The pre-manufactured sandwich panels (composite panels) are excellent choice for heat insulated roof and wall cladding of industrial and commercial buildings. Sandwich panels with coated steel armouring on both the external and internal sides and with a heat insulated filling (polyurethane or mineral wool with higher specific weight) are widespread in the construction industry.
Az önhordó, előregyártott szendvicspanelekkel a kivitelezés rendkívül gyors és gazdaságos.
The mounting of self-supported, pre-manufactured sandwich panels is remarkably fast and economic.
Swedsteel sandwich panels can be used with load-bearing structures of steel or reinforced concrete in case of industrial buildings for external and internal use (indoor and outdoor wall panels, roof panels). The broad range of panels regarding type, thickness and colour allows optimal choice in respect to aesthetics, function and technical requirements (load-bearing, heat insulation capability, fire resistance and soundproofing). The steel coating of the panels is available with statically defined thicknesses and colour according to demand of the investor.
The components of the sandwich panel
The main component parts of the sandwich panels are the double-sided armouring (steel sheets) ensuring external surface protection and the infill heat insulation material (insulation core). Building material pre-produced under in-plant circumstances is meant by using the expression “sandwich panel”. The most common and most often used sandwich panel in case of industrial hall buildings is the heat insulated, self-supported sandwich panel with double sided metal (hot-dip galvanized steel sheet in most cases) armouring. The filling heat insulation material can also be of various types (fibre or foam in general): mineral wool, glass wool, polyurethane foam, phenol foam expanded or extruded polystyrene. Every heat insulation material has pros and cons regarding the technical parameters, the most suitable one has to be chosen according to the concrete requirements in each case. Panels with PUR/PIR filling perform better considering the coefficient of thermal conductivity and specific weight, while panels with mineral wool filling have better parameters for fire-protection.
Technical specifications, utilization
Sandwich panels that are easy-to-mount but are really complex considering their technical specifications, since it depends both on the material of the different components and the cohesion (adhesion) between them. Fast and easy mounting is allowed with pre-manufactured, large-board, self-supported sandwich panels (longitudinal grooved joints and fastening with self-drilling screws) that is an economic solution in case of covering large, homogenous surfaces. Sandwich panel is the most widespread roof and wall cladding solution of industrial, agricultural, commercial and other type of hall buildings for that very reason.
Heat insulation capability: The heat insulation capability of the sandwich panel depends on the specifications of the filling material. The best thermal insulators are the panels with PUR and PIR foam infill with low thermal conductivity in case of specific panel width. The appropriate, airtight construction is necessary for efficient heat insulation and energetics (sealing tape factory produced or applied on-site).
Mechanic resistance, load-bearing: The load-bearing capacity of the sandwich panel is defined by the mechanical properties of the individual component parts (metal armouring, heat insulation core) and the cohesion and adhesion between them. It is complicated and has lots of uncertainty to define the load-bearing capability with solely theoretical calculations and as the values for designing are done based on laboratory tests made according to the EN14509 harmonised product standard. The typical impacts of a sandwich panel are meteorological loads (snow-load, wind-load), changes in temperature and building loads during construction.
Water-, air- and vapour tightness: The sandwich panels with double-sided armouring are absolutely water-, air- and vapour tight, the main reason of it is the metal base material of armouring. The final properties of sandwich panel claddings (internal and external wall, roof claddings) are influenced by the incidental splices, overlappings and closing edges. The precise production sizes and special sealing tape ensure the appropriate closure of the junctions of sandwich panels, beside of this all the other important conditions can be accomplished by appropriate and careful design and implementation and the compliance of technical guide rules.
Fire characteristics of sandwich panels: The fire-protection properties of sandwich panel can be grouped according to the followings.
- The fire class of panel (“reaction to fire”) shows the burning properties of product. The polystyrene has the worst fire resistance attributions, panels with PUR filling perform better, and PIR insulation with flame retardant additives (self-extinguish) can provide higher fire-resistance parameters. (even B2-s1,d0) Panels with fibre insulation material core (E.g. mineral wool) can insure the highest class of fire-resistance. (A2-s1, d0)
- The fire performance of sandwich panel expresses the time of resisting to fire (in minutes) as regards different types of physical characteristics. (“R” – load-bearing capacity, “E” – surface integrity, “I” – insulation capacity. (E.g the following fire resistance values may be applied: “REI30”). Generally panels with polystyrene core can insure at most 15 minutes fire resistance value; with PUR/PIR insulation can perform 15, 30 or even 45 minutes, while panels with mineral wool filling have the highest resistance values: even 90 or 120 minutes.
- The external fire spreading is the third fire property of the composite cladding products. Basically sandwich panels can be classified in the highest category (B,Roof) without applying any special analysis or test processes, because of the precise water-, air and vapour tight joints.
Acoustic properties: Two basic acoustic properties of external and internal cladding systems are known.
- Sound insulation is a physical value what shows the rate of sound energy decrease on the one side of a surface (e.g. wall or roof cladding), while the noise source is on the other side. So this acoustic value expresses the sound energy reducer capability of a material, surface or structure in dB. Generally, structures with higher weight are more appropriate to decrease the sound energy, depending on the frequency of sound. This is the reason why panels with mineral wool core can ensure higher sound insulation values than panels with PUR/PIR insulating.
- Sound absorption value also expresses the sound energy decrease (like sound insulation value), but in that case when the noise source and the noise sensor are on the same side of the surface. Panels with constant, uninterrupted armouring give almost back all of the sound energy (independent of the insulation material), they don’t have effectively sound absorption capability. The sound absorption values of panels can be increased by applying perforated internal armouring and mineral wool insulation core.