Americas Generators

What Do Generator Tiers Mean?

by 10. December 2015 08:01

Did you know that generators have different tier ratings? There are four tiers of generator ratings. What do they mean?

Key Features of Tier 1-3 Standards

  1. Tier 1-3 Standard relies on engine design that reduces emissions.
  2. Nonroad diesel engine Tier 1 is applicable to engines over 37kW. It was was adopted in 1994 and implemented between 1996-2000. Implementation was accompanied by a Statement of Principles (SOP) signed by the EPA, California ARB and several engine makers.
  3. A 1998 regulation introduced Tier 2 and 3 standards for all equipment to be introduced throughout 2000-2008. Tier 2 Standard took effect during 2001-2006, while Tier 3 Standard was introduced through 2006-2008.
  4. Tier 2-3 smoke opacity standards and procedures continue to apply in some engines. Exempted from these standards are those engines certified to PM emission standard at or below 0.07 g/k/kWh. Those engines are exempt because they inherently have low smoke emission.
  5. Tier 1-3 engines is required to have a sulfur level not greater than 2,000 ppm for certification testing.

Key Features of Tier 4 Standard

  1. EPA introduced Tier 4 in 2004, with implementation being introduced throughout 2008-2015. This tier requires that the emission of dangerous gases be reduced to 90% from the previous tiers. The reduction can be achieved through the use of improved technologies, like advanced exhaust after-treatment. This standard is similar to those required for highway engines as of 2007.
  2. Since Tiers 1-3 sulfur content was not covered by stringent environmental regulation, Tier 4 was mandated by EPA to reduce sulfur content.
  3. Tier 4 regulation does not require close crankcase ventilation in nonroad engines. However, in engines with an open crankcase, crankcase emission must be measured and added to exhaust emission in assessing compliance.
  4. In terms of fuel certification, starting 2011, all Tier 4 engines are tested using fuels of 7-15ppm sulfur content. The transition from 2000pp specification of Tier 1-3 to the 7-15 ppm specification of Tier 4 took place in 2006-2010 periods.
  5. It is expected that by 2030, 12,000 premature deaths would be prevented annually due to the implementation these higher standards.



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