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Multi-wall panels

High strength and rigidity

Various polycarbonate multi-wall panels are available for the infill of the EUROLIGHT and DELTALIGHT skylight systems, as well as for the use in shed glazing. Additionally, the systems can be designed as hard roofing elements.

Polycarbonate is a building material, perfectly suited as a lighting element. It features high stability, impact resistance and rigidity. Furthermore, it is resistant to many mineral acids, salts, oxidants and carbon hydride. Polycarbonate panels come with a coating for UV stability, thus their translucency changes but marginally to the indicated value over time. Its particular benefits, however, will start to reveal, when used as a multi-wall panel. Due to their low weight of 2.6 – 3.2 kg/m² (16 mm thick panel without filling), multi-wall panels offer a significantly lighter alternative to glazing infills. They provide brilliant U-values and the HR5 version is even hailstorm resistant up to a hail stone size of 55 mm according to SIA standard 280.

polycarbonate click-panels

for shed-roofs and facades

Hard roofing

When designed as a hard roofing element, the 16 mm polycarbonate multi-wall panel (marked in the table in orange) is combined with a 1.1 mm thick GRP panel, which is installed underneath.

meaning of U-value

The U-value is a factor that expresses the glazing system’s thermal conductivity. It is also known as the overall heat transfer coefficient or thermal insulation value. It indicates the volume of the thermal flow through the glazing material in relation to time and thus also expresses its insulating capability. It is the most important co-efficient in relation to heat insulation. Defined precisely, it indicates the amount of energy (in joules = watt seconds) that flow in one second through a surface of 1m2 if the air temperatures on the two sides differ in a stationary state by 1K (= degree Kelvin). It is a specific co-efficient of the material composition of a component. The lower the value, the better.

The U-value is determined in the glazing’s vertical position. In the case of air or gas-filled double-glazing panes and unfilled polycarbonate panels the values go down by c. 30% whenever they are laid horizontally. As Lumira® aerogel is a solid material, the U-values when glazing is laid vertically or horizontally are identical. This is a key advantage of roof glazing using Lumira® aerogel.

g-value and shading coefficient

Total energy transmittance is a measurement of the transmittance of energy through transparent or translucent building materials (translucent = lets light through, but cannot be seen through, e.g. frosted glass). It states the proportion of energy that can get through to the inside, e.g. through solar radiation, and contribute there to internal heating. As a level of total energy transmittance, the g-value is the sum of the direct transmission of solar radiation plus the secondary inward emission of heat through radiation and convection. Heat loss is created by reflection or absorption from or by the transparent structure. The g-value is expressed in percentage terms. A g-value of 0.5 thus corresponds to a gain of 50% of the inwardly radiating energy. In place of the g-value, data sheets often also state the solar transmission (ST) or total solar transmission (TST). The g-value corresponds to the total solar transmission divided by 100.

For example: TST = 83 corresponds to a g-value = 83 / 100 = 0.83

As well as permeability for visible light, the g-value is dependent above all on the permeability for infrared radiation, which is also referred to as thermal radiation. As it deals with the energy from the entire spectrum, the g-value cannot be used to make any direct statement about the brightness in a room. The reflected proportion of the energy is deemed a loss, as it no longer contributes to heating the building. The absorbed part, on the other hand, generates heat within the material and therefore contributes to the energy balance. However, there too energy is lost to the outside. With double glazing this loss through absorption varies greatly between the inner and outer pane, with a higher loss occurring from the outer one. With cellular polycarbonate panels a similar effect is seen between the different cells, varying from outside to inside.

High light transmission values mean that a lot of daylight is able to get into the building. In order to get as much daylight as possible into the building, the light permeability stated in percent (also referred to as the light transmission or LT value) should be as high as possible. High solar transmission values, i.e. a high g-value, mean by contrast, that a lot of thermal radiation can get into the building and that as a result of the incident sunlight the building can get very warm. The g-value should therefore be as low as possible.

Shading coefficient (b)

Manufacturers of glass and cellular polycarbonate panels often state the shading coefficient ‘b’ based on VDI 2078 instead of the g-value. The numeric value is proportionally higher, as the g-value of the pane or panel concerned is expressed in relation to the assumed g-value of a two-pane normal glazing unit. This results in:

b = g / 0.8

Until October 1994, the reference point was instead 3-millimetre single glazing with a g-value of 87%.  b = g / 0.87

roda PC16 HR5 ultra sturdy

multi-wall panels

The polycarbonate multiwall panel “roda PC16 HR5 ultra sturdy” is another novelty in our range of products. The panel features a high hailstorm-resistance and is classed with the hailstorm protection classification V, assessed by an independent Swiss test laboratory. Hailstorm protection classification HR5 means that hail stones with a diameter of 50 – 55 mm (that is about the size of a hen’s egg) can be resisted. With a weight of approximately 60 grams such a hail stone reaches a fall velocity of 30m/s and an impact energy of approximately 28  joule. In this case we are talking about a „big hail“, able to damage and even break through glazing and car windows and to chip smaller to medium size branches  off trees.

Characteristics of the roda PC16 HR5 ultra sturdy:

  • Description: Multiwall panel made from polycarbonate
  • Structure: 16/5
  • UV-protection: UV protected on both sides
  • Thermal insulation: 1,8 W/m²k
  • Translucency: 60% transparent / 40% opal
  • Solar factor: 62% transparent / 45% opal
  • Shading coefficient: 0,71 farblos / 0,52 Opal
  • Fire classification: B-s1,d0 colourless EN13501-1 /
    B-s2,d0 opal EN13501-1
  • Minimal bending radius: 3000 mm
  • Certificate: hailstorm protection classification HR5 according to testing report nº 446 of Nov 19, 2013

Characteristics of the roda PC16 HR5 ultra sturdy softlite:

  • Description: Multiwall panel made from polycarbonate
  • Structure: 16/5x
  • UV-protection: UV protected on both sides
  • Thermal insulation: 1,86 W/m²k
  • Translucency: 57%
  • Solar factor: 56%
  • Shading coefficient: 65%
  • Fire classification: B-s2,d0 (EN 13501-1)
  • Minimal bending radius: 2400 mm
  • Certificate: hailstorm protection classification HR5 according to test report nº H217VKF of Aug 25, 2014

Polycarbonate is a hygroscopic material which allows migration of vapour through the material. Occasional condensation within the panels depending on the temperature and the humidity inside and outside the building cannot be totally avoided and does not affect the quality of the product.