RICE NESHAP FAQ

RICE NESHAP is an acronym for Reciprocating Internal Combustion Engines National Emission Standards for Hazardous Air Pollutants.

In February 2010 the EPA officially made the RICE NESHAP ruling. The rule is intended to reduce emissions of toxic air pollutants such as formaldehyde, acetaldehyde, acrolein, methanol and other air toxics from several categories of previously unregulated stationary engines.

The affected stationary diesel engines must comply with CO emission limits or must be fitted with emission controls, such as diesel oxidation catalysts, to reduce CO emissions by 70%.

The rule also requires the use of ultra-low sulfur diesel fuel for stationary non-emergency engines greater than 300 hp with a displacement of less than 30 liters per cylinder. The regulation will be fully implemented by 2013.

The regulation includes a number of other provisions, including work practices for engine operators. Stationary engines above 300 hp must also be equipped with closed or open crankcase filtration system in order to reduce metallic HAP emissions. While the regulation does not mandate the emission control technology, the EPA designed the standards based on the capabilities of the diesel oxidation catalyst (DOC).

May 3rd, 2013.

This ruling affects existing stationary diesel engines in the following categories:

• Engines used at "area sources" of air toxics emissions and constructed or reconstructed before June 12, 2006
• Engines used at "major sources" of air toxics emissions, have a site rating of less than or equal to 500 hp, and constructed or reconstructed before June 12, 2006
• Engines used at "major sources" of air toxics for non-emergency purposes, have a site rating of greater than 500 hp, and constructed or reconstructed before December 19, 2002

Major sources of air toxins are defined as those that emit or have the potential to emit 10 short tons per year of a single hazardous air pollutant (HAP) or 25 short tons per year of any combination of HAPs.

Area sources are those that are not classified as major sources.

For engines at a major source:

For engines at an area source:

Diesel oxidation catalysts (DOC) are available and recommended by the EPA to meet the emission regulations. In addition, for engines greater than 500 HP a continuous parametric monitoring system (CPMS) must be utilized to measure pressure drop across the catalyst, as the pressure drop across the catalyst must not change by more than 2 inches of water from the pressure drop across the catalyst that was measured during the initial performance test. In addition, temperature must be measured to ensure that the catalyst inlet temperature is between 450F and 1350F.

Universal’s GreenShield Diesel Oxidation Catalyst reduces Carbon Monoxide (CO), Hydrocarbons (HC) and Particulate Matter (PM) to meet RICE NESHAP requirements.

To determine the HAP requirements for your specific engine, you must know the following information: Horsepower, operating hours per year, and if you have an area or major source of emissions.

The EPA has provided an applicability flowchart to determine what category your engine falls under: Applicability Flowchart PowerPoint.

The ruling made on February 17th 2010 only applies to diesel internal combustion engines. The EPA is expected to make a ruling on existing natural gas engines in August 2010.

An emergency engine is one that is operated for emergency purposes only. Examples include stationary engines used to produce power for critical networks or equipment when electric power from the normal power source is interrupted, or a stationary engine used to pump water in the case of a fire or flood. Maintenance checks and readiness testing of the engine is limited to 100 hours per year. The engine is allowed to operate for non-emergency purposes for 50 hours per year, but these 50 hours are counted towards the total 100 hours provided for operation other than true emergencies. The 50 hours per year cannot be used to generate income for a facility, such as supplying power to an electric grid.

A non-emergency engine is defined as an engine that is not an emergency engine.

HAP which have been measured in emission tests include: 1, 3-butadiene, acetaldehyde, acrolein, benzene, ethylbenzene, formaldehyde, n-hexane, naphthalene, PAH, polycyclic organic matter, styrene, toluene, and xylene. Metallic HAP from diesel fired stationary RICE that have been measured include: Cadmium, chromium, lead, manganese, mercury, nickel, and selenium.

CO is used as a surrogate for HAP emissions from CI engines. The EPA has determined a relationship between HAP emissions reductions and CO emissions reductions. As CO testing has many advantages over testing for HAP emissions, CO has been chosen as the surrogate of choice to measure for HAP emissions.

Non-emergency engines between 300 and 500 HP at either an area or major source:

An initial performance test is required to demonstrate that emission standards are achieved using the oxidation catalyst.

Non-emergency engines greater than 500 HP located at an area source:

Testing depends on the use of your engine. For "Not Limited Use Engines", you must perform an initial performance test and re-test every 8,760 hours of operation or 3 years, whichever comes first. You must also continuously monitor and record the catalyst inlet temperature, and perform monthly monitoring of the pressure drop across the catalyst. For "Limited Use Engines", you must perform an initial performance test and re-test every 8,760 hours of operation or 5 years, whichever comes first. You must also continuously monitor and record the catalyst inlet temperature, and perform monthly monitoring of the pressure drop across the catalyst.

For non-emergency engines greater than 500 HP located at a major source:

You must perform an initial performance test, and re-test every 8,760 hours of operation or 5 years, whichever comes first. You must also continuously monitor and record the catalyst inlet temperature, and perform monthly monitoring of the pressure drop across the catalyst.

Catalyst inlet temperature on non-emergency CI RICE engines greater than 500 HP is required to be continuously monitored and recorded. Pressure drop across the catalyst must also be measured on a monthly basis. There are currently no specific performance requirements promulgated by the EPA for the monitoring system, but they are expected in the 40 CFR part 63, subpart ZZZZ ruling expected in August 2010.

A limited use engine is one that operates less than 100 hours per year.

A not limited use engine is one that operates more than 100 hours per year.

The EPA RICE NESHAP Fact Sheet provides general information on the ruling

The ruling for emission standards can be found on the EPA’s website: EPA RICE NESHAP Ruling.

A PDF file of the final ruling is available here: EPA Final Ruling PDF.

Search for your regional EPA office here:

EPA Regional Office Locator

Or contact:

Ms. Melanie King
Energy Strategies Group, Sector Policies and Programs Division (D243–01), Environmental Protection Agency
Research Triangle Park
North Carolina 27711
Telephone: (919) 541–2469
Fax: (919) 541–5450
king.melanie@epa.gov