To calculate the weight of expandable polystyrene thermocol (EPS) if the density is given, you need to know the volume of EPS you are working with. Once you have the volume, you can use the density to calculate the weight. Here's the formula:

Weight = Density x Volume

* Weight: The weight of the EPS in kilograms (kg)

* Density: The density of the EPS in kilograms per cubic meter (kg/m³)

* Volume: The volume of the EPS in cubic meters (m³)

Here's an example:

If you have a piece of EPS with a density of 20 kg/m³ and a volume of 0.5 m³, the weight of the EPS would be:

Weight = 20 kg/m³ x 0.5 m³ = 10 kg