It is common for some sample types, such as viscous lube oils that fall within the scope of the method, to be prone to contain tiny bubbles soon after manufacture which can take a significant amount of time (e.g., up to 24 hours) for bubbles to completely dissipate before drawing an aliquot for analysis, causing an undue delay in performing measurements by this method. To address this issue, a proposed revision is identified to allow the optional use of an ultrasonic bath to effectively remove air or gas bubbles from viscous lube samples prior to analysis without adversely impacting results determined. The proposed revision is similar in nature to the language adopted in ASTM D4052, D1500, and D6045. Supporting data showing no material impact on results is included with the ballot item. After discussing the initial version of the proposed ballot item at the June 2013 ASTM meeting, a request was made by the SC7 membership to provide additional information about the typical operating frequencies and power outputs of the ultrasonic baths that were appropriate to use, which take into account the conditions used by labs in the data comparison to demonstrate that results were not materially impacted. As such, the initial ballot item was updated to reflect this information, as well as include a statement to give labs an opportunity to use ultrasonic baths with operating frequencies and power outputs outside this range, provided the laboratory conducts a data comparison study to confirm that results determined with and without the use of such ultrasonic baths does not materially impact results. Lastly, the SC7 membership requested additional information about the nature of the samples that were evaluated in the study as well as the guidance the labs were given in conducting the study. This information is included in the following section to address this request from the SC7 membership.
Keywordsdynamic viscosity; kinematic viscosity; viscometer; viscosity; Calibration--petroleum analysis instrumentation; Dynamic viscosity; Electrical insulating petroleum products; Kinematic viscosity; Viscosity--petroleum products;
Draft Under Development