ACTIVE AIR SAMPLING FOR CONTAMINANTS IN THE WORKPLACE

1
ACTIVE AIR SAMPLINGFOR CONTAMINANTS IN THE
WORKPLACE
Presented by
2
ACTIVE SAMPLING DEFINED

• The collection of airborne contaminants using
  a mechanical device such as a pump to draw the
  air/contaminant mixture into or through the
  sampling device such as a sorbent tube, filter,
  impinger, or sample bag.

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THREE KEY COMPONENTS FOR ALL ACTIVE SAMPLING

• A sampling pump
• Something to pull or push air
• A calibrator (flowmeter)
• Something to indicate how much air has
• been pulled or pushed
• The sampling media
• Something to pull or push the air through
• or into for analysis

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U.S. GOVERNMENT METHODS SAMPLING IN THE WORKPLACE

• National Institute for Occupational Safety and
  Health (NIOSH)
• Occupational Safety and Health
• Administration (OSHA)

5
NOTE ON SAMPLING METHODS

• OSHA does not mandate the sampling method to be
  used for compliance.
• The employer has the obligation of selecting a
  method that meets the accuracy/precision
  requirements of the standard i.e. 25 of the
  true value.
• NIOSH or OSHA methods are typically used in
  compliance sampling.

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WEBSITESFOR GOVT AGENCY METHODS

• NIOSH Methods
• http//www.cdc.gov/niosh/docs/2003-154/
• OSHA Methods
• http//www.osha.gov/dts/sltc/methods/toc.
• html

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EXAMPLE NIOSH METHOD
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EXAMPLE OSHA METHOD
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HELP FROM SKC SAMPLING GUIDE IN SKC CATALOG

• Lists all regulated chemicals
• Includes
• Agency Method Number
• Sampling Details such as Flow Rate, Time, Volume
• Analytical method
• Sample collection media and catalog number

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SKC AIR SAMPLING GUIDE
SKC Chemical Fact Files _at_ www.skcinc.com Click
Training or Sampling Help
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TYPES OF ACTIVE SAMPLESFOR VARIOUS EXPOSURE
PERIODS

• Integrated samples-Contaminants are collected and
  concentrated over a period of time to obtain
  average exposure levels during the entire
  sampling period
• Grab samples-Contaminants are collected into a
  device over a short interval of a few seconds or
  minutes to represent exposures at a given point
  in time.

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SAMPLING PUMPS FLOWRATE OPTIONS

• GASES AND VAPORS are sampled at low flow rates to
  allow effective adsorption to occur onto the
  sorbent material.
• PARTICULATES are sampled at high flow rates so
  that airborne particles can be effectively
  trapped onto the filter material.

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LOW FLOW PUMP SKC POCKET PUMP
Flow range of 20-225 ml/min
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HIGH FLOW PUMPWITH LOW FLOW OPTION
SKC AIRCHEK XR5000
Flow range of 5-5000 ml/min using either
lithium-ion or alkaline batteries
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SAMPLING PUMPSCONSIDERATIONS FOR USE

• Constant Flow-Is there an internal mechanism to
  compensate for restrictions to flow?
• Electromagnetic Susceptibility-Is there shielding
  from RFI/EMI?
• Backpressure-What is the maximum pressure drop
  that the pump can handle?

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PUMP CALIBRATORS

• Set and verify the flowrate of the pump to that
  required in the sampling method
• Should be done before and after every sample
• The average of the pre- and post- flowrates is
  used in calculations of air volume

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PUMP CALIBRATION A CRITICAL MEASUREMENT

• Purpose is to determine the volumetric flow rate
  that will pass through the sampling media during
  the time the sample is taken.
• The flowrate is used to calculate total air
  volume.
• FLOW RATE (ml/min or L/min) x SAMPLE TIME (min)
• AIR VOLUME (ml or L)

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TYPES OF CALIBRATORS

• PRIMARY
• STANDARDS
• involve the direct
• measurement of
• volume on the basis of
• the physical
• dimensions of an
• enclosed space which
• do not change over
• time.

• SECONDARY
• STANDARDS
• trace their calibration
• to primary standards
• and have shown to
• maintain their
• accuracy with
• reasonable handling
• and care in operation.

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PRIMARY STANDARDS

• Soap bubble meters/Film flowmeters
• Electronic bubble meters
• Electronic near frictionless piston
• meters

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SOAP FILM FLOWMETERS

• Pump pulls air through a glass tube with
  volumetric indications.
• The liquid film-a soap bubble-is interposed into
  the flow path.
• The air flow causes the bubble to move from one
  volume mark to another.
• The travel time is measured with a stopwatch
• By knowing the travel time and the tube volume,
  the flow rate can be calculated.

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CALCULATION

• Question If it took 128 seconds for the bubble
  
• to travel a 500 ml volume, what is the flowrate?
• 500 ml X 60 sec 234.4 ml/min
• 128 sec min

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TECH TIPS ON CALIBRATION

• It is not necessary for the flowrate to be the
  exact flow specified in the method. Just be sure
  you know exactly what it is.
• Take at least 3 flow measurements that agree
  within 5 and use the average of the readings as
  your flow rate measurement.
• If pre-and post-averages differ by more than 5,
  your sample is called into question.

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CALCULATIONS

• Given travel times for bubble 128.2 129.1
• 128.7 seconds.
• Average time 128.7 seconds
• 128.7 X 0.95 122.2
• 128.7 X 1.05 135.1
• All times are within 5 range of acceptability

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ELECTRONIC BUBBLE METERS

• Work on the same principle as a manual film
  flowmeter
• Infrared sensors electronically time the bubble
• Microprocessor instantly
• calculates flow rate and
• displays it digitally

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NEAR-FRICTIONLESS PISTON METERS

• The flow of the pump causes the piston inside a
  chamber to rise and fall.
• Photo-optic sensors sense the rise and fall of
  the piston.
• An electronic timer combine
• with a microprocessor to
• automatically measure travel
• time and calculate
• the flowrate.

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NOTES ON ELECTRONIC CALIBRATORS

• Both the electronic bubble meter and the piston
  meters use the volume of a cylinder to calculate
  the flow rate.
• Because of the fixed cell volume, these units are
  defined as primary standards by the manufacturer
  and are considered so by OSHA. They should be
  sent in for factory check annually or as needed.

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TECH TIPS ON CALIBRATION

• Let your pumps run 5 minutes before calibration
  after removing them from the battery charger to
  let the flow stabilize.
• The pump must be calibrated with representative
  sample media in line. Use a clean set of media
  to collect the sample in the field after
  calibration.

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SORBENT TUBE SAMPLING TRAIN
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TECH TIPS ON CALIBRATION

• When available, use a calibration adapter to
  attach the sampler to the calibrator.
• Alternatively, use a calibration jar of a size to
  fit the sampler.

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FILTER SAMPLING TRAIN WITH CALIBRATION ADAPTER
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SECONDARY STANDARDS

• Rotameters
• Internal flow sensor
• of an air sampling pump
• Wet Test Meter
• Dry Gas Meter

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ROTAMETERS

• Air passes through a vertical tube with
• a ball or float inside
• The flow of air upward through the tube
• causes the ball to stabilize at a certain
• point
• The flow rate is determined by the
• position of the ball in relation to the
• scale on the tube
• Affected by both temperature and pressure

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ROTAMETERSCONSIDERATIONS FOR USE

• If the rotameter was originally calibrated
• with one end open to the atmosphere (i.e.
• at atm. pressure) and you later use it for
• calibration in between the pump and
• media, the rotameter will indicate a
• lower flowrate.

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CALCULATION FOR ROTAMETERS

• Qnew Qntp (760/Pnew) (Tnew/298)0.5
• Q. A rotameter was calibrated at NTP and measured
  a flow rate of 2 L/min. If the conditions
  changes to 30 C and 1.2 atmospheres, what should
  the new flow be?
• A. Qnew 2 760/(760 x 1.2) (27330)/2980.5
• 1.84 L/min

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PROPER CALIBRATION

• ENSURES ACCURATE
• Air Volumes
• Measurement of exposure levels
• Flow Rate X TimeAir Volume
• Mass of contaminant/Air Volume

Concentration in Air
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SAMPLING MEDIA ACTIVE SAMPLING OF GASES AND
VAPORS
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DEFINING GASES AND VAPORS

• A substance is considered a GAS if this is its
  normal physical state at room temp (25o C) and
  one atm. (760 mm Hg) pressure (Example Carbon
  monoxide)
• If the substance is a liquid at normal temp and
  pressure, then the gaseous component in
  equilibrium with its liquid (or solid) state is
  called a VAPOR. (Example Benzene)

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SOLID SORBENTSINTRODUCTION

• Most widely used media for gases/vapors
• Consist of small granules or beads
• Adsorb the contaminant onto the surface
• Packed into tubes to collect various amounts and
  types of chemicals

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SAMPLE COLLECTIONWITH SORBENT TUBES

• Most tubes have 2 sorbent sections.
• Breakthrough (sample loss) is indicated when
  contaminant levels on the backup section are
  25 of the levels found on front sorbent
  section.

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MORE ON SAMPLE BREAKTHROUGH

• Causes
• High concentrations of target compound
• High concentrations of similar compounds
• High humidity
• High temperatures

• False Breakthrough
• Some chemicals may migrate from the front to the
  back sorbent layers upon storage.
• The method will specify freezer storage or the
  use of two separate tubes in these cases.

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SOLID SORBENTS SPECIFIED IN SAMPLING METHODS

• Trap and retain the contaminant even in the
  presence of other contaminants
• Allow desorption of the contaminant
• Have sufficient capacity to retain enough
  contaminant for analysis
• Will not cause a chemical change of the
  contaminant

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TYPES OF SORBENT MATERIALCARBON BASED SORBENTS

• Activated charcoal-Most widely used solid sorbent
  suitable for collection of non-polar organic
  compounds including benzene, toluene, and xylene.
  
• Anasorb 747-Beaded carbon material that can
  collect a variety of both nonpolar and polar
  organic compounds.
• Carbotrap and Carbosieve -High surface area
  useful for very volatile compounds.

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TYPES OF SORBENT MATERIALINORGANIC SORBENTS

• Silica gel-Used to collect polar organic
  compounds such as alcohols, amines, and phenols.
  Silica gel is commonly used as a desiccant as it
  readily adsorbs water vapor.
• Alumina-Not widely used at this time. Specified
  in one OSHA partially validated method for an
  amine.

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TYPES OF SORBENT MATERIALORGANIC POLYMERS

• Poropaks, Chromosorbs, XAD resins and Tenax.
• These sorbents are used to collect a variety of
  specialty compounds. Chromosorbs and XAD-2 are
  specified in NIOSH and OSHA methods for
  pesticides.
• Tenax is specified in thermal desorption methods
  for (sub) ppb level VOC sampling.

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SORBENT TUBES FOR SOLVENT EXTRACTION

• Sorbent tubes specified for workplace compliance
  sampling in the ppm range are designed for
  solvent extraction by the lab.
• The lab will break open the tube, pour the
  sorbent into vials, add a liquid solvent, and
  shake for a while so that the solvent extracts
  the contaminant from the solid adsorbent and into
  the liquid for GC analysis.

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SORBENT TUBES FOR THERMAL DESORPTION

• Sorbent tubes specified for low level sampling in
  the ppb range are designed for thermal desorption
  by the lab.
• The lab will place the tube into the thermal
  desorber and apply heat and an inert gas to drive
  contaminant molecules from the adsorbent material
  to the detector of the GC.
• Provide lower detection limits.

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TYPES OF SORBENT MATERIALMISC.

• PUF Cartridges-used for
• semi-volatiles including
• PCBs and pesticides by
• ASTM or EPA methods.
• Not specified in any
• workplace methods.

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TYPES OF SORBENT TUBESMISC.

• Sorbent/Filter Combinations
• Filters capture or scrub out particulate phase
  sorbents capture vapor phase.
• Specified in OSHA or NIOSH methods for
  pesticides, glycols, and hydrogen sulfide.

OVS
H2S
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TYPES OF SORBENT MATERIALWASHED OR COATED

• Some chemicals are not effectively trapped by any
  solid sorbent without special preparation.
• Washing is done of silica gel to trap inorganic
  acids such as hydrochloric or hydrofluoric.
• Chemical coating is done on various sorbents to
  trap aldehydes, nitrogen dioxide, amines, and
  many more compounds.

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SORBENT TUBE SAMPLINGADVANTAGES

• Sample is integrated over the entire period of
  exposure.
• Published methods exist with extensive testing
  and documentation of reliability.
• Workplace compliance officers typically use this
  sampling method.
• Air flow is calibrated and measured.
• Backup layer indicates sample breakthrough.

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IMPINGERSINTRODUCTION

• Impingers are
• specially designed
• glass bottles that are
• filled with a collection
• liquid specified in the
• sampling and
• analytical method.

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NOTES ABOUT IMPINGERS

• In some cases, the impinger
• nozzle is fritted or modified
• with thousands of small
• holes. This disperses
• the air and allows for better
• contact between the air
• sample and the impinger
• liquid.

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SAMPLE COLLECTION WITH IMPINGERS

• A sample pump is used to
• bubble air through the
• impinger which contains a
• liquid reagent that has
• been specified in the
• method. The liquid will
• physically dissolve or
• chemically react with the
• chemical of interest.

Trap
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CHEMICALLY TREATED FILTERSINTRODUCTION

• Alternative to wet chemistry methods
• Filters are used as a substrate for liquid media
  that can trap contaminants.
• Liquid media will chemically derivatize the
  contaminant of interest.
• Result is a more stable compound for storage and
  analysis.

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SAMPLE COLLECTIONWITH COATED FILTERS
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TREATED FILTERSCOMMONLY USED TYPES

• Chemical
• Treatment of
• Glass Fiber Filters
• 2,4 DNPH
• 1-(2-pyridyl) piperazine
• Sulfuric Acid
• Mercuric Acetate

• Applications
• Glutaraldehyde
• Diisocyanates
• (HDI,MDI,TDI)
• Aromatic Amines
• Mercaptans

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TREATED FILTERSADVANTAGES

• Sample is integrated over the entire period of
  exposure.
• Published methods exist with extensive testing
  and documentation.
• Workplace compliance officers use these methods
  for some compounds.
• Air flow is calibrated and measured.
• Front and back filter can be used in one cassette
  to determine breakthrough.

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SAMPLE BAGSINTRODUCTION

• Used since the 1950s to collect a fixed volume
  of an air-contaminant mixture into a flexible
  container for subsequent analysis
• Called grab samples in industrial hygiene and
  whole air samples in environmental field.

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SAMPLE COLLECTIONWITH SAMPLE BAGS
Positive Pressure
Negative Pressure
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SAMPLE BAGSSPECIFIED IN SAMPLING METHODS

• Nitrous Oxide by NIOSH 6000
• Sulfur hexafluoride in NIOSH 6602
• Trichloroethylene in NIOSH 3701
• Various hydrocarbons in EPA 0040 and EPA SOPs

• Benzene in NIOSH 3700
• Carbon Dioxide in OSHA ID 172
• Carbon Monoxide in OSHA ID 210
• Ethylene Oxide in NIOSH 3702

Also see www.skcinc.com for SKC studies on bags.
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SAMPLE BAGSBAG MATERIAL OPTIONS

• Tedlar-Classic bag for 1-2 day storage of
  organic vapors.
• SamplePro FlexFilm-Tedlar alternative Useful for
  storage times 3 days for many organic vapors.
• FlexFoil -Useful for gases such as CO, CO2,
  H2,methane, and hydrogen sulfide
• FlexFoil Plus-Suitable for all the same gases as
  FlexFoil (above) PLUS organic vapors

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SAMPLE BAGSAPPLICATIONS

• Leaks, spills, emergency situations requiring
  rapid collection and analysis
• Peak concentrations from specific plant processes
  or worker tasks
• Field applications using on site portable,
  direct-reading instruments like PIDs
• Gases or highly volatile compounds for which
  sorbent tubes are not suitable

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STAINLESS STEEL CANISTERS SPECIFIED IN EPA VOC
METHODS

• Canisters have been used as an air collection
  vessel for measurement of low level VOCs.
• The interior of the canister is treated in some
  way so that it does not react with collected
  compounds.

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STAINLESS STEEL CANISTERS SPECIFIED IN EPA VOC
METHODS

• The canister sampling
• train includes
• Stainless steel sampling inlet
• Particle filter
• Critical orifice
• Flow controller
• A vacuum gauge is used to
• visually monitor canister status
• during sampling.

Source www.restekcorp.com
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CANISTER SAMPLINGTHE BASICS

• Most canister sampling is done passively using
  a canister that has been evacuated to a specified
  vacuum level.
• Prior to sample collection, a qualified
  laboratory should clean and certify the canister,
  evacuate the canister to the appropriate level,
  and provide sample identification.
• At the sampling site, the valve is opened and air
  flows from the environment into the canister
  without the need for a pump.

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SAMPLING MEDIA ACTIVE SAMPLING FOR PARTICULATES
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DEFINING PARTICULATES

• Solid and liquid matter such as
• Dusts-particles rendered airborne during crushing
  or grinding of rock-like material
• Fumes-airborne solid particles formed above
  molten metal
• Mists-droplets rendered airborne by bubbling,
  boiling, spraying or splashing
• Smokes-particles resulting from incomplete
  combustion of organic matter

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THE HAZARD POTENTIAL OF AIRBORNE PARTICULATES

• Determined by
• Chemical composition
• Mass concentration
• Size characteristics

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SIZE CHARACTERISTICS OF AIRBORNE PARTICULATES

• Determine the
• deposition site in
• the respiratory
• tract. Smaller
• particles will tend
• to deposit deep into
• the gas exchange
• region of the lung.

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SIZE-SELECTIVE EXPOSURE GUIDELINES

• To more appropriately assess the possible
• health effects of airborne particulate matter,
• exposure guidelines have been
• issued for different sizes of particles.

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TRADITIONAL PARTICULATESIZE-SELECTIVE CRITERIA

• Total Dust

• Respirable Dust

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TOTAL DUSTDEFINED

• Dust that is captured onto a 37-mm filter loaded
  into a cassette and connected to a sampling pump
  calibrated to a flow of at least 1 L/min.
• The filter should be of a type and pore size
  appropriate to the particulate being sampled.
• Samples are collected in an area or in the
  breathing zone of workers.

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TOTAL DUST SAMPLINGIN THE BREATHING ZONE
INLET
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TYPES OF FILTER MEDIAMIXED CELLULOSE ESTER

• APPLICATION
• Asbestos, Fibers
• 25-mm with Conductive Cassette
• Metals
• 37-mm with SAN Cassette
• Oil Mist (Mineral)

• ANALYSIS
• Cleared, Microscopic Analysis
• Digested, Atomic Absorption or ICP
• Infrared Spectrophotometry

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TYPES OF FILTER MEDIAPOLYVINYL CHLORIDE

• APPLICATION
• Particulates, Not Otherwise Classified
• Silica
• Chromic Acid and Hexavalent Chromium

• ANALYSIS
• 2-hour equilibration, weighing
• X-Ray Diffraction or Spectrophotomery
• Visible Absorption Spectrophotometry or Ion
  Chromatography

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TYPES OF FILTER MEDIAGLASS FIBER/QUARTZ

• APPLICATION
• Pesticides
• Coal Tar Pitch Volatiles, Selected PAHs
• PCBs
• Mercaptans, Isocyanates and more when coated

• ANALYSIS
• Gas Chromatography
• High-Performance Liquid Chromatography
• (HPLC)

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TYPES OF FILTER MEDIAPTFE

• APPLICATION
• Select PAHs
• Ambient particulates

• ANALYSIS
• HPLC
• Gravimetric

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CLOSED-FACE VS OPEN-FACE SAMPLING WITH CASSETTES

• Closed-face sampling refers to sample collection
  with the inlet piece of the filter cassette in
  place.
• Open-face sampling refers to sample collection
  with the inlet removed. This approach is used
  for asbestos using 25-mm conductive cassettes.

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RESPIRABLE DUSTDEFINED

• Also collected onto a filter of a type and pore
  size that is appropriate for the particulate
  being sampled (typically PVC filters).
• Preceding the filter, however, is a particle
  size-selective device, typically a cyclone, that
  will separate the respirable fraction from the
  non-respirable fraction when connected to a pump
  sampling at the designated flow rate.

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CYCLONES

• Named for the rotation of air within a chamber
• Function on the same principle as a centrifuge
• Use rapid circulation of air to separate
  particles according to their aerodynamic diameter

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WHY USE A CYCLONE?

• Some chemicals are regulated as respirable dust
  and cyclones enable collection of the respirable
  fraction.
• Collecting larger, non-respirable particulates
  would inflate results of sample, overestimating
  exposure.

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CYCLONE OPERATION

• Air enters through a slit on the side of the
  cyclone which creates cyclonic action.
• Large particles fall into red grit pot and are
  discarded.
• Small particles are thrown onto the filter for
  analysis.

Red cap must be in place.
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50 CUT-POINTA PERFORMANCE SPECIFICATION

• The 50 cut-point is often used to describe the
  performance of size selective samplers.
• It is the particle size that the device can
  collect with 50 efficiency.

• Particles smaller than the 50 cut-point of the
  cyclone are collected with an efficiency greater
  than 50.
• Larger particles are collected with an efficiency
  less than 50.

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DIFFERENT CYCLONE OPTIONS

• All cyclones are not created equal!
• Each cyclone has different operating
  specifications and performance criteria.
• Be sure you know the flow rate specified to
  achieve the desired cut-point before using a
  cyclone.

85
CYCLONES AND AGENCY METHODS

• Currently, the only cyclone that OSHA inspectors
  can use is the nylon Dorr-Oliver at 1.7 L/min.
• The NIOSH method for respirable dust specifies
  the use of three cyclone options including the
  SKC aluminum cyclone at 2.5 L/min.

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NEW PARTICULATESIZE-SELECTIVE CRITERIA

• Adopted by many Global Occ
• Hygiene Agencies including ACGIH
• Inhalable Particulate Mass
• Thoracic Particulate Mass
• Respirable Particulate Mass

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INHALABLE PARTICULATEINTRODUCTION

• The new total. Term used to describe
  particulate matter that is hazardous when
  deposited anywhere in the respiratory system.
• This includes particulate matter that enters the
  head airways region including the nose and mouth.
• Also includes materials that can produce systemic
  toxicity from deposition anywhere in the
  respiratory system.

89
INHALABLE SAMPLERS

• Defined as having a 50 cut-point of 100 microns.
  
• Traditional filter cassettes do not effectively
  capture inhalable particulate matter.

• The efficiency of filter cassettes falls to zero
  with particle sizes of 30 um and larger.
• Of additional concern are sample losses that
  occur from particles that adhere to the interior
  cassette walls.

90
INHALABLE SAMPLERSDESIGNED FOR THE NEW CRITERIA

• The first personal sampler specifically designed
  for inhalable particulate mass was developed by
  Mark and Vincent in 1986 at the Institute of
  Occupational Medicine in Scotland.
• The sampler was named the IOM sampler and SKC
  Ltd. in the UK was the sole licensee and
  exclusive manufacturer of this sampler for more
  than 20 years.
• The patent has now expired, but SKC is still the
  only company that can call this device the IOM
  Sampler.

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IOM SAMPLERA GOLD STANDARD
Exploded View
SKC 225-70A
92
USING THE IOM SAMPLERGRAVIMETRIC ANALYSIS

• Load a 25-mm filter into the cassette using
  forceps and wearing gloves.
• Do not desiccate the filter/cassette.
• Equilibrate the filter/cassette assembly
  overnight under controlled humidity conditions
  then weigh them as a unit.
• Allow the assembly to stabilize a few minutes
  before taking a reading.

93
USING THE IOM SAMPLER GRAVIMETRIC ANALYSIS

• Place the IOM cassette/filter assembly into the
  sampler body, screw on the cover cap, and connect
  to the pump.
• Calibrate the flowrate to 2 L/min using the IOM
  calibration adapter or by placing in a
  calibration jar.
• Following sample collection, weigh the
  cassette/filter assembly again.

94
INHALABLE SAMPLERSBUTTON SAMPLER

• Alternative to the IOM sampler for inhalable
  particulates
• Inlet has a screen to keep large particles from
  landing onto the filter by blasting, splashing,
  or other inadvertent actions.

SKC 225-360
95
SAMPLE COLLECTIONWITH BUTTON SAMPLER

• A 25-mm filter is pre-weighed and loaded onto the
  stainless steel screen.
• The sample is collected at 4 L/min.
• The sample is weighed again after sample
  collection to determine exposure levels.

96
THORACIC PARTICULATEINTRODUCTION

• Materials that are hazardous when deposited
  anywhere within the lung airways and the
  gas-exchange region.
• Thoracic samplers have a 50 cut-point of
• 10 um.

97
THORACIC SAMPLERSOPTIONS

• SKC offers an impaction based sampler for
  thoracic particulate called the Parallel Particle
  Impactor or PPI.
• The thoracic PPI is used with a suitable
• 37-mm filter at a flowrate of 2.0 L/min.

SKC 225-381
U.S. Patent No. 7,073,402
98
PARALLEL PARTICLE IMPACTORHAS 4 INLETS OF
DIFFERENT SIZES

• Each impactor consists of an inlet nozzle and
  exit orifice that are appropriately sized to
  achieve a designated cut-point.
• The performance of each impactor matches part of
  the collection efficiency curve so that the
  overall performance closely matches the entire
  curve.

Inlet
Impaction Plate
Exhaust with Final Filter
99
THORACIC SAMPLERSAPPLICATIONS

• Thoracic TLVs
• Sulfuric Acid
• Cotton Dust

• NIOSH Methods
• NIOSH Method 5524, for metalworking fluids
  specifies a
• 2-um PTFE filter in a
• 37-mm filter cassette with an optional thoracic
  particulate cyclone.

100
DEFINING RESPIRABLE

• Throughout the history of occupational air
  sampling, several definitions of respirable
  particulate matter have been proposed by
  different organizations in various countries.
• The main difference in the definitions is the 50
  cut-point i.e. what size of dust is considered
  respirable.

101
SPECIFICATIONS FOR RESPIRABLE DUST SAMPLERS

• The British Medical Research Council (BMRC)
  originally specified samplers with a 50
  cut-point of 5 microns.
• In the US, government agencies including
  OSHA/MSHA specify samplers with a 50 cut-point
  of 3.5 microns.

102
SPECIFICATIONS FOR RESPIRABLE DUST SAMPLERS

• To reach world-wide
• consensus on the
• use of respirable
• dust samplers, a
• compromise spec
• was developed with a
• 50 cut-point of
• 4 microns.

• ACGIH and NIOSH have adopted this compromise
  spec.
• OSHA and MSHA require a change to the federal
  regulation to make this change from 3.5 to 4.0 um
  cut-point.

103
RESPIRABLE DUST

• Conflict and confusion
• in the USA
• NIOSH ? OSHA
• 50 cut-point of respirable samplers

104
CYCLONES LISTED IN CURRENT NIOSH METHODS

• Nylon
• at 1.7 L/min

• Higgins-Dewell
• at 2.2 L/min

105
CYCLONES LISTED IN CURRENT NIOSH METHODS

• Aluminum
• at 2.5 L/min

• Each cyclone has different operating
  specifications and performance criteria.
• Be sure you know the flow rate specified to
  achieve the desired cut-point before using a
  cyclone.

SKC 225-01-02
106
TIPS FOR SAMPLING WITH SKC Al OR GS CYCLONES

• Prepare 3-piece filter cassette.
• Place cyclone into middle ring.
• Calibrate the pump with sampler in line.
• Take sample at specified flow rate.
• Remove filter cyclone from sample train.
• Replace inlet piece and send filter cassette to
• the laboratory for analysis.

107
TIPS FOR CALIBRATION

• Calibration adapter
• The Aluminum cyclone has a calibration chamber
  that fits over the stem of the cyclone which
  allows standard tubing to be attached for
  connection to the pump calibrator.

SKC 225-01-03
108
TIPS FOR CALIBRATION

• Calibration Jar

Calibration jars can also be used. But do not
use an extremely large jar with the piston style
calibrators. The dead volume in the jar can
affect the rise/fall of the piston causing the
readings to be erroneously low!
SKC 225-111
109
TIPS FOR CALIBRATION

• Consider the jarless calibration method when
  using piston-style primary calibrators.
• Attach cyclone to calibrator pressure port and
  pump to suction port.

110
POST-SAMPLE CLEANING

• After sampling, clean all parts of the cyclone,
  with mild soapy water
• Dont forget to clean the grit pot.
• Dry the cyclone. (Air-dry or blow-dry)
• Wipe with a dust-free tissue or wipe with an
  isopropyl alcohol moistened pad.
• Caution Do not use strong solvents to clean
  plastic cyclones

111
THANK YOU FOR YOUR ATTENTION!

• Email
• skctech_at_skcinc.com
• with
• any technical
• questions.

www.skcinc.com