Busy Time for ISO TC 238

While the efforts of ISO TC 238 are ongoing, they are greatly accelerated each year during the annual plenary and working group meetings, which are being held in Espoo, Finland, May 28 to June 1.
By Chris Wiberg | May 24, 2018

As many pellet manufacturers are likely aware, ISO TC 238 is the International Standards Organization Technical Committee through which numerous countries around the world are working together to develop standards for solid biofuels. While the efforts of ISO TC 238 are ongoing, they are greatly accelerated each year during the annual plenary and working group meetings, which are being held in Espoo, Finland, May 28 to June 1. This year, the U.S. will be represented by three delegates, including Scott Cedarquist, administrator of the American Society of Agricultural and Biological Engineers’ U.S. Technical Advisory Group (ASABE is the direct representative of ANSI), Georgia Biomass’s Ritu Linhart, who is active on multiple ISO TC 238 Working Groups, and me, Chris Wiberg of Timber Products Inspection/ Biomass Energy Lab, and chairman of the U.S. TAG. These efforts are being sponsored by the Pellet Fuels Institute, as well as the employer of each delegate.

While there are always projects at different levels of development within ISO TC 238, this year, there are some projects of significant interest. An issue has been raised with the test method for determining fines content–ISO 18846. This method has been challenged as not being representative of the true amount of fines in the sample tested. The reasons behind this challenge are complicated, so it is anticipated that this method will be reviewed in detail, and could be altered, and/or a new method created, which could change the way fines are measured. We are expecting this to be a significant point of discussion and debate within the assigned working group. This issue is of particular interest to wood pellet producers who supply export power markets, due to an emphasis on fines content as part of contractual requirements. This project is expected to be jointly led by the U.S. and U.K.

A U.S.-led project of interest is a New Work Item Proposal for the determination of water sorption, and its effect on durability in thermally treated biomass fuel pellets. For biomass thermal treatment technology initiatives, a common selling point is that the material becomes water resistant and can be stored outside. This test method is designed to determine how much water sorption occurs in thermally treated biomass fuel pellets when immersed in water, and also assesses the durability of the product both before and after immersion. A weathered durability index is calculated as the difference between the durability of the as-received sample and the durability of the wetted product. Additionally, the amount of fines created as a result of immersion is reported as “weathered fines.”  This project is in its very early stages.

Also in development is a test method for hardgrove grindability in thermally treated biomass. The coal industry has long since had a test method for hardgrove grindability index, which is used to assess the hardness of coal and how much energy is required to grind it to a certain particle size. This test method has been of little use for the biomass industry due to the fibrous nature of biomass, which does not pulverize under pressure as coal does. The biomass industry is still in need of a similar test to determine grinding energy, and years of effort have not been fruitful—until now. This method has been proposed by Germany as a new work item, and is applicable to thermally treated biomass, as it has properties similar to coal. 

Yet another initiative that will be discussed is a test method for ash fusibility. This method has been in development for several years, and with successful validations over the past year, it is finally taking shape. Ash fusibility (the melting of ash into slag) is very complicated, and it is worth noting that when the European method for ash fusibility was published in 2006, it was published as a technical specification, and not as a complete standard.  This was due to issues with repeatability/reproducibility. This new method brings consistency to the measuring process, and has gone through great effort to assure consistent interpretation by computer systems and analysts in the laboratories. It will likely be another year before final publication, however, this method is well on its way to publication. The project is being led by Austria.

There are several other initiatives in the works, including a simplified sampling method proposed by Germany for small-scale applications, a French proposal for modifying the wood chip specification standard (ISO 17225-4) to include a table for industrial grade wood chips, and several safety standards that have been developing over the past few years, some of which are now approaching publication.

In conclusion, there is a lot going on within ISO TC 238. The U.S. Technical Advisory Group currently has approximately 50 members and is administered by ASABE. We are always looking for interested individuals to join our efforts in reviewing these standards as they are developed, to ensure they are well-thought-out, and reflective of U.S. interests in the global solid biofuels industry.  If you would like to join the TAG, please contact Scott Cedarquist at ASABE (cedarq@asabe.org).

Author: Chris Wiberg
Manager, Biomass Energy Laboratory