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Insulated Glass Info

The Case of the Inquisitive Insulation

Insulated Glass Question:

Dear Glass Detective,

Please help me understand technical information regarding the glass components of an insulated glass (also known as insulating glass) unit. Here are my questions:

  1. What residential construction industry standards or recommendations are there for the individual thickness of glass panes?
  2. What residential construction industry standards or recommendations are there for the overall thickness of insulated glass units?
  3. What are the benefits of Low-E, Sound Transmission Class (STC) Ratings, and Outdoor/Indoor Transmission Class (OITC) Ratings?


Miguel Tello


Thank you for making contact with the Glass Detective regarding your desire to get technical information on insulating glass (also known as insulated glass) units for residential use. The questions you ask are quite broad in scope and would take a fair amount of time to answer in any detail. So what I am going to recommend is that you go online to solicit specific information from the various large manufacturers of insulating glass units because these will better provide you with the exact information you are looking for.

You may be surprised to see how much information you will get. You may also be surprised at the variety of products available and their varying degrees of performance characteristics. You will also be able to get OITC ratings for the various products. Check for these under the category of sound-reducing glass assemblies.

As far as California code requirements for OITC, you will have to research that with information provided for California Building Codes (probably by geographical area). These sites will provide you with a great deal of information:


Guardian Architectural Glass

Insulating Glass Manufacturers Alliance

Oldcastle Building Envelope

Pilkington North America

Vitro/PPG Architectural Glass

Thank you again for contacting the Glass Detective with your questions and I hope this information is of some value to you. attempts to provide accurate information but cannot be held liable for any information provided or omitted.  You should always work with a licensed, insured and reputable glass shop that can assess your specific needs and local building codes and offer professional services. Never attempt to cut, install, or otherwise work with glass yourself. All content is provided on an informational basis only.

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