D’Ardenne and Burns say they were concerned about possible disadvantages to propane mowers.
Burns was concerned about possibly sacrificing power, but that has not been the case. Lab data suggest propane-powered engines produce more torque than other types of engines, which would be especially beneficial for mulching wet grass, D’Ardenne says.
In fact, propane is approved under the Energy Policy Act of 1992 for use by federal and state fleets as an alternative fuel, and it has an octane rating of 104 to 107. It also allows for a higher compression ratio. So a propane-powered engine can run just as powerfully and more efficiently than an engine powered by gasoline, which has an octane ratio between 87 and 93.
D’Ardenne says some crew members believed propane would be more dangerous than gasoline, but he says the evidence points in the opposite direction.
“Propane cannot be ignited like gasoline because it is released as a vapor from a pressurized container,” he says. “Also, propane won’t ignite when combined with air unless the source of ignition reaches 940 degrees.”
Also, manufacturers have improved propane cylinders based on experiences in the field. Early adopters of this technology used cylinders designed for use on forklifts, which often do not travel over rough terrain that can create fuel-delivery problems and frozen lines.
Now, cylinders for use on mowers effectively regulate the flow of propane, even on rough terrain. The cylinders are engineered to be rugged. Propane storage also offers safety advantages. Storage tanks are safer to have near a facility because they have been rated up to 20 times more puncture-resistant than gasoline tanks. D’Ardenne says he is happy with the propane mowers so far and plans to buy additional mowers.
“This is a really simple way to drastically increase the sustainability efforts of any grounds operation,” he says.
Burns concurs.
“As a grounds professional, I am charged with being a steward of the environment, while also staying within a budget,” he says. “From what I’ve seen so far, this mower is a no-brainer, both when it comes to my bottom line and preserving our natural resources.”
Eric Grammer is communications managerwith the Professional Grounds Management Society, www.pgms.org.
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