Natural convection is a mechanism that is only present with a gas, gravity and a temperature gradient. The resulting movement of the gas is an effective heat transport mechanism. Thermal insulation is always eliminating this natural convection by confining the gas, allowing only brownian movement of the gas molecules.
The simplest example is using fibers in the way birds build a nest. A typical example is ROCKWOOL® , where the fibers are made from melting rocks or ISOVER® with glass fibers. But if we need more mechanical stability, we need to use a cellular material. Expanded polystyrene (EPS) , Extruded Polystyrene (XPS) are again typical examples. But these materials are combustible and still allow diffusion of water vapour because they are organic. In case we need also a perfect vapour tightness (against internal condensation) and non-combustibility on top of mechanical stability and thermal resistance, we have to use cellular glass with closed cells. GLAPOR® is a very good example of that. Some of the above materials have a very large ecological footprint while cellular glass can have a very low one. Some materials have an extreme low thermal conductivity like SPACELOFT®, others have no ecological impact at all like sheep wool, flax wool or wood wool.
It is very difficult to define “the best thermal insulation”, because a certain weight to the different properties is to be assumed. As a consequence, the “best thermal insulation” does not exist.
It is the conviction of BELGLAS that the “best thermal insulation system” to the customer’s wish is a sandwich of different thermal insulation materials, where a layer of GLAPOR® is replacing the vapour screen and forms the first cm’s thermal insulation. Any other thermal insulation can be added to value the wish of the customer, which can be to get
- the lowest price
- the lowest ecological foot print
- the thinnest system for a certain thermal resistance
- the best inverted roof
BELGLASCZ realizes that a full thickness with cellular glass, although maybe the highest quality, is becoming too expensive and simply too thick (not elegant) to realize today’s requested thermal resistance. A sandwich of GLAPOR® with another thermal insulation contains all the intrinsic properties of cellular glass and even more.