French tableware glass specialist International Cookware is plotting a furnace rebuild next summer. As Johann Brunie tells Greg Morris, the company has been at the forefront of decarbonisation for 25 years.

While construction of a furnace rebuild at International Cookware’s glass manufacturing facility may not be for another seven months, it doesn’t mean that Johann Brunie and his team are not already busy.

Preparation work on the new oven has already begun, with discussions about the schedule, modelling of how the furnace will look and, importantly, the environmental aspects of the investment.

His team has already had discussions with modelling experts from Glass Service in the Czech Republic about the rebuilt furnace. The talks focused on the geometry of the new oven and ways to improve the modifications.

The glassmaker has already placed refractory orders with its long tem partner, French compatriot Sefpro, ahead of the construction next year.

The project has received funding from the France Relance project, a French government scheme to help boost domestic industry as it recovers from the lockdowns caused by the pandemic. Grants are given to companies which have decarbonisation strategies and that have aims to reduce their emissions.

The operation in summer 2022 will enable the glassmaker to further increase its energy efficiency and pursue its electrification aims.

The integration of the rebuilt gas-oxygen/electricity combination oven will increase the electrification rate from 49% to 54%. It will save 3800MWh of power a year, or 1100 tonnes of CO2e per year.

Mr Brunie, who is International Cookware’s Technical Director, said: “We were talking about the decarbonisation of furnaces nearly 25 years ago when our engineers decided to test the electrification of the furnace in 1998. So you could say we were decarbonisation pioneers.

“At the time we were thought of as quite strange by focusing on environmental issues but today decarbonisation is a huge issue.”

Even 16 years ago, the reduction of emissions was a theme at the site. In 2005 its engineers cut NOx emissions by switching from air gas burners to oxy gas burner, which have been in place ever since.

International Cookware is known for producing the Pyrex brand of kitchen cooking glass, under licence from brand owner, Corning. From its site in Chateauroux, France the cookware is distributed to Europe, the Middle East and Africa.

The facility produces a variety of shapes, weights and dimensions of cookware glass for the international brand. While the majority of production is for Pyrex it does take the occasional order for cookware glass from other companies as well, usually retail stores.

Unlike container or float glass manufacturers, International Cookware only produces borosilicate glass. This type of glass is manufactured at a temperature approximately 200 Celsius higher than soda lime glass. This has consequences for the furnace, which ages more rapidly than those used in other glass manufacturing sectors.

Borosilicate glass contains boron, and when this evaporates it attacks the furnace crown. Subsequently, it means furnaces have to be rebuilt every five years compared to approximately 10-12 years in container and 15 years for float glass.

Mr Brunie said: “While it is expensive to have to rebuild a furnace every five years, from a technical perspective it is very interesting. It means we have to evolve every five years and means we can add the latest furnace technology.

“It also means we stay up to date on the latest furnace designs in the glass industry.

“A furnace rebuild is always a challenge but it is easier for us because we do it so often.”

Such is the company’s own in-house expertise that it does not have to rely on traditional furnace suppliers such as Sorg and Horn to provide furnace equipment.

“We don’t buy furnaces from the traditional furnace suppliers, we own our own drawings, we have our own technology and we have people in the team able to modify drawings. We know our furnace and forehearth internally and we are able to carry out a rebuild by ourselves.”

But every five years they will talk to technology experts and preferred suppliers to discuss subjects such as geometrics of the furnace and for their views on technologies for the new oven.

The rebuild itself will take place for two months beginning at the end of June. The Chateauroux site has one furnace, while the company also owns another furnace at the recently acquired Duralex site in Loiret, France.

While larger glass manufacturers have the luxury of many furnaces, where they can trial new innovations on, International Cookware does not have this.

“We have to study a lot about what we can put inside our furnace and that is the point of working with Glass Service and FIC UK, for example.”

A huge maintenance project will also take place at the same time with the modernisation of some of its presses. The site has four presses and one is set to be retrofitted during the rebuild.

Alongside this in the cold end, the group has invested in robotic stacking to stack its dishes automatically. Such is the variety of shapes and dishes produced by the factory that it had taken time to find the right provider.

It has adapted its lines and a provider, Prototig based in Limoges, France, will provide customised machines for two of its four lines.

The average production time of a Pyrex product is 28 to 30 hours. Due to the huge variety of weight, shapes and dimensions it manufactures, staff on three of its four production lines will switch from one product to another each day.

The complexity of the glass shapes means it has not yet found the right automatic inspection solution.

It has tried with several suppliers and a variety of cameras. The first technical challenge is to get the right view because, unlike a bottle, when you inspect the side of a Pyrex dish it is hard to see anything while a camera from the top is problematic because of the conveyor.

“A big challenge is the view itself as well as the variety of dishes, so it is a huge challenge to get good automatic inspection.”

International Cookware acquired the struggling French tableware manufacturer Duralex only in January this year. At the time International Cookware said it would allocate a budget of €17 million to invest in the site by 2024.

Mr Brunie’s role as Technical Director will be to oversee any technical investments at the Loiret site. So far the group has provided maintenance of the site’s equipment but the aim is to transfer the technologies used at Chateauroux to the Duralex site.

Any future investments will focus on reduced emissions.


A major talking point in the industry has been the transition to the use of renewable energy in the manufacturing process.

A number of potential energies have been discussed industry-wide such as biofuels, increased use of electricity and lastly hydrogen. International Cookware is investigating the latter in a project alongside Air Liquide and Sefpro.

In a project called Hyrex, it will focus on the use of hydrogen in its glass furnaces during next year’s rebuild and will trial the use of hydrogen injection inside its burners.

The trial aims to observe the impact the flame on the glass quality. All being well the company hopes to assess the impact and then prepare the use of hydrogen in a rebuild in 2027 or 2032.

While modelling carried out by Glass Service was positive, Mr Brunie acknowledges the company needs to take it step by step and assess how the furnace behaves with more electricity.

The grant from the France Relance project has helped the company to take on such a rebuild after the Covid pandemic. The plant had to reduce capacity at the start of the pandemic but, from the second half of the year, saw a huge upturn thanks to the increase in people cooking at home.

The plant employs 390 people working in rotating five shifts. Johann has worked at the company for 13 years in what will be his third furnace rebuild.

“I was young in 2012, I was in charge in 2017 and will be in charge again in 2022.

“For me a furnace rebuild is what makes the enjoyment of my job. It is a huge challenge making again a furnace for a factory where there is only one furnace and it is what provides the spice of my job.

"However, I will lose 5kg during the rebuild because it will be very stressful, but it is part of the job!

“The manufacture of glass is a fantastic process. Glass by itself is a fantastic material and when you work for Pyrex it is a high quality product. There is investment and the resources to make this improvement on energy and our environmental footprint.”

International Cookware, Chateauroux, France,