Standards Development

Scope

This document defines a method for using Optical Gas Imaging (OGI) within a leak detection and repair programme. It specifies the scope of application, performance requirements on OGI equipment, QA/QC procedures, and data processing steps to report mass emissions using correlation.

Purpose

The measurement and management of fugitive emissions is recognised as BAT in a number of BREFs and BAT Conclusions under the IED, including the Refining of Mineral and Gas BREF and Waste Treatment BREF. One mechanism identified as BAT to reduce certain fugitive emissions is the use of a leak detection and repair (LDAR) programme. This can use sniffing or optical techniques to find leaking components. The Waste Treatment BAT Conclusions define an LDAR programme as the following: “A structured approach to reduce fugitive emissions of organic compounds by detection and subsequent repair or replacement of leaking components. Currently, sniffing (described by EN 15446) and optical gas imaging methods are available for the identification of leaks.”

The current European Standard EN 15446:2008 Fugitive and diffuse emissions of common concern to industry sectors – Measurement of fugitive emission of vapours generating from equipment and piping leaks provides a method to identify leaking components on industrial sites and to quantify the leaks using correlation/emission factors based on the ‘sniffing’ approach. This is based on the use of point gas detectors to identify elevated concentrations of VOCs in the vicinity of leaking components. Since the publication of EN 15446 an alternative approach using optical gas imaging (OGI) for leak detection and repair is being used more widely.

As described in the WT BAT Conclusion OGI methods: “Optical imaging uses small lightweight hand-held cameras which enable the visualisation of gas leaks in real time, so that they appear as ‘smoke’ on a video recorder together with the normal image of the component concerned, to easily and rapidly locate significant organic compound leaks. Active systems produce an image with a backscattered infrared laser light reflected on the component and its surroundings. Passive systems are based on the natural infrared radiation of the equipment and its surroundings.”

CEN/TC 264/WG 38 has recently developed a standard method for the other techniques described in the BAT Conclusions to provide measurement of diffuse VOC emissions (prEN 17628:2020), however, there remains no standardised method for the use of OGI in its role within an LDAR programme. A number of studies on the use of OGI for leak detection programmes have been reported in conferences and in the literature. The US EPA has also recognised its use in the so called ‘Smart LDAR’ approach.

EN 15446 itself recognised the potential future need for this and states in its scope “Optical methods are currently under development to ease the detection of leaks in plants and use of this standard in conjunction with these methods might be possible. In any case, measurements have to be performed according to the requirements of this standard. To enable direct quantification of total fugitive emissions based only on these methods, a subsequent revision of this standard will be needed.”

This new work item will develop a Technical Specification addressing the role of OGI in an LDAR program, defining the method for using OGI, performance requirements on OGI equipment, QA/QC procedures, and data processing steps to report mass emissions using correlation.