Minimum Detection Limit (Methane)

Minimum detection limit (methane) (MDL) refers to the lowest emission rate a methane detection system claims it can detect, but it does not indicate how consistently a technology can detect emissions of that size. MDL is often established in laboratory or other controlled settings. It’s typically expressed in kilograms per hour (kg/hr) and often used as a shorthand for comparing technology performance.

However, because detection sensitivity depends heavily on environmental conditions and system design, the minimum detection limit (methane) is an incomplete and sometimes misleading metric.

Instead of using the minimum detection limit (methane), Bridger Photonics defines performance using emission rate detection sensitivity with an associated probability of detection (PoD), which provides a clearer picture of real-world performance.

Why Minimum Detection Limit (Methane) is Misleading

Minimum detection limit (methane) is often cited in technology specs, but without context, it can overpromise what a system can consistently detect. In practice, the meaningful question isn’t “what’s the smallest leak you’ve ever detected?” It’s “what size leak can you detect reliably?”

For technical buyers evaluating vendors, a robust emission rate detection sensitivity metric should be used instead, since it includes the statistical likelihood that an emission of a given size will be detected. A complete emission rate detection sensitivity statement should include:

• Emission rate (e.g., kg/hr, or SCFH)
• Detection probability (e.g., 90%)
• Typical operating conditions

Bridger Photonics provides this context: For the production sector, our system detects emissions of 1 kg/hr or greater with 90% PoD under typical conditions. For the distribution sector, we offer even finer sensitivity—0.5 kg/hr at 90% PoD—tailored to lower-emission systems.

This transparency helps buyers assess system performance with more confidence and compare vendors using apples-to-apples data.

How Minimum Detection Limit (Methane) Works (Brief Technical) 

Detection limits are not fixed. They vary because of factors like:

• Ground wind speed and direction, or gusts
• The reflectivity of the ground surface
• Flight altitude and flight speed for airborne remote sensors
• The number of sensors and sensor spacing for point sensors

That’s why Bridger avoids promoting an absolute minimum detection limit (methane) and instead quantifies performance using a sensitivity threshold (e.g., 3 kg/hr) combined with a statistical confidence level (e.g., 90% PoD). This approach more accurately reflects how the system performs across many flight and site conditions, not just under ideal circumstances.

Key Applications in Oil and Gas

By using an emission rate detection sensitivity with an accompanying probability of detection, oil and gas operators can: 

• Compare vendor capabilities for leak detection and LDAR programs
• Ensure that a vendor can achieve operational thresholds for repair prioritization
• Provide the necessary data for compliance with EPA or state-level regulations
• Inform ESG disclosures with reliable detection benchmarks
• Design survey frequency and coverage based on detection reliability

Related: Methane Detection Sensitivity, Gas Mapping LiDAR™, Scan Density (Methane), Quantification, Probability of Detection

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