Sass 4000 aerosol concentrator

SASS® 4000 is a concentrator of biological aerosols present in large volumes of air. It concentrates the biological particles in 10% of the sampled volume (4000 liters/ minute), so that another biocollector such as the Sass 2300 or the Sass 3100 connected to the Sass 4000 can collect them

Sass 4000

A biological environmental or epidemiological  investigation of air, or during a removal of doubt of the NRBC teams of the Police or Firebrigades must allow to find a biological agent in diffused presence whether release accidentally or voluntarily.

But the biocollection of aerosol samples in outdoor or large indoor areas faces several problems.:

  •  The biological agent is present in very low concentration dispersed in large volumes of air
  •  The low volume of air sampled by classic air samplers are not representative of the sampling site leading to false conclusions.
  •  The analytical screening method requires a sufficient concentration of the targeted pathogen to detect it, but the amount collected is unsufficient and leads to false negatives .

SASS 4000 is the only biological aerosol preconcentrator available on the market able to overcome these limitations of bioaerosol containing a biological agent in diffuse presence.


  • No moving parts other than the primary fan.
  • Minimum maintenance.
  • Very wide operating temperature range.
  • Particularly resistant to clogging.
  • Maximized sampled air volume
  • Activated Sludge of Wastewater treatment plants
  • Underground Sewage systems
  • Public transportation air quality
  • Veterinary Epizooties
  • Human disease outbreaks
  • Nuclear or radiological incidents
  • Hospital or clinical nosocomial investigations
  • Health and safety at work.
  • Civil Defense (Nrbc Police & Firebrigades teams)  

How does the Sass 4000 aerosol concentrator work?

A concentrator treats large volumes of ambient air, continuously transferring particles from a primary air stream to a much smaller secondary air stream (see diagram on the left).

As a result, the secondary air stream can reach aerosol concentrations from 4 to 15 times higher concentration than original particle concentration in the incoming air stream. The concentrator amplifies the ambient aerosol concentration, while keeping in the secondary stream most of the particles that were present in the incoming air stream.

Particles are conveyed into the secondary flow by forcing air from the primary air stream to flow through specially shaped channels where centrifugal force and particle momentum are used to isolate and concentrate particles.

The internal structure of the Sass 4000 has been designed so that the smallest flow section has a 0.6 mm wide x 6.35 cm long channel, providing good resistance to clogging by larger particles.

A coarse screen with 5.4 mm square openings limits entry of large debris.


Air flows radially into the concentrator through the square mesh screen. This radial inward flow allows for a 360 degree sampling of the surrounding aerosol environment.

The quick-release tripod supplied as standard with the Sass 4000
allows the preconcentrator section to be placed at a height between
0.6 m to 1.43 m above the tripod.

The primary fan and a curved air hood are mounted above the concentrator
the concentrator, channeling exhaust air in a vertical flow away from the
inlet air zone.

Air from the secondary concentrator is available at a spline fitting nominally designed for a 3.8 cm I.D. hose. This allows the discharged aerosol concentrate to be delivered with minimal hose length to a dosing system or biocollector that is located on the floor below the concentrator.

We recommend that the aerosol concentrate be delivered to its destination using a smooth-surfaced tube of at least 3.5 cm ID and a length of no more than 3 meters – 2 meters being preferable.

Any sudden change in the cross section of the aerosol tube should be minimize particle loss from the tube wall and excessive pressure drop. The radii of curvature of the tube should also be as large as possible
possible to minimize secondary circulation patterns and particle collisions with the tube wall.


The particle concentration process takes place mainly inside 20
rectangular collection “blades” that slide into slots which slide into
radial slots in the main structure.
These blades are precisely shaped to the desired form using using state-of-the-art CNC machining centers.

This manufacturing method ensures that air moves as intended through the
inner channels and minimizes particle loss due to collision with  the
walls, while minimizing the overall pressure difference required to push
the air through the device.

Sass diagramm
Airflow pattern of the Sass 4000 connected to Sass 2300 air sampler
Lamelles du Sass 4000

Graph on the right: shows typical data for concentration factor as a function of particle size for a primary air flow of about 3000-3600 LPM and secondary air flow of 300 LPM. This Figure is based on tests that used fluorescent polystyrene microspheres (density=1.05 g/cc) and fragments thereof, as test particles. Concentration factors were determined from multiple test runs using a Met One 200L laser particle counter.

The Figure shows that aerosols of this density and with
effective optical diameters in the range of 0.5 to 1.0 microns were concentrated by a factor of 3X to 4X. Particles in the range of 1.0 to 2.0 microns were concentrated by a factor of 4X to 5X, while larger respirable particles were concentrated by a factor of about 6X.

Particle concentrations in the secondary flow of airsampler (here Sass 3100) connected to a Sass 4000 preconcentrator, can be further enhanced by reducing the secondary airflow (red line), as shown  on the figure on the right

For example, at a secondary airflow of about 40LPM, the concentration factor is increased by about 3X relative to operation at 300 LPM. However, please note that the total amount of particulate matter collected (blue line) begins
to fall substantially for secondary airflows below about 200 LPM.

Reduced airflow can be of significant value if the detection method requires small amounts of fluid.

For example, Research International’s standard air sampler, the SASS 2300 , has an airflow of about 300 LPM when connected to the SASS 4000 Concentrator, and operates with a water inventory of about 5 ml. The SASS 2400 , however, which has a nominal airflow of 40 LPM, has a liquid inventory of only about 1 ml. Hence, the Mini-SASS may show a concentration increase of about 15X for this example case, as compared to 5X for the SASS 2300.

However, the total amount of particulates collected within a fixed period by the Mini-SASS may be only 40% of that collected with the larger wet sampler. Which overall collection strategy is best will depend on application specifics.

Taux de concentration d'aérosol d'un biocollecteur connecté au Sass 4000 en fonction de la taille des particules et de la vitesse d'air aspiré par le Sass 4000
Impact of secondary flow rate of the Sass 3100 connected to the Sass 4000 on the concentration rate and the total number of particles collected.

Primary airflow:  4,000 liters/min is sampled uniformly from around the pre-concentrator’s circumference.

Secondary airflow:          30–360 LPM at +0.4 cm of water static head maximum; aerosol concentrate typically delivered to a wet or dry sampler such as the SASS 2300 or SASS 3100, respectively.

Aerosol range: Aerosols greater than 0.5 microns in diameter at a particle density of 1.0 g/cc.

Secondary airflow connection: Hose barb fitting on base surface for nominal 3.8 cm ID hose.

Concentration enhancement:    4–15 times typical for aerosols greater than 0.5 microns in size. Performance also influenced by secondary airflow- request specific data for your application.

Overall size:       38 cm high x 25.4 cm diameter max.

Weight:               6.32 kg (13.9 lbs.)

Operating temperature range: -40°C to 70°C

Power consumption:          160 watts at 24VDC; brushless drive motor with 70,000 hour life at 40°C.

    100 to 230 VAC lump-in cord AC/DC converter supplied.

Sound level:       72 dBA @ 1 meter radius on inlet equatorial plane.

Mounting:          Quick-detach tripod legs; 0.53m to 1.46m adjustable height.

Accessories:       Hard shell carrying case.

  • SASS® 4000 Concentrator includes:

power supply + user’s manual

Ref: 7000-165-201

Shock-proof carrying case for Sass 4000 with custom-cut foam insert.

Ref.: 7100-163-400-03

Adapter hose to connect the SASS 4000 to the Sass 3100 biocollector.

Ref: 7100-165-230-01

Sass 4000 adapter plate for electret filter
Ref: 7100-163-160-01

Particle extractor SASS 3010
Ref.: 7000-162-100-07


  • SASS 3010 extractor
  • Two (2) D batteries
  • User’s manual

Autoclavable manual particle extraction kit

Ref.: 7000-170-100-01

Standard welded electret filter:

P/N: 7100-134-230-04

Welded HEPA electret filter

P/N: 7100-134-231-01

Welded electret filters are recommended when using the SASS 3010 particle extractor

Standard electret filter with removable support:
Ref.: 7100-134-232-01

HEPA electret filter with removable support:
Ref: 7100-134-233-01

Extraction kit for SASS 3010

Ref: 7000-162-134-02


  • (1) standard welded electret filter
  • (1) 8 ml bottle of extraction reagent
  • (1) 14 ml bottle of Sass 3100 leaching reagent

Shelf life: 2 years from date of manufacture.

Bottle of extraction reagent SASS 3010

  • Ref : 7000-162-133-08 (8 ml)
  • Ref : 7000-162-133-125 (125 ml)

Shelf life: 2 years from date of manufacture.

SASS 3010 washing reagent bottle
Ref : 7000-162-132-08 (15 ml)

Shelf life: 2 years from date of manufacture.

Portable power station. P/N: 7000-163-450-02

Provides a mobile power source for instruments without built-in batteries and extends the operating time of battery-powered devices. Contains two lithium-ion batteries, P/N: 1000-0003-12 (not included).

Does not include charging capability; please purchase chargers separately (P/N: 1000-0003-13).

Adapter cable for portable power station. P/N: 7200-163-105-01

Required for use of the portable power station with SASS 2300, SASS 2400, SASS 3100, TacBio or Tac-7 instruments.

Not required for SASS 4000 series instruments.

15V Lithium Ion rechargeable battery.
Ref: 1000-0003-12

*Note on battery shipping: In accordance with IATA dangerous goods regulations, the batteries we offer are classified as hazardous and are subject to special shipping procedures. For orders shipped within Europe, batteries must be shipped by ground.

For international orders, batteries will be shipped separately from the rest of your items by a third party shipping service. All shipping, handling, duties and taxes (if applicable) will be added to your final invoice.

Lithium Ion battery charger.

Ref: 1000-0003-13

Rechargeable 15V Lithium Ion Battery
Sass 4000 + power supply + User's manual
Sass 4000 shockproof carrying case
SASS 4000 to 3100 Hose Assembly
SASS 4000 Electret Filter Adapter Plate
SASS 3010 Particle Extractor
Electret Filter Cartridge Assembly, Welded (standard or HEPA)
Electret Filter Cartridge Assembly, removable (standard or HEPA)
Portable power station
Adapter cable for power supply station.
Charger for Lithium Ion Battery