Ceiling Unit Removes Harmful Diesel Soot
Vol 21 No 5
When diesel fuel burns in an engine, the resulting exhaust is made up of soot and gases which may contain thousands of different chemi-cal substances, said Murray Lewis of New Jersey-based Air Technology Solutions.
Diesel exhaust fumes contain carbon monoxide, oxides of sulfur and nitrogen and unburned and partial burned hydrocarbons. These chemical compounds and gas phase pollutants attach themselves to tiny particles, circulate on air currents and adhere to walls, offices, stairwells, fire hose, kitchen areas and sleeping quarters.
"Diesel exhaust can spread quickly through an entire building, where it can darken walls and settle on food and clothing, creating an indoor air pollution hazard," Lewis said.
To deal with the problem, Air Technology has developed the AirMATION air purification system. Suspended from the ceiling above the rear of the fire truck, the unit is powered by a 3,000 cubic feet per minute direct drive blower that captures soot, fumes and gases. A progressive filtering system comprised of mechanical filtration and activated carbon absorption purifies the air before it is recirculated throughout the station.
Filtration begins with a blend of high loft synthetic and natural fibers that arrest more than 90 percent of the particulate as small as 4 microns in size, Lewis said.
"The second stage is a high efficiency ultra-fine glass fiber media that removes particulate as small as 0.3 microns," Lewis said. "It captures the finest sub micron particles and diesel particulate. It is a 95% /98% (MERV 16) DOP Filter (DiOctyl Phthalate), hospital grade filter."
This filter is moisture resistant and has a UL Class 2 flammability rating. It is also designed to function in 100% humidity environments and remain effective for 10 to 48 months or greater depending on environmental conditions and running time.
Several automatic activation solutions have been designed to eliminate the possibility of releasing exhaust into the station without the filtration system functioning at full capacity. Each AirMATION unit is wired to an electronic timer that can be programmed to operate the unit for run-times between one and 100 minutes. Preset at the factory to 20 minutes, activation periods can be manually changed according to the customer's preference.
"We recommend that after a long run or emergencies where firefighters have encountered heavy smoke that the interval be increased to 40 minutes or greater," Lewis said.
An electric eye is used to activate the unit's pre-set timer whenever the station's bay door is raised or lowered. AirMATION can also be activated by motion detectors on a tone alarm system. The unit can also be activated by remote control from any of the vehicles using the station. As an ultimate safeguard, the unit comes with a gas detector that can activate the AirMATION if gases rise to unsafe levels.
In the past, firefighters have used hose capture systems connected to the truck's tailpipe to remove dangerous fumes. However, this system is only effective when firefighters make the connection to the tailpipe.
"In inclement weather, and especially in severe conditions, firefighters may be adverse to hopping off the apparatus to attach the hoses," Lewis said. "As trucks enter a fire station, the engines emit deadly diesel exhaust fumes which are not captured by the yet unconnected hose."
Air Technology Solution offers third party verification of its product's effectiveness, Lewis said. In April 2003, an installed AirMATION system was tested in an independent environmental study under the guidelines set forth by the City of Philadelphia Safety Committee. The test substantiated that AirMATION removes the diesel exhaust-related particulate, contaminants and carcinogens found in firehouses.
Similar testing by the Toronto EMS showed the AirMATION kept concentrations of carbon monoxide, nitrous oxide, sulphur dioxide and airborne dust well below established exposure limits.
"We were not even told this testing would take place," Lewis said. "They tested them after the units were installed." o