Blackout scenarios and new safety concepts in lift construction

The debate surrounding security of supply has become significantly more heated in recent years. Power failures, grid overloads and increasing dependence on digitally controlled infrastructure are also casting lift construction in a new light.

What was long considered a theoretical risk is now seen as a real scenario that operators, manufacturers and maintenance companies must prepare for. This is giving rise to new requirements and solutions, particularly in the field of safety technology. A family-owned company based near Vienna, Austria, has been working on precisely these issues since the late 1990s. The company was built up within the family and is now run by the second generation. The focus is on lift technology, in particular safety-related applications that go beyond classic standards and respond specifically to critical situations.

Safety technology as a key area of development

In lift construction, safety is not an abstract concept, but is clearly standardised. Applications are classified according to defined safety levels, from SIL 1 to SIL 3, with the highest level corresponding to the maximum safety requirements that are standard in this industry. This is precisely the area in which new systems are being developed. The aim is to increase the reliability of systems while at the same time being prepared for exceptional events. This is not just a matter of mechanical safeguards or redundant components. Modern safety technology considers the interaction between sensor technology, control systems and power supply. The more complex lifts become, the more important it is to be able to react in a controlled manner even in the event of external disruptions.

Blackouts as a realistic assumption

One key scenario that is increasingly coming into focus is large-scale power failures. Public debate has shifted in this regard. The question is no longer whether a blackout is possible, but rather when it might occur. For lifts, a complete power failure poses a considerable risk, as people can become trapped in the cabins. While modern new installations often already have integrated emergency functions, this is not the case for older installations in many instances. Existing installations in particular often lack solutions that enable automatic and safe evacuation in an emergency. This is where the development of special systems that can operate independently of regular grid operation comes in.

Automated emergency release in the event of a power failure

Essentially, this involves a system that continuously monitors the status of the lift. If the power supply fails, the technology detects the failure within the safety chain. Instead of abruptly stopping the lift, the brake is opened in a controlled manner. A so-called stutter circuit ensures that the cabin moves slowly and in a controlled manner without uncontrolled acceleration. Meanwhile, sensors detect the position of the cabin. As soon as a point is reached where safe opening is possible, the system reacts. Optical signals indicate the status, doors are released and the trapped persons can leave the lift. The system is then taken out of operation to rule out further risks. This type of emergency rescue is particularly relevant for existing systems. It enables a large proportion of the affected lifts to be secured automatically without the need for manual rescue. Even if not every system can be fully covered, the personnel required for emergency rescues is significantly reduced.

Technical basis and power supply

The technical basis for such systems lies in an independent power supply. An uninterruptible power supply ensures that the necessary functions remain available even if the public grid fails. It is important that only the safety-relevant components are supplied in order to use energy as efficiently as possible. A prerequisite for use is that the lift system can move independently when the brake is open. If this is the case, emergency rescue can be retrofitted relatively easily. This is precisely where there is a decisive advantage for operators of older systems, who would otherwise have little opportunity to respond to blackout scenarios. Typical features of such safety solutions include:

• Permanent monitoring of the safety chain
• Controlled opening of the brake in the event of a power failure
• Controlled movement of the cabin without acceleration
• Sensor-based detection of safe stopping points
• Automatic door release for evacuation

Retrofitting instead of complete replacement

An important aspect is the question of cost-effectiveness. Completely replacing an lift system is expensive and often involves considerable structural work. Safety solutions that can be retrofitted offer a realistic alternative here. They significantly increase the level of safety without fundamentally changing the existing system. Variotech GmbH specialises in precisely this interface. The company develops systems that can be integrated into existing structures while still meeting the high requirements of modern safety standards. The approach is pragmatic: maximum effect with as little intervention as possible.

Safety as a continuous process

The development of such solutions shows that safety in lift construction is not a static state. New risks, changing conditions and technical advances require continuous further development. Exceptional scenarios such as a widespread power failure in particular highlight the importance of forward-looking concepts. Variotech GmbH does not see safety as an additional function, but as an integral part of modern lift technology. The combination of experience, a family-like corporate structure and clear specialisation results in solutions that respond to real problems. This addresses an area that is likely to become even more important in the future.