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  • Environmental Power Solutions
  • Environmental Power Solutions

Understanding Tier 1, 2, 3 & 4 Rating Rules & Requirements for Diesel Engine Generators

To curb the proliferation of atmospheric pollutants the U.S., government began taking steps in the mid-1950s forcing generator manufacturers to limit the pollutants released by engines into the atmosphere. The government started passing regulations to govern diesel engine emissions. The government targeted a wide range of products including diesel engines. By the strict oversight of the U.S. Environmental Protection Agency (EPA), the production of today’s diesel engines that are widely used by electric generators, are covered. To give scientists, manufacturers, and the market time to improve technologies, knowledge, as well as to absorb the cost of compliance, the EPA Emission reductions have been carried out in phases. Today we at Environmental Power Solutions would like to explain the tier rating for generators to help consumers better understand.

Generator Tier 1, 2, 3 and 4 Ratings

With each tier covering a phase-in over several years, the non-road engine regulations were structured as a 3-tiered progression in 1998; a set of horsepower ratings were involved in each tier.
The phases of the emission reductions include the following:
Tier 1: The 1st phase started in 1990 as authorized by the federal government to issue permits to stationary power sources. With the exception of the engines in locomotives and marine vessels, it covered the first batch of emission standards that govern all new mobile non-road diesel engines of any horsepower category.
Tier 2: The 2nd phase added more stringent regulations in 1998. Unburned hydrocarbons, carbon monoxide, NOx (the generic term for the mono-nitrogen oxides NOx2 and NO), as well as particulate matters emitted were all addressed. All sizes of engines that were manufactured between 2001 and 2005 were covered in Tier 2.
Tier 3: For engines with 50 to 750 hp, the exhaust emissions was restricted, and this phase was implemented from 2006-2008.
Tier 4: Signed on May 11, 2004 the final ruling would set out for the last phase over time from 2008 to 2015. A 90% reduction of MP and NOx emissions is the new standard requirement. Similar to the 2007 to 2010 requirements for high engines, the target emission standards are to be achieved through new control technologies also include advanced after-treatment of exhaust gas.

Emergency & Non-Emergency Diesel Engine Rules

Depending on the range of power of the diesel engine, stationary diesel engines must meet the emission requirements of Tiers 2 to 4, stipulated by the New Source Performance Standards (NSPS). Covered by Tier 4 regulations include non-emergency diesel engines that use 10 liters per cylinder or less and greater than 175 horsepower as of 2011. A generator that is classified for emergency use must not run unless the primary source of power is not available, like in a power outage for example. For not more than 100 hours per year the engine may be allowed to run for maintenance and testing however.

Clean Diesel Generators for Sale, Lease or Purchase

When you get a diesel powered generator with Environmental Power Solutions we can explain the tier rating and all other specs and happily answer any of your questions. Call us today get started on your backup generator needs.