SASS® 3100

In a test¹ that compared the performance of ten different wet and dry portable sampling systems from different manufacturers at the U.S. Army’s Edgewood CB Center, the SASS 3100 was the top performer (Figure 1).

Ref. 1: Test Report, Technology Evaluation Readiness Evaluation 08-2, CBR Technology Evaluation Branch, Edgewood CB Center, U.S. Army RDECOM, December, 2008.

The capture element is a 44 mm diameter felt-like polymer disc with an electric field “frozen” into each fiber (electret media). These fields induce a charge in aerosols passing through the filter and provide a capture mechanism much more effective than impaction—up to 50× more efficient than conventional glass or cellulosic filters. The media is stable to 70 °C, is virtually inert, has a 10-year shelf life, and high holding capacity due to a large internal surface-to-volume ratio.

Collection efficiency versus particle diameter for polystyrene test beads shows that particles in the 0.3–0.5 µm range are captured with almost 50% efficiency; 1.0 µm and larger are captured at 80%+ (Figure 3).

Across the suggested 50–300 L/min sampling range, collection efficiency changes modestly (Figure 4). At 120 LPM, efficiency is ~92% for 0.5–5.0 µm particles. At 360 LPM, efficiency is ~78–79% for similar-size particles—but the total capture rate is higher at the greater flow.

Air velocities at the filter face are relatively low versus sieve impactors (≈3.5 m/s at 300 L/min vs. ~20 m/s typical in ISO 14698-1 impactors), providing gentler capture conditions for delicate microorganisms.

Over a 7.5-hour collection (≈140 million particles/cm² deposited, 0.9 µm polystyrene spheres), collection efficiency for 0.5–5.0 µm particles increased by ~20%, with a similar ~20% rise in pressure drop (Figure 5).

The capture disc can be processed in the SASS 3010 Manual Extractor for a liquid sample, or placed directly in a 50 mm petri dish for culture-based assay.

A brushless DC motor drives a centrifugal fan (expected life 30–40k hours). Power draw is ~8 W; noise is 45–61 dB(A) at 1 m. Peak acoustic level occurs ≈30° from the exhaust port (Figure 6).

Subsystems are controlled by an embedded microprocessor; operating characteristics such as fan speed and sampling behavior can be adjusted via Windows® software, over RS-232 (USB adapter optional) or optional RF wireless.

Compatible with BA-5590/U (primary, ~210 Wh) and UBI-2590 (rechargeable, ~250 Wh). Continuous run times are approximately 21 h and 25 h, respectively; standby (fan off) ~8.75 and 10.4 days. Software displays % capacity and voltage when connected. Universal AC supply supports 82–265 VAC, 47–63 Hz.

Electronics and battery are enclosed in a leak-tight extruded aluminum shell; the fan rotor projects from and is protected by the filter-mounting plate. Includes carrying handle and two ¼-20 female bosses (handle and base). Approx. 15 cm W × 17 cm L × 20 cm H; weight 1.8 kg.

Pull-through fan minimizes test-to-test contamination. Unit is designed for wash/spray with 5% bleach or gas-phase microbicide. The rotor housing separates via three finger-tight hold-downs; rotor may be sprayed/dunked in situ. Motor and electronics are sealed; motor/rotor service is straightforward if shaft seal ever needs replacement.

Standard DB-9 RS-232 connector; optional military CCSI-style available. RS-232→USB adapter and RF link are offered. Inlet/outlet accept air-tight tube adaptors for routed airflow (e.g., inside a vehicle). Contact us for application-specific fittings.

Create and store protocols on PC, run directly from PC, or download to the 3100 so it auto-runs when powered. Airflow set via slider or counts; set delays, fan-on time, pauses, cycle count, or target total air volume.

Auto Mode allows initial delay, per-cycle fan times, pauses, total cycles, and total air volume control. Cleaning routines can flood/circulate/pump to flush contaminants at cycle end.

The Operating Manual provides a set of ASCII commands (20+ for SASS 3100) to control or interrogate the sampler over the serial link for integration into proprietary systems.