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Ravago
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HALL 13 BOOTH C15
RAVATHERM XPS features at a glance
The content matters
• Energy efficiency and Thermal insulation • High water and vapour resistance • Long-Term proven performances • High Mechanical performances • Lightweight • Easy to use
The importance of choosing the right core material for sandwich panels
W
hen manufacturers of motorhomes and caravans build the walls, floors and ceilings of their vehicles, they know that as structural elements they need to withstand a wide variety of loads and weathering conditions over several years vehicle’s life time. Selection and quality of the materials used are critical for the overall performance and longevity of the vehicle; as the core material within the composite panels has significant impact on: • insulation performance • damp and moisture resistance • overall assembly strength. RAVATHERM XPS core material for sandwich panels produced by Ravago Industry Solutions has numerous benefits and in particular helps achieving the best insulation performances, while keeping moisture at negligible levels. Why this? The blue and the grey XPS foam panels have a closed cell structure which gives them excellent insulating properties, long-term moisture resistance as well as high mechanical strength. Let’s have a look at how RAVATHERM XPS matches the specific demands of the motorhome and caravan industry leaders compared to alternative core materials in particular concerning moisture uptake. Foam cores The main materials used in leisure vehicle industry are extruded Polystyrene (XPS) foams, as well as some Polyurethane (PU) and Expanded Polystyrene (EPS). Tests results The tests conducted in Rheinmünster (Germany) central laboratory of Ravago Building Solutions and confirmed by independent European laboratories, are highlighting significant behaviour differences specifically in wet environment. Water pick up test (EN 12088) The graph below is a side-by-side comparative testing of RAVATHERM XPS LB blue and high quality “moisture resistant” EPS. Bath temperature 50°C. Samples’ thickness 30-mm. WPU by diffusion testing time /days
7
14
49
57
EPS
Water Pick Up /vol %
5.2
9,1
21,2
24,4
LB
Water Pick Up /Vol %
2,6
4,3
11,0
12,4
94
Physics fundamentals: • Heat and vapour flows are moving through a panel from the warm side to the cold side. • Vapour is the moisture content in the air. Moisture content could be high in confined spaces in particular in wet rooms as bathrooms, toilets, kitchen corners; and is also generated by the breathing of people or animals. • If temperature of the room or of the surfaces is above the dew point, humidity content in the air will condense into water. • Vapour may travel through a panel using surface porosity of the warm side or via openings / joints even extremely small. While going through the panel, the temperature will decrease and may lead to condensation inside the core material. Vapour flow may also be blocked whenever cold side is more vapour tight than warm side of panel. All this will lead to accumulation of water in the panels’ core, which will eventually lead to an increased weight of the panel, rotting, mold development, and even icing if in cold climates. The mechanical action of icing will further damage the panel’s structure accelerating the phenomenon. Tests: The test has been extended to 2 months to illustrate a typical lifetime of a vehicle used in various climates and conditions.The homogeneous closed cell structure of XPS is showing limited water diffusion through the cell walls. With XPS the process is affecting primarily the area next to entry point and is propagating very slowly. As a consequence if the entry point is limited only a minor portion of XPS core material will be involved; unlike the opened beadsstructure of expanded polystyrene – EPS - where vapour will rapidly diffuse through the entire EPS panels via the voids in-between the beads: even with
