ISO-CONNECT VARIO SD – How it works

ISO-CONNECT VARIO SD is a special film for sealing construction connection joints on windows and doors in compliance with EnEV and RAL requirements.

Thanks to the special sealing membrane of the ilm, the sd-value (vapour diffusion equivalent-air layer thickness) of the film adapts to different relative air humidities and can be used both on the inside and outside of the construction connection joint. The sd-value changes depending on the air humidity flowing against it. This function guarantees that the construction connection joint remains dry and functionally reliable. In the winter, during the customary heating period in our buildings, the vapour pressure gradient moves from the inside to the outside. Warm and humid room air flows against the film. The humidity-sensitive film membrane reacts to the humid air flow and changes the sd-value to the best = highest sd-value. The film installed on the outside of the construction connection joint only has low humidity to deal with in the outside climate and remains open to vapour diffusion. As soon as the load conditions change, the flow of humid air through the film changes.

In summer, the water vapour pressure gradient in our region is reversed, e.g. in air-conditioned buildings. The climate conditions outside are warm and humid (close), whereas the conditions inside are cool and drier. The water vapour pressure gradient is then from the outside to the inside. The film is able to deal reliably with this reversed climate situation, too. The construction connection remains dry, particularly since there are no condensation problems in summer due to the higher temperatures. This has to be proved in tests of course. During the required product tests, different relative air humidities are applied to the film and the sd-value reached is checked.

Technical data: (extract)

Driving rain impermeability: ≤ 1050 Pa

The micro-perforation in the film guarantees the high driving rain impermeability (or – resistance?).

Air permeability coefficient: a ≈ 0 m³/[h•m(daPa)^2/3] = airtight

sd-value (vapour permeability): 0.2 mm to 5 mm depending on the average air humidity according to DIN EN ISO 12572

The film is bonded to the masonry using the MS polymer adhesive ISO-TOP FLEX-ADHESIVE XP.