SIBATA OFD-1 Digital Orifice Plate Flowmeter

Overview

The SIBATA OFD-1 Digital Orifice Plate Flowmeter is a portable, field-deployable differential pressure-based instrument engineered for high-accuracy volumetric flow verification and calibration of high-volume air sampling systems—primarily those compliant with ISO 10780, ISO 16000-2, and EPA Method TO-11A. It operates on the fundamental principle of ISO 5167-compliant orifice plate flow measurement, where airflow induces a measurable pressure differential across a precision-machined orifice, enabling calculation of volumetric flow rate under actual ambient conditions. Unlike fixed-installation flowmeters, the OFD-1 integrates real-time temperature and barometric pressure sensing to automatically convert raw differential pressure into standardized volumetric flow (e.g., L/min at 25 °C and 101.3 kPa), eliminating manual correction factors and reducing operator-induced error. Its compact, battery-powered architecture supports direct in-situ validation at sampling points—critical for environmental monitoring networks, occupational hygiene surveys, and regulatory compliance audits requiring traceable flow verification.

Key Features

• Integrated dual-sensor compensation: Onboard Pt100 temperature sensor and piezoresistive barometric pressure sensor enable continuous real-time standardization of flow readings per ISO 5167-2 and ASTM D2122.
• Auto-recognizing orifice plate interface: Detects and identifies two pre-calibrated orifice plates (included) via mechanical encoding—preventing misinstallation and ensuring correct K-factor application during calculation.
• Dedicated USB communication port: Proprietary serial protocol enables seamless bidirectional data exchange with SIBATA HV-R series air samplers for automated flow calibration routines and firmware synchronization.
• Traceability-ready operation: Generates timestamped, sensor-compensated flow records with embedded environmental metadata—supporting GLP-compliant documentation and audit trails for laboratory accreditation (e.g., ISO/IEC 17025).
• Field-optimized ergonomics: Rugged ABS housing, low-power design (4×AA alkaline, >12 hr typical runtime), and compact footprint (105 × 225 × 180 mm) facilitate transport and handheld use in industrial or outdoor sampling environments.

Sample Compatibility & Compliance

The OFD-1 is validated for use with SIBATA’s HV-F and HV-R series high-flow air samplers (nominal flow range: 100–1500 L/min), commonly deployed for PM₁₀, PM_2.5, VOC, and asbestos fiber collection per EN 12341, ISO 7708, and NIOSH Method 7400. It complies with the physical and metrological requirements of JIS Z 8401 (Guide to the Expression of Uncertainty in Measurement) and supports alignment with ISO/IEC 17025 clause 6.4.2 (Equipment Verification). While not certified as a primary standard, its ±3% full-scale accuracy—verified against NIST-traceable laminar flow elements—is suitable for secondary calibration verification in accordance with EPA QA/G-5 and EU Directive 2008/50/EC Annex III.

Software & Data Management

The OFD-1 operates autonomously without host software but interfaces exclusively with SIBATA’s HV-R Calibration Manager (v3.2+), a Windows-based utility supporting automated calibration sequence execution, deviation reporting, and CSV export of compensated flow logs. All measurements include embedded UTC timestamps, ambient T/P values, orifice ID, and raw ΔP—enabling retrospective uncertainty analysis. Data files adhere to 21 CFR Part 11–compatible audit trail principles when used within validated HV-R workflows, including electronic signature prompts and immutable record generation. No cloud connectivity or proprietary drivers are required; USB connection uses CDC ACM class for plug-and-play enumeration.

Applications

• Field verification of high-volume air sampler performance prior to and following environmental monitoring campaigns.
• Annual or semi-annual calibration checks per ISO 17025 internal quality control protocols.
• Validation of flow stability during long-term indoor air quality (IAQ) studies involving HVAC duct sampling.
• Supporting regulatory submissions requiring documented flow traceability (e.g., EU ETS monitoring plans, US OSHA PEL compliance reports).
• Educational use in environmental engineering labs for hands-on instruction in orifice metering theory and gas dynamics.

FAQ

Is the OFD-1 suitable for calibrating non-SIBATA air samplers?
Yes—when paired with an appropriate mechanical adapter and configured for known orifice geometry and discharge coefficient, though auto-recognition and USB automation are limited to HV-R/HV-F series.
Does the OFD-1 require annual recalibration?
SIBATA recommends verification against a NIST-traceable reference flowmeter every 12 months; the unit’s internal sensors are factory-calibrated with documented uncertainty budgets.
Can historical OFD-1 data be imported into LIMS systems?
Yes—CSV exports from HV-R Calibration Manager contain structured fields compatible with common LIMS ingestion pipelines (e.g., LabWare, Thermo SampleManager) via flat-file import modules.
What is the minimum detectable flow rate under low-pressure conditions?
At 90 L/min (lower limit), the device maintains ±3% accuracy down to 85 kPa ambient pressure and 0 °C, provided relative humidity remains below 90% RH to prevent condensation-induced sensor drift.
Are replacement orifice plates available with NIST-traceable certificates?
Yes—SIBATA offers certified orifice plates (Part No. OFD-PLATE-KIT) with individual calibration reports traceable to NMIJ (National Metrology Institute of Japan), issued per ISO/IEC 17025.