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RESPIRABLE DUST SAMPLERS
Presented by
www.skcinc.com
THE HAZARD POTENTIAL OF AIRBORNE PARTICULATES
Determined by: Chemical composition Concentration in air Size characteristics
SIZE CHARACTERISTICS OF AIRBORNE PARTICULATES
Determine the
deposition site in
the respiratory
system and the
ultimate health
effects for exposed
individuals.
SIZE-SELECTIVE EXPOSURE LIMITS AND GUIDELINES
To more appropriately assess the possible
health effects of airborne particulate
matter, occupational exposure limits and
guidelines including the Threshold Limit
Values (TLVs®) have been issued for
different sizes of particles.
RESPIRABLE DUSTDEFINED
The TLV booklet defines respirable particulate matter as those materials that are hazardous when deposited in the gas-exchange region of the lung.
Samplers designed to collect only the respirable fraction of airborne particulate matter should be used when the target compound has an established limit issued as respirable dust.
WHY USE A RESPIRABLE DUST SAMPLER?
Size-selective respirable dust samplers enable separation and collection of this specific size fraction from all the suspended particulates in air.
Collecting larger, non-respirable particulates would inflate results of the sample, overestimating exposure.
SPECIFICATIONS FOR RESPIRABLE DUST SAMPLERS
Performance specifications for respirable dust samplers have been issued by various scientific organizations and standard setting bodies throughout the world.
The performance specifications are issued as collection efficiency curves that specify the efficiency of a dust sampler for particles of designated sizes.
50% CUT-POINT:A PERFORMANCE SPECIFICATION
The 50% cut-point is often used to describe the performance of respirable dust samplers.
It is the particle size that the sampler 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%.
CURRENT SPECIFICATIONS
Most organizations involved in occupational hygiene now recommend the use of respirable samplers designed to meet the specifications in ISO Standard 7708:1995.
This ISO standard has already been adopted by ACGIH, CEN, and NIOSH. U.S. OSHA has proposed adoption of this ISO Standard in their 2013 notice of proposed rulemaking for respirable crystalline silica.
CURRENT SPECIFICATIONS
The ISO standard for respirable dust samplers specifies the collection efficiency curve for respirable dust samplers.
This curve includes a 50% cut-point of 4 um. This is a more conservative curve than the
existing U.S. OSHA/MSHA regulations that specify a collection efficiency curve with a 50% cut-point of 3.5 um.
TRADITIONAL RESPIRABLE DUST SAMPLERS: CYCLONES
Named for the rotation of air within the chamber
Function on the same principle as a centrifuge
Use rapid circulation of air to separate particles according to their aerodynamic diameter
CYCLONE OPERATION Air enters through a slit on
the side of the sampler which creates cyclonic action.
Large particles fall into the cap (grit pot) and are discarded.
Small particles are thrown up onto the filter for analysis.
Cap must be in place.
CYCLONES AVAILABLE FROM SKC
Aluminum Cyclone Meets ISO/CEN criteria at
flows of 2. 5 L/min Eliminates adverse
electrostatic effects Specified in NIOSH
Methods for respirable dust and respirable crystalline silica
SKC 225-01-01/02
CYCLONES AVAILABLE FROM SKC
GS-3 Cyclone Conductive plastic Suitable for underground
mine use Eliminates adverse
electrostatic effects Multi-inlet design
overcomes orientation bias Listed in OSHA proposed
rulemaking on silica Meets ISO/CEN criteria at
flows of 2.75 L/min
CYCLONES AVAILABLE FROM SKC
GS-1 Cyclone Constructed of same
conductive plastic material as GS-3
Single inlet design serves as a Dorr-Oliver equivalent for existing U.S. OSHA/MSHA requirements
• Meets ISO/CEN criteria at flows of 2.0 L/min
SKC 225-100/103
CYCLONES AVAILABLE FROM SKC IN UK
Conductive Plastic
Cyclone Meets ISO/CEN criteria at
flows of 2.2 L/min Features a snap together
cassette Static dissipating
SKC 225-69/-37
IMPORTANT NOTE ON FLOWRATE
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 any cyclone.
TIPS FOR SAMPLING WITH SKC AL OR GS CYCLONES
Load filter into a 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. Recap and send filter to lab.
Clean cyclone before reuse.
TIPS FOR CALIBRATION
SKC Aluminum CycloneHas a handy calibration adapter that fits over the cyclone and allows standard tubing to be attached for connection to the pump calibrator.
The chamber fits both the 25-mm and the 37-mm aluminum cyclones.
SKC 225-01/2
SKC
225-01-03
TIPS FOR CALIBRATION Calibration Jar SKC 225-111/112
Very large jars are not recommended when calibrating with the piston-style primary calibrators like the Defender. The dead volume in the jar can affect the rise/fall of the piston causing the readings to be erroneously low!
TIPS FOR CALIBRATION Calibration Jar SKC 225-111/112
Use the smallest jar possible to contain the cyclone/filter assembly. SKC offers a calibration jar suitable for the SKC GS or other samplers of similar size.
TIPS FOR CALIBRATION Another option is the so-
called “jarless” calibration method when using piston-style primary calibrators.
Attach the pump only to the suction port and the cyclone/filter assembly to the other port on the calibrator. This will create the same pressure drop as the sampling train assembled in the field.
POST-SAMPLE CLEANING After sampling, clean all parts of the cyclone, with mild
soapy water Don’t 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
A NEW RESPIRABLE DUST SAMPLER FROM SKC
SKC has developed a new impactor based sampler for respirable dust called the Parallel Particle Impactor or PPI.
The PPI was designed to improve performance characteristics evidenced with older traditional cyclones.
PPI SAMPLERS FROM SKC
Specifically designed to precisely match the new criteria for respirable samplers specified in the ISO 7708 standard that is followed by most occupational hygiene organizations around the globe.
PPI SAMPLER PERFORMANCECOMPARED TO CRITERIA
0
25
50
75
100
1 10
Aerodynamic Particle Diameter, da, mm
Pene
trati
on, P
, %
Respirable PPI, 2.0 L/min
Respirable PPI, 4.0 L/min
Respirable PPI, 8.0 L/min
ISO/CEN Respirable Criteria
5
SKC RESPIRABLE PPI:FUNCTIONALITY
The disposable models of the PPI look and function very much like a traditional 37-mm cassette.
But the inlet comes pre-loaded with size-selective impactor plates that scrub out non-respirable dust.
PPI samplers are smaller than traditional cyclones and can fit under a welder’s helmet or other PPE.
SKC RESPIRABLE PPI:FLOWRATES
Single-use, disposable PPI models are available for use at either 2, 4, or 8 L/min.
This provides flexibility in pump options, sample duration, and concentration.
4 L/min: 225-387
8 L/min: 225-384
2 L/min: 225-385
IMPORTANT NOTES ON THE PPI
Disposable PPI samplers are available from SKC pre-loaded with designated filters or your lab can load the filters into the PPI.
Reusable PPI samplers made of aluminum are also available for those that want to assemble, clean, and reuse.
A calibration adapter is available for the PPI as SKC 225-389.
THANK YOU FOR YOUR INTEREST
Please visit the SKC website for more training options and details on SKC samplers.
Email [email protected] with questions or contact your local SKC representative.
www.skcinc.com