EPA Tiers and What They Mean

The Breakdownnonroad diesel engines and marine diesel engines.
In lasts months newsletter we discussed Tier 4The signatories of the (SOP) agreed to pursue
emissions regulations and how they have effectednew standards and methods which would reduce
off road equipment manufactures and theNOx and PM emissions by more than two-thirds
struggles faced by design engineers workingof their current levels.
around Tier 4. This month we will break downThe Tier 1 standard which was adopted in 1994
each Tier stage and briefly describe thefor engines over 50 hp had a phase in schedule
fundamentals behind each Tier in hopes offrom 1996 to 2000. A program for the finalization
shedding a little more light on the EPAof more stringent emission standards for nitrogen
(Environmental Protection Agency) Tier programoxides, hydrocarbons, and particulate matter from
and its dark matter.new nonroad diesel engines was introduced to
included the first set of Tier 1 standards for
While many whom work in and are affected bynonroad diesel engines applying to engines with
these emissions standards fully understand theirless than 50 hp phasing in between 1999 and
importance and their role in the environment,2000.
many more have simply heard about the emissionThis final rule was signed August 27, 1998
standards but never fully understood what theyreflecting the provisions of the SOP. This new
meant and the roles they play. In the followingfinalization included marine engines in this size
article, we will break down the EPS's different Tierrange as well. It also phased in more stricter "Tier
stages and try to provide a better understanding2" emission standards from 2001 to 2006 for all
of what they mean and how they affectengine as it added yet more stringent "Tier 3"
individuals lives.standards for engines from 50 to 750 hp from
The EPA conducted a study in 1991 to estimate2006 through 2008.
the amount of NOx (Nitrogen Oxide) emitted by1998 Regulations
nonroad diesel engines. This study concluded thatEstimations by the EPA at the time of the 1998
nonroad diesel engines emitted along the lines ofruling estimated that by 2010, NOx emissions
10% of the nations NOx levels. It also concludedwould be reduced by about one million tons per
this figure to be significantly higher in U.S. citiesyear. Equivalent of taking approximately 35 million
whose air quality was at a poorer level. The Statepassenger cars off of the road. Estimations also
of California conducted a similar study. In this,concluded the purchase price of a typical nonroad
California's State Implementation Plan projecteddiesel equipped machine to have less than 1%
nonroad diesel engines would contribute aboutexpected increase in purchase price.
one-quarter of the total NOx emissions for theTier 3 Regulations
city of Los Angeles and the Los Angeles area byThe phase-in period for Tier 3 began in 2006. Tier
2010.3 standards for nitrogen oxides and hydrocarbons
As diesel engines are a major contributor ofwere similar to those of the 2004 standards for
particulate matter, the EPA projected by 2010,on-road engines. However, the Tier 3 standards
nonroad diesel engines would emit as mush asfor particulate matter were never adopted for
three-quarters of all Particulate Matter if significantnonroad.
changes and standards were not implemented.Tier 4 Regulations
The Introduction of the TierThe EPA signed the final ruling introducing Tier 4
The first federal Tier 1 standard for new off-roademission standards on May 11, 2004. The new
equipment was established in 1994. This newTier 4 standards are to be phased in over a 6
standard affected nonroad diesel poweredyear period from 2008-2015. PM and NOx levels
equipment over 50hp. A statement of principleswill be reduced by about 90% for this newest
(SOP) was signed between the United StatesTier.
EPA, California ARB (CARB-California AirWork Cited
Resources Board) and manufacturers of nonroad"Regulations and Standards." Nonroad Diesel
diesel engines. This (SOP) served as a blueprint toEquipment. 14 Oct. 2009. U.S. Envionmental
a multistep, long-term process of a controlProtection Agency. 22 Mar. 2010. epa.gov
program for nonroad diesel engines.nonroad-diesel/regulations.htm
The (SOP) called for stringent standards in the"Nonroad Diesel Engines." Emission Standards.
admittances of nitrogen (NOx), hydrocarbon (HC),DieselNet. 22 Mar. 2010. dieselnet.com/standards
and particulate matter (PM) for land-basedus/nonroad.php.