The State Revolving Fund requires contractors on State Revolving Fund projects to have pollution controls in their equipment engines.
Guide Reducing Air Emissions from Diesel Construction Engines
Retrofit Requirements for Equipment Used in Wastewater and Drinking Water Infrastructure Projects
In addition to emitting smog-forming pollutants, construction equipment engines produce more than 25 percent of all diesel fine particulate matter (PM) pollution in Massachusetts. Fine PM contributes to the state's already high rate of asthma and is also a probable carcinogen. In response to these health and environmental impacts, the Massachusetts Department of Environmental Protection (MassDEP) requires contractors working on projects financed by the State Revolving Fund (SRF) to install retrofit pollution controls in their construction equipment engines. This fact sheet discusses the SRF retrofit requirements.
State Revolving Fund Retrofit Requirements
Operated by the MassDEP Division of Municipal Services, the SRF program provides financial assistance for municipal wastewater treatment and drinking water infrastructure projects. The SRF program's retrofit requirement is part of the larger Massachusetts Diesel Retrofit Program (MDRP), which was developed to respond to excessive diesel emissions at state-funded construction projects.
MassDEP's SRF program includes a requirement that all non-road diesel equipment rated 50 horsepower or greater that will be used on a project site meet EPA's Tier 4 emission limits or be retrofitted with appropriate emission reduction equipment. Emission reduction equipment includes EPA-verified, CARB verified or DEP-approved Diesel Oxidation Catalysts (DOCs) or Diesel Particulate Filters (DPFs). There are a few exemptions to the retrofit requirements which are identified in the SRF document, Plans and Specifications Checklist.
The SRF program uses the federal Environmental Protection Agency's definition of non-road diesel equipment which basically includes all diesel equipment not considered a motor vehicle. Wheeled excavators, dozers, backhoes and other similar equipment are not considered motor vehicles as they are not inherently designed for road use, lack safety features typical of motor vehicles and are rated at speeds of 25 mph or less. Almost all diesel powered equipment on a construction site is required to be retrofitted, including skid steers, telehandlers and pavers, since the equipment is rarely new enough to be Tier 4 (i.e. a 2012 model) and the motors are rarely smaller than 50 hp. The main equipment excluded from the retrofit requirement based on the EPA definitions is wheeled towable compressors and generators.
Typical Diesel Construction Equipment requiring Retrofits
- Backhoe, wheeled
- Backhoe, tracked
- Dozer, wheeled
- Dozer, tracked
- Excavator, wheeled
- Excavator, tracked
- Loader, tracked
- Loader, wheeled
- Skid steer (e.g. Bobcat), wheeled
- Skid steer (e.g. Bobcat), tracked
- Telehandler (e.g. Lull)
What is a DOC?
A DOC is a reliable, relatively inexpensive technology that is installed either as an on-line engine muffler replacement system or as an add-on control device. Retrofitting an off-road engine with a DOC typically costs between $800 and $3,500, including parts and labor. A DOC contains a flow-through metal or ceramic core that is coated with a precious metal catalyst such as platinum. This catalyst core is packaged into a metal container similar to an exhaust muffler/resonator and sits in a vehicle's exhaust stream to help break down pollutants into less harmful components.
DOCs can reduce fine PM by 25 percent, toxic carbon monoxide by 60 percent and smog-forming volatile organic compounds by 60 percent.
Under the SRF program, each DOC/DPF must be verified by the U.S. Environmental Protection Agency (EPA) or the "equivalent." Equivalent is considered equipment verified by the California Air Resources Board (CARB) or equipment verified by the manufacturer to meet the same reductions as EPA or CARB verified equipment. To achieve EPA or CARB verification, a technology must meet pollutant reduction, durability and operating performance criteria. Contractors installing EPA or CARB-verified DOCs can trust that these units will meet pollution reduction targets without affecting the performance of their engines.
What is a DPF?
A DPF is a Diesel Particulate Filter.
A DPF is a reliable technology that is usually installed as an on-line engine muffler replacement or included on new machines as standard equipment. Providing there is available space in the engine, the installation of a DPF is generally straightforward and takes four to eight hours. Retrofitting an off-road engine with a DPF typically costs between $8000 and $20,000, including parts and labor. There are a few DPF designs, however the most common DPF contains a flow-through metal or ceramic core that is coated with a precious metal catalyst such as platinum (basically a DOC), followed by a filter. This catalyst core and filter is packaged into a metal container similar to an exhaust muffler/resonator and sits in a vehicle's exhaust stream to help break down pollutants into less harmful components. DPFs need heat to oxidize the particles from the filter, so a temperature profile of the diesel equipment should be reviewed to determine whether a passive or active DPF is appropriate, or whether a DOC is a better technology.
DPFs can reduce fine PM by 85 percent or more, as well as smaller reductions in CO and VOCs.
Under the SRF program, each DOC/DPF must be verified by the U.S. Environmental Protection Agency (EPA) or the "equivalent." Equivalent is considered equipment verified by the California Air Resources Board (CARB) or equipment verified by the manufacturer to meet the same reductions as EPA or CARB verified equipment. To achieve EPA or CARB verification, a technology must meet pollutant reduction, durability and operating performance criteria. Contractors installing EPA or CARB-verified DPFs can trust that these units will meet pollution reduction targets without affecting the performance of their engines.
A DOC/DPF can be installed on most diesel construction equipment. Engines that may not be suitable for this technology include those older than model year 1990, engines that consume excessive amounts of lubricating oil (high oil levels in exhaust can clog the flow channels of the catalyst core), and those that meet EPA Tier 4 emission standards. Tier 4 engines, which are being phased in over model years 2008 through 2014, are equipped with manufacturer-installed emission control devices and emit much less PM than older engines.
Installation, Maintenance & Durability
On average, a construction engine emits four times as much fine particulate pollution as a school bus.
Providing there is available space in the engine, the installation of a DOC is generally straightforward and takes only a few hours. A DOC can be installed either as a replacement for an existing muffler/resonator, with the catalyst and a resonator packaged into the same container, or as an addition to the existing muffler/resonator, in which case it would consist only of a catalyst core.
Because DOCs are usually packaged in stainless steel containers and do not generate ash or other emission residue, they require virtually no on-going maintenance and can last six years or longer.
The installation of a DPF is a little more difficult than for a DOC. A DPF is usually installed as a replacement for an existing muffler/resonator.
In order to run properly, an engine retrofitted with a DOC/DPF may only use diesel fuel with a maximum allowable sulfur level of 500 parts per million (ppm). Because this off-road low sulfur diesel (LSD) fuel is currently available, contractors should not notice additional fuel costs after installing a DOC/DPF.