Specific
Gravity (SG) is the ratio of objects 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 @ 60ºF / 15.6ºC |
Liquid |
SG @ 60ºF / 15.6ºC |
| Tap Water (Reference) |
1.0 |
Machine Lubricants |
.88 - .94 |
| Automotive Oil |
.88 - .94 |
Milk |
1.02 - 1.05 |
| Beer |
1.01 |
Peanut Oil |
.92 |
| Carbon Tetrachloride CCl4 |
1.59 |
Propylene Glycol |
1.038 |
| Corn Oil |
.924 |
Sodium Chloride 5% |
1.037 |
| Crude Oil |
.79 - .86 |
Sodium Hydroxide (caustic soda) |
1.22 |
| Diesel Fuel Oils 20 |
.82 - .95 |
Sulphuric Acid 95% |
1.839 |
| Ethylene Glycol |
1.125 |
Sulphuric Acid 20% |
1.14 |
| Gasoline |
.68 - .74 |
Triethylene Glycol |
1.125 |
| Kerosene |
.78 - .82 |
Turpentine |
.86 - .87 |
| Jet Fuel (av) |
.62 |
Water, Fresh |
1.0 |
| Lard Oil |
.91 - .93 |
Water, Sea |
1.03 |
