Met One GT-521 Dual-Channel Laser Particle Counter
| Brand | Met One |
|---|---|
| Origin | USA |
| Model | GT-521 |
| Instrument Type | Handheld |
| Flow Rate | Low-flow (2.83 L/min) |
| Flow Accuracy | ±1% of full scale |
| Timing Accuracy | ±1 second per hour |
| Repeatability | ≤±1% RSD |
| Size Channel Resolution | Two simultaneous channels (0.3 µm and 0.5 µm) |
| Counting Efficiency | ≥50% at 0.3 µm, ≥100% at ≥0.5 µm (per ISO 21501-4) |
| Data Storage | Internal memory for up to 1,000 sample records |
| Power Supply | Rechargeable Li-ion battery (up to 8 hours continuous operation) |
| Interface | RS-232 serial output |
| Compliance | ISO 21501-4, JIS B 9921, ASTM F328 |
Overview
The Met One GT-521 is a handheld, dual-channel laser particle counter engineered for real-time airborne particulate monitoring in cleanrooms, pharmaceutical manufacturing environments, HVAC validation, and controlled laboratory settings. Utilizing a proven 650 nm diode laser light source and forward-scatter detection optics, the GT-521 measures particles via single-particle optical sensing (SPOS) principles. Its dual-channel architecture enables concurrent counting of particles ≥0.3 µm and ≥0.5 µm—providing immediate insight into sub-micron contamination trends without requiring post-processing interpolation. Designed to meet the metrological rigor of ISO 21501-4, the instrument delivers traceable, reproducible data essential for ISO 14644-1 classified environments and FDA-regulated facilities where particulate control is critical to product quality and process validation.
Key Features
- Dual simultaneous size channels: 0.3 µm and 0.5 µm thresholds, enabling granular assessment of fine particulate generation or filtration breakthrough
- Low-flow sampling at 2.83 L/min (0.1 CFM), optimized for extended battery life and minimal disturbance to laminar airflow during point-of-use testing
- High-reliability optical system with integrated zero-count verification and automatic background compensation
- User-configurable sampling parameters: programmable duration (1 sec–24 hr), interval timing (1 sec–24 hr), and auto-start triggers
- Internal non-volatile memory stores up to 1,000 complete sample records—including timestamp, location ID, channel counts, and environmental metadata (when paired with optional G3120 probe)
- RS-232 serial interface supports direct connection to PCs or PLC-based monitoring systems; compatible with Met One’s legacy data management software suite
- Robust industrial enclosure rated IP54 for dust resistance and incidental water exposure during field deployment
Sample Compatibility & Compliance
The GT-521 is validated for use with ambient air, compressed gases (dry, oil-free), and filtered process air streams. It is not intended for high-humidity (>80% RH), corrosive, or explosive atmospheres. All calibration and performance verification are traceable to NIST-traceable polystyrene latex (PSL) reference standards. The device conforms to ISO 21501-4:2018 for light-scattering airborne particle counters and satisfies the minimum requirements of JIS B 9921 and ASTM F328-98 (reapproved 2022) for cleanroom monitoring instrumentation. When operated under documented procedures and logged with audit-ready timestamps, GT-521 data supports GLP/GMP compliance and 21 CFR Part 11 readiness when paired with validated software and electronic signature workflows.
Software & Data Management
The GT-521 interfaces with Met One’s legacy Windows-based data analysis software (v3.x), which enables batch export to CSV or Excel, statistical summary reports (mean, standard deviation, UCL), and ISO 14644-1 classification mapping. Raw data files retain full metadata including instrument serial number, calibration date, operator ID, and sampling configuration—supporting full data integrity and ALCOA+ principles. While the GT-521 itself does not feature onboard Wi-Fi or cloud connectivity, its RS-232 output can be integrated into third-party SCADA or MES platforms via protocol converters. Firmware updates are performed offline using the supplied utility and require no internet connection—ensuring secure, air-gapped maintenance in regulated environments.
Applications
- ISO Class 5–8 cleanroom certification and routine surveillance per ISO 14644-1 and EU GMP Annex 1
- Filter integrity testing (HEPA/ULPA) through upstream/downstream challenge comparisons
- Personnel gowning qualification and procedural compliance audits
- Pharmaceutical aseptic processing line monitoring (fill-finish, isolator, RABS)
- HVAC system commissioning, balancing, and requalification
- Microelectronics fabrication environment baseline characterization
- Research-grade aerosol behavior studies in controlled test chambers
FAQ
What is the minimum detectable particle size?
The GT-521 detects particles ≥0.3 µm with ≥50% counting efficiency and ≥0.5 µm with ≥100% counting efficiency, as verified per ISO 21501-4.
Can the GT-521 operate continuously for extended periods?
Yes—its rechargeable lithium-ion battery supports up to 8 hours of continuous sampling at 2.83 L/min flow rate, with low-power sleep mode extending standby time to 72 hours.
Is external environmental sensor integration supported?
Yes—the optional G3120 plug-and-play probe provides real-time temperature and relative humidity readings, automatically synchronized and embedded in each sample record.
Does the GT-521 require annual recalibration?
Per ISO 21501-4 and industry best practice, we recommend annual verification against traceable PSL standards; full recalibration is required if performance drift exceeds ±5% on reference aerosol challenges.
Can data be exported in compliant formats for regulatory submissions?
Yes—CSV exports include all raw channel counts, timestamps, and instrument metadata; when used within a validated software workflow, outputs satisfy FDA 21 CFR Part 11 documentation requirements for electronic records.
