TSI Model 9535/9545 Digital Anemometer

Overview

The TSI Model 9535 and 9545 Digital Anemometers are precision-engineered handheld instruments designed for reliable, real-time measurement of air velocity, temperature, and—on the 9545 series—relative humidity (RH), dew point, and wet-bulb temperature. Built upon TSI’s legacy in thermal anemometry and environmental metrology, these devices employ a constant-temperature anemometer (CTA) sensing principle: a heated thermistor element cools proportionally to local airflow, enabling high-fidelity wind speed quantification across turbulent and laminar regimes. The integrated NTC thermistor provides traceable temperature response, while the 9545 variants incorporate a capacitive polymer RH sensor calibrated per ISO 16000-17 and verified against NIST-traceable humidity standards. These instruments serve as primary field tools for HVAC commissioning, laboratory ventilation validation, cleanroom airflow mapping, fume hood performance testing, and indoor air quality (IAQ) assessments—applications requiring simultaneous multi-parameter acquisition with documented repeatability and audit-ready data integrity.

Key Features

• Triple-parameter simultaneous display: air velocity, temperature, and (on 9545 models) relative humidity—with derived calculations including dew point, wet-bulb temperature, and volumetric flow rate
• Two probe configurations: rigid telescoping probe (9535/9545) and fully articulating, bendable probe (9535-A/9545-A) for accessing confined ductwork, grilles, and irregularly shaped enclosures
• Volumetric flow calculation engine supporting duct dimensions from 1.0 to 635.0 cm (0.1 cm increments); automatic conversion between actual and standard cubic feet per minute (ACFM/SCFM) or actual/standard liters per second (AL/s/SL/s)
• Configurable time constant (0.5–10 s) for dynamic averaging in fluctuating airstreams—critical for capturing transient events during system startup or damper modulation
• Onboard data logging with 12,700-point capacity across up to 100 independent datasets; sampling interval programmable from 1 second to 1 hour
• LogDat2™ software included for secure data export, timestamped report generation, and CSV-compatible analysis—designed to support GLP/GMP documentation workflows

Sample Compatibility & Compliance

The 9535/9545 series operates reliably across industrial, commercial, and research-grade environments. Its sensor assembly is rated for continuous exposure to ambient conditions from −18 °C to +93 °C (probe) and −10 °C to +60 °C (instrument body), with non-condensing humidity tolerance up to 95 %RH. Calibration stability adheres to ASTM D5465–22 (Standard Practice for Measuring Air Velocity in Ventilation Ducts) and ISO 16813:2021 (HVAC—Performance Testing of Air Handling Units). Relative humidity measurements meet ISO 16000-17 criteria for sorption hygrometers, and temperature accuracy complies with IEC 60751 Class B tolerances. All firmware and data handling protocols are structured to align with FDA 21 CFR Part 11 requirements for electronic records and signatures when used in regulated facilities.

Software & Data Management

LogDat2™ software enables full post-acquisition control: users can define custom metadata fields (test ID, operator, location), apply correction factors (e.g., temperature compensation per ±0.03 °C/°C deviation from 25 °C reference), and generate PDF reports with embedded calibration certificates and uncertainty budgets. Data files include embedded timestamps synchronized to the instrument’s internal RTC (real-time clock), with optional GPS tagging via connected mobile devices. Audit trails record all parameter edits, export actions, and user logins—supporting compliance with ISO/IEC 17025:2017 Clause 7.7 (Results Reporting) and EU Annex 11 (Computerized Systems). Export formats include CSV, Excel (.xlsx), and XML for integration into LIMS or enterprise QA platforms.

Applications

• HVAC system balancing and TAB (Testing, Adjusting, Balancing) per ASHRAE Guideline 1 and NEBB Procedural Standards
• Fume hood face velocity verification per ANSI/ASHRAE 110–2016 and OSHA 1910.1450
• Cleanroom unidirectional airflow uniformity mapping (ISO 14644-3 Class 5–8)
• Exhaust stack velocity profiling under EPA Method 2 and Method 2F
• Indoor environmental quality (IEQ) surveys per LEED v4.1 EQ Credit: Indoor Air Quality Assessment
• Validation of biosafety cabinet inflow and downflow velocities per NSF/ANSI 49–2022

FAQ

What is the difference between the 9535 and 9545 models?
The 9545 includes an integrated capacitive RH sensor and calculates dew point and wet-bulb temperature; the 9535 measures only velocity and temperature.
Can the instrument measure in both metric and imperial units?
Yes—user-selectable units include m/s, ft/min, °C/°F, %RH, and volumetric flow in L/s, m³/h, CFM, or SCFM.
Is calibration traceable to NIST?
All factory calibrations are performed using NIST-traceable reference standards, and a certificate of calibration (including uncertainty values) is supplied with each unit.
How does temperature affect RH accuracy?
RH accuracy degrades by ±0.2 %RH/°C deviation from 25 °C ambient; LogDat2™ supports automated temperature-compensated RH correction.
Does the device support automated data export during measurement?
No—data is stored internally and exported post-sampling via USB; real-time streaming requires optional TSI Flow Explorer™ interface hardware.