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Rationel Forma FormaPlus Triple Glazed Chop Sample

Forma & FormaPlus

Designed for a more traditional style of building, the Rationel FORMA window has an all-timber construction with slim, non-continuous bars. Featuring an ovolo moulded profile and angled glazing bead, FORMA is perfect for older, classic and country style houses. The aluminium external cladding also has a unique curved edge.
In terms of frame construction, the Rationel FORMAPLUS window is identical to FORMA. The only difference between them is the addition of external aluminium cladding included on the FORMAPLUS window. This inclusion ensures both minimum and easy maintenance characteristics.

  • Rationel Windows is a manufacturer with more than 60 years experience. Rationel employs 1,050 people in Denmark, England, Ireland and Poland; manufacturing premium quality, durable and stylish windows and doors.

    Rationel Aura and AuraPlus Options

    Both Forma and FormaPlus have a wide variety of opening designs, glazing options and configurations. Along with the typical styles, Rationel FORMA and FORMAPLUS can be manufactured in bespoke shapes to correspond to an assortment of openings. Featuring fully adjustable and secure ironmongery (Secure by Design part Q compliant hardware), two gaskets and the option of trickle vents; FORMA and FORMAPLUS are carefully engineered with the customer in mind. Furthermore, all Rationel products prioritise energy efficiency. The slim design naturally takes advantage of the solar heat from daylight, and the exceptional insulating qualities reduce CO2 emissions significantly.
    Due to their energy efficient characteristics, both Rationel FORMA and FORMAPLUS are suitable for Passiv Haus buildings.
    Thanks to constantly enhancing efficiency and optimising the products, Rationel windows are designed to withstand all weather types, attempted break-ins, and finally the constant wear and tear of repeatedly opening and closing windows year after year.

    Marine Suitability

    Rationel aluminium profiles are coated with a minimum of 60 microns thickness and are pre-anodized so can be called marine grade. The windows and doors will require regular maintenance as per the OE manual shown in the downloads tab of this page.

    Efficiency, Solidity, Dependability

    The Rationel product development is primarily based on Danish market and associated climate i.e. predominantly coastal, similar to North Scotland so the products are suitable for coastal locations. We treat the aluminium for filiform corrosion prior to powder coating, and the products are salt-spray tested at R&D stage. Furthermore, salt-spray batch testing is completed on all metal components from cladding to hinges. Even to staples used to fix packaging for delivery also takes place.

    “We basically offer a complete service. For over 60 years our company has been based on excellent craftsmanship. This is still the case. At Rationel we take a pride in delivering high quality,” Rationel CEO Thomas Tvedergaard Larsen.

  • Typical LifespanFORMA: 60 years
    FORMAPLUS: 85 years
    Lead Time8-10 weeks from sign off
    Best U-Value0.78 W/m^2k
    Finishes Any RAL Colour
    for both timber and aluminium (FORMAPLUS only)
    GlazingDouble, Triple, Obscure, Solar, Toughened
    Performance and
    Air Permeability: 600 PA
    Wind Resistance: 1600 PA
    Operation: 10,000 cycles
    Water Tightness: 600 PA
    Manufactured inPoland

  • Fixed Frame

    Fixed Frame Configuration

    Side Guided

    Side Guided Configuration

    Side Hung

    Side Hung Configuration

    Top Guided

    Top Guided Configuration