RICE NESHAP Frequently Asked Questions (FAQ)
What does RICE NESHAP mean?
RICE NESHAP is an acronym for Reciprocating Internal Combustion Engines National Emission Standards for Hazardous Air Pollutants.
In February 2010 the Environmental Protection Agency (EPA) officially made the RICE NESHAP ruling for compression ignition engines. The official EPA ruling for spark ignition engines was announced in August 2010. These rules are intended to reduce emissions of hazardous air pollutants (HAP) from previously unregulated engines.
What is the difference between NSPS and RICE NESHAP?
- NESHAP for Stationary Reciprocating Internal Combustion Engines (RICE)
- 40 CFR part 63 subpart ZZZZ
- Applies to existing, new and reconstructed stationary CI and SI engines
- Focus is on air toxics (30 HAPs)
- NSPS (New Source Performance Standards) for Internal Combustion Engines (ICE)
- Stationary Compression Ignition (CI) ICE
- 40 CFR part 60 subpart IIII
- Stationary Spark Ignition (SI) ICE
- 40 CFR part 60 subpart JJJJ
- Applies to new, modified and reconstructed stationary CI and SI engines
- Focus is on criteria pollutants (CO, NOx and SOx)
- Stationary Compression Ignition (CI) ICE
What are the requirements of the ruling?
The affected stationary compression ignition 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 May 2013.
The new regulations include provisions affecting work practices, metallic HAP emissions, operating limits, start-up requirements, regulation compliance and reporting of test results. The new regulations do not mandate a specific emission control technology but the EPA designed the standards based on the capabilities of current oxidation catalysts (OCs).
When do I need to retrofit my engine with an emission control product to meet the requirements?
May 3rd, 2013 for compression-ignition (diesel) engines, and October 19th, 2013 for spark-ignited (gaseous-fueled) engines.
Who is affected by the RICE NESHAP ruling?
This ruling affects existing stationary diesel engines in the following categories:
- Engines used at “area sources” of HAP and constructed or reconstructed before June 12, 2006.
- Engines used at “major sources” of HAP, 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 HAP for non-emergency purposes, have a site rating of greater than 500 hp, and constructed or reconstructed before December 19, 2002.
If not in a non-attainment zone, is RICE NESHAP still in effect?
Yes. Non-attainment zones have no bearing on this ruling. Each diesel engine in the US is affected by this rule one way or another. The area source and major source categories are determined by that engine’s specific pollutant output, in this case carbon monoxide.
How is a major source of emissions defined?
Major sources of air toxins are defined as those that emit or have the potential to emit 10 tons per year of a single hazardous air pollutant (HAP) or 25 tons (total) per year of multiple HAPs.
How is an area source of emissions defined?
Area sources are those that are not classified as major sources.
What levels of emission control must be achieved through RICE NESHAP?
For engines at a major source:
Subcategory | Numerical Emission Standards (Except during Start-up) |
Non-emergency CI 100≤HP≤300 | 230 ppmvd CO at 15% O2 |
Non-emergency CI 300<HP≤500 | 49 ppmvd CO at 15% O2 or 70% CO reduction |
Non-Emergency CI >500 HP | 23 ppmvd CO at 15% O2 or 70% CO reduction |
For engines at an area source:
Subcategory | Numerical Emission Standards (Except during Start-up) |
Non-Emergency CI 300<HP≤500 | 49 ppmvd CO at 15% O2 or 70% CO reduction |
Non-Emergency CI>500 HP | 23 ppmvd CO at 15% O2 or 70% CO reduction |
What emission control products are offered to meet RICE NESHAP requirements?
Diesel oxidation catalysts (DOC) are recommended to meet the new emission regulations. Diesel particulate filtration (DPF) is also offered. For engines greater than 500 HP a continuous parametric monitoring system (CPMS) is required to satisfy monitoring of pressure drop across catalyst and temperature at catalyst. The pressure drop across the catalyst cannot exceed 2″H2O and temperature at the catalyst must remain between 450°F and 1350°F to ensure an efficient catalytic reaction.
What levels of emission control can be offered with a Diesel Oxidation Catalyst (DOC)?
Diesel oxidation catalysts are capable of reducing carbon monoxide (CO) emissions by 90%, hydrocarbon (HC) emissions by 80% and particulate matter (PM) emissions by 20%. The EPA is requiring a 70% reduction of CO emissions for the new ruling.
How can I determine if my engine needs to comply with the ruling?
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. To determine your specific applicability, try using this tool.
Are there different rulings for natural gas engines versus diesel engines?
The ruling made on February 17th 2010 only applies to diesel internal combustion engines. The EPA made a ruling on existing natural gas engines in August 2010.
Are emergency engines affected by RICE NESHAP?
Yes. Emergency engines are affected by the current ruling made by the EPA, but have different requirements than non-emergency engines.
How is an “emergency” engine defined?
An emergency engine is one that is operated for emergency purposes only. Maintenance and 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. Use is unlimited in emergency situations.
How is a “non-emergency” engine defined?
A non-emergency engine is any engine not defined as an emergency engine.
What pollutants are regulated through RICE NESHAP?
Tetrachloroethane | Dichloropropane | Butadiene | Dichloropropene | PAH |
Acetaldehyde | Acrolein | Acroylonitrile | Arsenic Compounds | Benzene |
Beryllium Compounds | Cadmium Compounds | Chloroform | Chromium Compounds | Dioxins |
Ethylene Dichloride | Ethylene Oxide | Formaldehyde | Hexachlorobenzene | Hydrazine |
Lead Compound | Manganese Compounds | Mercury Compounds | Methylene Chloride | Nickel Compounds |
Polychlorinated biphenyl | Quinoline | Tetrachloroethylene | Trichloroethylene | Vinyl Chloride |
How are HAP emissions measured?
Because carbon monoxide (CO) has many measurement advantages over the above-listed HAPs, CO is used as the surrogate for HAP emissions from CI engines. Using a relationship determined by the EPA, HAP emission reduction is determined from CO emission reduction instead of individually measuring the 30 urban HAPs.
Do I need to do testing on my engine after it is retrofit with an emission control device?
For 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.
For 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.
Is a monitoring device required to comply with RICE NESHAP?
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. Performance requirements for the monitoring system can be found in 40 CFR part 63, subpart ZZZZ.
How is a “limited use” engine defined?
A limited use engine is one that operates less than 100 hours per year.
How is a “not limited use” engine defined?
A not limited use engine is one that operates more than 100 hours per year.
Where can I look for basic information on the ruling from the EPA?
The EPA RICE NESHAP Fact Sheet provides general information on the ruling.
Who is the proper person to contact at the EPA for further information?
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
Need more help navigating toward RICE NESHAP compliance?
Here is a handy guide to assist you along the way!