Biodiesel Standard (ASTM D 6751)
All engines are designed and manufactured for a fuel that has
certain characteristics. In the US, the industry organization
that defines the consensus on fuels is the American Society for
Testing and Materials (ASTM). In the case of diesel fuel (and
biodiesel), the responsibility for setting standards lies within
ASTM Committee D02 on Petroleum Products and Lubricants. In order
to assure that the standards are rigorous and robust, ASTM committee
D02 is comprised of fuel producers, engine equipment manufacturers,
and third party interests (users, government agencies, consultants).
ASTM also uses a complicated ballot process in which a single
negative vote is enough to defeat a ballot, so this is a true
consensus organization. An ASTM standard is not easily achieved.
Some standards can take over 10 years to gain agreement and be
issued by ASTM. This rigorous, time-consuming process is why ASTM
standards are recognized and adopted by others worldwide.
fuel standards are the minimum accepted values for properties
of the fuel to provide adequate customer satisfaction and/or protection.
For diesel fuel, the ASTM standard is ASTM D 975. All engine and
fuel injection manufacturers design their engines around ASTM
D 975. In cooperative discussions with the engine community early
in the biodiesel industry's development, engine manufacturers
strongly encouraged the biodiesel industry to develop an ASTM
standard for biodiesel fuel which would allow them to provide
their customers with a more definitive judgment on how the fuel
would affect engine and fuel system operations compared to ASTM
D 975 fuel for which an engine was designed.
June of 1994, a task force was formed within ASTM Subcommittee
E on Burner, Diesel, Non-Aviation Gas Turbine, and Marine Fuels
of ASTM Committee D02, with the expressed objective of developing
an ASTM standard for biodiesel. The biodiesel standard, ASTM PS
121-99, was approved by Subcommittee E, and subsequently issued
by ASTM in June of 1999 (for copies, see the ASTM web site at
www.astm.org). In December of 2001, ASTM approved the full standard
for biodiesel, with the new designation of D-6751 (succeeds PS
121-99). This standard covers pure biodiesel (B100), for blending
with petrodiesel in levels up to 20% by volume. Higher levels
of biodiesel are allowed on a case-by-case basis after discussion
with the individual engine company, since most of the experience
in the US thus far has been with B20 blends.
approval of this biodiesel standard, and the technical reviews
necessary to secure its approval, has provided both the engine
community and customers with the information needed to assure
trouble free operation with biodiesel blends.
All diesel engine companies warranty the product they make - engines.
They warranty their engines for “materials and workmanship.”
If there is a problem with an engine part or with engine operation
due to an error in manufacturing or assembly within the prescribed
warranty period, the problem will be covered by the engine company.
Typically, an engine company will define what fuel the engine
was designed for and will recommend the use of that fuel to their
customers in their owner's manuals.
companies do not manufacture fuel or fuel components. Therefore,
engine companies do not warranty fuel - whether that fuel is biodiesel
or petrodiesel fuel. Since engine manufacturers warranty the materials
and workmanship of their engines, they do not warranty fuel of
any kind. If there are engine problems caused by a fuel (again,
whether that fuel is petrodiesel fuel or biodiesel fuel) these
problems are not related to the materials or workmanship of the
engine, but are the responsibility of the fuel supplier and not
the engine manufacturer. Any reputable fuel supplier (biodiesel,
petrodiesel, or a blend of both) should stand behind its products
and cover any fuel quality problems if they occur.
the most important aspect regarding engine warranties and biodiesel
is whether an engine manufacturer will void its parts and workmanship
warranty when biodiesel is used, and whether the fuel producer
or marketer will stand behind its fuels should problems occur.
major engine companies have stated formally that the use of blends
up to B20 will not void their parts and workmanship warranties.
This includes blends below 20% biodiesel, such as the 2% biodiesel
blends that are becoming more common. Several statements from
the engine companies are available on the NBB website. Some engine
companies have already specified that the biodiesel must meet
ASTM D-6751 as a condition, while others are still in the process
of adopting D-6751 within their company or have their own set
of guidelines for biodiesel use that were developed prior to the
approval of D-6751. It is anticipated that the entire industry
will incorporate the ASTM biodiesel standard into their owner's
manuals over time.
National Biodiesel Board, the trade association for the biodiesel
industry, has formed the National Biodiesel Accreditation Commission
(NBAC) to audit fuel producers and marketers in order to enforce
fuel quality standards in the US. NBAC issues a 'Certified Biodiesel
Marketer' seal of approval for biodiesel marketers that have met
all requirements of fuel accreditation audits. This seal of approval
will provide added assurance to customers, as well as engine manufacturers,
that the biodiesel marketed by these companies meets the ASTM
standards for biodiesel and that the fuel supplier will stand
behind its products.
biodiesel that meets the D-6751 specification, there have been
over 45 million miles of successful, problem-free, real-world
operation with B20 blends in a wide variety of engines, climates,
and applications. The steps taken by the biodiesel industry to
work with the engine companies and to ensure that fuel meets the
newly accepted ASTM standards provides confidence to users and
engine manufacturers that their biodiesel experiences will be
positive and trouble-free.
: National Biodiesel Board, USA