The density of plastic films is determined by placing test specimens in water and adding isopropanol (or other liquid if sample density > 1 kg/m3) until the plastic sample achieves a neutral buoyancy in the solution.
The density of plastic films is tested to British standard and International standard ISO 1183.
The density of plastic and other non-absorbent materials such as glass in finished form can be determined by weighing a sample in air, and in a test liquid, using a balance and pan straddle.
Smithers Pira testing is made in accordance with British standard BS 2782:6 method 620A or ASTM D792.
The density of cellular plastics can be determined following British standard BS EN ISO 845, International standard ISO 845 or ASTM D1622.