Work Item
ASTM WK81157
Revision of D2639/D2639M-21a Standard Test Method for Plastic Properties of Coal by the Constant-Torque Gieseler Plastometer
Rationale
Establishing a standardized motor r/min for this test method would greatly improve the overall reproducibility of the test method, as well as the repeatability. This is important because breaks directly correlate to the industry-wide variation in maximum DDPM’s being reported. This is often because the runs that are ‘breaks’ are included in the final reported maximum DDPM, which skews interlaboratory results, and yields a higher DDPM. Users of D2639 are in the position of re-running a sample multiple times simply because of the higher probability that motors with an r/min greater than 300 that come standard on the new plastometer instrumentation will produce a break. Additionally, it is being suggested, as a requirement, that the hysteresis brake torque be checked every 25 runs or more frequently. This could potentially improve interlaboratory results as well.
Work Item Status
Date Initiated: 03-03-2022
Technical Contact: Gregory Nichols
Item: 006
Ballot: D05.15 (22-01)
Status: Negative Votes Need Resolution