Flare Gas Meters

Flare gas meters are specialized flow instruments used to track the highly variable gases routed to flare systems in refineries, petrochemical plants, and oil & gas facilities. Unlike stable process lines, flare headers see extreme swings in flow, rapid upset events, and changing gas composition, so dependable measurement is essential for safety, environmental compliance, and meaningful operations data.

At Clipper Controls, we typically apply Panametrics ultrasonic flare gas meters on refinery, petrochemical, and hydrocarbon service flares, and use the Kurz 454FTB-WGF thermal mass flow meter for wet biogas flares at wastewater treatment plants and landfills. That gives us two proven technologies to match very different flare conditions.

👉 Talk to a flare gas measurement specialist to review your flare header conditions, regulatory drivers, and instrumentation options.

Ultrasonic flare gas meter system with transmitter, probe assembly, and wall-mount control unit, shown with a “wet gas” badge — Flare gas meters by Panametrics and Kurz Instruments

What Is a Flare Gas Meter?

A flare gas meter (or flare gas flow meter) measures the flow of gas sent to a flare stack or enclosed combustor. These gases are usually a mix of hydrocarbons, inert gases, and steam from process units, relief valves, and safety systems across the plant.

In normal operation, flare flow is often very low—sometimes near zero—yet still needs to be measured for emissions accounting and leak detection. During upset conditions, those same lines may see extremely high velocities as multiple relief valves open. A good flare gas meter must reliably track both extremes.

In refineries, petrochemical plants, and gas processing facilities, flare gas meters support:

Industrial flare gas monitoring and visibility into what’s going to the flare
Emissions measurement for greenhouse gas and regulatory reporting
EPA 40 CFR Part 60/63 flow monitoring and related compliance needs
Safety assurance, confirming relief and overpressure events are correctly routed
Operational insight, identifying chronic low-level flaring and process inefficiencies

Because of these demands, ultrasonic flare gas measurement has become the preferred approach for serious industrial flare gas monitoring.

A flare gas meter (or flare gas flow meter) measures the flow rate of gas sent to a flare stack or enclosed combustor. That gas is usually a blend of hydrocarbons, inert gases, and steam coming from process units, relief valves, and safety systems across the plant.

Most of the time, flow to the flare is very low—sometimes near zero—but still needs to be monitored for emissions accounting and leak detection. During trips or relief events, those same lines can see extremely high velocities as multiple valves open at once. A good flare gas meter must reliably capture both ends of that range.

In refineries, petrochemical plants, and gas processing facilities, flare gas meters support:

Industrial flare gas monitoring and visibility into what’s going to the flare
Emissions measurement for greenhouse gas and regulatory reporting
EPA 40 CFR Part 60/63 flow monitoring and related compliance work
Safety assurance, confirming relief and overpressure events are handled correctly
Operational insight, helping identify chronic low-level flaring and process issues

Because of these demands, ultrasonic flare gas measurement has become the default choice for many refinery and petrochemical flares, while wet-gas thermal mass is often the better tool for saturated biogas flares.

Diagram of a transit-time ultrasonic flare gas meter with opposing wetted transducers measuring flow across a flare header.

Why Flare Gas Measurement Is So Challenging

Flare systems push almost every flow technology to its limits. A single header has to be measured accurately through all of the following:

Extreme turndown and changing flow

Very low purge and leak rates in normal operation
Very high velocities during trips, blowdowns, and upset events
Turndown ratios that can be in the hundreds or thousands to one

Variable gas composition

Continuously changing hydrocarbon mix from different units
Steam or air assist being added for smokeless operation
Inert gases and occasional oxygen ingress from leaks or vents

Meters that expect fixed gas properties often drift or lose accuracy as composition moves around.

Pulsating and bidirectional flow

Chattering relief valves and complex header geometry can create unstable, swirling, or pulsating flow profiles
Some systems see bidirectional flow in common headers or near tie-ins

Technologies intended for steady, single-direction flow can misread or drop out in this environment.

Low pressure, wet and dirty service

Flare headers are often near atmospheric pressure
Ideal straight-run piping is rare
Condensed liquids, slugs, and contamination are routine

This combination of extreme turndown, changing composition, and rough piping is exactly why you need instrumentation designed specifically for flare service—whether that’s an ultrasonic meter on a refinery flare header or a wet-gas thermal mass meter on a biogas flare.

Why Ultrasonic Flare Gas Meters Are Preferred

(For refinery / petrochemical / O&G flares)

For refinery flare system monitoring, petrochemical emissions measurement, and oil & gas flare gas compliance, ultrasonic technology lines up well with the realities of the header.

How ultrasonic flare gas measurement works

Transit-time ultrasonic flare gas meters use a pair of transducers to send sound pulses both with and against the flow. The difference in travel time between those directions is used to calculate velocity; from there, the meter computes volumetric or mass flow.

Because measurement is based on time-of-flight instead of a physical restriction:

There is no additional pressure drop from the meter
There are no moving parts to wear, foul, or stick
The same meter can measure very low background flows and high upset flows

Key benefits of ultrasonic flare gas meters

Non-intrusive measurement – no orifices, restrictions, or turbines in the header
Very wide turndown – a single system covers background leaks and full-blown relief events
Handles changing composition – well suited for mixed and variable gas streams
Works in low-pressure, wet, dirty service – with Panametrics wet-gas compensation improving performance in difficult conditions
Bidirectional and pulsating flow capability – appropriate for complex, multi-header systems
Rich diagnostics – signal quality, path availability, and meter health indicators that help you trust the data

NIST-traceable test results showing Panametrics DigitalFlow XGF868i ultrasonic flare gas meter linearity up to 120 meters per second.

Panametrics Flare Gas Meters and Flare Solutions

Clipper Controls supplies and supports Panametrics flare gas metering solutions, centered around the DigitalFlow GF868 and DigitalFlow XGF868i ultrasonic flare gas meters and flare optimization tools such as flare.IQ.

DigitalFlow XGF868i Ultrasonic Flare Gas Flow Meter

The DigitalFlow XGF868i is an explosion-proof, field-mounted ultrasonic flow meter designed for continuous measurement of flare and vent gas:

Built for high-turndown, low-pressure flare systems
Non-intrusive measurement—no extra pressure drop added to the header
Measures both very low background flows and high upset flows with one meter
Provides standard volumetric and mass flow outputs for your control system
Hazardous-area design with options for remote electronics to improve accessibility

For many facilities, the XGF868i is the primary workhorse for EPA-driven flare gas monitoring where uptime and data quality are critical.

Panametrics DigitalFlow XGF868i ultrasonic flare gas flow meter for hazardous area installations.

DigitalFlow GF868 Ultrasonic Flare Gas Flow Meter

The DigitalFlow GF868 is a high-performance ultrasonic flare gas mass flow meter aimed at demanding flare applications:

Measures velocity, volumetric flow, and mass flow of flare gas
Uses Panametrics Correlation Transit-Time™ technique and advanced digital signal processing
Supports very wide rangeability (up to 4000:1 turndown) so one system can watch for leaks and capture large trip events
Can calculate average molecular weight and net heating value (NHV) of vent gas when paired with appropriate inputs
Engineered to stay on-spec under unsteady, bidirectional, and pulsating flow with changing gas composition and temperature
GF868 transmitters are typically mounted in analyzer houses or control rooms, with flexible I/O and the ability in some configurations to serve multiple flare lines from a single unit.

Panametrics DigitalFlow GF868 wall-mounted ultrasonic flare gas mass flow meter.

Typical temperature and pressure transmitter mounting for a flare gas flowcell used with an ultrasonic flare gas mass flowmeter.

Integrating with Panametrics flare.IQ

For plants interested in flare optimization and better emissions performance, flare.IQ ties flow, composition, and other process data together to:

Calculate net heating value (NHV) for the flare
Adjust steam or air assist for smokeless, efficient combustion
Provide a platform for automated flare control, alarming, and reporting

Together, the DigitalFlow GF868, DigitalFlow XGF868i, and flare.IQ form a complete toolkit for refinery flare system monitoring and optimization.

Panametrics flare.IQ for flare optimization and control — Panametrics flare.IQ platform for flare optimization, NHV calculation, and automated steam or air assist control.

Transducer options for challenging flare applications

Panametrics pairs GF868/XGF868i electronics with different wetted ultrasonic transducers so the installation can be tuned to your line size and velocity range. Two of the most common for flare gas are T5 and T17:

T5 flare gas transducers – Explosion-proof, all-welded titanium insertion transducers designed for steam and flare gas duties. A strong option for typical flare headers, with multiple head angles and velocity ranges to suit real-world piping.
T17 high-power transducers – High-output wetted gas transducers engineered for large-diameter pipes and challenging flare applications, with excellent sensitivity at both low and high velocities. Common when you need long acoustic paths and the best low-flow resolution in major refinery or petrochemical flare lines and stacks.

Selecting the right electronics and transducers together is key to getting reliable data, especially at the low flows that matter for leak detection, background flaring, and emissions reporting.

Panametrics T5 and T17 wetted ultrasonic transducers used with GF868 and XGF868i flare gas flowmeters for different pipe sizes and velocity ranges.

Kurz 454FTB-WGF for Wastewater and Landfill Flare Gas

For wastewater treatment plant and landfill flares, the process looks very different from a refinery header. Gas is typically saturated biogas, lines can be compact, and condensation is a fact of life. In these applications, a wet-gas-capable thermal mass meter is often a better approach than ultrasonic.

The Kurz 454FTB-WGF is a single-point insertion thermal mass flow meter purpose-built for wet, condensing gas, including:

Digester gas at wastewater treatment plants
Landfill gas collection and control systems
Other saturated biogas applications

Its patented sensor design separates the dry gas flow signal from the effects of moisture in the stream, helping avoid the large “spike” readings and over-reporting that can happen when droplets hit a conventional thermal sensor.

Kurz 454FTB-WGF single-point insertion thermal mass flow meter with probe-style sensor and explosion-proof transmitter housing. — Kurz 454FTB-WGF wet-gas thermal mass flow meter for wastewater treatment plant and landfill biogas flare applications.

For wastewater and landfill flares, the Kurz 454FTB-WGF offers:

Optimized wet-biogas performance – Designed specifically for saturated, condensing gas where standard thermal mass meters may struggle to stay stable or accurate
Direct mass flow measurement – Reads biogas mass flow directly, without separate pressure and temperature compensation, simplifying wiring and calculations
Single-nozzle insertion design – A rugged welded probe that can be installed through one nozzle, ideal for existing flare and biogas piping in brownfield plants
A good match for smaller lines and moderate velocities – Well suited to the pipe sizes and flow regimes typical of wastewater and landfill gas systems
Support for reporting and compliance – Provides stable, repeatable biogas mass flow data that can feed into EPA and local air district reporting tools

For many municipal wastewater utilities and landfill operators, the 454FTB-WGF is a more practical and economical fit than a large ultrasonic flare gas meter, especially where wet biogas and compact flare piping are the norm.

Clipper Controls can help you decide whether a Panametrics ultrasonic or a Kurz wet-gas thermal mass solution is the better match for your specific flare, gas quality, and regulatory requirements.

👉 Ready to compare flare gas technologies or plan a project? Contact Clipper Controls to discuss your flare header, process conditions, and which flare gas meter is the best fit for your site.

Regulatory Drivers: EPA 40 CFR Part 60/63 and Compliance

Regulations such as EPA 40 CFR Part 60 and Part 63 increasingly call for continuous monitoring and documentation of flare system performance. Typical requirements include the ability to:

Measure and record flare gas flow
Demonstrate adequate combustion performance and heating value
Produce defensible data for emissions inventories and reports

Reliable flare gas flow measurement is the foundation for those records. When applied correctly, Panametrics ultrasonic flare gas meters and Kurz 454FTB-WGF biogas meters help plants build monitoring systems that tie into existing DCS, SCADA, and reporting platforms.

(Clipper Controls does not provide legal or regulatory advice. Facilities should consult their environmental professionals regarding specific obligations.)

Key Features to Look for in a Flare Gas Meter

When comparing flare gas metering technologies and models, maintenance, reliability, and I&C teams should keep an eye on:

Turndown and low-flow sensitivity – Essential for leak detection, background flaring, and high-flow upset events
Performance with changing composition – Especially important for emissions and mass balance calculations
Intrusiveness and pressure drop – Non-intrusive or minimal-restriction designs help preserve flare capacity and reduce fouling
Bidirectional and pulsating flow capability – Real-world flare headers rarely behave like textbook straight runs
Wet-gas robustness – Ability to handle entrained liquids and mixed-phase conditions, either via ultrasonic wet-gas compensation or wet-gas thermal designs
Diagnostics and health monitoring – Signal quality, meter status, and alarm outputs that make it easy to see when something isn’t right
Integration options – Analog and digital outputs that connect cleanly to DCS, SCADA, and flare control systems

For refinery, petrochemical, and hydrocarbon flares, Panametrics ultrasonic meters such as the DigitalFlow GF868 and DigitalFlow XGF868i check these boxes. For saturated biogas flares, wet-gas thermal mass solutions such as the Kurz 454FTB-WGF often provide a better fit.

Typical XGF868i ultrasonic flare gas meter installation showing temperature and pressure inputs for volumetric or mass flow measurement.

Typical Flare Gas Meter Applications

Ultrasonic and thermal flare gas meters are commonly applied in:

Refineries – Main and unit flare headers for system monitoring, event reporting, and air permit compliance
Petrochemical and chemical plants – Relief and vent headers for emissions measurement and MACT/NSPS requirements
Gas processing, LNG, and midstream – Plant and terminal flares to track lost product and methane emissions
Tank farms and terminals – Vapor collection headers routed to flares or enclosed combustors
Offshore platforms and FPSOs – Tight spaces where non-intrusive or transmitter-style ultrasonic meters are preferred
Wastewater treatment plants and landfills – Wet biogas flares where wet-gas thermal mass meters like the Kurz 454FTB-WGF are typically the better option

Across all of these applications, the goal is the same: accurate, reliable, defensible flare gas measurement.

How Clipper Controls Supports Flare Gas Projects

Choosing a flare gas meter isn’t just a catalog exercise. Clipper Controls works with you from concept through commissioning to make sure the solution fits your process, flare hardware, and compliance requirements.

Application review

Line size, pressure, and temperature
Minimum, maximum, and upset flows
Gas composition ranges and how they change
Available straight run and piping constraints
Applicable environmental and reporting requirements

Flare stack burning gas against a blue sky

Solution selection and integration

Recommending DigitalFlow GF868, DigitalFlow XGF868i, Kurz 454FTB-WGF, and related Panametrics solutions as appropriate
Selecting the mounting and installation approach: spool piece, insertion transducers, or other approved configurations
Integrating with DCS/SCADA and, where needed, flare.IQ or other optimization/analytics platforms

Lifecycle support

Configuration and optimization after startup
Diagnostic review and troubleshooting when conditions or requirements change
Expansion to additional flare headers, biogas lines, or units over time

Talk to a Flare Gas Metering Expert

Reliable flare gas flow meters give you:

Clear visibility into flaring activity
Solid data for EPA 40 CFR Part 60/63 and other reporting frameworks
Insight to cut unnecessary flaring and emissions
Confidence that safety and relief systems are doing their job

👉 Ready to improve flare visibility and compliance?

Contact Clipper Controls to discuss your flare header conditions, emissions goals, and the right Panametrics flare gas meters for your facility.

​​Flare Gas Meters

​​What Is a Flare Gas Meter?

​​Why Flare Gas Measurement Is So Challenging

​​Why Ultrasonic Flare Gas Meters Are Preferred