EPA Standards Emission For Diesel Generator

EPA Standards Emission For Diesel Generator

The Environmental Protection Agency (EPA) has been aggressively enforcing policies to enhance air quality by increasing harmful emissions since the 1950s. Diesel exhaust is one of those harmful emissions and as such, the regulations have affected on-road and off-road vehicles and engines, including non-road diesel engines and stationary generator sets of diesel engines. But while this may sound like it was a challenge for this industry. it has led to changes to engines that reduce emissions and boosts performance. 

Day by day the EPA standards for diesel generator have achieved the great quality of diesel engines and reduce the pollution level. 

To make the process run smoother, a framework of application is designed to enable all participants— including scientists and suppliers, among others — to build the knowledge and technology necessary to meet these regulatory objectives. The implementation model is defined as a level system set up to manage the mechanism more correctly. Here we outline what you ought to know about the diesel generator tier emission ratings.


                                               Diesel Emission Tier graph

Tier level for diesel engine generator 

Four tiers are in to eliminate harmful gasses in the air, and each rank has been built from the other to make regulation more manageable. Each level of the tier also has a certain level of harmful emissions and provides a limit at which point emissions must be limited. According to the tier level, the standard progresses over the years.

The reduction of intended and primary emissions includes:

  • Nitrogen oxides (NOx)
  • Hydrocarbons (HC)
  • Carbon monoxide (CO)
  • Particulate matter (PM)
  • Non-methane hydrocarbons (NMHC)

Currently, all engines (with a few exceptions –discussed later) are at level 4. That means the harmful emissions have been significantly reduced just as they have significantly improved engine performance. But it’s still a work in progress, especially for on-and off-road diesel engines.

How to relates tier level and generators

During the first publishing and introduction of the EPA rules, diesel engines were not the initial target. But these laws are now very much the focus of them. Non-road engine regulations were adopted in 1998 as a 3-tiered structure (later included in the 4th tier). The rising-rate includes a cycle of phase-in over many years and in line with the horsepower rating of the engine. An outline of these three rates and how they apply to generators is given below.

Diesel generator EPA emission with tier 1

While Tier 1 specifications were released in 1991, the introduction of diesel engines and generators did not begin until 1996 with the goal of compliance with all diesel engines and generators by 2005. From the period of 1996 to 2000 tier 1 regulation mainly focused on a diesel engine which is less than 50 Hp

Diesel generator EPA emission with tier 2 & 3

Tier 2 guidelines were released in 1999 and soon afterward Tier 3 standards were issued. Nonetheless, these processes did not start until 2001, with all engines scheduled to comply by 2008. To meet the criteria set out in the regulations, these two levels required engines that were more sophisticated in design and advanced in performance. The table below identifies Tier 2 and 3 standards to be limited in terms of diesel engine power and harmful gases.

Diesel generator EPA emission with tier 4

Tier 4 is where we are now and this is a clear target. All the diesel generators present in tier 4 level. For example, this is the most strict of all laws. If you are environmentally conscious, much of your standards may be fulfilled by this point. The most advanced technologies are being used here to accomplish today’s biggest emission reduction. The target and the contribution of tier level 4 is to reach the emission level at zero.


                                Diesel engine EPA emission

Reason to care diesel generator emission

As a plant manager or as someone who just wants to buy a generator. You may wonder if these laws have a meaningful effect on you or if they are merely a problem for manufacturers.

Under the tiered application of new emission standards. The EPA allowed manufacturers to sell new generators that did not meet more stringent standards. They had the new standards rolled out within two years of the turbine being installed by the manufacturer. Nevertheless, these generators had to be installed within two years of having to comply with previous engine emission regulations. The generators had to meet the current standards after these two years.

regulatory compliance

It means that it may not comply with T4F legislation if you purchase a generator installed before January 2015. Therefore, even if the generator is unused, if it doesn’t reach requirements, you’ll have to retrofit it to code it. The explanation is that the EPA does not find the date. In that case, an engine was designed as much as when it was assembled. Now that it has been over two years since the entry into force of the T4F regulations (2015), the new criteria must be fulfilled by all mounted generators. Older criteria are used to judge generators built before T4F regulations were launched.


The original rules were specifically intended at the earlier stages of the plan to reduce the amount of pollution generated by automobiles and diesel and petrol non-road engines. Nevertheless, these requirements were not applicable until recently for stationary diesel generators. On July 11, 2006, a new directive was released to make the new law relevant to modern stationary diesel engines like those used in diesel generator sets.