The Volkswagens of the Glass Tempering Business

In recent weeks, the world has been captivated by the Volkswagen emissions scandal. If you’ve missed the headlines, here’s a quick summary: since 2009, Volkswagen had been installing software in its vehicles that artificially reduced emissions during testing. The deception left the world in shock, angered by the company’s disregard for the environment and ethical business practices.

Lesson learned: Cheating is not a sustainable business model.

This raises the question: how do other industries, such as the glass industry, measure up when it comes to transparency and honesty?

This week, I attended the Vitrum exhibition in Milan, where suppliers in the glass industry showcased their latest innovations. As I wandered through the exhibition, one particular display by an Italian tempering line manufacturer caught my eye. It featured an image

accompanied by some bold claims about energy consumption.

Is the glass tempering industry falling into the same trap as Volkswagen?

To explore this possibility, let’s delve into the physics behind glass heating. Consider a piece of 5 mm thick glass with a loading area of 2.3 m x 4.4 m, as depicted in the image. The manufacturer claims that the energy consumption per load is just 10 kWh.

But here’s the thing: glass requires a specific amount of energy to reach the tempering temperature, a figure determined by the laws of physics, not the tempering line. The precise energy requirement is 0.476 kWh per square meter per millimeter of thickness (kWh/m²*mm). In simpler terms, each square millimeter of glass needs 0.476 kWh to reach the necessary heat for tempering.

Quick Tip: If you want the full formula and a more detailed explanation, download the “Tempering Line Buyer’s Guide” and refer to pages 37–38.

Using this principle, 5 mm glass requires a minimum of 2.38 kWh/m² to reach the prime heating condition. For a load with an area of 10.12 m² (2.3 m x 4.4 m), the theoretical minimum energy needed is 24 kWh.

Here’s the problem: The claimed 10 kWh is only enough to heat less than half of the load, and that’s without accounting for the energy needed for tempering (also known as quenching). Simply put, the claim in the image is inaccurate, bordering on false advertising.

Conclusion

The unfortunate reality is that customers often rely heavily on the data provided by suppliers. This places a significant responsibility on manufacturers, as “normal” customers may not have the knowledge to recognize when they are being misled.

If you’re planning to invest in a tempering line and want to ensure the energy consumption figures are accurate, here are a few tips:

1. Demand that energy consumption figures are contractually binding with penalties for exceeding the specified values.

2. Define the basis for energy consumption: specify the glass type, loading area, production speed, and quality. Clarity on these points is crucial.

3. Double-check the values using basic physics calculations and strive to understand the factors that impact energy consumption in tempering lines.

For a more comprehensive understanding, I recommend downloading the “Tempering Line Buyer’s Guide.” This eBook provides detailed information on energy consumption in tempering lines, along with other essential factors to consider before making an investment.

Transparency and honesty in business are not just ethical imperatives; they are essential for long-term success. Let’s ensure that the glass tempering industry doesn’t follow in Volkswagen’s footsteps.