Insulated glass units consist of two or more glass panes connected with a spacer bar and sealed with a dedicated IG sealant. Due to requirements for high thermal insulation, triple-glazed units become more and more popular. Insulated glass units may be generally divided into the following types based on their basic function:
- Heat-insulating glass units (Q4 Term) – their task is to ensure the best possible thermal insulation, measured using U value. Typical values are within range of 0.5-1.1 W/m2K, and depend on the build-up of an insulated glass unit.
- Solar control glass units (Q4 Sun) – their task is to limit the amount of solar energy transmission into a room, measured using a g-value (solar factor).
- Glass units with noise reduction function (Q4 Silence) – their purpose is to reduce noise coming from the outside. Sound reduction at the level of 28-53 dB may be achieved through appropriate glass specification – this is so-called Rw factor.
- Safety glass (Q4 ESG, Q4 VSG/ESG) – their task is to ensure safety (or rather reduce the risk of injury) in case of breakage. This is achieved by toughening and/or laminating glass panes and thus minimising the risk of injuries of people present in the vicinity in case of cracking of particular layers.
- Impact resistance glass (Q4 Safe) – these are IG units consisting of multiple laminated panes with increased resistance to breaking, which provides greater security against burglary. The most popular anti-burglary categories are P4A-P8B, whereas the higher digit indicates greater resistance.
Insulated glasses may combine several, and even all functions, in a single specification, therefore, the manufacturing process of this product, albeit seemingly simple and uncomplicated, require great skill.
Legal requirements for insulated glasses are specified by PN-EN 1279.