WHAT IS HEAT INSULATION?
Heat insulation is the method of preventing heat from escaping a container or from entering the container.
In other words, thermal insulation can keep an enclosed area such as a building warm, or it can keep the inside of a container cold.
Heat is transferred from one material to another by conduction, convection and/or radiation.
Insulators are used to minimize transfer of heat energy.
Molded Expanded Polystyrene (MEPS) Foam Board
MEPS is a closed-cell material that can be molded into many items, such as coffee cups and shipping materials, or into large sheets as construction insulation.
This material is commonly
known as "bead board," and
it has R-value of about
4 per inch of thickness [2.54 cm].
The R-value of a material is its resistance to heat flow and is an indication of its ability to insulate. It is used as a standard way of telling how good a material will insulate.The higher the R-value, the better the insulation.
The physical properties of MEPS vary with the type of bead used, but the density of the board is usually one pound per cubic foot (16.3 kilograms per cubic meter.)
MAKING OF POLYSTYRENE
To make bead board, loose, unexpanded polystyrene
beads containing liquid pentane are mixed with a blowing agent and poured into an enclosed container.
The mixture is then heated
to expand the beads many
times their original size.
The beads are then injected
into a mold and under more
heat and pressure expand to become foam blocks that
are then shaped as required.
Bead board is manufactured at various densities, depending on the application.
Bead board for roofing materials has to be dense enough to walk on without damage.
Wall insulation boards are several times less dense than roof boards.
R-values range from 3.8 to 4.4 per inch (2.54 cm) of thickness.
Since spaces between the foam beads can absorb water, a vapor diffusion retarded is necessary if water transmission through the insulation might cause a problem for the user.
Roofs, walls, foundations, entry and overhead garage doors, pipes and tanks, under basement slabs, or over a slab-on-grade floor.