A vacuum seal between the panes of a double-paned window or insulated glass unit (IGU). A hermetic seal that fails causes permanent fogging between the panels of the IGU.
A hermetic seal is any type of sealing that makes a given object airtight (excludes the passage of air, oxygen, or other gases). The term originally applied to airtight glass containers, but as technology advanced it applied to a larger category of materials, including rubber and plastics. Hermetic seals are essential to the correct and safe functionality of many electronic and healthcare products. Used technically, it is stated in conjunction with a specific test method and conditions of use.