Telescopic
Telescopic sliding doors: a wide opening in a short track
When the facade cannot give a standard sliding door the wall space to park in, telescopic sliding doors fit the same clear opening into roughly half the track. Supplied, installed, commissioned and serviced across South Africa.
How they work
Two leaves a side, moving at different speeds
A standard sliding door parks one leaf beside the opening, so it needs as much wall space as the leaf is wide. Telescopic sliding doors split that leaf in two and nest the panels as they open.
The lead panel travels roughly twice as far as the trailing one, and they arrive together. Because the two panels stack rather than sitting end to end, the whole assembly parks in about half the width a single leaf would need. That is the entire point of telescopic sliding doors: the same clear opening, far less wall to give up.
They can be single-sliding, with both panels running one way, or bi-parting with two panels a side. Requirements for powered pedestrian doors in South Africa are published through SABS. Bi-parting clears the widest opening for a given track length, because each side only has to travel half the distance.
When to specify
The problem they solve
Telescopic sliding doors are almost always a response to a constraint rather than a preference. The usual one is a facade that simply has nowhere for a leaf to go: a shopfront that ends in a return wall, a lobby where the glazing runs to a column, or an opening cut into an existing building where widening it is not an option.
They also come up where the clear opening has to stay generous for trolleys, beds or stock movement, but the structure will not carry a single leaf of that width. Splitting the leaf reduces the weight hanging from any one carriage.
The trade-off
Telescopic or standard sliding?
If you have the wall space, a standard sliding door is the simpler answer: fewer moving parts, fewer carriages and a lower price. We will say so rather than sell you the more complicated door.
Telescopic sliding doors earn their place when the wall space is not there. The trade-off is mechanical: more panels, more carriages and a belt arrangement that has to keep two leaves synchronised, which is a little more to maintain and a little more to set up correctly at commissioning.
What they should not be chosen for is speed. Both panels have to complete their travel before the door is fully open, so a telescopic door is not the answer to a throughput problem on its own.
Where they end up
Common applications
Healthcare is where we see telescopic sliding doors most often. Wards, imaging rooms and theatre corridors need an opening wide enough for a bed or a trolley to pass, in buildings where the corridor walls were never designed to swallow a leaf that size.
The other regular use is retail and hospitality shopfronts that end in a return wall or a structural column, and refurbishments where an opening is being widened inside an existing facade. In all three cases the constraint is the same: the clear opening has to grow without the wall space growing with it.
Quoting
What we need to price a telescopic opening
Telescopic sliding doors are more sensitive to the survey than a standard slide, because the whole reason for choosing them is a space constraint that has to be measured rather than assumed.
The clear opening width and height you need when the door is fully open, not the size of the existing frame.
How much wall you have either side for the panels to park in. This is the number that decides telescopic versus standard.
A photograph of what sits above the opening, which tells us whether there is headroom for the operator and what the structure above it is.
Whether there is power at the head of the door, and any access control, locking or fire interface the entrance has to work with.
Operator selection, leaf weights and configuration are confirmed on survey and stated on the quotation, so you get figures for your actual opening rather than a brochure range.
Afterwards
Servicing a telescopic door
Wear tracks cycles rather than the calendar, and a telescopic door has more running gear to keep in adjustment than a single-leaf slide. Synchronisation between the lead and trailing panels is the thing that goes out first, usually showing as panels that no longer arrive together or a door that judders near the end of its travel.
In high-traffic areas we recommend servicing every three months, with sensor and safety testing as routine work at every visit. We service telescopic sliding doors from other manufacturers as well as our own.
Survey
What a site survey establishes
Three things decide whether telescopic Sliding Doors goes in cleanly: the structural opening, what the head can carry, and where the power arrives. We measure the structural opening rather than any existing frame, check whether the head is level and adequately supported, and establish what sits above it, because a bulkhead, a sprinkler line or a services void will all dictate where an operator header can physically go.
Where a quotation is prepared from photographs and dimensions rather than our own survey, the figure is confirmed after measuring. We do not price revolving or hermetic entrances without seeing them, and where a site visit is chargeable we tell you before we attend.
Power
Power, load-shedding and access control
Decide early whether the entrance should fail open for escape or fail secure for stock, and whether a battery backup keeps it running through a load-shedding slot. Staff need to be shown the manual release either way.
Access control belongs in the same scope: card readers, push buttons, intercoms and time clocks all interrupt or enable the operator, and running cable into a finished ceiling afterwards costs far more than including it with the installation.
Systems
Choosing the right system
Traffic and wall space decide the layout. A single sliding leaf suits a shop door or a reception; a bi-parting pair moves the same opening in half the travel, which is why malls, hospitals and busy retail use it. A telescopic arrangement stacks the leaves where the wall beside the opening is short, and a swing operator automates a hinged door you already have.
- MC-125 sliding operator: single leaf up to 150 kg, or bi-parting 2 × 120 kg, clear openings 1450–5000 mm.
- MCW-100 swing operator: existing hinged doors up to 1,200 mm and 150 kg (interdependent), push-arm or pull-arm.
- Both are imported and assembled at our Laser Park facility in Johannesburg, and carry a 24-month warranty on the operator.
Common questions
Questions we are asked
Does the entrance work during load-shedding?
With a battery backup it keeps operating through a slot. Without one it parks in the fail-open or fail-secure state chosen for the building, and the manual release is demonstrated at handover.
Do you service other manufacturers equipment?
Yes. Where we take over an entrance somebody else installed, we report its condition before committing to a maintenance interval.
What warranty applies to the operator?
The MC-125 and MCW-100 carry a 24-month (two-year) warranty. The warranty that applies to your installation is the one recorded on your quotation and invoice.
Send us the opening
Width, height, how much wall you have either side and a photograph of the head is enough for us to tell you whether telescopic sliding doors are the right answer, or whether a standard slide would do the job for less.