Over the past several years, I have been in several discussions regarding fuel oils and most of these discussions have concentrated on number 2 home heating oil and on biofuel. The latter seems to be the hottest topic currently. However, there are several other grades of oil that have been used in the past, ranging from number 1 through number 6.
Many of you who have been in the oil business probably are familiar with theses grades and may have installed and serviced equipment burning the heavy oils.
I would guess that most readers will recognize that industrial boiler installations and service have become a specialized field of business. Some of you may recognize the names of some popular heavy oil burners that are still produced, for example Webster and Power Flame, to name two brands. (Another brand, Iron Fireman, is no longer manufactured, an online search indicates, although parts remain available.) Such burners, designed to burn the heavier-grade fuels, often require what is referred to as a pre-heater. The pre-heater was attached to the fuel system and would raise the temperature of the fuel allowing it to flow easier and burn correctly.
Today, many commercial boilers are equipped with commercial burners such as those made by Riello, Carlin, and Beckett, to name a few. The commercial boilers of this generation are now able to function on the standard #2 fuel oil and burn with higher efficiency and often require standard, in-stock, less expensive parts. These same burners can also function on a high/low fire which supports lower annual fuel consumption, which in turn translates to savings in dollars, especially during off-peak heating season when hot water is the only demand.
For those of you who are not acquainted with what is referred to as heavy oil, here is a brief primer on the different grades:
#4 Oil–Often described as a hybrid grade fuel, being a distillate low grade with low viscosity. Because of its low viscosity it has occasionally been used without a pre-heater. Generally, it is used in smaller applications such as schools and apartment buildings.
#5 Oil—This grade of oil very seldom will come from a refinery like other grades of fuel. Number 5 oil is generally a blend created by adding a degree of six oil for it to meet different viscosity requirements. This fuel can also be used in smaller equipment with lower burning rates. Some companies have used this fuel without a pre-heater, but for higher-viscosity (thicker) fuel, a pre-heater is required to achieve desired flow and proper burn.
#6 Oil—Often referred to as “Bunker C grade oil,” this product is black, very thick, and messy. It is extracted from crude once the lighter fuel products, such as gasoline, kerosene and other lighter fuels, have been removed.
My own experience with these fuels was supplying #4 oil, which later became homogenized from being blended with #2 oil. I delivered it to Rhode Island ferry boats, schools and factories. This was in the early 1960’s when the heavy oils were in demand.
Now with the building of bridges and newer commercial heating equipment being installed in these same buildings, the demand for heavy fuel has become almost extinct. Unless of course you’re in the freighter business. To that end I’m glad that most of you will never have to work with heavy oil. That at times was a very messy profession!
Pictured: Columnist Charles Bursey Sr.