Volume 39, Issue 2, February  2004

Low-Maintenance Low-Down
How Self-Cleaning Products have Morphed 
Into Low-Maintenance Glass Since their Launch

by Ellen Giard Chilcoat

It’s been almost three years since the world was introduced to the term “self-cleaning glass.” In 2001, Pilkington was first with its Activ™, followed by PPG with SunClean™. AFG next introduced its Radiance Ti. Guardian, which had originally planned to launch a similar product in 2002, has been slower to make the introduction. The company has delayed the launch a few times and now says it plans to introduce DiamondGuard LMG (low-maintenance glass) this spring.

The term “self-cleaning” has not been without question. While the products do reduce the amount of upkeep necessary to keep the glass clean, some effort is still required. In an article titled “Self-Sufficient” from the January 2002 USGlass (see page 34), representatives from each company offering a self-cleaning/low-maintenance product all said that yes, windows would still need some sort of hand-washing, though not as much as windows with clear glass. If some hand washing is still required, how, then, can we call these products self-cleaning? Thus, as USGlass publisher Deb Levy wrote in last month’s issue (see January 2004 USGlass, page 4), we at USGlass have decided to start referring to all of these products as low-maintenance (low-M) glass.

With that said, it’s time to find out what the current status is of these products. We’ve gathered updates from Pilkington, PPG and Guardian. For this article AFG chose not to participate. In an interview last February (see the February 2003 USGlass, page 58) Roger Kennedy, then president of AFG, said he wasn’t very enthusiastic about the products. 

“I think, at least initially, the way it’s marketed is not right,” Kennedy said. “We have it available because our competitors do, but it’s not high on the radar screen. Window manufacturers are not knocking down our doors for it,” he added.

Pilkington’s Activ
Since its launch, the composition of Activ has remained unchanged and, according to Richard McCurdy, Pilkington North America’s senior manager for Specialty Glass Products and Architectural Testing Services, has been well received in both the residential and some aspects of the commercial markets.

“Looking back, the growth rate [of Activ] is similar to what we expected, and is similar to the growth of low-E in the 1980s,” said McCurdy. “We thought initially it would end up being an enhanced growth rate compared to low-E; in general, we’re waiting for the channel to embrace it. It’s a product that has to be introduced carefully,” he added.

Though Activ has been used in both residential and commercial projects, the product has seen most of its success in the residential arena. McCurdy said this has to do with the silicone sealants used in many commercial projects. He explained that the oils in silicone sealants are hydrophobic, which causes water to bead (Activ is hydrophilic, which causes the sheeting action). 

“When the window is wet, you still get the sheeting action, but along the periphery you can see the water bead up,” said McCurdy. He added that Pilkington was working aggressively to resolve the bleed-out issue with the silicone sealants.

As far as new developments, McCurdy said his company is looking for ways to combine different functions. Such an example is Pilkington’s new Activ SP™, which is a “self-cleaning,” low-E, solar-control, UV-control, sound-absorbing, impact-resistant glass. Activ SP is made by laminating (with PVB) a 1/8-inch lite of Activ with a 1/8-inch lite of Pilkington’s Solar E™ solar-control low-E glass. 

And as far as far as the future of clear glass, McCurdy says it lies in the low-maintenance products.
“We firmly believe this is the future of clear glass,” he said. “Our job is to give people the functions they have with their current product, but now with [low-maintenance] glass.”

PPG’s SunClean
PPG is focusing its efforts with SunClean purely in the residential arena, and since the product was launched in 2001 it has been used in more than 184,000 windows.

Lisa Detwiler, residential products marketing manager for PPG flat glass, said the company has have been moderately happy with the progress SunClean is making.

“We believe this is an industry that is slow to change and accept new products,” she said. “We’re interested in talking with the larger window manufacturers to have them adopt this technology. We feel it’s something that will really spark their interest.”

While Detwiler said they have no plans to expand into the commercial sector, they are looking at other potential markets.

“We want to try and get more leaders to adopt the product,” she said, “and we’re looking at other areas of responsibility, such as builders and architects.”

As far as plans for SunClean, Detwiler is hopeful and positive the product’s acceptance will continue to grow.
“We’d really like to see the product substituted, long term, for clear glass,” she said. “If we could convert 10 percent to 20 percent of clear glass [used in residential windows] to SunClean we’d be thrilled,” she said. 

DiamondGuard LMG
According to the website of Auburn Hills, Mich.-based Guardian Indus-tries, DiamondGuard© LMG will soon be available. The product is designed to provide water and dirt management properties, while also providing color neutrality, optimal insulating glass configuration flexibility and scratch-resistance. 

“With the opportunity to increase the overall performance and value of a window, configuration flexibility will become increasingly important to window manufacturers who integrate these product options into their window platforms,” said Tony Hobart of Guardian in an article submitted to USGlass in January 2003.

“Homeowners consistently express a preference for color-neutral and non-reflective coated glass products,” said Hobart in the article. “As additional coatings are added to a glass surface to provide a full range of value-added performance, many pyrolytic products sacrifice color neutrality and non-reflectivity. DiamondGuard LMG offers consumers value-added coatings without sacrificing the desirable characteristics of color neutrality and a non-reflective surface.”

According to Guardian’s website, DiamondGuard LMG follows the company’s Durable-by-Design© philosophy, “creating a total performance, low-maintenance glass product that benefits manufacturers, fabricators, suppliers, installers and consumers. 

Is it All that Good?
But despite the fact that these products are marketed to offer a great advantage—a glass that cleans itself—they are not without controversy. The fact remains, the windows still have to be cleaned occasionally.

“The public thinks it’s getting this magical potion of a product, and it isn’t. Some maintenance is still required,” said one fabricator who preferred to remain anonymous. “We are up front with our customers and tell them that it’s not self cleaning, but rather low maintenance.”

Another industry source, who also wished to remain anonymous, agreed that, yes, there are issues and concerns with these products. The first, he said, has to do with the fact that they are photocatalytic, meaning they have to be exposed to ultraviolet (UV) light in order to be activated.

“If you need UV light, what happens if you have screens on the windows or if you’re in a Northern elevation?”
Another concern he noted was that these products require water to wash away organic materials that can accumulate on glass. For arid climates, such as in Arizona, this can be a problem. 

When self-cleaning glasses first came on the scene, to handle such a situation, some glass manufacturers said the glass could be activated by simply spraying it with a garden hose. This, too, has been controversial.

“Window manufacturers will tell you to never spray windows with a hose because it can damage the sealant system,” said the source.

The third issue with these glass products involves contamination from silicone sealants. As mentioned previously, silicone sealants are hydrophobic and the coating used on these products is hydrophilic.

“This is concerning because it really could cause the glass to become hydrophobic,” he added.

So, regardless of what it’s called, the fact remains: though it may be minimal, these products still require some maintenance work and still have kinks to be ironed out before they will truly be the great glass innovation. 


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