AP Buck LP-20 Portable Constant-Flow Air Sampler
| Brand | AP Buck |
|---|---|
| Model | LP-20 |
| Flow Range | 5–20 L/min (constant-flow mode) |
| Accuracy | ±5% of setpoint (at <5 L/min, with APB-109030 controller) |
| Max Backpressure | 60" H₂O (15 kPa) |
| Power | Rechargeable NiCd battery pack (4.8 V, 1.0 Ah) |
| Operating Temperature | 0–40 °C |
| Dimensions | 11.4 × 10.2 × 5.0 cm (H × W × D) |
| Weight | 879 g |
| Inlet Port | 3/8" OD / 1/4" ID |
| Display | EZ-Backlit™ LCD with multilingual UI (English, Spanish, French) |
| Data Logging | Built-in sampling time, flow rate, and total volume tracking |
| Compliance | Designed for OSHA, NIOSH, and ISO 17025-aligned field sampling workflows |
Overview
The AP Buck LP-20 Portable Constant-Flow Air Sampler is an engineered solution for quantitative air sampling in occupational health, environmental monitoring, and industrial hygiene applications. Based on positive-displacement diaphragm pump technology with integrated closed-loop flow control, the LP-20 maintains a user-defined volumetric flow rate across variable backpressures—up to 60 inches of water column (15 kPa)—ensuring metrological consistency when sampling through adsorbent tubes (e.g., charcoal, silica gel), filter cassettes (including 25 mm, 0.45 µm membrane filters), cyclonic pre-separators, or impingers. Its constant-flow architecture eliminates manual recalibration during extended deployments, making it suitable for both personal (belt-mounted) and area-based sampling protocols compliant with NIOSH Manual of Analytical Methods (NMAM) and OSHA Sampling & Analytical Methods.
Key Features
- True constant-flow operation across 5–20 L/min range, with automatic flow compensation against filter loading and tubing resistance
- Robust diaphragm pump delivering high torque at low power draw—optimized for extended runtime on a single NiCd battery charge
- EZ-Backlit™ monochrome LCD interface supporting English, Spanish, and French—enabling intuitive configuration without external software
- Onboard data logging of cumulative sample volume, elapsed time, and real-time flow rate—exportable via serial interface for audit-ready reporting
- Rapid 1-hour recharge capability; intelligent battery management maintains operational control even at ≤10% state-of-charge
- Compact footprint (11.4 × 10.2 × 5.0 cm) and lightweight design (879 g) certified for field portability under ANSI Z88.2-2018 ergonomic guidelines
- Standardized 3/8″ OD inlet port compatible with NIOSH-approved sampling trains—including sorbent tubes, PM10/PM2.5 cyclones, and bioaerosol impactors
Sample Compatibility & Compliance
The LP-20 interfaces seamlessly with widely accepted air sampling media: 25 mm mixed-cellulose ester (MCE) or polyvinyl chloride (PVC) filters for particulate matter; glass or stainless-steel sorbent tubes packed with activated carbon or Tenax® TA for VOC collection; and Andersen-style or slit-to-agar impactors for viable airborne microorganisms. Its flow stability meets NIOSH Method 0500 (total dust), 5515 (formaldehyde), and ISO 16000-6 (indoor air VOCs) requirements. The device supports GLP-compliant workflows through timestamped, non-erasable sampling records and is routinely validated in laboratories accredited to ISO/IEC 17025:2017 for calibration traceability to NIST SRMs.
Software & Data Management
No proprietary desktop software is required for basic operation—the LP-20 functions autonomously with local parameter storage and real-time display. For integration into centralized monitoring systems, ASCII-formatted serial output (RS-232) provides raw timestamps, flow setpoints, actual flow readings, and accumulated volume in liters. Logged datasets are structured to align with EPA Compendium Method TO-17 and ASTM D5466-22 data formatting conventions. Audit trails include firmware version, battery voltage history, and flow deviation alerts—supporting FDA 21 CFR Part 11 readiness when paired with validated electronic lab notebooks (ELNs).
Applications
- Personal exposure assessment for respirable crystalline silica (NIOSH 7602), hexavalent chromium (NIOSH 7600), and organic vapors
- Indoor air quality (IAQ) surveys targeting formaldehyde, benzene, and terpenes per ISO 16000-22
- Microbial air monitoring in pharmaceutical cleanrooms (ISO 14644-1 Class 5–8) using agar-based impactors
- Stack and fugitive emission screening where portable, battery-operated flow accuracy is critical
- Field validation of fixed-site air monitors and sensor networks requiring reference-grade flow verification
FAQ
Does the LP-20 require periodic calibration with a primary standard?
Yes—per ISO/IEC 17025 and NIOSH BC 100 recommendations, annual calibration using a NIST-traceable primary flow standard (e.g., bubble meter or mass flow calibrator) is required. The unit includes a dedicated calibration mode accessible via service menu.
Can the LP-20 operate while charging?
No—charging must be performed separately from sampling to ensure thermal stability and flow integrity. Battery replacement kits (APB-109020) are available for hot-swap field maintenance.
Is the device rated for use in explosive atmospheres?
No—the LP-20 is not intrinsically safe or ATEX-certified. It is intended for general industrial and laboratory environments only.
What is the maximum allowable inlet temperature for continuous operation?
The specified operating range is 0–40 °C ambient. Inlet gas temperature should not exceed 45 °C to prevent diaphragm elastomer degradation and flow sensor drift.
How does the auto-restart function respond to flow interruption?
Upon detection of >10% flow deviation lasting >3 seconds, the system pauses sampling, logs the event timestamp and deviation magnitude, then resumes at the original setpoint after confirming mechanical stability—no manual reset required.
