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Reciprocating Internal Combustion Engines (RICE)

What Are Reciprocating Internal Combustion Engines or RICE?

RICE use pistons that alternatively move back and forth to convert pressure into rotating motion. They're commonly used at power and manufacturing plants to generate electricity and to power pumps and compressors. RICE are also used in emergencies to produce electricity and pump water for flood and fire control. The U.S. Environmental Protection Agency (EPA) has recently finalized new air quality regulations that place requirements on owners and operators of a wide variety of stationary RICE.

Why Does EPA Regulate RICE?

RICE are common combustion sources that collectively can have a significant impact on air quality and public health. The air toxics emitted from stationary engines include formaldehyde, acrolein, acetaldehyde and methanol. Exposure to these air toxics may produce a wide variety of health difficulties for people including irritation of the eyes, skin and mucous membranes, and central nervous system problems. RICE engines also emit the conventional air pollutants created when fuel is burned including carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOCs), and particulate matter (PM). The health effects of these pollutants include a range of respiratory (breathing) issues, especially asthma among children and seniors.

How Does EPA Regulate Stationary Engines?

EPA air quality requirements for stationary engines differ according to:

• whether the engine is new or existing, and
• whether the engine is located at an area source or major source and whether the engine is a compression ignition or a spark ignition engine. "Spark ignition" engines are further subdivided by power cycle - -i.e., two vs. four stroke, and whether the engine is "rich burn" (burning with a higher amount of fuel as compared to air) or "lean burn" (less fuel compared to air) engine.

Several regulations have expanded the number and type of stationary RICE that must comply with federal requirements. These include:

• National Emission Standard for Hazardous Air Pollutants (NESHAP) for Reciprocating Internal Combustion Engines (RICE) – 40 Code of Federal Regulations 63, Subpart ZZZZ ("the Rice rule")
• New Source Performance Standards (NSPS) - Standards of Performance for Stationary Spark Ignition Internal Combustion Engines (40 CFR 60 Subpart JJJJ - Scroll to reach the Subpart.) – "the Spark Ignition NSPS rule"
• Standards of Performance for Stationary Compression Ignition Internal Combustion Engines (40 CFR 60 Subpart IIII - Scroll to reach the Subpart.) – "the Compression Ignition NSPS rule"

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RICE Rule Applicability

The RICE rule Does Not Apply to:

1. Motor vehicles, or to non-road engines, which are:
   • self-propelled (tractors, bulldozers)
   • propelled while performing their function (lawnmowers)
   • portable or transportable (has wheels, skids, carrying handles, dolly, trailer or platform). Note: a portable non-road engine becomes stationary if it stays in one location for more than 12 months (a shorter time period if a seasonal source)
2. Existing emergency engines located at residential, institutional, or commercial area sources.  Engine must meet Subpart ZZZZ definition of emergency engine:
   • There are no limits on hours of operation for emergency service
   • Maintenance checks & readiness testing limited to 100 hrs/yr
   • If engine is >500 horsepower (HP), located at a major source, and installed prior to June 12, 2006, there is no limit on maintenance/testing hours
   • 50 hrs/yr allowed for non-emergencies (counts as part of the 100 hr/yr maintenance & testing limit)
   • Engine cannot be used for peak shaving or as part of financial arrangement with another entity, except 15 of the 50 non-emergency hrs/yr can be used for demand response in emergency situations (e.g., imminent blackout)
   • Engines that are >500 HP, located at a major source, and installed prior to June 12, 2006 do not have the allowance for 15 hours of demand response

The RICE rule Applies to:

1. Engines >500 Horsepower (HP) at major source of HAP:
   Existing engines if constructed before December 19, 2002
   New engines if constructed on or after December 19, 2002
   Reconstructed engines if reconstruction began on or after December 19, 2002
2. Engines ≤500 HP located at major source of HAP and engines of all horsepower located at an area source of HAP:
   Existing engines if constructed before June 12, 2006
   New engines if constructed on or after June 12, 2006
   Reconstructed engines if reconstruction began on or after June 12, 2006

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Determining RICE Rule Compliance Requirements

RICE Rule requirements are complex – but they are similar for several groups of engines, as summarized in the tables below.

Existing Non-emergency Engines	Compliance Requirements
SI 100 - 500 HP at major source SI > 500 HP at area source that are 4SLB or 4SRB and are used >24 hours/year CI ≥ 100 HP at major source CI > 300 HP at area source (see additional requirements)	Initial emission performance test Subsequent performance testing every 8,760 hours of operation OR 3 years for engines >500 HP (5 years if limited use) Operating limitations - catalyst pressure drop and inlet temperature for engines >500 HP Notifications (Refer to Tools box) Semiannual compliance reports (annual if limited use) In addition for CI >300 HP: Ultra low sulfur diesel (except rural Alaska) Crankcase emission control requirements
Other Existing Engines	Compliance Requirements
All Engines < 100 HP at major source Emergency/black start ≤500 HP at major source All at area source CI ≤ 300 HP non-emergency at area source SI ≤ 500 HP non-emergency at area source SI 2SLB > 500 HP non-emergency at area source SI LFG/DG > 500 HP non-emergency at area source SI 4SLB or 4SRB > 500 HP non-emergency at area source and are used ≤24 hours/year	Option 1: Change oil/filter, inspect air cleaner or spark plugs, hoses/belts on prescribed schedule OR Option 2: May use oil analysis program instead of prescribed oil change frequency Must complete Option 1 or 2 above, AND: Operate/maintain engine & control device per manufacturer’s instructions or owner-developed maintenance plan Emergency engines must have a non-resettable hour meter and record hours of operation and document hours spent in emergency or non-emergency operation. If engines used for demand response, keep record of notification of emergency situation and time operated. Keep records of maintenance Notifications not required
New Engines	Compliance Requirements
SI 4SRB > 500 HP new non-emergency at major source SI 2SLB  > 500 HP new non-emergency at major source SI 4SLB > 250 HP new non-emergency at major source CI > 500 HP new non-emergency at major source	Initial emission performance test Subsequent performance testing semiannually (may reduce frequency to annual) Operating limitations - catalyst pressure drop and inlet temperature Notifications (Refer to Tools box) Semiannual compliance reports
Existing SI 4S RB Engines at Major Source	Compliance Requirements
SI 4SRB > 500 HP operating >24 hrs/yr	Initial emission performance test Subsequent performance testing semiannually (may reduce frequency to annual) Operating limitations - catalyst pressure drop and inlet temperature Notifications (Refer to Tools box) Semiannual compliance reports
Other New Engines	Compliance Requirements
Emergency/limited use >500 HP new at major source	Initial notification only (Refer to Tools box)
Non-emergency LFG/DG >500 HP new at major source	Initial notification Monitor/record fuel usage daily Annual report of fuel usage

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Emission Standards

CO = carbon monoxide     CH₂0 = formaldehyde

Limits highlighted in yellow below are expected to require emissions control retrofit

HP	Existing RICE at Major Sources
	Non-emergency					Emergency
	CI	SI 2SLB	SI 4SLB	SI 4SRB	SI LFG/DG
<100	Work practice standards					Work practice standards
100-300	230 ppm CO	225 ppm CO	47 ppm CO	10.3 ppm CH2O	177 ppm CO
300-500	49 ppm CO or 70% CO reduction
>500	23 ppm CO or 70% CO reduction	No standards (2004 rule)	No standards (2004 rule)	350 ppb CH2O or 76% CH2O reduction (2004 rule)	No standards (2004 rule)	No standards (2004 rule)

HP	Existing RICE at Area Sources
	Non-emergency					Emergency or Black start
	CI	SI 2SLB	SI 4SLB	SI 4SRB	SI LFG/DG
≤300	Mgmt practice standards	Mgmt practice standards	Mgmt practice standards	Mgmt practice standards	Mgmt practice standards	Mgmt practice standards
300-500	49 ppm CO or 70% CO reduction*
>500	23 ppm CO or 70% CO reduction		47 ppm CO or 93% CO reduction*	2.7 ppm CH2O or 76% CH2O reduction**
*Except engines in rural Alaska **If engine used >24 hrs/yr

HP	New RICE at Major Sources
	Non-emergency					Emergency
	CI	SI 2SLB	SI 4SLB	SI 4SRB	SI LFG/DG
≤250	Comply with CI NSPS	Comply with SI NSPS	Comply with SI NSPS	Comply with SI NSPS	Comply with SI NSPS	Comply with CI/SI NSPS
250-500			14 ppm CH2O or 93% CO reduction (also comply with SI NSPS)
>500	580 ppb CH2O or 70% CO reduction (also comply with CI NSPS)	12 ppm CH2O or 58% CO reduction (also comply with SI NSPS)		350 ppb CH2O or 76% CH2O reduction (also comply with SI NSPS)	No standards (also comply with SI NSPS)	No standards (also comply with CI/SI NSPS)
Notes: New limited use engines >500 HP at major sources are not required to meet any emission standards under the NESHAP. New engines may also be subject to the NSPS.

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Determining RICE New Source Performance Standards Compliance Requirements

The NSPS rules include two alternative compliance approaches:

1. Operators comply by purchasing an engine certified by the manufacturer. 
2. Operators comply by meeting emission limits for an engine not certified by the manufacturer.

If you own or operate a Compression Ignition engine you are subject to the NSPS at 40 CFR 60, Subpart IIII if the engine was:

• Constructed (ordered) after July 11, 2005, and manufactured after April 1, 2006 (July 1, 2006 for fire pump engines), or
• Modified or reconstructed after July 11, 2005.
• Except for engines > 30 liters per cylinder (l/cyl) displacement, performance testing is not required - you achieve compliance by:
  • purchasing a new engine that has been certified by EPA, and
  • installing, configuring, operating, and maintaining the engine per the manufacturer’s instructions.

If you own or operate a Spark Ignition engine you are subject to the NSPS at 40 CFR 60, Subpart JJJJ if the engine was:

• Constructed (ordered) after 6/12/2006 and the engine is
  • >500 HP manufactured on/after 7/1/2007 (except lean burn 500≤HP<1,350)
  • lean burn 500≤HP<1,350 manufactured on/after 1/1/2008
  • <500 HP manufactured on/after 7/1/2008
  • emergency >25 HP manufactured on/after 1/1/2008
  • modified/reconstructed after 6/12/2006.
• For certain Spark Ignition engines manufactured on/after July 1, 2008, the engine manufacturer is required to certify that the engine meets emission limits. As the owner or operator of the engine you can comply by purchasing a certified engine, and operating it according to manufacturer’s instructions. These SI engine types include:
  • ≤ 25 HP,
  • gasoline non-emergency engines > 25 HP, and
  • rich burn LPG engines >25 HP.
• For other Spark Ignition engines, EPA made it optional for the manufacturer to certify that their engines meet the applicable emission limits. Owners or operators can comply either by purchasing an engine that the manufacturer has voluntarily certified, or by conducting performance testing to demonstrate that the engine meets the applicable emission limits.

For more information on applicable NSPS emission limits, which engines must be certified by manufacturers, and which engines can be voluntarily certified by the manufacturer, visit the Combustion Portal.

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