Determination of density

The UL Thermoplastics Testing Center performs detailed tests on your behalf to determine the density of highly diverse specimens.

The choice of method for determining the density is based on the type of material as well as on the size and shape of the specimen. A further criterion is the required degree of precision. The density is determined from the calculated volume and the mass of the specimen and is given in g/cm³.


The following methods can be carried out at UL TTC:

Hydrometer method
This method uses solid specimens or specimens from moldings. The volume is calculated by dispersing and agitating the solid in distilled water or another suitable liquid.

Degree of precision: 3 decimal places.

Air comparison pycnometer
This method uses powdery, porous and irregularly shaped solids. It involves calculating the volume of air displaced by the specimen in a measuring cylinder.

Degree of precision: 2 decimal places.

Apparent density
The apparent density of granular, powder or free-flowing materials is calculated by filling a measuring beaker with a defined volume of the specimen and weighing it according to the method described in the standard. The apparent density is given in g/cm³. Amongst other things, the apparent density provides a starting point for calculating a cavity when injection molding compounds are processed.