"In many building and renovation projects, light-flooded and transparent outer shells are currently the main focus," says Dennis Schneider, Managing Director of Sunflex Aluminiumsysteme GmbH. "Glass systems have to comply with the energy-saving ordinances according to the DIN standard, which means that they lose very little heat.
What general conditions do folding-sliding systems have to fulfil?
Before dealing with design issues, it is first necessary to define technical requirements. These include, for example, dimensions, number of elements, glazing as well as resistance to burglary, sound insulation and air permeability. "Certain decisions, such as the size of the entire glass front and individual system elements or whether they should not open at all, to one side or in both directions, for example, result in certain structural and security requirements," clarifies Dennis Schneider.
Glass systems should be rated at burglary resistance class 2. Here, for example, fittings are concealed within the profiles, which makes it more difficult to prise them in or knock them out. With a standard value of 36 decibels according to DIN EN ISO 140-3, windows and doors considerably reduce sound and external noise.
And what level of energy efficiency is required?
Current building projects are also characterised by their great energy-saving potential. To achieve this, the glass elements must meet high requirements. Because nowadays the maximum values for the so-called heat transmission coefficient are 1.0 watts per square metre and Kelvin (W/m2K) for low-energy buildings and 0.8 for passive houses.
While highly thermally insulated building elements with three panes were extremely thick years ago, newer glass systems such as the SF 75 and SF 75c are characterised by slim overall widths of between 75 and 95 mm despite having triple glazing. "A high-quality finish of the glass-frame composite as well as the composite between the sash and the frame is important for resistance to burglary and aspects such as airborne sound insulation and air permeability," says Schneider.
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"Despite security and energy specifications, modern systems offer many options for adapting them in terms of visual form entirely according to individual preference," explains Dennis Schneider. Whether different colours of sash and frame, floor rails attached or recessed, or the opening directions of the sashes, homeowners decide this for themselves.
Which materials does Sunflex use?
Sunflex relies on aluminium for all folding-sliding systems. "The material is durable, easy to maintain, dimensionally stable and does not rust. If you still prefer the comfortable material of wood, you can choose an internally ventilated wooden cladding," says Dennis Schneider.
To ensure that folding-sliding systems are easy to handle in everyday life, the rollers should be made of stainless steel for heavy sashes. This enables smooth and quiet movement.
