Casella CEL-240 Digital Sound Level Meter

Overview

The Casella CEL-240 Digital Sound Level Meter is a rigorously engineered, Class 2-compliant instrument designed for occupational noise assessment, environmental monitoring, and general-purpose acoustic surveys in industrial, municipal, and laboratory settings. Based on the internationally recognized IEC 61672-1:2013 standard for sound level meters, the CEL-240 employs precision electret condenser microphone technology coupled with high-stability digital signal processing to deliver repeatable, traceable measurements across its full dynamic range of 30–130 dB(A) and 35–130 dB(C). Unlike analog predecessors, its fully digitized front-end architecture eliminates drift-related errors and ensures consistent performance under variable thermal and humidity conditions. The device operates without external calibration during routine use—its internal reference circuitry supports stable gain tracking, while optional periodic verification against an accredited acoustic calibrator (e.g., Casella CEL-590) maintains metrological integrity. Its compact, IP54-rated housing provides resistance to dust and light water ingress, making it suitable for field deployment in demanding environments.

Key Features

• Intuitive two-button interface with context-sensitive soft keys—no menu navigation required for core functions
• High-resolution backlit LCD displaying real-time Leq, Lmax, Lmin, and time-history waveform (up to 16 seconds scrollable trace)
• Integrated Max Hold function for capturing peak sound pressure levels during transient events
• Dual-channel weighting support: A (for hearing damage risk assessment), C (for peak analysis), and Z (linear, unweighted) per IEC 61672
• Time-weighting options: Fast (125 ms), Slow (1 s), and Impulse (35 ms rise time) compliant with ANSI S1.4 and IEC 61672
• USB 2.0 interface enabling real-time streaming to PC and direct firmware updates
• Alkaline battery operation exceeding 35 hours—optimized power management with auto-sleep mode
• All configuration parameters retained after power-off; no re-initialization required at startup

Sample Compatibility & Compliance

The CEL-240 is validated for use with standard ½-inch electret condenser microphones meeting IEC 61094-4 requirements. It is certified to IEC 61672-1:2013 Class 2 and ANSI S1.4-2014 Type 2 specifications, ensuring conformity with occupational health frameworks including EU Directive 2003/10/EC and OSHA 29 CFR 1910.95. While not intended for legal metrology or court-admissible evidence without additional chain-of-custody documentation, its measurement uncertainty (±1.0 dB at 1 kHz, reference to 20 µPa) meets GLP-aligned QA/QC requirements for internal noise mapping and baseline compliance screening. The device does not incorporate integrated dosimetry or octave-band analysis; users requiring frequency-selective evaluation should consider the CEL-244 or CEL-246 variants with optional software-based spectral post-processing.

Software & Data Management

The optional dB24 PC software (v5.2+) provides full interoperability with the CEL-240 via USB connection. It supports real-time logging at 1-second resolution, timestamped export to CSV/Excel-compatible formats, and configurable alarm thresholds. For laboratories operating under FDA 21 CFR Part 11 or ISO/IEC 17025, dB24 offers optional audit-trail logging (user login, parameter changes, export events) when deployed with Windows domain authentication. Stored measurement files include embedded metadata: date/time stamp, instrument serial number, calibration history ID, and operator-defined site tags. No cloud upload or remote telemetry is implemented—data remains locally controlled, aligning with GDPR and HIPAA-aligned data sovereignty policies.

Applications

• Workplace noise exposure assessment per ISO 9612 and NIOSH REL guidelines
• Pre- and post-engineering control verification in manufacturing facilities
• Environmental noise monitoring near construction zones, transport corridors, and residential boundaries
• Educational acoustics labs for teaching fundamental sound propagation and perception principles
• Building commissioning—HVAC system noise validation against ASHRAE Standard 110
• Acoustic pre-survey for ISO 3744 or ISO 3746 sound power determination

FAQ

Does the CEL-240 support octave-band or 1/3-octave analysis?
No. The CEL-240 is a broadband integrating sound level meter. Frequency-selective analysis requires the CEL-244 (with optional dB24 spectral module) or dedicated analyzers such as the Casella dBadge2+.
Is calibration certificate included with purchase?
Yes—a UKAS-accredited calibration certificate (traceable to NPL) is supplied with each unit. Recalibration is recommended annually or after any physical impact.
Can the CEL-240 be used for personal noise dosimetry?
No. It lacks wearable mounting hardware, continuous wear-time tracking, and dose calculation algorithms. For regulatory dosimetry, refer to Casella’s dBadge series.
What file format does dB24 generate?
CSV and XLSX (Microsoft Excel-compatible), with columns for timestamp, LAeq, LCpeak, LAFmax, and user-defined annotations.
Is the CEL-240 compatible with macOS or Linux?
USB communication is class-compliant HID; however, dB24 software is Windows-only (Windows 10/11, 64-bit). Raw data export via USB mass storage mode enables cross-platform analysis using Python, MATLAB, or LibreOffice Calc.