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What do I do for fun when I’m on an organized RV caravan trip? I wake people up early in the morning when it’s quiet so we can test the noise levels coming out of their generators! Seriously. Check out the video!
So, in a very rural and quiet setting, I realized I had Gasoline, Propane, and Diesel powered generators all in the same vicinity, mounted in motorhomes. I pulled all three of these into the same spot on the road, and had them fire up their generators while I measured things with a sound level meter and a tape measure. My goal with this was to see if each of the generators – as mounted by Winnebago in these coaches – passed the National Park Service generator standard of 60 decibels (A weighted) at a distance of 50 feet. That number is derived from the Code of Federal Regulations, 36 CFR Section 2.12 which prohibits:
Now, I don’t know if I’m a “reasonably prudent person”, but I can at least read a sound level meter.
The good news is that ALL OF THEM PASSED. But there were some interesting observations to be made along the way. First, here are the results in tabular form:
|2 feet||10 feet||25 feet||50 feet|
|2800 Watt Gasoline Generator||86 dB||76 dB||65 dB||60 dB|
|2500 Watt Propane Generator||87 dB||75 dB||65 dB||60 dB|
|3200 Watt Diesel Generator||80 dB||69 dB||61 dB||57 dB|
So probably the most interesting thing to me was that the largest generator was also the quietest. The 3200 watt diesel generator bested its gas and propane brethren at all distances. I can think of three possible explanations for this:
- The diesel generator was mounted behind a door, whereas the gas and propane generators were suspended from above. The door and compartment mounting helped deaden the sound.
- The diesel was the physically largest and heaviest of the generators. Just like in my shop tools, more mass means less vibration and consequently, less noise.
- The sound frequencies produced by the diesel generator are lower, and those are represented less in an A-Weighted decibel measurement.
In any case, the diesel generator was certainly the most pleasant of the three to be near.
The other interesting observation was that the gasoline and propane generators were basically equivalent in noise output, with the propane generator perhaps slightly louder at close ranges. This was not what I expected – I expected the gasoline generator to be the loudest by a clear margin. I don’t have a good answer for this one, but I’m pretty happy about it – since we have a gasoline generator in our new coach!
So, while this may not have been the most controlled experiment I’ve ever run, I think it was worth doing. The combination of these Cummins-Onan generators, and the way that Winnebago had them mounted in the Travato and Navion coaches, proved enough to meet the standards for running generators in our National Parks. (During permitted hours, of course!) Please use them responsibly.