The Varec Hydrostatic Tank Gauges provide a mass-based approach to measuring inventory in bulk liquid storage tanks.
The system measures the hydrostatic pressure created by the liquid column and combines pressure data with product-temperature information for tank inventory calculations.
Depending on the configuration, one or more HART® pressure transmitters and a compatible temperature device are integrated through a tank side monitor.

A single pressure measurement requires a manually entered product density. Additional pressure measurements can support calculated density and vapor-pressure compensation.
Liquid level, volume, and density are derived values rather than direct measurements in a hydrostatic tank gauging system.
Key Characteristics
- Mass-based tank gauging using hydrostatic pressure measurement
- Configurable with up to three pressure transmitters and one or more temperature elements
- Integration of compatible HART® pressure and temperature instrumentation
- Tank-side processing of pressure, temperature, and configuration data
- Support for transferring measurement and calculated inventory data to a control-room system
- Use of tank strapping-table data within configured inventory calculations
- Configuration-dependent calculation of product density, liquid level, volume, and mass
Ideal Applications
- Measuring tank inventory when product quantities are accounted for by mass or weight
- Integrating pressure and product-temperature measurements at the tank side
- Calculating product density using multiple pressure measurements
- Accounting for vapor pressure within configured hydrostatic calculations
- Transferring hydrostatic tank measurement data to a control-room inventory system
- Bulk storage applications where hydrostatic measurement is selected for petroleum or viscous products
Product Family Includes
- NRF81 Tank side Monitor
- Prothermo NMT532, and NMT539 Average Temperature Converters
- Compatible HART® pressure transmitters
- Compatible spot or average temperature devices
- 4590 Tank side Monitor — discontinued legacy component referenced in the hydrostatic solution documentation
Industries Served
- Oil and Gas
- Petroleum
- Refining
- Petrochemical
- Bulk Liquid Storage









