Polycarbonate solar panel or window glazing:

This article discusses the properties of polycarbonate glazing used in solar applications, including its impact resistance, thermal movement, scratching, discoloration, and solar transmittance.

Polycarbonate Glazing for Solar Applications, Windows, Greenhouses

Accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. Our photograph (left) shows an interesting sloped window installation on the roof of a barn silo that had been converted to living space. Conventional wood-frame double-hung windows were set into the sloped silo roof - this was not a successful installation and the windows rapidly rotted, leaked, and disintegrated. Our photo of sloped glazing at page top was taken by the editor (DF) at Taliesin West in Scottsdale, AZ.

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.

Topic: What is Polycarbonate glazing, does it prevent "ultraviolet radiation seepage", Where can I get some?

Question:

I recently (1985) read an advertisement fdor a product that touts its covering as being made of "polycarbonate," which prevents ultravoilet radiation seepage. What is this stuff and where can I buy it? - Gary Allen, Palo Alto, CA.

Notes on the sketch above:

Double-paned glass is shown to have a low-e and/or solar control coating, a gas fill between the double panes, and a spacer at the base of the window between the panes.

On the interior of the house is a strip of wood at the bottom edge of the window labeled the stop, and just in front of it is a step-like shelf labeled the stool. Beneath the stool and on top of a two by four is a thin pipe labeled the backer rod.

On the exterior of the house, the illustration shows the frame of the window labeled the sash, and the shelf in front of the window labeled the sill.

Weatherstripping is shown to be between the sill and sash. Beneath the sash, vertical against the house, is a strip of wood called the apron or flange, and the jamb is on the end of the sill. The caption reads: Energy-efficient window technologies are available to produce windows with the U-factor, SHGC, and VT properties needed for any appl ication.

- This article series combines, quotes from, supplements, and expands energy efficient building suggestions for new and older homes, provided by the U.S. Department of Energy. In the text we add commentary, photographs, and links to related material beyond the U.S. DOE content.Sketch, U.S. Department of Energy.

Answer:

Polycarbonate is one of several thermplastic glazing materials used in solar applications. Polycarbonate glazing is also used in greenhouse construction and hurricane-damage-resistant windows. Manufacturers assert that polycarbonate glazing is "200 times stronger than glass" (Gallina) and the material is lighter in weight than glass as well.

Greater resistance to impact is a main advantage of polycarbonate glazing over acrylic or glass glazing materials, but it is more expensive than either of them. Some manufacturers (Gallina, below) offer tongue-and-groove sheets, modular polycarbonate roof panels, insulated polycarbonate windows, and related glazing products.

Like all plastics, polycarbonate glazing expands and contracts under thermal stresses, so glazing stops must accommodate a fair amount of movement.

Also, polycarbonate glazing can abrade and discolor ovcer time, thus losing a certain amount of solar transmittance. And like other plastics, it is vulnerable to deterioration caused by ultraviolet radiation.

Polycarbonate sheet products that have been well known since the mid 1980's and are available through glazing distributors. Some sources of polycarbonate glazing products include:

• ARCAT lists current manufacturers of polycarbonate sheet glazing, including Polygal Inc., SABIC (Originally General Electric Plastics), Sheffield Plastics, CO-EX, C.R. Laurence- Retrieved 11/29/2010, original source: http://www.arcat.com/divs/sec/sec08841.shtml
• General Electric (Lexan, now produced by Sabic - see below). According to GE, Daniel W. Fox, a GE Chemist who was seeking an improved wire enamel, first discovered and discovered the polycarbonate resin used to produce Lexan in 1953. Lexan and related plastics have become widely used in the ensuing half-century and include products well beyond glazing, such as the production of CDs.
• Lasco Industries ( Lascolite)
• Cy/Ro (Cryolon SDP)
• Gallina USA LLC. (Arcoplus) 4335 Capital Circle, Janesville, WI 53546 Tel: 608-531-0450., Email: todd@gallinausa.com - Retrieved 11/29/2010, original source: http://www.gallinausa.com/
• Professional Plastics, (Acrylite) distributes products from 35 manufacturers. Tel: 888-995-7767. Quoting:
  Lexan polycarbonate resin is an amorphous engineering thermoplastic, characterized by outstanding mechanical, optical, electrical and thermal properties. The Lexan portfolio provides broad design versatility through its wide range of viscosities and product options such as: environmentally conforming flame retardancy, scratch resistance, toughness, heat resistance, weatherability, biocompatibility, optical quality, and compliance with stringent FDA and USP requirements. - Retrieved 11/29/2010, original source: http://www.professionalplastics.com/MAKROLONGP-polycarbonate
• Sabic (originally GE Plastics) produces Lexan - Retrieved 11/29/2010, original source: http://www.sabic-ip.com/gep/Plastics/en/ProductsAndServices/ProductLine/lexan.html

Readers who are building their own windows or who are installing factory-built windows should also

see SLOPED GLAZING DETAILS

and VERTICAL GLAZING DETAILS. For suggestions about how to diagnose and repair leaks in existing skylights,

see SKYLIGHT LEAK DIAGNOSIS & REPAIR.

Also see THERMAL EXPANSION of MATERIALS and see if you are constructing site-built storm windows using this or any other glazing product, see our discussion of storm window weep holes and why they are critical: STORM WINDOW WEEP HOLES

Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

The link to the original Q&A article in PDF form immediately below is preceded (above) by an expanded/updated online version of this article.

• Q&A Polycarbonate Glazing - PDF form, use your browser's back button to return to this page. Original article, Solar Age Magazine, January 1985, adapted and updated for InspectAPedia.com November 2010.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: is polycarbonate glazing safe?

Nick said:
Is it safe, or is it like other plastics such as BPA? (Feb 16, 2012)

Reply:

Nick, BPA concerns mainly deal with plastics used to store and re-heat food or beverages. Theoretically, polycarbonate, a #6 plastic, would give you BPA if you microwaved food on it (BTW, styrofoam is 'air-entrained' polycarbonate). But since we don't use PVC pipes for our potable hot water, I'd say this is not a window topic.

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Continue reading at WINDOW EFFICIENCY FEATURES & RATINGS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• AIR LEAK DETECTION TOOLS
• ENERGY SAVINGS in BUILDINGS articles on ways to cut heating and cooling costs in buildings.
• WINDOW SHADING, SCREENING and also see WINDOW GLAZING BASED on CLIMATE
• WINDOWS & DOORS - home
• WINDOW / DOOR ENERGY EFFICIENT, DOE

Suggested citation for this web page

POLYCARBONATE GLAZING at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to DOORS & WINDOWS

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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