03/01/2010

Self-Cleaning Glass Saves Time, Money, and Water

This type of glass uses a photocatalytic process and rainwater to wash the windows so that you don’t have to

By Kylie Wroblaski

 
  • Self-Cleaning Glass Saves Time, Money, and Water

    Self-Cleaning Glass Saves Time, Money, and Water

    /Portals/1/images/Magazines/0310/B_0310_SB_Envelope2.jpg

    The dome of the newly renovated Robson Square ice rink in Vancouver, BC, is covered with nearly 9,000 square feet of self-cleaning glass, combined with low-E glass. PHOTO COURTESY OF PILKINGTON NORTH AMERICA INC.

    Self-Cleaning Glass Saves Time, Money, and Water
  • Self-Cleaning Glass Saves Time, Money, and Water

    Self-Cleaning Glass Saves Time, Money, and Water

    /Portals/1/images/Magazines/0310/B_0310_SB_Envelope1.jpg

    The Museum of Earth in Ithaca, NY, uses a combination of self-cleaning and low-E glass, which cuts down on maintenance and operating costs. PHOTO COURTESY OF PILKINGTON NORTH AMERICA INC.

    Self-Cleaning Glass Saves Time, Money, and Water

Factoring in the price of window cleaning for your building may be a thing of the past, thanks to self-cleaning windows.

Self-cleaning glass includes an applied titanium-dioxide (TiO2) metal coating, which helps windows clean themselves in two ways: 1) the breakdown of organic materials deposited on the glass, and 2) the sheeting of rainwater, which washes the glass.

How it Works
"The titanium dioxide is activated by UV light exposure," says Russell Davies, senior project manager at Simpson Gumpertz & Heger Inc. "It takes about 5 or 7 days of exposure before it becomes fully active."

UV light breaks down organic dirt or material deposited on the window’s surface through hydrolysis (the breakdown of water into hydrogen and oxygen). "This hydrogen is the same type of hydrogen used in compost heaps to break down organic materials," Davies says. "The hydrolysis brings about the breakdown of organic soils that might be on the glass."

In self-cleaning glass, the glass surface is also hydrophilic (meaning that the glass doesn’t form droplets of water, but forms almost an even spread, or sheet, of water over the glass surface). The coating "spreads the water out and, as the water sheets and flows off, especially if it has a slope, it will carry the dirt with it. It carries not only the organic dirt that’s been partially decomposed, but also any inorganic mixed with organic soils that are also on the glass," says Davies.

Another advantage of this coating is that it dries quickly because of the way the water sheets on the glass. "It tends not to leave as many streaks, bubbles, or after effects of the soils being deposited," says Davies.

"The glass uses the natural daylight and the rainwater to break down organic materials," says Sharon Urban, marketing communications specialist at Pilkington North America Inc. "As long as you have those two properties, it’s virtually maintenance free." Self-cleaning glass reduces window cleaning, which provides a savings to building owners.

When the Glass Won’t Clean Itself
When a building is exposed to large amounts of inorganic materials, such as salt or sand, those materials will deposit on the glass, but won’t be broken down. As a result, they’ll stay there until water is introduced to the surface to flush them off, says Davies.

If buildings exposed to salt and sand were then exposed to water, they would still have the advantage of the sheeting action – the inorganic materials would be washed off the glass better than they would be on an uncoated glass. But they wouldn’t have the benefit of a UV reaction taking care of any organic materials that inorganic compounds are in contact with or connected to, Davies explains. "The photocatalytic process doesn’t work, and the glass performs the way it would if it didn’t have any self-cleaning coating on it."

In climates where it doesn’t rain very often, the windows can be sprayed to loosen the organic material, says Urban. "That will reduce window cleaning and provide better views."

The self-cleaning property remains with the glass as long as it’s exposed to UV light (even on cloudy days) and water. "In terms of life-cycle, the coating is integral with the glass," says Davies. As long as the glass remains, there should be no change in the photocatalytic performance of the coating. "It’s a catalyst, so it’s not sacrificial; it maintains itself. It’s integral with the glass and shouldn’t degrade over time."

Kylie Wroblaski (kylie.wroblaski@buildings.com) is associate editor at Buildings magazine.

 

Need portable cooling?

Rent or buy spot coolers from full-service locations nationwide. On call “24/7”. Primary, supplemental or emergency cooling. Atlas Sales & Rentals, Inc., or call (800) 972-6600.

Click here for more info


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

Yaskawa drives offer quality performance for air handlers and cooling towers on the roof to secondary chilled water pumps in the basement

Bluebeam® Revu® simplifies digital facilities document management from design review to leveraging as-builts, maintenance manuals and O&Ms submittals.

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.

Need portable cooling?

Rent or buy spot coolers from full-service locations nationwide. On call “24/7”. Primary, supplemental or emergency cooling. Atlas Sales & Rentals, Inc., or call (800) 972-6600.

Click here for more info


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

Yaskawa drives offer quality performance for air handlers and cooling towers on the roof to secondary chilled water pumps in the basement

Bluebeam® Revu® simplifies digital facilities document management from design review to leveraging as-builts, maintenance manuals and O&Ms submittals.

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.


 
comments powered by Disqus

Related Products

Tools, Services and Software
Tools, Services and Software

Sponsored Links