Flare Gas Flow Meter
Flare Gas Flow Meter
Flare gas measurement is driven primarily by regulatory requirements. EPA 40 CFR Part 60 and Part 63 require flare gas flow monitoring at refineries, chemical plants, and other facilities as part of air emissions reporting. The measurement has to be reliable across an enormous range of flow conditions — from near-zero during normal operations to very high flows during process upsets — and it has to hold calibration in a demanding environment.
Thermal mass flow meters are well suited for flare gas because they measure mass flow directly without needing pressure or temperature compensation, handle very wide turndown ratios, and work accurately at the low line pressures typical of flare headers.
Key requirements for flare gas measurement
Wide turndown ratio is the defining challenge. A flare that handles 10 MMSCFD during an upset may run at 50 SCFD during normal operations — a 200,000:1 turndown. Conventional differential pressure devices can't cover this range. Thermal mass flow meters achieve turndown ratios of 1000:1 or more from a single meter, and with multiple range configurations can cover even wider ranges.
Low pressure operation is the norm in flare headers — often just a few inches of water column above atmospheric. Meters that require minimum line pressure for accurate operation won't work. Thermal mass meters have no minimum pressure requirement and read accurately at essentially atmospheric pressure.
Variable gas composition is common in flare gas — the mixture changes depending on what relief valves open and which process units are contributing. Our meters can be configured with Gas Conversion Factors for specific gas mixtures, and the industrial thermal mass meter's sensitivity to composition can be minimized through careful calibration and configuration.
Common flare gas flow meter applications
• EPA emissions monitoring — document flare gas volume for regulatory reporting under 40 CFR Part 60/63
• Refinery flare headers — measure total flare gas flow across all relief valve contributions
• Chemical plant flare systems — monitor emergency relief flows and continuous purge gas
• Upstream oil and gas — measure gas sent to flare at wellsites and gathering systems for production accounting
• LNG and gas processing — flare system monitoring at liquefaction and fractionation facilities
• Greenhouse gas accounting — calculate CO2 equivalent emissions from flared gas volumes
What to look for when selecting a flare gas flow meter
Pipe size and insertion vs inline — for large flare headers (6" and above), insertion thermal mass meters are more cost-effective than full-bore inline meters. For smaller lines (½" to 4"), inline meters provide better accuracy and lower installation cost.
Turndown ratio — confirm the meter's turndown ratio covers your full operating range from minimum purge flow to maximum upset flow. Specify both values when ordering.
Hazardous area classification — flare systems are typically Class I Division 1 or 2. Confirm the meter's explosion-proof rating matches your area classification.
Output and data logging — most flare monitoring installations require 4-20 mA output to a data acquisition system, plus local display for visual confirmation. Modbus RTU is available for digital integration.
|
Application |
Recommended Meter |
Why |
|
Flare header, ½" to 8" |
Industrial Thermal Mass Flow Meter |
Wide turndown, low pressure operation, direct mass flow |
|
Large flare headers, 8"+ |
Insertion Thermal Mass Flow Meter |
Cost-effective for large diameter headers |
|
High accuracy custody / emissions |
Coriolis Flow Meter |
±0.1% accuracy where regulatory precision is required |
|
Data logging, EPA reporting |
Any meter + Cloud Data Logger |
Automated data collection and reporting |
In stock and ready to ship
Industrial thermal mass flow meters for flare gas ship from Salinas, CA. Contact us with your pipe size, gas composition (if known), and flow range — we'll configure the meter for your application before it ships.
Call (831) 244-8080 to discuss your flare monitoring requirements, or go straight to the product page.