Some ways to provide automatic heat to a home include electric resistance, geothermal, solar, heat pump, natural gas, propane, and heating oil. In areas where the outdoor temperatures and the electricity rates aren’t severe, heat pumps may have the lowest life cycle cost; especially if the ductwork can be eliminated. For this post though, we will compare burning properties of natural gas, propane, and fuel oil.
The video below (includes a link within it if you want to see propane) shows different fuels being tested in order to determine how easily they burn. Many people are surprised when they find out that jet fuel extinguishes a lighted match. The higher flash points of diesel fuel and fuel oil make it safe enough for tank storage in enclosed spaces like basements.
Even though fuel oil must be placarded as “flammable” when more than 1000 pounds (roughly 140 gallons) are transported according to D.O.T. regulations, it may really be a combustible liquid when it is classified according to its flash point. Years ago, if a loading facility was strictly fuel oil, it was common for oil truck drivers to smoke a cigarette while loading his truck.
Even though fuel oil and diesel fuel are basically the same thing, one of them burned a little and the other did not. The only difference between the two fuels I can come up with is that fuel oil does not need a cetane rating on its MSDS.
Natural gas was not tested in the video above. As far as its burning properties are concerned, it is the most dangerous of the three. If fuel oil or diesel fuel leaks a little, the worst thing that can happen is contamination of the surrounding area. Leaks are expensive to clean up for sure but its vapors will not ignite with a spark or match when in confined spaces unless it is really hot.
After watching the videos, you should understand why why you may have seen an oil tank close to an oil burner but never a propane tank next to a propane/natural gas burner. This also illustrates why fuel oil explosions in the news are usually misclassified but a two second search would turn up plenty of (natural) gas explosions. It makes you wonder why it is so rare to see gas to oil conversion marketing campaigns.