The densometer test measures the time required for a specific volume of air (2.5cc to 30cc), at a constant pressure of 12.33 inches W.C., to flow through a standard area of the material being tested. The air pressure is supplied by a weighted inner cylinder floating freely within an outer cylinder which is partially filled with oil to act as a seal. The sample material is held between clamping plates having a circular orifice area of 1.0 square inch (standard).
High pressure units are recommended whenever a standard unit would yield excessive measurement times. Porosity readings with the high pressure densometer are much faster than those taken with a regular  densometer. This difference can be as great as twenty-five times faster since higher air pressure is used and air volumes are one-tenth those measured with a standard densometer. Readings also can be affected by using different adapter plates with smaller orifices on all models.

• Coated Papers
• Plastics
• Membranes

TAPPI T-536-88 and ASTM D-726-58, Method B