Flare Stack Monitoring Systems & Solutions

A flare stack is an industrial combustion device used to safely burn off excess or waste gases at oil refineries, chemical plants, and gas processing facilities. It prevents the release of unburned hydrocarbons into the atmosphere, managing pressure relief and byproduct gases while minimizing environmental impact. Monitoring the flare stack ensures complete combustion and regulatory compliance.

Stack monitoring involves measuring parameters such as gas velocity, flow rate, temperature, opacity, and pollutant concentrations within an industrial stack or duct. Methods include optical scintillation — as used in OSI's OFS sensors — which provides non-intrusive, cross-stack velocity measurement. This data supports EPA emissions reporting, mass flow calculations, and continuous compliance monitoring without interrupting process operations.

A flare is a combustion device that burns off waste gases through an open flame, typically at the tip of a tall pipe. A stack is a chimney-like structure that exhausts combustion byproducts or process gases from equipment such as boilers, furnaces, or oxidizers. Both require flow monitoring for environmental compliance, but flares present unique challenges including extremely wide velocity ranges, from near-zero to very high flow.

Yes. OSI's OFS series optical flow sensors are specifically designed and certified for EPA 40 CFR Part 75 compliance. They use a NIST-certified measurement algorithm supported by over 20 million hours of observation data. The sensors provide the continuous emissions monitoring data required by the EPA for power plants, refineries, and other regulated industrial facilities.

No. OSI's OFS sensors are factory-calibrated and feature built-in automatic calibration checks that eliminate the need for field calibration. With no moving parts and an essentially maintenance-free design, the only recommended maintenance is semi-annual window cleaning if required. This dramatically reduces operational downtime and total cost of ownership compared to traditional flow measurement devices.

OSI offers two measurement range configurations. The standard OFS-2000 covers 0–100 m/sec, suitable for general stack and industrial applications. The OFS-2000F is specifically engineered for flare stacks, covering an extended range of 0.03–170 m/sec to accommodate the extreme low-to-high velocity variations typical in flare gas flow. Both achieve ±2% measurement accuracy.