• Cracked/broken panes;
  • Binding during operation;
  • Failure to lock;
  • Hardware damaged/inoperable/out of adjustment;
  • Missing/stripped cranks;
  • Operator arm failure;
  • Moisture damage;
  • Sun damage;
  • Weather-stripping components


Tempered glass will be permanently marked as tempered- usually by etching- in a corner or along one edge.

Tempered glass is required where ALL OF THE FOLLOWING apply:

  • The glass is larger than 9 square feet;
  • The bottom edge of exposed glass is within 18 inches of the floor/walking surface;
  • The top edge of the glass is more than 36 inches above the floor/walking surface;
  • There is a walking surface within 36” horizontally from the edge of the glass;
Other locations:
  • Glass in a tub or shower where the bottom edge of the glass is less than 60 inches above the floor/walking surface;
  • Glass adjacent to a door where the nearest vertical edge is within 24” of the arc of the door and whose bottom edge is less than 60” from the floor or walking surface.
  • Glass in stairways, landings, and ramps when the walking surface is within 36” of the glass, and the bottom edge of the glass is less than 60” from the walking surface.


Thanks to Will Keeler for getting this answer from Pella Windows:
Argon has been the gas most often used in IG for several decades now. In some applications, Krypton is used and performs better and allows thinner Insulating Glass (IG), but is cost prohibitive, and becoming more cost prohibitive recently because of its use in other industries along with reduced worldwide capacity to extract Krypton from air.
Generally, desiccants adsorb as opposed to absorb. See the following for the difference. Read about the difference
Several desiccants are still used to pull out moisture between panes of glass at the time of IG build as well as collect any moisture that gets through the IG seals. These include silica and molecular sieves. These desiccants pull out moisture and can collect volatile organic compounds that may be present in internal components like grilles, etc. but are designed to not adsorb the insulating gases like argon or krypton. Below is an old primer on desiccants. It’s old, but still relevant and fairly easy to digest.  Read about desiccants
As far as overall trends, desiccants continue to be made with higher and high adsorption capacities. Sealants continue to be made with better moisture barrier properties (Moisture vapor transmission rate or MVTR). From a product reliability standpoint, window and door certification bodies now include IG durability testing as part of their certification programs. From an overall energy perspective, codes and energy star and other bodies are encouraging, and in some cases requiring, lower u-values which is changing the low-e types that are being used and will likely start to move the industry into a more widespread use of triple IG and perhaps more advanced solutions (electrochromics, VIG, suspended films, etc.)