High Flow Respirable - Thoracic Cyclones


The GK2.69 Cyclone was originally developed as dual use cyclone for both Respirable and Thoracic personal sampling applications. It has significant advantages in both size ranges. Applications

As a Thoracic sampler the GK2.69 has been adopted by NIOSH in their Manual of Analytical Methods (NMAM) as part of Standard Number 5524 for sampling airborne concentrations of Metalworking Fluids (MWF). There is no other cyclone available which fulfills the requirements of the method.

 A stainless steel version has been introduced (below) for any purpose but principally to satisfy the desires of Canadian clients who have a Sulfuric acid sampling requirement.

Thoracic fiber sampling studies published in the istinguished Annals of Occupational Hygiene demonstrate that the GK 2.69 is superior for this application.

The cyclone is also seeing wide use for the measurement of PM10. Although EPA and NIOSH have differing definitions of Thoracic/PM10 they are fundamentally the same.

As a high (4.2 lpm) flow rate Respirable sampler it is frequently utilized for the sampling of silica dust to achieve more reliable sensitivities than the current 1.7 or 2.2 lpm flow rates normally utilized. To facilitate the informational requirements of investigators measuring Crystalline Silica to a standard of 0.05 mg/m3 we have determined that a sampling time of 3.17 hours is required. A spread sheet permitting the calculation of Method Sensitivity is directly available. 



Until 1994 the U.S. considered a D50 cut of 3.5 micrometers to be the respirable standard while the rest of the world used 5 micrometers.1, 2Since then, there is international agreement that 4 micrometers is the standard value for respirable particulates.3,4 Following on this recent intense interest in respirable sampling, criteria has been internationally established for thoracic and inhalable sampling. The thoracic curve has a D50 cut of 10 micrometers. The inhalable criteria state that 50% of the particulates are less then 100 micrometers.5

With the intensifying interest in size selective sampling, BGI has taken advantage of a recently presented scientific study to produce a dual function, size selective cyclone which will serve as a high flow respirable sampler or a normal flow thoracic sampler.6

A study of six personal thoracic samplers7 showed the GK2.69 to have the closest adherence to the thoracic curve and the least sampling bias. The cyclone has been widely used for the sampling of cutting fluid oil mist.

The instrument shown in the figure is known as the GK2.69. This nomenclature is the same as that used by the authors of the study and indicates the origin of the design model and the internal diameter of the cyclone, in centimeters. It is fabricated from aluminum and protected against wear and corrosion with an electroless nickel plated surface finish. Disposable 37 mm 3 piece cassettes are utilized for sample collection. For high flow respirable sampling, fiberglass or Gelman Teflo media are recommended. For normal flow thoracic sampling, the preceding media may be utilized or membranes, such as 5 micrometer PVC or 0.8 micrometer MCE.


Flow Rates

The D50 cut for respirable sampling is achieved at a flow rate of 4.2 Lpm. A thoracic curve flow rate is recommended at 1.6 Lpm. Both of these flow rates may be achieved with a variation of the BGI Personal Sampler, designated AFC123RT.

The performance curve at the left details real and extrapolated performance which may be of additional interest to investigators interested in exploring "cuts" other than respirable and thoracic.
Media Type
37 mm
Flow Rate
Pressure Drop
cm of H2O
GF/A Fiberglass
GF/A Fiberglass
GF/A Fiberglass
Gelman Teflo
Gelman Teflo
Gelman Teflo
0.8 micrometer MCE
0.8 micrometer MCE
0.8 micrometer MCE
*Flow media achievable with AFC123RT pump

Height 3.9 in (9.9 cm) 3.9 in (9.9 cm)
Width 1.6 in (5 cm) 1.6 in (5 cm)
Depth 2.0 in (5 cm) 2.0 in (5 cm)
Weight 3 oz (86 g) 6.3 oz (178 g)
Length/Suction Hose 42 in (1.06 m) 42 in (1.06 m)
Materials of Construction Anodized Aluminum 316 Stainless Steel

Ordering Information
Click on a part number to add that item to your Price Quote List. .
GK2.69 Respirable/Thoracic Cyclone (Anodized Aluminum)
GK2.69SS Respirable/Thoracic Cyclone (316 Stainless)
AFC123R/T Special Personal Sampler for above
BGI4.4 "O" Ring for Cassette 6/pkg.
BGI4.3 "O" Rings for Grit Pot 6/pkg.
GK2 Grit Pot
GK3 Replacement Tubing with Luer Adapter
GK4 "O" Ring for Top of Cyclone 6/pkg.
GK5 "O" Ring for Clean Out Plug 6/pkg.
AFC5 Luer Adapter
Alligator Clip w/ Screw & Washer
  1. American Conference of Governmental Industrial Hygienists (1964) Particle Size Selective Sampling in the Workplace. Pub. No. 0830 ACGIH, Cincinnati, OH.
  2. Hamilton, R.L.J. and Walton, W.H. (1961) The Selective Sampling of Respirable Dust. "Inhaled Particles and Vapors". (Ed. by Davies, C.N.) pp 465-475. Pergamon Press, Oxford.
  3. Maynard, A.D. and Kinney, L. Performance Assessment of Three Personal Cyclone Models using an Aerodynamic Particle Size. (1995), Journal of Aerosol Science (No. 4, Vol. 25).
  4. D.L. Bartley et al. Respirable Aerosol Sampler Performance Testing (1994), American Industrial Hygiene Assoc. Journal (No. 11, Vol. 55).
  5. Conference of Governmental Industrial Hygienists (1995-1996) Threshold Limit Values. p 47, ACGIH, Cincinnati, OH.
  6. L.C. Kinney and Gussman, R.A. Characterisation and Modelling of a Family of Cyclone Aerosol Preseparators (1997), Journal of Aerosol Science (No. 4, Vol. 28).
  7. A. Maynard. Measurement of Aerosol Penetration Through Six Personal Thoracic Samplers Under Calm Air Conditions (1999), Journal of Aerosol Science (No. 9, Vol. 30).