Kerosene, a clear liquid derived from petroleum, is used as a fuel for heating and as a primary component in many jet fuels. Understanding the weight of this hydrocarbon mixture is important for commerce, logistics, and accurate usage. The weight is determined by measuring the mass within a fixed volume, typically expressed in pounds per US gallon.
Standard Weight of a Gallon of Kerosene
A US gallon of kerosene typically weighs between 6.5 and 6.8 pounds, with the accepted commercial average being approximately 6.7 pounds per gallon. This measurement is not fixed, as it depends on the fuel’s exact composition and the temperature at which it is measured. In the metric system, kerosene generally has a density of 0.78 to 0.81 kilograms per liter.
This weight is significantly lighter than the 8.34 pounds a US gallon of water weighs, highlighting kerosene’s lower concentration of mass. When dealing with large volumes, such as in aviation or bulk heating oil delivery, this standard weight provides the baseline for all calculations.
The Role of Density and Specific Gravity
The weight of a liquid like kerosene is fundamentally determined by its density, which is the amount of mass contained in a specific volume. Density is a physical property that dictates how heavy a substance is. The weight of one gallon is simply the density of the kerosene multiplied by the volume of one gallon.
A related concept used for hydrocarbons is Specific Gravity (SG), which is the ratio comparing the density of kerosene to the density of water. Kerosene typically has an SG ranging from 0.78 to 0.82. Since this value is less than 1.0, kerosene is less dense than water and will float on top of it. This measurement provides a standardized way to compare the physical characteristics of different fuel types.
Why Kerosene Weight Varies
The weight of a gallon of kerosene is not static because its density changes based on several external factors. Kerosene, like most liquids, experiences thermal expansion; it occupies more volume as its temperature increases. This means that a gallon of hot kerosene is less dense and therefore weighs slightly less than a gallon of cold kerosene. Industry standards often define the weight at a reference temperature, such as 60 degrees Fahrenheit, to maintain consistency in transactions. A small temperature change, even just 10 degrees, can slightly alter the weight, which becomes a significant factor when measuring thousands of gallons.
Furthermore, the specific grade of kerosene affects its density. Different grades, such as Jet A aviation fuel or K-1 heating oil, have varying chemical compositions, resulting in minor but measurable differences in weight per gallon. This variability is crucial for ensuring accurate commercial measurements and proper storage capacity management.