Liebherr SRFfg 5501 Explosion-Proof Precision Refrigerator

Overview

The Liebherr SRFfg 5501 is a CE-compliant, ATEX-certified explosion-proof precision refrigerator engineered for safe, stable, and traceable storage of temperature-sensitive hazardous materials in laboratories, pharmaceutical cleanrooms, chemical synthesis facilities, and quality control environments. Designed and manufactured in Germany under strict DIN EN ISO 9001 quality management protocols, the unit operates on the principle of forced-air convection cooling with microprocessor-controlled thermal regulation—ensuring uniform internal temperature distribution across its 558 L upright chamber. Its certified Ex d IIB T4 Gb / Ex tb IIIC T135°C Db protection rating (per Directive 2014/34/EU) confirms intrinsic safety in Zone 1 and Zone 21 classified areas where flammable vapors or combustible dusts may be present. Unlike standard laboratory refrigerators, the SRFfg 5501 integrates spark-free mechanical components, intrinsically safe electronics, and sealed control architecture to eliminate ignition sources while maintaining high-fidelity thermal performance between +3 °C and +16 °C.

Key Features

• ATEX 95 (2014/34/EU) certified for use in explosive atmospheres — validated by notified body testing and full documentation package provided
• Precision temperature control with ±0.1 °C stability and < ±0.5 °C uniformity across all shelf levels (measured per IEC 60068-3-5)
• Four independent alarm channels: temperature deviation, door open, sensor fault, and power failure — each logged with timestamp and event type
• Non-volatile memory storing the last three complete alarm sequences, including duration, trigger value, and recovery status
• Volt-free relay outputs enabling integration into central building management systems (BMS) or SCADA networks
• RS485 Modbus RTU interface supporting daisy-chained monitoring of up to 20 units, with real-time temperature curves and alarm history exportable via compatible software
• Optional external PT100 input channel for redundant or remote sensing — configurable as primary or secondary monitoring point
• Automatic, spark-free defrost system compliant with EN 60079-0 and EN 60079-15 requirements for Ex e and Ex tD equipment
• Reversible door hinges and ergonomic slim-profile stainless-steel handle designed for frequent access in constrained lab layouts
• GlassLine tempered glass shelves rated for 40 kg static load per level; reinforced stainless-steel frame ensures long-term structural integrity

Sample Compatibility & Compliance

The SRFfg 5501 is suitable for storage of volatile organic compounds (VOCs), solvent-based reagents, peroxide-forming chemicals, lithium battery cells, and other Class I (gaseous) or Class III (dust) hazardous substances requiring controlled ambient conditions. Its SN-ST climate classification (10–35 °C ambient operating range) ensures consistent cooling capacity under variable facility conditions, meeting ASTM E644 and ISO 17025 environmental monitoring prerequisites. All electrical components comply with EN 60079-11 (intrinsic safety), EN 60079-15 (type of protection “n”), and EN 60079-31 (dust ignition protection). The unit supports GLP/GMP audit readiness through time-stamped alarm logs, user-accessible calibration records, and optional 21 CFR Part 11–compliant software modules for electronic signature and audit trail generation.

Software & Data Management

Liebherr provides native firmware with embedded data logging (1-minute interval, 30-day buffer) and configurable alarm thresholds. When connected via RS485, the refrigerator integrates with Liebherr LabMonitor Suite or third-party platforms (e.g., LabWare LIMS, Siemens Desigo CC) using standard Modbus register mapping. Exported CSV files include ISO 8601 timestamps, sensor IDs, temperature values, alarm flags, and operational status codes. Firmware updates are delivered via secure USB interface with cryptographic signature verification. Audit trails record all configuration changes, user logins, and alarm acknowledgments — fully traceable for FDA inspection or ISO/IEC 17025 accreditation assessments.

Applications

• Storage of flammable solvents (e.g., acetone, ethanol, ether) in analytical chemistry labs
• Controlled-temperature holding of reference standards and certified reference materials (CRMs) under ISO Guide 34 requirements
• Stabilization of temperature-critical catalysts and reactive intermediates in process R&D
• Secure cold storage for battery electrolytes and energy storage test samples in EV material development
• Compliance-driven archiving of QC samples in pharmaceutical manufacturing (aligned with EU GMP Annex 15 and USP <1079>)
• Environmental monitoring sample preservation in accredited air/water testing laboratories

FAQ

Is the SRFfg 5501 suitable for Zone 0 or Zone 20 classified areas?

No. It is certified for Zone 1 (gas/vapor) and Zone 21 (combustible dust) only, per its Ex d IIB T4 Gb / Ex tb IIIC T135°C Db marking.
Can the unit operate continuously at 35 °C ambient temperature?

Yes — its SN-ST climate class guarantees specified temperature stability and compressor duty cycle within 10–35 °C ambient, verified under EN 62552 test conditions.
Does the refrigerator support NIST-traceable calibration?

Yes. Internal PT100 sensors are factory-calibrated against NIST-traceable references; users may perform field verification using external calibrated probes per ISO/IEC 17025 procedures.
What is the expected service life under continuous lab operation?

Designed for ≥15 years of 24/7 operation, supported by Liebherr’s 2-year comprehensive warranty and global service network with certified Ex technicians.
How is data integrity ensured during power interruptions?

Non-volatile memory retains alarm history and configuration settings for ≥72 hours without backup power; optional UPS integration is recommended for mission-critical deployments.