1. RESPIRABLE DUST SAMPLERS DEFINITIONS, CRITERIA, AND OPTIONS
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2. RESPIRABLE DUST DEFINED
Respirable dust (or more generally respirable particulate matter) consists of small particles which may penetrate down to the lower gas exchange region of the lung and contribute to lung disease.
Samplers designed to collect only the respirable fraction of airborne particulate matter should be used when the target compound has an established exposure limit issued as respirable dust.
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3. WHY USE A RESPIRABLE DUST SAMPLER?
Ultimately, respirable dust samplers are used because that is what is specified in government agency methods.
Technically, size-selective respirable dust samplers enable separation and collection of the respirable size fraction from the dust cloud.
Collecting larger, non-respirable particulates would inflate results of the sample, overestimating exposure.

4. PERFORMANCE CRITERIA FOR RESPIRABLE DUST SAMPLERS
Most organizations and standard setting bodies in occupational health and safety around the world have adopted the performance criteria specified in ISO 7708.
ISO 7708 is also known as the ISO/CEN convention.
ISO=International Standards Organization.
CEN=Committee for European Normalization.

5. PERFORMANCE CRITERIA FOR RESPIRABLE DUST SAMPLERS
In the U.S.A., ISO 7708 has been adopted by ACGIH and is described in the TLV booklet.
U.S. NIOSH also specifies ISO performance criteria in their respirable dust methods.
U.S. OSHA has adopted ISO 7708 in the final rule on respirable crystalline silica.

6. WHAT IS THE ISO 7708 CRITERIA FOR RESPIRABLE DUST SAMPLERS
The performance criteria is essentially a collection efficiency curve that specifies the efficiency of the sampler for particles of designated sizes.

7. A FREQUENTLY USED SPECIFICATION: 50% CUT-POINT
The 50% cut-point is the particle size that the sampler collects with 50% efficiency.
Looking at the ISO curve shown, you can see that the size of dust that the samplers must collect with 50% efficiency is 4 um.
Particles smaller than 4 um are collected with an efficiency greater than 50%.

8. TRADITIONAL RESPIRABLE DUST SAMPLERS: CYCLONES
Function on the same principle as a centrifuge
Use rapid circulation of air to separate particles according to their aerodynamic diameter when connected to a sampling pump at the designated flowrate.

9. 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) at the bottom and are discarded.
Small particles are thrown up onto the filter for analysis.
Cap (grit pot) must be in place during sampling.

10. CYCLONES AVAILABLE FROM SKC
Aluminum Cyclone
Meets ISO/CEN criteria at a flowrate of 2.5 L/min
Eliminates adverse electrostatic effects
Listed in OSHA final rule on silica
Listed in NIOSH Methods for respirable dust and respirable crystalline silica
SKC /02

11. CYCLONES AVAILABLE FROM SKC
GS-3 Cyclone
Conductive plastic
Eliminates adverse electrostatic effects
Not a spark hazard for underground mines
Multi-inlet design overcomes orientation bias
Listed in OSHA proposed rulemaking on silica
Meets ISO/CEN criteria at flows of 2.75 L/min

12. 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 MSHA requirements
SKC /103

13. CYCLONES AVAILABLE FROM SKC
SKC PLASTIC CYCLONE
Manufactured at SKC Ltd. in the UK
Widely used in Europe, Australia, and New Zealand
Available in 25- or 37- mm options for use at 3.0 L/min (flowrate changed in 2018)
225-69

14. IMPORTANT NOTE ON FLOWRATE
All cyclones are not created equal!
Be sure you know the flow rate specified for the cyclone being used.
If you use the wrong flowrate, your data is meaningless.

15. TIPS FOR SAMPLING WITH SKC AL OR GS CYCLONES
Load filter into a 3-piece filter cassette.
Remove entire inlet piece and place cyclone into
middle ring of cassette.
Calibrate the pump with sampler in line.
Take sample at specified flowrate.
Remove sampler from the worker and remove
cyclone from filter cassette being careful not to invert.
Recap with inlet and send filter to lab.
Clean cyclone with soap/water before reuse.

16. TIPS FOR CALIBRATION SKC Aluminum Cyclone
A handy calibration adapter fits over the cyclone and allows standard tubing to be attached for connection to the pump calibrator.
The calibration adapter fits both the 25-mm and the 37-mm aluminum cyclones.
SKC
(37-mm)
SKC

17. TIPS FOR CALIBRATION SKC 225-111/112 Calibration Jar
The SKC GS cyclones and the nylon Dorr- Oliver cyclones (not sold by SKC) do not have a calibration adapter.
In this case, you will need to place the cyclone into a calibration jar to measure the flowrate.

18. 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

19. A NEW RESPIRABLE DUST SAMPLER FROM SKC
SKC has developed a new impaction based sampler for respirable dust called the Parallel Particle Impactor or PPI.
The PPI is available in reusable aluminum or disposable plastic.

20. SKC RESPIRABLE PPI: FUNCTIONALITY
The disposable models of the PPI look very much like a traditional 37-mm cassette.
But the inlet comes pre-loaded with size-selective impactor plates that scrub out the larger non-respirable dust.
The smaller respirable dust is collected onto the PVC filter for analysis as usual.
SKC calls this sampler a Paralled Particle Impactor or PPI and here you can see the operating principle.
Read bullets.
Note that you are NOT concerned about how much particualte is collected at each of the individual inlets, but only what is collected on the final filter.
This is a precise match to the current collection efficiency curves.

21. SKC RESPIRABLE PPI: FLOWRATE OPTIONS
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.
2 L/min:
8 L/min:
4 L/min:

22. PPI SAMPLER PERFORMANCE COMPARED TO ISO CRITERIA

23. MORE PPI ADVANTAGES: CONVENIENCE
A handy calibration adapter is available to attach the PPI to the calibrator (flowmeter).
No calibration jar is needed.

24. MORE PPI ADVANTAGES EASE OF USE
No tipping hazard. You can invert the sampler without causing large particles to land on the filter invalidating the sample.

25. THANK YOU FOR YOUR INTEREST
Please visit the SKC website for more training options and details on SKC samplers.
with questions or contact your local SKC representative.