Application Note Specific Gravity (SG)

Specific Gravity (SG) is the ratio of object's density to that of water. Since water has a specific gravity of 1 at sea level, liquids and substances with a specific gravity lower than 1 will float in water. Therefore it is improtant to select the proper float switch and float for your application. When using oils, Buna or NBR floats are best. These floats have a low specific gravity, around .5, and will float well in in most petroleum products ranging from .7 to .86 SG. For example a float switch with a specific gravity of .8 will float well in water but will sink in alcohol which is around .72 SG.

Below is a table liquids for reference.

 

Liquid SG @ 60°F / 15.6°C
Tap Water (Reference) 1.0
Automotive Oil 0.88 - 0.94
Beer 1.01
Carbon Tetrachloride CCl4 1.59
Corn Oil 0.924
Crude Oil 0.79 - 0.86
Diesel Fuel Oils 20 0.82 - 0.95
Ethylene Glycol 1.125
Gasoline 0.68 - 0.74
Kerosene 0.78 - 0.82
Jet Fuel (av) 0.62
Lard Oil 0.91 - 0.93
Liquid SG @ 60°F / 15.6°C
Machine Lubricants 0.88 - 0.94
Milk 1.02 - 1.05
Peanut Oil 0.92
Propylene Glycol 1.038
Sodium Chloride 5% 1.037
Sodium Hydroxide (caustic soda) 1.22
Sulphuric Acid 95% 1.839
Sulphuric Acid 20% 1.14
Triethylene Glycol 1.125
Turpentine 0.86 - 0.87
Water, Fresh 1.0
Water, Sea 1.03

For more information on SG, please visit the following:

Specific Gravity Liquids