Vent Gas Monitoring

Accurate, Reliable Vent Gas Flow Measurement

Thermal mass flow meters provide direct mass flow measurement of vent gas in the oil and gas industry. Common sources include tank batteries or vented gases at the well site. Whether the vent gas comes from well completion, maintenance, or storage, an accurate flow measurement device is critical for emissions monitoring and safety.

Help Me Choose A Flow Meter
Gas flow sensors help monitor flow at both high and low velocities, making them ideally suited for the oil industry.

Fox Thermal Flow Meters provide...

Wide Turndown

Our mass flow meter technology allows exceptional low-flow vent gas sensitivity, providing accurate measurement over a wide range of vented gases in gas operations.

Direct Mass Flow Measurement

Thermal mass flow rate measurement requires no additional temperature and pressure compensation equipment or calculations.

Easy Interface

Fox Thermal’s meters are available with a variety of built-in alarms, totalizers, and communications protocols for easy interfacing with your emissions management system.

More About Vent Gas Monitoring in Oil & Gas Production

Thermal Mass Flow Meters from Fox Thermal can be used to continuously monitor the flow of gas in the pipes between the equipment found at these oil well sites:

  • Gas from the separators
  • Gas from/to the VRUs (Vapor Recovery Units)
  • Gas flowing to/from the tank batteries

Vent gas can often be tricky to measure. Some gas flow meter technologies can only monitor flow accurately at high velocities, and others at lower velocities.

Thermal mass gas meter vent technology is a proven solution that is able to measure gas flows at very high and very low flow rates.

All Fox Thermal mass flow meters are rugged and accurate meters that can be used in a wide variety of applications involving both low and high-velocity gas flows. With repeatability and a low turndown, our flow meters were designed to be durable and versatile.

Help Me Choose A Flow Meter
Gas flow sensors help monitor flow at both high and low velocities, making them ideally suited for offshore oil and gas drilling operations.

Vent Gas Monitoring for Emissions Regulations and Safety Requirements

Rising levels of volatile organic compounds (VOCs) in the atmosphere are a subject of increasing environmental regulation by bodies such as the US EPA, and other international, state, and local governments.

To monitor and quantify emissions, VOC concentrations as well as VOC flow rates must be measured to evaluate mass emission rate. Vent gas flow meters are commonly used for this purpose.

In addition to providing information for environmental audits, VOC monitoring can also help operators:

  • Identify opportunities to reduce emissions
  • Evaluate performance of existing abatement equipment
  • Identify and correct sources of fugitive emissions
  • Demonstrate continual improvement in environmental performance
  • Meet health and safety requirements and improve working conditions
  • Optimize process flows throughout the plant or storage facility

Thermal mass flow meters provide a direct reading of mass flow rate without additional pressure and temperature instrumentation, making it ideal for measuring flow rates in flare stacks, ducts, and tank vent pipes.

See how the Model FT3 is used frequently for this purpose in this Fox Thermal case study on VOC emissions.

Thermal mass flow meters are ideal for measuring flow rates in flare stacks.

Gas-SelectX® for Superior Vent Gas Monitoring

Oil & Gas tank batteries that generate vent gas may store gas of different compositions from time to time. When the composition changes, the Gas-SelectX® settings in certain Fox Thermal flow meter models can be accessed on site to update the gas composition. This will ensure that the flow sensors will continue to monitor the varied vent gas compositions accurately.

The Fox Thermal Model FT4A is equipped with the Gas-SelectX® feature, making it ideal for vent gas flow measurement.

Use This Online Tool to Select the Right Gas Flow Sensor Model for Your Vent Gas Monitoring System

Our new app can help you choose the right flow meter model fast.

If you’re not sure which meter is right for your application, our Help Me Choose app walks you through a short series of questions to help you choose the ideal meter.

Once you’ve selected a model, fill out the questions in our meter configurator form.

Next, enter your process data and flow meter requirements into our automated product configurator. Drop-down menus and Help icons will guide you to answer each question.

Save and submit your application data to us for a quote - it’s that easy!

Save the data you entered into the configurator to create a PDF with a model code and AppID. When you're ready, submit your application to Fox Thermal for a quote.

Discover the Fox Thermal Advantage

Flow Meters for Vent Gas Monitoring

fox thermal product ft1

Model FT1

The Model FT1 thermal flow meter is available with Gas-SelectX® and can be easily reprogrammed in the field with the help of DDC-Sensor™ for calculating accurate gas correlations. It can measure a single gas or a mixture of up to 5 specified gases. The CAL-V™ Calibration Validation test feature ensures the meter retains its original NIST calibration.

Model FT1
fox thermal product ft3 meter

Model FT3

The FT3 can operate over higher temperatures and measure a wide range of dry pure gases and gas mixes. Comes with CAL-V™ and Zero CAL-CHECK®. An optional Data Logger is available.

Model FT3
fox thermal product ft4A meter

Model FT4A

This versatile gas flow meter is available with CAL-V™ Calibration Validation, DDC-Sensor™, and Gas-SelectX® allowing it to be programmed to measure any combination of gases in the gas mix menu in 0.1% increments to create a custom gas mix.

Model FT4A
fox thermal product ft4X meter

Model FT4X

The Model FT4X features CAL-V™ Calibration Validation, DDC-Sensor™, and Gas-SelectX®. For oil & gas applications affected by BLM 3175 and API 14.10, the FT4X is accuracy compliant. It also comes with a built-in data logger for advanced record-keeping and data retention that maintains a 7-year history.

Model FT4X

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News & Innovation

Fox Thermal case study on VOC emissions

This field study by the Texas Commission on Environmental Quality (TCEQ) evaluated VOC emissions factors from oil and natural gas condensate storage tanks using Fox Thermal meters.

Learn More
Flow Meter Comparison

This discussion of the different types of flow meters will help you understand the best gas flow measurement technology for your application.

Learn More
More Literature

Download helpful whitepapers, product literature, and more, including Fox Thermal Application Guides such as Direct Mass Measurement of Vent Gas (Flash Gas) Flow Rates.

Learn More

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