all test
  positions.

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Face Hood Surface Scan
ANSI/ASHRAE 110-1995

• To observe leakage point of the hood opening.
• Tracer gas probe is held 1 inch away from the
  edge of sash opening, and move along the edge
  with a speed of 3 inch per second.
• Spillage shall not exceed 0.1ppm, in all test
  positions.

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Sash Movement Effect
ANSI/ASHRAE 110-1995

• To test the effect on containment when opening or
  closing the sash.
• Sash is moved at a smooth motion between 0.3
  0.5m/s.
• Sash movement Closed ? Full opening ? Closed,
  repeat 3 times.
• Conducted with ejector Located in 3 positions
• Center
• 300mm from the left
• 300mm From the right

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Increased Severity Challenges
ESCO Fume Hood

• Face velocity in 0.50m/s, 0.40m/s, 0.30m/s to
  test the hood performance.
• FFU to create cross draft.

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Increased Severity Challenges
ESCO Fume Hood

• Moving vertical board to pretend door open or
  close.

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ASHRAE Test Result for EFD-4
ESCO Fume Hood

• Face velocity
• Sash 100 open 0.50 m/s
• Sash 50 open 0.83 m/s
• Sash 25 open 1.15m/s
• Smoke visualization

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ASHRAE Test Result for EFD-4
ESCO Fume Hood

• Static test

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ASHRAE Test Result for EFD-4
ESCO Fume Hood

• Face hood surface scan
• Sash movement effect

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SafetyEssential
Safety Essentials
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Fume Hood Location
Safety Essentials
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Fume Hood Location
Safety Essentials
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Work Safety
Safety Essentials

• Fume hood is not a storage!
• Always keep fume hood clean and clear.
• Action must be taken immediately if spillage
  happen.

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Work Safety
Safety Essentials

• Raise bulky equipment 1-2 inch off the work
  surface.
• Place bulky equipment towards the rear of hood
  and away from the side walls.

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Work Safety
Safety Essentials

• Keep sash as low as possible when conducting
  experiment.
• Do not block the airfoil.
• Reduce pedestrian traffic in front of the hood
• Minimize rapid movement in front of hood.
• Always keep laboratory windows and doors closed.

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Work Safety
Safety Essentials

• Do not use a hood for any function for which it
  was not intended.
• Certain chemicals or reactions require specially
  constructed hoods.
• Perchloric acid hoods shall be made of stainless
  steel and equipped with a wash down system.
• Polycarbonate sash shall be applied when using
  hydrofluoric acid.
• Work involving harmful micro-organisms should be
  done in a biosafety cabinet, rather than a
  chemical fume hood.
• Close the sash when finished hood work or leaving
  experiments or chemicals unattended.

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Thank you!
End