Round Robin Testing
Nothing is 100% pure. In commercial products, standards define the allowable amount of impurities and companies design their products around it. For example, manufacturers design water filter systems to capture a year’s worth of impurities. Without the standard, the filter might work for a month in one person’s faucet and a year in another person’s faucet.
Quality standards for hydrogen used in a fuel cell have already been established, allowing companies that make fuel cells and components for hydrogen dispensers to design their products around it. The next important step is to test hydrogen to see if it complies with the standard.
ASTMAmerican Society for Testing and Materials International, an independent standards-setting organization for testing and measuring processes, ensures that all the standards it publishes are reliable and repeatable for regulatory bodies, analytical laboratories and other stakeholders to use.
CaFCP works with ASTM on eleven hydrogen quality standards. One of those is D7653, a repeatable procedure for measuring ammonia, carbon dioxide, carbon monoxide, formic acid, and water in hydrogen fuel. This method is designed to measure the very low levels of each constituent by a method called Fourier Transform Infrared Spectroscopy (http://en.wikipedia.org/wiki/Fourier_transform_infrared_spectroscopy).
D7653 is in the last stages of an Inter Laboratory Study (ILS), which means that different labs independently perform the same test several times. ASTM’s ILS uses multiple independent scientists performing the test with the use of the same method and conducting a statistic analysis of the results from the different laboratories.
U.S. Department of Energy, ASTM and CaFCP funded the first ILS for six laboratories, including California Division of Measurement Standards’ lab, the agency charged with ensuring hydrogen fuel quality in the state of California. Each lab received cylinders of sample gases containing the constituents listed above, ran tests using method D7653 and sent their results to ASTM for statistical analysis. Results will show the difference between the laboratories to draft a precision and bias statement which will be added to the standard.
ASTM standards and Inter Laboratory Studies ensure that a measurement and testing standard will result in procedures that are not dependent on a particular lab or specific pieces of equipment for routine testing. Future rounds of testing are crucial for completing these standards.