What Are Window Glass Standards?

What Is An Acceptable Piece Of Glass?

It’s a question that we hear and it’s a valid question. What should you expect when it comes the glass in your new windows? Are defects acceptable at all? If so, to what degree?

Glass, like any other manufactured good, is never completely perfect. Everything that is made has some sort of tolerance or standard that it is evaluated against to determine if it “makes the cut”. Glass is no different. This post will go through the standards set forth by the Fenestration & Glazing Industry Alliance (FGIA), which window manufacturers adhere to.

One interesting thing to note before we begin is that while there are hundreds of window manufacturers in the US they all get their glass from one of four glass manufacturers. Of those four, Cardinal Glass stands out as the choice for top-tier products that require the best insulated glass units in the industry. Every brand of window that we carry uses Cardinal Glass, it’s simply the best.

window glass standards
Cardinal Insulated Glass Units

Nothing Is Perfect

Even the best glass (or best anything for that matter) isn’t perfect. The FGIA has developed a detailed set of industry standards that you can find here. These are technical descriptions for a host of glass applications. For our purposes, the place to start is below.

Glass Inspection For The Homeowner

Just like it says, the Glass Inspection For Homeowners is a guide laying out the process of how to inspect your glass, what to look for, and what constitutes flaws that are outside of the accepted range. This guideline, in essence, serves as a tool for the homeowner to flag anything that may warrant further inspection and even replacement.

Inspection Steps

  • The glass should be illuminated by daylight but not direct sun
  • Clean the glass thoroughly, on both sides
  • Stand 90º to the surface, 10 feet away
  • If a flaw or blemish is readily apparent, measure its size
  • Contact the manufacturer if the flaw exceeds the acceptable limit as stated by the guideline

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Our Services include: Replacement Windows Houston, TX metro area. Houston Window Experts is a privately owned and operated company in Houston TX. For more information about us, please write to info [at] or call our Houston office at (832)900-7024. All material is copyright of Houston Window Experts. Houston, TX.

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