Responsibility for the glass edge bond – what exactly does that mean, Sebastian Plettenberg?

In an interview with “Glas & Rahmen” back in 2018, you made it clear that Technoform would be taking responsibility for the whole glass edge bond. What exactly does that mean and why is the subject so important? 

For one thing, the glass edge bond plays an important role with regard to the thermal performance of insulating glass. It is too important to just be treated as a “side issue”, particularly since the requirements for durability and quality of insulating glass have continued to increase over the past few years and will continue to do so in the future too.  

In addition, the glass edge bond in its own right is a complex system of individual components that need to be optimally harmonized with each other in order to satisfy the high requirements for sustainability and durability in the sense of an optimized glass edge bond. We take responsibility for ensuring that our products make the best possible contribution in that respect. However, their full potential can only be realized in conjunction with other components such as sealants, connectors, desiccants, etc.. 

In order to optimally harmonize all these individual components with each other, an expert eye needs to be cast over the glass edge bond as a complete system and full responsibility needs to be taken for quality and durability. With our many years of experience and expertise, we want to take that full responsibility, and not just for our spacers. 

As requirements continue to increase, “one-fits-all” is definitely not the right approach to take – instead, the glass edge bond should be thought about holistically and optimally designed based on requirements. In addition to our thermally optimized spacers and solutions, we can help all the parties involved – from planners to window constructors and ultimately insulating glass manufacturers – to do that with the help of thermal, mechanical or acoustic calculations and design the glass edge bond accordingly.

Technoform’s important contribution comes in the form of thermally optimized plastic spacers. When it comes to making the glass edge bond more durable, who might be important?

Up to eight different parties can be involved in the planning, manufacture and installation of Warm Edge glass elements, according to the size and complexity of the individual project.  We are talking less about single-family houses – ones fitted with standard double-glazed windows produced in corresponding large quantities based on “simple” requirements – here and more about larger projects with more complex requirements because that is when it becomes clear just how many technical disciplines and trades are involved in working together on the glass edge bond. 

Firstly, there are the planners and architects who translate the developer’s interests into technical requirements. Even during this design phase, it is important to take account of “details” for the glazed building envelope such as the glass edge. In order to ensure this, planners need to be supported with regard to the importance of the glass edge bond which, of course, means providing the appropriate expertise. For that is the only way that they will be able to achieve energy efficiency and durability. 

Besides the planners, the designers of insulating glass elements – the “window constructors” – are another important group as they realize the requirements of the planners and decide how to install the insulating glass. There is little point having the best insulating glass with thermally optimized glass edge bond if the context is not thermally optimized, e.g. thermal bridges in window frames which cancel out the energy performance of a window. The task of the window constructors is literally to create the optimal framework for insulating glass.

The third important group consists of the insulating glass manufacturers who make sure that each glass element, including the glass edge, meets the desired requirements. As there are enormous risks involved in production which have a decisive influence on the performance of the insulating glass, special attention needs to be paid to the interaction between the individual components in the whole glass edge bond system.

Sustainability is about more than just energy efficiency. What role do durability, appearance and price play if you want the glass edge bond to provide the end consumer with real added value and achieve sustainability at the same time?  

We have noticed that “Warm Edge” is often reduced to energy efficiency. Which is understandable with “Warm” appearing in the name. Thermal efficiency is also the parameter on which environmental standards and sustainability certification schemes for insulating glass are based. In recent years, this has led to manufacturers doing their homework and continuously optimizing the thermal performance of their products in terms of technology and building physics. 

Today, there is not much room for improvement in terms of performance. That doesn't mean that we won’t continue to carry out research and develop our products further. However, we are currently focusing our attention on aspects that play an important role in practice and where there is indeed still room for improvement. These include the durability of the glass edge bond in its entirety in particular.

In our opinion, durability is as much a part of sustainability as energy efficiency. This can be seen from the fact that plastic spacers like the ones we produce have a longer lifetime than comparable products made of metal and therefore have less impact on the environment at the end of the day: our plastic profiles last longer and are optimally recycled at the end of their lifelime. 

Our solutions enable us to offer our customers – the insulating glass manufacturers – products of a quality that goes far beyond the normal warranty periods and has also proven this in practice. The manufacturers can pass on this added value to window constructors and planners which ultimately benefits the end consumer. 

Durability and quality come at a price. What would you recommend to planners, window constructors and manufacturers who concentrate on looking for the cheapest (rather than the best technical) solution for them and their customers?

Unfortunately, many value chains in the construction sector, but also in industry or mechanical engineering, are dominated by price wars. Everyone is looking for the potential to cut costs and squeeze prices. In fact, many decisions that should be based on technical considerations are made primarily based on budget. This approach overlooks the fact that saving money in the wrong place can be costly in the long term. Every planner and every manufacturer is aware of this and yet they are often unable to break away from the dictate of price. 

As manufacturers of high-end solutions for the glass edge bonds, quality and sustainability are naturally at the heart of our ethos and operations. For that is the only way that we can realize our aim to take full responsibility for the glass edge bond. We cannot afford to save on materials, for example, if we want to provide high-quality products. Although sustainability and added value do not come “cheap”, they are the more economical choice in the long run.

What use is it to the developer of an office building if he buys hundreds of square meters of insulating glass without thermally optimized glass edge bonds today and then in a few years' time, he has material defects to contend with? If in doubt, he will have to completely redo his glass facade at his own expense because it is outside the warranty. That is why we always try to raise awareness of the importance of looking at the costs and quality in the long term. 

Accordingly, taking responsibility for the glass edge area also means fighting for quality and durability and defying the dictate of price together.

Sebastian, thank you very much for the interesting interview!