Standards-testing authority ASTM has a new voluntary standard for biodiesel, designed to meet the needs of customers using ultra-low-sulfur diesel and new diesel engine and after-treatment technology.

A new voluntary No. 1-B grade for biodiesel (B100) passed the ASTM D2 Committee on Petroleum Products and Lubricants this past spring and the results were sanctioned by the ASTM Committee on Standards in a meeting held late last week.

ASTM D6751, the ASTM standard for pure biodiesel (B100) prior to blending, was modified to create a new voluntary No. 1-B grade. The new grade provides more stringent controls for minor components in raw materials used to make biodiesel, such as vegetable oils and animal fats. The specification values of the current standard will become the No. 2-B grade in D6751 without change.

The finished blended fuel standards -- D975 for on/off road diesel up to 5% biodiesel (B5), D7467 for B6-B20 on/off road applications -- do not change. B100 used for D975, D7467, and D396 must continue to meet D6751 (either the No. 1-B or the No. 2-B grade) prior to blending.

The choice of the No. 1-B and No. 2-B designations were selected to make the standard as similar as possible as the current mode of operation with No. 1 and No. 2 diesel fuel. Most users utilize No. 2 diesel fuel, but if they experience unexpected filter clogging they can switch to No. 1 diesel fuel, use additives or other means to prevent unexpected filter clogging. The same philosophy is to be maintained with the No. 1-B and No. 2-B biodiesel specification, i.e. most users will continue to utilize the No. 2-B biodiesel but if unexpected filter clogging is experienced, No. 1-B can be used for blending.

The interest in creating No.1-B specification was triggered by instances with USLD fuel experiencing unexpected filter clogging above the cloud point of the finished blend, which mostly occurred with low aromatic No. 1 type diesel blends.