Negative Deflection the Blight of Insulating Units

 An insulating Glass Unit (IGU) is a double or triple sealed system of two or three panes of glass separated by a spacer bar.  There is a partial vacuum with some nitrogen or argon gas in between.  It is that space that creates a thermal barrier and helps keep the cold or heat outside.  The spacer bars around the four edges of the IGU contain a certail amount of dessicant powder to absorb any moisture/water vapor.  If the "seal" fails vapor will come inside and will condense on the inside of the glass.  It first shows up as clear water.  But over time it chemically reacts with the glass as the window heats up in the sun, and literally etches the glass.  Thus giving the glass a patchy white effect.  This is permanent damage.  It cannot be repaired.  The only fix involves changing out the individual IGU or swapping out the entire window.  Either or is never an inexpensive process.

I have a friend who was cleaning windows on a home one day.  It was a cool day with a high barometric pressure.  He cam around the corner only to hear what he thought was an explosion.  It was quite loud.  As it turned out it was an implosion.  Which happens when the IGU loses too much gas causing the two plates to become concave.  Or literally get "sucked in".  If argon is used it can leak out slowly over time but without allowing even air to come back inside.  So the IGU loses more gas then it takes back.  This causes what is called a negative deflection.  When a window has it bad enough you never know when it will blow.  Should the atmospheric conditions be just right.  Or the window also acquires a point indent fracture or a PIF.  Maybe a bad scratch.  Or some other defect that wasn't caught or noticed when the window was installed.  Such as a nickel sulphide inclusion.  This is a VERY widespread problem.  

These are the reasons why a good glass inspection should be performed on a regular basis.  When the windows are cleaned.  NEGSA Window Cleaners have access to specialty products, services, and inspection tools that other companies do not have.  Here is a simple test for Negative Deflection that anyone can do.  But a window cleaner can use it on every window they clean as they move along.  Remember that even brand new windows just put in can have serious problems with negative deflection.  It is reason to have ever window replaced.  Best to have the windows inspected/tested BEFORE they are installed!

There are many other reasons to have windows properly inspected by a qualified NEGSA Window Cleaner.  Point Indent Fractures, and scratches also are routine problems occurring in brand new glass, windows, and mirrors.  Inclusions sound like sandpaper when anything is ran over a defective glass surface.  There are at least 80 DIFFERENT types that have been identified by Glass Technology Services in the UK.  A very longstanding company that has worked with the float glass manufacturers for many decades.  The scratches they can cause are very different from one window to the next.  It is a ver diverse and widespread global problem.  A NEGSA window cleaner will be able to identify the problem and safely maintain a window with it using Glass Smart products.    

Written by Henry Grover Jr.

henrygrover222@gmail.com