Compare Exhaust Removal Technologies
Source Capture Systems
This type of system uses a hose and nozzle, a rail or track with movable trolley or expandable flexhose, ductwork and an exhaust fan to draw the vehicle exhaust emissions out of the firehouse. The nozzle connects to the vehicle exhaust pipe, making it the most effective way to eliminate hazardous diesel exhaust emissions “at the source.” When responding to an alarm, the system remains connected until the apparatus reaches the doorway, at which time the nozzle automatically releases.
Source capture systems use magnets in three different ways to connect the nozzle:
- Magnetic-assisted (MagneGrip) – magnets support a mechanical connection and the nozzle releases when lifted at a set angle.
- Magnetic grabber – magnets hold the nozzle onto the tailpipe and use a moving thrust-action to detach the nozzle;
- Electro-magnetic – a magnetic plate on the hose attaches to the side of the apparatus, holding the nozzle over the tailpipe. Electric wiring must carry current along the track and down the hose to trigger the release when exiting.
Pneumatic systems are an older source-capture method of placing a rubber bladder over the tailpipe and then inflating the bladder. This requires running an air hose from an operating compressor along the rail and down the side of the flexible hose. The nozzle release occurs when a mechanism is tripped causing the bladder to deflate and fall away.
Diesel Particulate Filter
This is an underbody, canister-type filter that manufacturers install on apparatus beginning with 2007 models, as mandated by the EPA. These filters can also be purchased for older model apparatus. The filter’s primary purpose is to capture the particulate that is at its greatest concentration when a vehicle is started. The filters may also capture some gases, but underbody filtration technology is not capable of eliminating most of the toxic gases and fine particulate in diesel exhaust emissions.
Air Cleaning Systems
These systems use a series of ceiling-mounted air filtration units in the bay area to pull in exhaust fumes and other pollutants. The systems are set to operate automatically. Contaminated air is drawn through a series of filters to trap particulates and gases, and then the cleaned air is dispersed back into the facility. The two primary types of air circulation patterns used in air cleaning devices are vertical and horizontal patterns. Vertical air circulation pulls in contaminated air at the base of each unit and sends filtered air out from the top. Horizontal air circulation pulls in contaminated air at one end of the unit and sends filtered air out the other end to create a continuous pattern of filtration.
A photo-catalytic oxidizer can be used as a fourth stage of filtration in some air cleaning devices for additional protection. The PCO contains ultraviolet lamps and a specially coated grid to neutralize toxic compounds such as carbon monoxide and nitrous oxide. The UV lamps kill airborne contaminants such as viruses, bacteria and mold spores.
Other types of air filtration devices, such as ducted and portable units, may be used in other parts of a facility, such as turnout gear rooms, living quarters and offices.
This is a type of source capture system that uses a damper nozzle to connect the hose to the vehicle exhaust pipe. The nozzle must be manually connected and disconnected. These “simple drop” systems do not use a track or rail; instead, the hose connects directly to overhead ductwork and can be wound up on a reel when not in use. These systems are used for non-emergency firehouse vehicles, buses, OTR trucks, and heavy equipment. They are used to capture and remove exhaust emissions anytime vehicles are operated in an enclosure such as a maintenance facility or garage.