John Hollis, who recently joined the USGlass magazine/ team, was invited to tour PPG’s plant yesterday. Below is his report on his first glass-industry tour.

It’s the constant motion that first grabs your attention as you enter the cavernous PPG plant in scenic Carlisle, Pa.

Carlisle - approved glass tank image 2Twenty-four hours a day, seven days a week, 365 days a year. Glass is always on the move, meaning there’s always something to be done with the plant’s two parallel float glass production lines that each extend a quarter mile in length and are collectively responsible for producing 350,000 tons of glass per year. That’s enough to build two roads from Carlisle to California and back, says plant manager Tom Abbas.

Anything else would be problematic.

“Once we start it the first day, we don’t shut it down for 10 or 12 years,” says Dick Weller, the retired PPG employee serving as the tour guide for selected media. “There is no interruption in the operation.”

Now in its 41st year of service, the plant serves as testament to industry advances in both technology and efficiency. The constant action among the plant’s more than 400 employees has been the common denominator throughout the decades.

glassphoto04Constantly reloading the precious materials is necessary to keep the two, 650-ton float machines going at all times has been paramount with raw materials coming from far and wide to manufacture the premium Starphire® glass imported from the Dominican Republic. Additional sand is hauled in from nearby West Virginia and other needed supplies hail from all over, meaning that loaded trucks and trains making their way into the PPG compound are a common sight.

Day or night.

“We win or lose with forecasting,” says Robert Struble, PPG’s senior manager for brand and communication strategy. “Simple as that.”

PPG, which makes glass, coatings and specialty products for use in a variety of industries throughout the world, counts nearly 50 percent of its overall glass business in coated glass or low-iron glass, Abbas said. Largely powered by natural gas, the Carlisle facility also boasts two coaters for low-E applications, allowing the company to better energy efficiency, carbon dioxide reduction and power consumption for its clients. The plant is capable of making a lite of glass as big as 130 inches-by-220 inches, Abbas says.

Each of the plant’s six batches of dry ingredients weighs 5,700 pounds, with some consisting of sand with iron it and some without it. The materials are placed in the mixer, squared and blended with both a little moisture to avoid dust issues and cullet to help the sand burn quicker. The move allows the glassmaker to avoid wasting glass, while also lowering the company’s power consumption by limiting the heat necessary to melt the sand.

As it is, the plant is good for six-figure power and seven-figure gas bills each month, Weller said.

Once completely batched, the sand is transposed into a furnace that reaches 2,950 degrees Fahrenheit. The heat is so great that the temperature of the room in the warehouse that houses the furnace feels like 162 degrees. Employees working in that area are constantly told to hydrate, but usually carry several changes of clothes each day as they sweat profusely.

The surrounding rooms are kept warm to avoid the tendency for the glass to break in cold air, Weller says.

glassphoto03Appearing more like a liquid gel at that point rather than a hardened surface, the still-hot glass then heads to a refiner, where stone defects and bubbles in the glass are identified. Gaining added thickness throughout the process as it cools, the glass is then sent to a tin bath for further refining and forming.

The annealing process begins with heat still visibly simmering off the glass that is now at 300 degrees. The inspection and cutting process come next, with each of the malformed or bad pieces of glass singled out to be broken and thrown into the cullet pile for later use.

Machines use suction cups to package the finished glass and make it ready for shipping.

“Really, the first people to touch our glass are our customers,” Abbas says.

The largely mechanized effort has significantly cut down on plant mishaps, although it is also largely responsible for the disappearance of a lot of jobs. The PPG Carlisle plant had employed as many as 1,350 employees during its heyday in the 1970s and ‘80s, Abbas says.

But like the plant as a whole, progress never slows down.