Three proposed biodiesel specifications have taken the next step toward final approval as ASTM International consensus standards. The specifications include:

-Adding requirements for up to 5 percent biodiesel to existing ASTM D975, Specification for Diesel Fuel Oils;

-Revising the existing ASTM D6751, Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels, to include a requirement for cold soak filterability; and

-A new specification for blends between 6 (B6) and 20 (B20) percent biodiesel for on- and off-road diesel.

Biodiesel and petroleum companies, engine and fuel equipment manufacturers, automakers, government, academia and testing laboratories have all participated in this effort within Committee D02 on Petroleum Products and Lubricants.

In addition, another biodiesel standard has also taken another step forward; it adds biodiesel blend specifications up to 5 percent by volume (B5) to ASTM D396, Specification for Fuel Oils.

Before the four standards can be published, however, additional steps must be taken according to ASTM International standards development requirements. "ASTM's consensus process requires a procedural review that is now under way," says David Bradley, D02 staff manager. "After completion and acceptance of the review, the standards will be prepared for publication."

When these standards are published, the marketplace will have finished specifications to use in engine design, to include in bid and purchasing contracts or to check fuel quality at the pump, according to Steve Howell, president of MARC-IV Consulting Inc. in Kearney, Mo., and chair of the D02 biodiesel task group that developed the specifications. ASTM D6751 also has regulatory use as a federal biodiesel requirement in the United States and as a reference in regulations of certain countries in Asia, Central and South America, and Europe.

"We based the standards on physical and chemical properties necessary to run well in an engine, not on the specific process used or not on the feedstock that's used," Howell says. "The spec contains a verbal definition for biodiesel as well as all of its properties."

As defined in the proposed standards, biodiesel is a "fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats, designated B100." Based on extensive testing and research, the specifications detail requirements for the fuel characteristics as well as the relevant standard test methods to use for each.

Howell says that ASTM's electronic capabilities contributed greatly to the faster advancement of the standards, but the real 'accomplishment' comes from the broad representation in the document development. "It's a huge accomplishment, it was a lot of work by a lot of people," he says. "If it weren't for the cooperation with the petroleum companies, engine companies working with the biodiesel companies, we would never have been able to pass committee ballot."

For more information about ASTM's biodiesel standards activities or Committee D02, contact David Bradley (phone: 610-832-9681; dbradley@astm.org).