OK Walk-in Constant Temperature & Humidity Room OK-STH-1.2

Overview

The OK Walk-in Constant Temperature & Humidity Room OK-STH-1.2 is a purpose-built, large-scale environmental control facility engineered for long-term, high-stability maintenance of precise temperature and relative humidity conditions within a fully accessible, room-scale enclosure. Unlike accelerated environmental test chambers designed for stress screening, this system operates on the principle of steady-state thermodynamic equilibrium—leveraging high-efficiency refrigeration, precision PID-controlled steam or ultrasonic humidification, and low-velocity, high-volume air distribution to sustain microclimate stability over continuous 7×24 operation. Its architecture follows ASHRAE Guideline 180 and ISO 16730 principles for controlled environment design, with thermal inertia optimized to minimize setpoint drift and spatial gradient under variable internal heat loads (e.g., personnel, instrumentation, lighting). The system functions as an integrated environmental infrastructure—not a test instrument—but rather a calibrated ambient platform essential for metrology-grade calibration labs, GMP-compliant pharmaceutical storage, archival conservation, and precision manufacturing processes where dimensional stability, electrostatic control, and material aging kinetics are directly governed by ambient conditions.

Key Features

• Modular high-density polyurethane or rock wool insulated panels (≥100 mm thickness), rated for thermal conductivity ≤0.022 W/m·K and vapor permeance <0.1 ng/(Pa·s·m²)
• Hermetic sealing at all penetrations, double- or triple-glazed observation windows with low-emissivity coatings and argon fill, and pass-through airlock ports to minimize infiltration during access
• Industrial-grade constant climate air handling unit (AHU) featuring inverter-driven scroll compressors, EC plug fans, stainless-steel steam humidifiers, and direct-expansion cooling coils with microchannel heat exchangers
• Multi-point sensor network: redundant platinum resistance thermometers (PT100 Class A) and capacitive RH sensors (±1.5% RH accuracy, 0–95% RH range) mounted at strategic locations per ISO 14644-3 sampling protocols
• Integrated energy recovery system: enthalpy wheel or plate-type heat exchanger recovering ≥65% of sensible and latent energy from exhaust airstreams
• Acoustic optimization: interior sound pressure level maintained below 62 dB(A) at 1 m distance from wall surfaces, compliant with ISO 7730 thermal comfort criteria

Sample Compatibility & Compliance

The OK-STH-1.2 accommodates heterogeneous operational loads—including human occupancy (up to 4 personnel), active instrumentation (CMMs, interferometers, mass spectrometers), and passive storage of hygroscopic or thermally sensitive materials (e.g., lithium-ion battery cells, photographic film, reference standards, archival documents). It meets structural and operational requirements aligned with ISO 14644-1 (Class 8 cleanroom compatibility when equipped with FFU filtration), USP for pharmaceutical storage environments, and ASTM E644 for humidity measurement system validation. All control logic and data logging comply with FDA 21 CFR Part 11 Annex 11 requirements for audit trails, electronic signatures, and data integrity—enabling full traceability in GLP/GMP-regulated facilities.

Software & Data Management

The embedded controller features a 10.1-inch industrial touchscreen HMI with real-time trend visualization, alarm history, and event-driven reporting. Remote monitoring and configuration are supported via secure HTTPS-based web interface compatible with common SCADA platforms (OPC UA, Modbus TCP). Data is logged at user-configurable intervals (minimum 1-second resolution) to encrypted onboard storage (≥32 GB) with automatic rollover and optional cloud backup (AWS IoT Core or Microsoft Azure IoT Hub). Calibration certificates for all critical sensors are traceable to NIM (China National Institute of Metrology) or NIST-equivalent national standards. Full I/O mapping, firmware revision logs, and system health diagnostics are exportable in CSV/Excel format for quality assurance audits.

Applications

• Precision metrology laboratories requiring ISO/IEC 17025-compliant environmental conditioning for coordinate measuring machines, laser trackers, and optical interferometers
• GMP-certified cold chain storage for biologics, reference standards, and controlled substances per EU Annex 15 and WHO TRS 992
• Conservation-grade archival vaults for libraries, museums, and national archives operating under PAS 198:2012 environmental guidelines
• Long-term reliability testing of electronics under static environmental bias (e.g., zero-stress aging of MEMS devices, PCB solder joint evaluation)
• Material science research on moisture diffusion kinetics in polymers, composites, and battery electrolytes under stabilized hygrothermal conditions
• Calibration of humidity sensors and temperature probes using multi-point validation per ISO/IEC 17025 clause 5.10.4

FAQ

What distinguishes the OK-STH-1.2 from a standard walk-in environmental test chamber?
It prioritizes long-term stability (±1°C/±3% RH), low spatial gradients, energy efficiency, and human occupancy suitability—rather than rapid cycling or extreme ranges. Its control architecture is optimized for 24/7 operation with minimal maintenance downtime.
Can the chamber be validated for ISO 17025 or GMP compliance?
Yes—full IQ/OQ/PQ documentation packages are available, including uncertainty budgets, sensor calibration certificates, and protocol-driven mapping studies per ISO 14644-3 and EU GMP Annex 15.
Is customization available for non-standard temperature/humidity setpoints or acoustic requirements?
All units are engineered to order; options include ultra-low noise configurations (<55 dB(A)), enhanced humidity control down to 5% RH, and extended low-temperature capability to −80°C with cascade refrigeration.
How is thermal uniformity verified across the working volume?
During factory acceptance testing, 9–16 PT100 and RH sensors are deployed on a 3D grid per ASTM E744, with results reported in a certified uniformity map showing maximum deviation from setpoint at all monitored locations.
Does the system support integration with existing building management systems (BMS)?
Yes—native BACnet MS/TP and Modbus RTU interfaces are standard; optional BACnet/IP and MQTT gateways enable seamless interoperability with enterprise-level facility management platforms.