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The Environmental Protection Agency (EPA), created in 1966, is a federal body in the United States which was created to regulate and facilitate the protection of the environment and human health by writing and enforcing regulations which will be passed by the Congress. To regulate the emissions of engines, i.e. generators, compressors, etc., it introduced a “Tier system” in 1996. For more information on EPA and their regulatory clauses, you can check out www.epa.gov.

Until 1994, there were no written regulations or laws pertaining to quality of emissions released in to the air by industrial units. Therefore, the engine units used before 1994 were Tier 0. In the same year, the Tier 1 regulations were adopted and Tier 1 engines were phased in from 1996 to 2000. On August 27, 1998, the EPA signed the final rule reflecting all the provisions of the Tier 1 regulations. Similarly, with a view to make regulations more stringent gradually, Tier 2 was phased in 2000 and Tier 3 was phased in 2008. Tier 4 Interim was phased in 2011 and Tier 4 Final in 2015. These are applicable to all types of compressor based equipment, like HVAC, etc.

But what exactly are the regulations that we keep mentioning?

	Tier 2	Tier 3	Tier 4A (Interim)	Tier 4A (Final)
Engine Technology	Charged Air Cooling	Charged Air Cooling	Charged Air Cooling	Charged Air Cooling
	Optimum Combustion	High Pressure Common Rail Fuel Injection	High Pressure Common Rail Fuel Injection	High Pressure Common Rail Fuel Injection
	Advance Turbochargers	Exhaust Gas Recirculation	Cooled Exhaust Gas Recirculation	Cooled Exhaust Gas Recirculation
Exhaust After Treatment			Diesel Oxidation Catalyst (DOC)	Diesel Oxidation Catalyst (DOC)
			Diesel Particulate Filter (DPF)	Diesel Particulate Filter (DPF)
				Selective Catalytic Reduction (SCR)
Requirements of Fluid			Ultra Low Sulphur Fuel Required	Ultra Low Sulphur Fuel Required
			Low Ash Engine Oil Required	Low Ash Engine Oil Required
				Diesel Exhaust Fluid (DEF)

 

As seen in the table, at the beginning of the Tier system, the engine technology was the focal point of the research. Once that was established in the Tier 2 and Tier 3 technology engines, the after-treatment of by-products and emitted particles became a concern for the engines. The EPA, in its effort to reduce the emissions and promote better quality engines, has gradually stepped up the complexity of the Tiers.

Tier 4 regulations were introduced in two parts – Interim and Final. As seen in the table above, the Interim itself introduced the Exhaust after Treatment and Fluid Requirements, which weren’t present in the earlier Tier regulations. Going a step further, Tier 4 Final engines have made catalyst reduction and diesel exhaust fluid compulsory.

These regulations will only contribute in keeping the air breathable. Find out more about how to treat air for residential purposes. Also, check out how the global residential air treatment market works.

Although the regulation making Tier 4 Final engines compulsory is expensive financially, it will help conserve our environment to a large extent and ensure that that we pass on a cleaner planet to our future generations.