ISO/TC 197 WG13 Hydrogen Detectors Holds Meeting in Seoul, Korea
Karen Hall, National Hydrogen Association
ISO TC 197 WG 13, which is preparing an international standard for hydrogen detection apparatuses where multi-level sensing is required, met on June 8 and 9 in Seoul, Korea.
The Working Group (WG) spent the two days reviewing and resolving comments received from member countries on the ISO Committee Draft 26142: Hydrogen Detection Apparatus. The meeting focused on the technical comments with the potential to require discussion and resolution. Additional comments will be resolved for the next meeting.
A representative from a testing lab in Germany, as well as an expert from IEC TC 31 from Italy attended the meeting to help resolve comments and improve the document. They were a valuable addition to the discussion. Also represented were: Canada, Japan, South Korea, and USA.
Key issue: Japan continues to press for a lower detection limit of 100 ppm. All other delegates present want an option for up to 1000 ppm. The group spent most of the meeting on this point, and the associated tolerances to the results of testing the sensors at four points in or above the flammability range. The standard applies to refueling stations as well as other stationary applications where the user desires the ability to monitor hydrogen concentrations.
Japan is mainly concerned with detection apparatuses installed some distance from outdoor refueling stations, where the concentration of hydrogen at the detector may be significantly lower than the concentration near the leak. Other experts want the flexibility to have manufacturers declare the lower detection limit from 0-1000 ppm, and have the first test point at that declared value.
Representatives from Canada, Germany, Italy and the U.S. noted that no action would be required at or near 100ppm, and that a requirement to select hydrogen at this level would result in many sensor technologies being excluded from applications covered by the standard. In addition, increased resulting false positive readings may actually compromise the safety of the system. Those from Japan, on the other hand, presented data of fuel stations with settings at 500 ppm, and even less in some cases, as well as a brochure of electrochemical sensors capable of detecting hydrogen at 100 ppm, reiterating that they share the same philosophy of finding the proper combination of the performance of detectors required based on a wide range of installations and locations, and available detection technologies.
As a compromise, the Working Group agreed to work on the language to allow a range of lower detection limits, as declared by the manufacturer, so that the resulting standard would be more usable for a variety of stationary applications where continuous monitoring and multi-level sensing is desired.
Although the WG worked very hard, the time was insufficient to resolve all the comments received. Therefore many technical issues resulting from the CD comments are being addressed through homework assignments in advance of the next WG13 meeting, which will take place in conjunction with the ISO Plenary meeting in Italy in early November.
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