# Privacy Policy & Engineering Disclaimer for Refrigerant Charge Calculator and other apps by Critical Engineering Design
Last updated: November 2026
Critical Engineering Design operates the Refrigerant Charge Calculator mobile application. This document outlines our data privacy practices and technical operating parameters.
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### 1. Technical Operating Scope & Design Basis
* Intended Application: This calculation utility is engineered primarily for direct-expansion air conditioning equipment operating within standard indoor design conditions of 22°C to 24°C dry-bulb room temperature.
* Guidance & Advisory Use Only: All calculations, pressure-temperature (P-T) relationships, target superheat/subcooling values, and charge estimations provided by this application are for preliminary technical guidance only.
* Variable Operational Conditions: Actual field results, operating pressures, and optimal refrigerant charge quantities vary considerably based on system-specific parameters, including but not limited to:
* Metering device type (fixed orifice/capillary vs. thermostatic or electronic expansion valves)
* Outdoor ambient temperature and coil airflow conditions
* Line set length, elevation difference, and liquid line volume
* Indoor relative humidity and sensible heat ratio (SHR)
* Equipment age, compressor volumetric efficiency, and duct static pressure
* Professional Verification Required: Service technicians and engineers must independently verify system parameters using manufacturer nameplate data, certified gauge manifolds, weighing scales, and manufacturer charging charts. Critical Engineering Design assumes no liability for equipment malfunction, compressor damage, refrigerant loss, or regulatory non-compliance resulting from field actions taken using these estimates.
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### 2. Information Collection and Storage
Refrigerant Charge Calculator functions entirely as an offline technical utility:
* No Personal Data Collected: We do not collect, store, transmit, or share personally identifiable information (PII), contact lists, device identifiers, or GPS locations.
* Local Processing: All input values (pressures, temperatures, refrigerant types) are computed locally in real time on your device hardware and are discarded upon closing the app.
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### 3. Advertising & Third-Party Code
The application contains no third-party tracking SDKs, device telemetry, or advertising modules.
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### 4. Device Permissions
The application requires only the basic system permissions strictly necessary to display the user interface. It does not request access to device cameras, microphones, external photo libraries, contacts, or local file storage.
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### 5. Contact Information
For technical audit inquiries, engineering support, or questions regarding this policy:
* Entity: Critical Engineering Design
* Website: https://www.ced-engineering.com