EPA Sets Standards for Diesel Fluid
Systems; Adopts Relief Measures for
Nonroad Equipment
The U.S. Environmental Protection Agency (EPA) has established
minimum refill intervals for the diesel exhaust fluid (DEE) used in
selective catalyst systems to reduce nitrogen oxides (NOx) from diesel
engines. EPA has also adopted regulatory flexibility for nonroad equip'
ment that can be used during emergency responses.
Selective Catalytic Reduction Maintenance
Why is EPA Taking This Action?
Selective Catalytic Reduction (SCR) is now a common technology in the trans-
portation sector. This technology requires use of a diesel exhaust fluid that reacts in
the system, is consumed, and must be periodically refilled to sustain control of the
nitrogen oxides (NOx) emissions. Until now, EPA has been relying on a case-by-case
approval of refill intervals - regulated as scheduled emission-related maintenance.
This final rule improves the clarity and transparency of EPA's requirements, by add-
ing diesel exhaust fluid replenishment to the required emission-related maintenance
and setting minimum refill intervals.
What Revisions is EPA Adopting?
EPA is setting a minimum fluid refill interval of 4,000 miles for light-duty vehicles
and light-duty trucks that use SCR.1 For example, a vehicle with a 400 mile fuel
range would need to refill the DEE tank no more frequently than every tenth fuel fill-
up. For operators who change oil every 7,500 miles and fill the DEE tank at the time
of the oil change, no more than one DEE refill would be needed between oil changes.
This is a shorter interval than we proposed, because oil change intervals are generally
lengthening, there are trade-offs with the weight of over-sized DEE tanks, and DEE is
becoming more available to consumers.
1 Such as a half-ton diesel pickup truck or a diesel SUV
United
Environmental Protection
Office of Transportation and Air Quality
EPA-420-F-14-017
July 2014
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For all heavy-duty engines, EPA is setting a fluid refill interval at least as far (in miles or hours)
as the vehicle's fuel capacity. This means the DEF refill must have, at a minimum, a 1:1 ratio
with the distance between fuel refills. This is the same interval we proposed for engines in
centrally-fueled vocational trucks, but it is shorter than the 2:1 ratio we proposed for engines
in long'haul trucks.
For SCR'equipped nonroad diesel engines, EPA is finalizing a DEF refill interval at least as long
(in engine-hours) as the vehicle's fuel capacity, which is unchanged from the proposal.
Nonroad Engines in Temporary Emergency Situations
Why is EPA Taking This Action?
Diesel engines in most modern nonroad equipment are subject to EPA's technology-forcing
standards, phasing in through 2015. When routine emission-control maintenance (such as
DEF refill) does not occur as designed, many engines are set to reduce power to prevent excess
emissions. For nonroad equipment, this final action allows temporary relief from performance'
related emission control protections, when such equipment is needed to respond to an emergency.
This will facilitate the use of a variety of nonroad equipment in performing life-saving work
during rescue and recovery from accidents, floods, hurricanes, and other emergency situations.
What Revisions is EPA Adopting?
EPA is adopting revisions that allow manufacturers of nonroad engines to request and EPA to
approve a new kind of auxiliary emission control device (AECD) as part of the engine certification
process. This flexibility is intended primarily for new engines used in construction equipment
and portable equipment used for temporary power generation and flood control. Manufacturers
will be responsible for activation of any such AECD as well as providing reports to EPA on use
of these AECD's.
Expansion of Emergency Vehicle Provisions
In June 2012, EPA adopted regulatory flexibility for fire trucks and ambulances, to prevent
emission'related power loss on these emergency vehicles. On diesel-powered vehicles, when
emission-related maintenance does not occur as designed, many engines are set to cut power to
prevent abnormal conditions from causing damage or excess emissions. However, EPA's 2012
rule finalized a new kind of AECD so engine manufacturers can have the flexibility to avoid
such abnormal conditions and avoid reduced performance for fire trucks and ambulances.
In today's final action, EPA is expanding the application of this AECD to allow case-by-case
approval for engines used in other types of emergency vehicles. The intent is to cover vehicles
that are regularly used in emergency situations, and where the functioning or malfunctioning
of the standard emission control system may prevent the vehicle from performing as necessary
when the vehicle is needed to perform work related to reducing risk to human life.
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Benefits and Costs of the Rule
In this action, EPA is providing regulatory certainty that will allow affected manufacturers to
plan their future product development. The amendments in this action would only have a small
cost impact for those manufacturers who elect to develop and deploy upgrades to nonroad
engines as allowed by this rule. EPA does not expect these regulatory changes to have an
environmental impact.
For More Information
You can access the final rule, regulations, and related documents on EPA's Office of
Transportation and Air Quality (OTAQ) Web site at:
www.epa.gov/otaq/hd-hwy.htm
For more information on this and related rules, please contact the U.S. Environmental
Protection Agency, Office of Transportation and Air Quality at:
E-mail: otaq@epa.gov
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