1. Scope

Keywords

Rationale

A typical optical gas imaging (OGI) device (e.g., hyperspectral, multispectral, etc.) relies upon molecular contrast signals to generate a detection. This detection is then post-processed using a type of visualization logic. It combines pixel velocity (referenced by known dimensions/geometry) and pixel opacity (signal strength) to derive volumetric and/or mass emissions rate estimates. Additionally, an OGI device allows for immediate localization of release events providing the operator/user with the ability to witness detailed material characteristics of gas behavior at the source. This emphasizes the need to understand gas behavior and other thermodynamic attributes upon release. However, without a standardized approach to linearity evaluation, atmospheric impact analysis, and detection/quantification certainty, it is difficult establish meaningful minimum detection limits (henceforth “MDL”) and probability of detection (PoD) based on operational and environmental flux. Furthermore, if one considers that a point-source monitor (i.e., fence-line) receives signal different from that of an optical-based system, it becomes clear that a specific methodology/practice is required to objectively evaluate or “challenge” an OGI instrument with known values – in accordance with its detection principles and capabilities. In an authentic operating environment, gas is subject to a variety of temperatures, pressures, flowrates, and other thermodynamic forces (i.e., friction, volatilization, thermal conductance, etc.). Therefore, to understand both the capabilities and limitations of an OGI device, it is imperative to understand gas behavior through any type of system – under a variety of operating conditions (environmental flux notwithstanding). The proposed methodologies contained in this data package provide procedures for evaluating system performance and integrity of OGI systems in a parametric manner.