Chemical Hazards and Reactions

Specific Gravity/Density

Specific gravity (SpG) is the ratio of the density of a substance (at a given temperature) to the density of water at the temperature of its maximum density. Numerically, SpG is equal to the density in g/cc, but is expressed as a pure number without units. If the SpG of a substance is greater than 1 (the SpG of water), it will sink in water (e.g., methylene chloride). The substance will float on water if its SpG is less than 1 (e.g., oil/petroleum products). This is important when considering containment, cleanup, disposal and treatment alternatives.

Density of a substance is its mass per unit volume, commonly expressed in grams per cubic centimeter (g/cc). The density of water is usually accepted as 1 g/cc since 1 cc has a mass of 1 g for water at 4°C. Note: This information only applies to the insoluble portion of the material.