Sunday, 19 January 2020
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More options thanks to slim lift doors

The special challenge in modernising a lift is getting the most in space and comfort out of the existing structural circumstances.


In the context of the modernisation trend and the rising number of new lifts being installed in existing buildings, owners no longer tolerate any losses in the floor area of the lift. Not least to ensure barrier-freedom and in this way also keep the upper floors attractive for leasing or sale.

Riedl’s slim LIZ 3.0 sliding door opens up completely new options for new construction and modernisation to lift builders. It is available as a two-, three-, four- or six-leaf door. The entire door package of landing and car door is only 103 mm net or 130 mm including landing door frame or 146 mm net and 173 mm including frame in the two- and four-leaf versions.

Space can be saved in the car

These dimensions refer to installation directly on the masonry or hinged door frame. Consequently, a lot of space can be saved in the car when switching from hinged to sliding doors. When using conventional sliding doors one would instead have to accept a loss of about 150 mm.

"We are talking about a total package thickness that would only cover the car door in the case of standard doors,” explained Peter Andrä. "And that’s just the beginning. Just as there has been no end to the reduction in the shaft head in lift construction, the package thickness in doors will continue to shrink in the years to come. In future slim sliding doors will be standard.”"

Optimal strength thanks to modern joining process

HandwerkAnyone who believes it is necessary for this reason to make compromises in the strength of their lift doors has to clear up some prejudices. The entire LIZ range has been tested and approved according to EN 81-20 and already passed all pendulum impact and pressure tests, as well as the fire test for steel and stainless steel versions according to EN 81-58 in the E120/EW60 classification. Additional bracing on the frames results in maximum strength in LIZ 3.0.

During the pendulum impact test required according to EN 81-20/50, a dynamic force action of about 720 kg is achieved. This is after all equivalent to the weight of a Bavarian Fleckvieh cow. At the same time the third generation of LIZ manages completely without indenting of the door leaf in the standard stainless steel threshold. Hence the required strength is achieved solely through the sturdy design of the door leaf, direct attachment to the impost and the robust, but flexibly adjustable door guides.

In practice when in use a lift door does not enjoy the clean conditions of a test rig. Soiling in the shaft, such as road grit and other foreign bodies, wears out the indenting as well as the door leaf. Consequently, Riedl relied on an easy-to-clean threshold with dirt openings in the design of LIZ.

Upgrade through modernisation

Wide door clearance width is very important in boosting the utility of a lift. Thanks to its extremely compact door package, the opening widths of the three- and six-leaf LIZ versions have the same outer widths as the two- and four-leaf versions. In practice, instead of a standard two-leaf door with door width 700 mm, you would use a Liz 3S/K with a door width of 900 mm and as a result, depending on the standard door model, still have created approximately 70-130 mm more space in depth in the car.

Every lift builder is aware of the fact that great tolerances can occur at the masonry. Liz has a solution for this too: with the attachment brackets especially developed by Riedl (RIEDL-flex), even severe unevenness in the corners and on the plain can be compensated. In this way, tension-free installation in alignment is always guaranteed.

Anyone who modernises their lift also wants to upgrade it at the same time. Thanks to the bonded design, coloured, titanium-look or ground and embossed design surfaces are possible. Riedl can also use framed glass door leaves, which are fully compatible with their steel equivalents, in combination with the above-mentioned surfaces. Thanks to the sturdy design, even portal frames with fire protection or glass can be used.

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