Revamped air quality regulations over the last ten years have raised the bar on reducing pollution and managing emissions from diesel engines, especially in the diesel engines of older truck fleets. But truck engines are not the only diesel-powered engines subject to emission requirements. Diesel backup generators also have to comply with air quality standards, even when they are only powered up for a limited period of time. Let’s explore diesel particulate matter and the role a diesel particulate filter plays in meeting emission requirements.
What is Diesel Particulate Matter (PM)
Diesel PM is defined as “the particles found in the exhaust of diesel-fueled compression ignition (CI) engines as determined in accordance with the test methods” of the California Air Resources Board, the California Code of Regulations, and International Organization for Standardization. In simple terms, it is the soot produced by diesel engines- the same soot that can cause asthma and lead to lung cancer.
How can a Diesel Particulate Filter (DPF) help with Diesel PM? DPFs trap the soot produced by diesel engines. The South Coast Air Quality Management District (AQMD) defines them as “an emission control technology that reduces PM emissions by trapping the particles in a flow filter substrate and periodically removes the collected particles by either physical action or by oxidizing (burning off) the particles in a process called regeneration.”
Passive vs. Active Filter
DPFs can come as passive filters or active filters, depending on your needs. Passive filters are less expensive up front, but they require annual maintenance that can run anywhere from $2,500 to $5,000 annually. Also, they do not come equipped with a self-cleaning system; they need to be cleaned out annually by a service provider. Another scenario to consider is this: if an alarm goes on your passive system during an emergency, and your DPF is clogged, it can force your generator to shut itself down so the back pressure coming from the filter doesn’t damage your engine, rendering your generator useless. You can set the parameters during the installation process for when the alarm sounds due to clogging, generally it will sound at about 90 percent.
There are three ways you can clean passive DPFs:
– Burn out the soot using a resistive load bank
– Pull the filter from the system and bake for 8 hours to burn out the soot
– Use compressed air to blow out the soot
Active filters, on the other hand, clean themselves without fail. Both passive and active filters have their own monitoring system onboard that sound an alarm when the filter needs cleaning (regeneration). The advantage of active filters is they regenerate and clean a portion of the DPF each time the engine runs, whether it’s an emergency or an exercise, so you will never get an alarm indicating the filter is clogged.
As you can see, there are several factors to consider when choosing the appropriate DPF for your generator. Your generator technician can recommend the best filter to satisfy your air district, your manufacturer’s specs, and your budget.
Determining if you Need a DPF
So, do you need a DPF for your backup generator? The easiest way to find out is to consult with your generator maintenance provider or vendor. Your local air district- South Coast Air Quality Management District (SCAQMD) here in LA- will list on the air permit specific to that generator what the owner is required to do regarding maintenance and testing, including the PM filter, if necessary. It is also important to note rule 1470 which requires a filter on any new generator with break horsepower (BHP) greater than 50 that is also within 100 miles of a “sensitive receptor” (schools, hospitals, condos, residences, etc..).
When we provide service at Duthie Power, we help the customer read all permits and show them what they need to be doing. The maintenance technicians and sales reps at Duthie Power Services are familiar with the standards that need to be met for your diesel generator and diesel fire pump engine to comply with local diesel particulate matter standards. Installing pollution control devices is driven by air regulations and professional guidance is recommended, as reading through the AQMD or other local regulatory bodies’ emission requirements is not for the faint-hearted.
Whether installing a passive filter or an active filter, we work with engine manufacturers to determine the best course of action to ensure your generator meets emission requirements. There are many more acronyms we can also define and assist you with- DOCs (diesel oxidation catalysts), DEFs (diesel exhaust fluid), and TCB (takin’ care of business), to name a few.
Don’t Wait Until It’s Too Late
The last thing you want is to put off maintenance until an emergency hits and you discover your generator is out of compliance. It’s not just emergencies to worry about, either. You could get a surprise inspection from your local air district inspector, putting you at risk of getting a citation, if you are out of compliance, that can run you several hundred dollars a day. Schedule regular maintenance for your generator and ensure that, especially for older equipment, your generator meets emission requirements. California has specific mandates that differ from other national standards and we know California best, as Duthie Power has been the number one name in generators in Southern California for 50 years.