Door type

Insulated high-speed door

An insulated high-speed door is a high-speed door with an insulated door leaf – a double membrane, an insulated curtain with a foam core or insulated aluminium slats. It significantly reduces heat transfer through the closed surface while keeping open times short.

An insulated high-speed door combines two effects that a door at a temperature boundary needs: it keeps open times short, and it insulates while closed. A single-skin PVC curtain only achieves a U-value above around 5 W/m²K and separates areas mainly through speed. Depending on the design, an insulated high-speed door reduces heat transfer to guide values between around 4 and 1 W/m²K.

The term covers three designs: the double-skin PVC curtain with an air cushion, also known as a double membrane; the insulated curtain with an inserted foam core; and the curtain of insulated aluminium slats used by the high-speed roller shutter and the spiral door. The type is also searched for as an insulated roller door, thermally insulated high-speed door or high-insulation door. The designs differ in insulation value, weight, speed and wind stability.

Typical locations are doors of heated buildings in the external wall, transitions into cold rooms at positive temperatures, air-conditioned production areas and separations between heated and unheated parts of a building. If the cold side is permanently below freezing point, insulation alone is no longer enough: a heated freezer door is then needed so that condensate does not freeze in the guides and on the floor.

Key features

• Insulated door leaf as a double membrane, an insulated curtain with foam core or a curtain of insulated aluminium slats
• U-value depending on design, as a guide approx. 1 to 4 W/m²K instead of over approx. 5 W/m²K for a single-skin curtain
• Opening speed typically approx. 1 to 2.5 m/s, depending on design and size
• Drive with frequency inverter, sized for the higher weight of the door leaf
• Seals all round at sides, header and floor
• Without heating, suitable for cold sides permanently above 0 °C

How it works

Like any high-speed door, an insulated high-speed door opens on a signal from a radar detector, induction loop or pull switch and closes automatically after the passage. Because the insulated door leaf is heavier than a single layer, a frequency inverter controls starting and braking so that it runs quickly and gently despite its mass.

Heat is lost through a door in two ways. When the door is closed, heat flows through the door surface and through leaky joints; this share is described by the U-value. When it is open, the air masses exchange: warm air flows out at the top and cold air in at the bottom, driven by the temperature difference and wind. Per second, an open doorway loses many times what escapes through the closed surface, even a single-skin one. A short open time is therefore the first lever, insulation the second.

A calculation example shows the order of magnitude of the second lever: for a door of 4 × 4 m, i.e. 16 m², and a temperature difference of 20 K, a single-skin curtain at around 5.5 W/m²K loses about 1.8 kW of heat through the closed surface, an insulated curtain at around 2 W/m²K about 0.6 kW. This difference applies in every hour the door is closed – which for most doors is by far the largest part of the operating time.

Design and components

The double membrane consists of two layers of PVC-coated fabric enclosing a still layer of air. It is the lightest insulated design, remains easy to coil and achieves around 2.5 to 4 W/m²K as a guide value. In an insulated curtain with foam core, a foam core a few centimetres thick sits in pockets or chambers between the fabric layers. It achieves around 1.5 to 2.5 W/m²K as a guide value, but it is heavier, forms a thicker coil and usually runs somewhat more slowly.

Insulated aluminium slats are double-skin profiles with a PU foam core, often thermally broken. They form the curtain of a high-speed roller shutter or a spiral door and achieve around 1 to 2.5 W/m²K as a guide value; thick, thermally broken slats are at the lower end of the range. Among high-speed doors, high-insulation doors with U-values around 1 W/m²K are therefore mainly slat doors with thick profiles, usually spiral doors.

Important for any comparison: a data sheet may state the U-value of the curtain or that of the entire door. The door U-value, calculated to EN 12428, includes side frames, seals, vision panels and edge connections and depends on the door size. Air tightness matters too: only tight side, header and floor seals ensure that the insulation value is achieved in practice.

Technical data

Feature	Guide value
U-value, double membrane with air cushion	approx. 2.5–4 W/m²K, depending on chamber construction and door size
U-value, insulated curtain with foam core	approx. 1.5–2.5 W/m²K, depending on core thickness
U-value, insulated aluminium slats	approx. 1–2.5 W/m²K, depending on slat thickness and glazing
For comparison: single-skin PVC curtain	over approx. 5 W/m²K
Opening speed	with double membrane typically approx. 1.5–2.5 m/s; with foam core or slats rather approx. 1–2 m/s
Closing speed	reduced, typically approx. 0.5–1 m/s
Cold side temperature	permanently above 0 °C, e.g. cold room approx. 0 to +8 °C
Wind resistance class to EN 12424	indoors class 0; outdoors with wind bars typically class 2–3, with slats typically 3–5
Headroom	curtain door approx. 450–650 mm, high-speed roller shutter approx. 500–800 mm, spiral door approx. 700–1,200 mm

Guide values – exact figures depend on size, curtain and design.

Advantages

• Much lower heat transfer than a single-skin curtain while the door is closed
• Short open times are maintained, as the drive is sized for the higher weight
• Fewer draughts and more stable temperatures at workstations near the door
• Less condensation on the warm curtain surface
• Relieves heating and refrigeration systems, especially with large door areas
• With insulated slats, also suitable for wind-exposed external walls

Limitations

• Insulates less well than an insulated sectional door with PU panels
• Higher weight costs some speed, depending on the design
• The thicker coil needs more headroom than a single-skin curtain
• Without heating, not suitable for cold sides permanently below 0 °C
• Cracks or leaking chambers reduce the insulating effect without the door failing

Typical applications

• Doors of heated production and storage buildings in the external wall
• Transitions into cold rooms and fresh produce areas at around 0 to +8 °C
• Air-conditioned production, assembly and testing areas
• Separation between heated and unheated parts of a building
• Heated workshops, wash bays and vehicle halls
• Second door behind a sectional door that stays open during the day

What to consider when choosing

Whether an insulated high-speed door is worthwhile depends on three factors: the temperature difference between the two sides, the door area and the time the door is closed. The greater each of these, the more the lower U-value pays off. This is almost always the case in the external wall of a heated building or in front of a cold room; between two areas at the same temperature, a single-skin curtain is sufficient.

The design follows from insulation requirement, wind and traffic. The double membrane suits moderate temperature differences and high cycle rates, because it stays light and fast. The insulated curtain with foam core suits cold rooms at positive temperatures and heated buildings with a larger temperature gradient. Insulated slats are the choice for wind-exposed external doors; for curtain doors in the façade, the wind resistance class also has to be considered – see outdoor high-speed door.

Check the open time first: a door that stays open for a long time after every passage loses more energy than the best insulated curtain can save. Precise activation, a short hold-open time and tight connections are therefore part of the specification. Enter dimensions, design and location in the configurator for insulated high-speed doors.

Planning and installation

An insulated door leaf needs more space above the opening than a single-skin curtain, because the coil becomes thicker. As guide values, allow around 450 to 650 mm of headroom for curtain doors, around 500 to 800 mm for high-speed roller shutters and around 700 to 1,200 mm for spiral doors, plus around 150 to 400 mm of side room per side depending on the design. How to take both measurements is explained on the sizes page.

For the insulation to work, the connection to the wall must be tight; the door is usually mounted on the inside face of the wall and sealed all round. In sandwich panel walls, it is fixed via reinforcements or a sub-frame that does not create new thermal bridges. The floor around the door must be level so that the floor profile seals tightly; the drive requires 230 V or 400 V depending on the version.

In existing buildings, an insulated high-speed door is often installed behind an existing sectional door: the sectional door stays closed at night and at weekends, while the high-speed door handles traffic during the day and is then the only closure against the outside air. In new heated buildings, the thermal transmittance of the doors feeds into the energy performance calculation required by national building regulations; notes on specifications can be found on the page high-speed doors for planners. The door is delivered direct from the factory, and installation and commissioning are carried out by your installer – see delivery and installation.

Typical sizes

2,000 × 2,500 mm to 5,000 × 5,000 mm. Enter your exact size in the configurator, together with curtain, colour, drive and accessories. Common sizes are listed under High-speed door sizes.

Safety and standards

The insulated high-speed door is also a power-operated door under the product standard EN 13241. Its declaration of performance may include information on thermal transmittance and air permeability – ask for these values when comparing quotations. Safety in use according to EN 12453 is ensured by a light curtain and safety edge; because the insulated door leaf is heavier, closing speed and closing forces are limited accordingly.

In the event of a power failure, an emergency opening by hand crank, chain or backup battery clears the opening. A separate door for pedestrians is usually provided; the requirements follow the national workplace regulations in the country of installation. Every person must be able to leave a cold room safely at any time, usually via a separate door with internal release.

Maintenance and service life

Power-operated doors must be inspected by a competent person before first use and at regular intervals – according to the manufacturer’s instructions and the national workplace regulations in the country of installation, and more frequently with high cycle rates. On an insulated door, the condition of the door leaf is explicitly part of this: cracks in one layer, leaking air chambers, shifted foam cores or deformed slats reduce the insulation value without the door failing.

Wear parts are the curtain or individual slats, the seals and the floor profile. A torn side or floor seal in the external wall can cost more energy than the difference between two insulation levels. The design is typically rated for several hundred thousand cycles. Inspection and maintenance are carried out by your installer or a maintenance provider.

Cost and price factors

The price of an insulated high-speed door is determined mainly by design and size. The double membrane is generally the least expensive insulated version and insulated slats, especially in a spiral door, the most elaborate; door leaf weight and drive power increase with area. Added to this are wind resistance class, vision panels, sensors and emergency opening. Installation by your installer, including fixing to panel walls, is a separate cost item on your side.

The investment pays off over the service life: the lower U-value saves heating or cooling capacity in every closed hour, and the short open time limits ventilation losses. The larger the door area and temperature difference, the faster the additional cost compared with a single-skin door is recovered. The price factors are explained on the page high-speed door cost.

Compared with other door types

The insulated high-speed door and the freezer door share the insulated curtain but differ in heating. The freezer door additionally has heated side frames, guides and bottom seal, plus cold-flexible materials, so that condensate does not freeze at around −18 to −28 °C. The insulated door without heating is the right choice as long as the cold side stays above 0 °C. With a very humid warm side, or on external doors in locations prone to frost, heated guides can still make sense.

An insulated sectional door with PU foam panels achieves around 0.5 to 1.5 W/m²K as a guide value and therefore insulates better than any curtain door, but at around 0.2 m/s it opens many times more slowly. It is the better night closure; the insulated high-speed door is the better closure for ongoing traffic. If you need both in one door leaf, consider a spiral door with insulated slats.

Criterion	Insulated high-speed door	Freezer door	Insulated sectional door
Opening speed	approx. 1–2.5 m/s depending on design	approx. 1.5–2 m/s	approx. 0.2 m/s
Thermal insulation when closed	good, U approx. 1–4 W/m²K	good, multi-layer insulated	very good, U approx. 0.5–1.5 W/m²K
Cold side temperature	permanently above 0 °C	typically down to approx. −28 °C	usually outside air
Heating	not required, optional for guides	side frames, guides, bottom seal	not required
Cycle rate	high	high	low to medium
Behaviour on impact	curtain gives way, slats may need replacing	flexible curtain, crash protection depending on version	panels dent
Typical role	ongoing traffic at temperature boundaries above 0 °C	ongoing traffic at the freezer boundary	night closure, infrequent opening

Other door types