Standardization
| January 29, 2013 | Filled under Com I |
|
established Oviedo, 1983
Conveners
Previous Convener: Dr. Walter Pickel† (2008 to 2022)
Members
Introduction
Photomicrograph of RIC08 round robin sample (Australia, Bowen Basin)
The Standardization WG is the longest running working group of Commission I and its objectives have been adapted over the time moving the focus according to the new developments in definitions and methodology. The main objectives can be summarized as:
- Organize and evaluate round robin exercises related to analysis procedures, recent discussions and definitions/classifications established or to be established by the ICCP.
- Contribute to the revision of the existing standards for petrographic analysis of organic rocks
The working group has been holding round robins on lignite, sub-bituminous and bituminous coals with varying emphasis. Reflectance analysis, maceral group, maceral sub-group and maceral analyses or a round robin on a set of glass standards were topics of the ring analyses. The results from the round robins inter alia established experimental data for the reproducibility, contributed to the idea of the ICCP Accreditation Program and caused the ICCP to have its own reflectance standards against which other standards can be calibrated.
The working group was originally convened Carl Ottenjann (as the Standardization of Analyses Working Group) then by the late Werner Pfisterer followed by the late Walter Pickel, Harold Read, Walter Pickel and Ivana Sykorova and in 2022 by Stavros Kalaitzidis replacing Walter.
Recent Activities
2022 A review of the ICCP contribution to the development of standard procedures, which is an updated of the plenary talked given by A.G. Borrego in The Hague Meeting was presented within the WG during the Meeting in India. It was agreed that A.G. Borrego and Stavros Kalaitzidis will co-convene the WG.
2023. The ICCP has formally established a category C liaison with ISO and the new convener of the Standardization W.G. (A.G. Borrego) will be the contact person with ISO in addition to the President. A.G. Borrego attended the ISO TC27/SC5 meeting in Delft representing ICCP where it was established to open again the revision of the 5 ISO 7404 standards dealing with petrographic analysis of coals. Feedback on a proposal presented to ISO TC27/SC5 WG14 by Kazakhstan delegation to establish the level of oxidation of a coal using petrographic methods has been provided to ISO.
For 2023-2024 an exercise is also prepared based on photomicrographs, in which the participants will have to identify macerals of lignite rank samples.
Historical Development
At the meeting in Oviedo 1983, the structure of the Standardization WG within Commission I was established as having three main activities:
- Maceral/Reflectance (W. Pfisterer) The maceral/Reflectance branch focused on relevance of calibration and performing Round Robin exercises on Vitrinite Reflectance and maceral analysis to test reproducibility. RIC83, RIC85, RIC87 were conducted showing that vitrinite reflectance results were close to ISO reproducibility limits. Since 1991 W. Pickel took over the convenorship dealing essentially with reproducibility of maceral analysis and vitrinite reflectance. A split of the standardization W.G. focusing on the establishment of the Accreditation Program was convened by R. Kutzner (see Historical Development of ICCP Accreditation Programs). In the forthcoming exercises (RIC92, RIC93, RIC99) the Vitrinite classification ICCP1994 system was used. In general, vitrinite reflectance results were closer to each other than maceral analysis results. The agreement was good at maceral group level but discrepancies increased at maceral subgroup and maceral level. No improvement was observed in successive exercises.
The activities of the W.G. on reproducibility of Maceral analysis continued under the convenorship of H. Read since 1999. The objectives focused on:
i) Verification of the new vitrinite, inertinite and liptinite classifications. Under this objective the following Round Robin exercises were carried out:
RIC2000 (Australian medium volatile bituminous coal) few analysts replied but a difficulty in distinguishing semifusinite and fusinite became clear. Results are summarized in ICCPNews25 (2001).
RIC2003 (Inertinite-rich Australian medium volatile bituminous coal). Quite poor results attributed partially to instructions not precise enough
RIC2005 (2 Greek Lignites) to test the Huminite classification ICCP System 1994 (ICCPNews36, 2005). Overall good agreement for maceral groups and vitrinite reflectance but poor agreement for macerals and subgroups. Work should concentrate on improving the definitions for major macerals, eg fusinite/semifusinite; collotelinite/ collodetrinite, etc.
RIC2008 (Gregory, Bowen Basin, Queensland (AU) German Creek Seam. Late Permian. Medium Rank B-C according to ISO 11760). I. Sýkorová joint W. Pickel as convenor for this exercise. As reported in the ICCPNews48 (2009), 22 participants reported results and agreement was good at maceral group level but very poor at maceral sub-group level essentially because of the misinterpretation of the meaning of gelification (gelo-vitrinite) in the medium rank stage. The discussion on a collection of images provided proved to be useful and it was decided to run an exercise on microscopy images of the same coal.
RIC2010. The same coal used in RIC2008 was used to obtain the images for this exercise. The exercise consists of a pdf file with images with marked fields that the participant is expected to assign to a vitrinite subgroup: telovitrinite, detrovitrinite or gelovitrinite according to vitrinite 1994 ICCP system (ICCP; 1998: The New Vitrinite Classification (ICCP System 1994) – Fuel, 77: 349-358). The exercise also consist of an excel sheet where the participant is expected to report the results and send them back to the organizer and detailed instructions to perform the exercise. It is possible to run this exercise (contact angeles@incar.csic.es).
RIC2016. Two lignite samples from the Lausitz Lignite District, Open Cast Nochten, 2nd Lausitzer Main Seam, Miocene, kindly supplied by Claudia Niemtz from Vattenfall AB, were distributed for analysis. The samples were very difficult and reproducibility of results were very poor.
ii) Assist ISO in the revision of the ISO 7404 standard methods. This activity incorporated within the objectives of the WG at the meeting in 1999. At the Meeting in Patras (2005) three contact persons were established for each of the standards under revision: part 2-sample preparation (D. Pearson); part 3-maceral group composition (H. Read) and part 5-Measurement of vitrinite reflectance (W. Pickel). At the time of the Bandung Meeting (2006) the three standards under discussion were ready. Part 2 revision included solid media for preparation of samples. Part 3 revision succeeded in its objective to cover coals of all ranks, but failed to expand coverage to include maceral subgroups and macerals. These 3 standards were finally published in 2009.
At the meeting in Beijing (2012) the revision of part 1-Vocabulary by ISO has been formally initiated, but it was not clear if the part 4-microlithotype analysis was worth to be revised. After the discussion held in Commission I, it was agreed to ask ISO to formally initiate the process. The contact person was H. Read. The revised version of part 1 incorporating the ICCP 1994 System for vitrinite, huminite, inertinite and liptinite was published in 2016. The revised version of part 4 without considering the rule of 5% for purity of the microlithotypes was published in 2017. ISO formally approved the revision of part 2-, 3- and 5- in order to incorporate last advancements in microscopy. The chair of ISO TC27/SC5 WG14 dealing with petrographic analysis of coals was W. Pickel and therefore a smooth transfer of the ICCP knowledge into the ISO WG14 was guaranteed.
At the Meeting in The Hague (2019) it was discussed again the convenience of having an ICCP representative in ISO WG14 formally bringing to ISO the view of the ICCP. This was attempted during A. C. Cook presidency and a formal liaison was established but without resulting in a continuous exchange with ISO WGs.
The unexpected passing of W. Pickel in 2022 caused the cancellation of the ISO 7404 revision process, which has been re-activated again in 2023 under the convenorship of L. Williamson. The ICCP has formally established a category C liaison with ISO and the new convener of the Standardization W.G. (A.G. Borrego) will be the contact person with ISO.
iii) As an additional activity of the standardization W.G., it was decided at the Meeting in Heerlen in 1996 to focus the efforts of the W.G. on the quality of the standards for reflectance measurements. This topic was covered initially within the W.G. by K. Ottenjann that presented a paper in 1983 on calibration of reflectance standards. The methods of calibration (i.e. measuring refractive index or photometric measuring substances of known optical properties) were discussed. Diamond and Silicon Carbide were used as reference standards and oil and water as immersion media. In the meantime, numerous standards have become available and it was need to test the reliability of the standards. The objectives established were:
-
- To give each participant the possibility of comparing his calibration method and standard with others.
- To get an idea of the possible variations of reflectance measurement data due to calibration
Round Robin exercise on reflectance of standards (W. Pickel, D. Pearson, R. Javier). The objective of the exercise was to measure the random and maximum reflectance of 3 glass standards (reflectance ~0.50%, ~1.01%, and ~1.90%) against the standard(s) used in the participating laboratories. 34 analyst reported Rr results, most of them (26) also Rmax. The results showed that there was a wider than expected, although acceptable variation (ICCPNews22, 2000). As a result, Commission I purchased two YAG standards (Klein & Becker), calibrated them against the round robin results and declared them the ICCP Standards. These could be available through the Reflectance Standard Checking service to interested laboratories.
- Fluorescence (P van Gizel) The fluorescence branch focused on finding suitable standards in the whole range of the spectrum and measuring the fluorescence intensity of low fluorescing components. Since 1984 the convener of the group was K. Ottenjan and the main outcome was the sheets of the Handbook:
-
- Fluorescence Part I. Measurement of Fluorescence Intensity (1989)
- Fluorescence Part II. Measurement of Spectral Distribution (1992). The document was not considered definitive and J. Quick and C. Thompson-Rizer took over as conveners. The final title of the sheets as published in the 3rd supplement of the handbook was “Fluorescence Microscopy Photometry Part II. Measurement of Fluorescence Spectra”, which were accepted at the meeting in Wellington 1997 for publication.
Further developments on standardization of Fluorescence measurements were carried out within Commission II in the Thermal Indices WG, that for a period (1994-1998; B. Pradier Convenorship) focused on standardization of spectral fluorescence measurements. The effort is now centred on fluorescence lamps calibration and is continued by J. Kus within Commission II.
- Automated systems (K. Dawson) The standardization of automated focused on the comparability of automated and manual analysis. These activities started as early as 1983. Few participants were contributing to the ring analysis and the W.G. was resting for a period. In 1988 the W.G. had been re-named to Automation and was reporting in Commission III with R. Munnix acting as convener.