JEFFERSON CITY, Mo. -- ASTM International has released a new standard for biodiesel that will help ensure that biodiesel blends of up to 20 percent will be compatible with future diesel exhaust emissions technology.

The new standard, D 6751-06a, adds new limits on calcium and magnesium, which can be introduced during the biodiesel manufacturing process.

"The biodiesel industry is committed to working with engine makers and exhaust after-treatment companies to do what it takes to boost automakers' support of biodiesel blends with new diesel technology," said Steve Howell, National Biodiesel Board technical director and chairman of the ASTM Task Force on biodiesel standards. "That means ensuring that high quality fuel specifications exist, which recognize and adapt to important changes in diesel technology."

The new changes specifically address the potential effects of small levels of calcium and magnesium on particulate traps used as part of the diesel exhaust after-treatment systems. Previous changes to limit sodium and potassium, used as catalysts in the biodiesel manufacturing process, passed earlier this year. Particulate traps are needed to meet EPA 2007 emissions standards, which reduce particulate matter by more than 90% from new diesel engines.

"Engine manufacturers were concerned that even very small amounts of minor compounds could build up in particulate traps and eventually cause the traps to clog," said Howell. "The new ASTM specification addresses these concerns and demonstrates the industry's eagerness to work with manufacturers to ensure compatibility between the equipment and the fuel."

The new biodiesel specification was released the first week of October. The changes were part of nine ballot items on changes to the existing biodiesel specification that were voted on at the ASTM Petroleum Products and Lubricants D02 technical committee meeting the week of June 26, 2006 in Toronto, Ontario. These changes were necessary to move forward on approval of a blended fuel specification for B20 -- a 20 percent blend of biodiesel with petroleum diesel.

Although this specification covers pure biodiesel, the majority of original equipment manufacturers (OEMs) view the adoption of an ASTM blended fuel specification as a key component for full, universal acceptance of B20.

A subcommittee vote on an ASTM B20 specification will happen in December. Depending on the results, final approval for biodiesel blend specifications could come as early as the spring or summer of 2007.

All major OEMs support B5 and lower blends, provided they are made with biodiesel meeting the ASTM standard. Use of blends higher than B5 will not necessarily void existing warranties.

Biodiesel is a renewable diesel fuel that is made from domestic resources such as soybean oil or other domestic fats and vegetable oils. B20 and lower blends can be used in any diesel engine with no modifications. Biodiesel significantly cuts harmful environmental emissions, promotes greater energy independence, and boosts our economy.

ASTM International, originally known as the American Society for Testing and Materials, is the standards forum of choice for a diverse range of industries wanting to solve standardization challenges.

Additional information about biodiesel is available online at This material sponsored by the USDA Biodiesel Education Program.

SOURCE: National Biodiesel Board.