IZO When it comes to thermal, solar and sound insulation, as well as the esthetic s, glass is the most important element of the window. The glass we use nowadays in architecture is IZO glass. Common terms used for this kind of glass are Thermal insulation glass or Termopan package.

IZO glass is consisted of two glass panels, mostly 4 mm thick, connected along the edge with 16 mm space between each other. Connection between two glass panels must ensure adherence in order to prevent passage of humid air. The space in between is filled with dry air (dew point around -30 C)or another gas like Argon, Krypton, etc...

Main characteristics of IZO glass is that it reduces thermal exchange between two areas and has plenty of advantages: reduced costs of installation of air conditioning and heating, reduced energy costs, reduced draft by window because there was no ice /rain on the inner side of the panel, possibility to use larger glass surfaces for specific room temperature without increasing of energy expenses.

IZO glass

IZO glass is the glass consisted of two or more glasses mutually separated by hermetically closed space (insulation chamber-IZO chamber) which can be filled by air or some other rare gases. Another  therm for IZO glass is vacuum glass, but one should know that technically IZO glass is not vacuum glass and it is the popular term used by common people.  By using qualitative glasses for production of IZO glass, the following characteristics of IZO glass are preserved:

· Incurved outer image of the environment
· Specific value of light penetration
· Specific value of visibility
· Specific value of energy loss
· Specific value of thermal insulation

These are the characteristics of the glass produced by FLOAT technology and is mainly used for production of IZO glass

Construction of IZO glass

Construction of IZO glass is consisted of:
Glass-it is important that glass is produced by FLOAT technology, that glass is of proper thickness, pursuant  to sizes and requested characteristics. Characteristics of IZO glass will depend on  chosen glasses for production.

Interspaces-is always filled with air or another rare gas, such as Argon, Krypton, Xenon or SF6. Thermal insulation depends on type of gas. If the gas is heavier, thermal insulation will be better, but one has to take care of interspaces’ width. Optimal width of interspaces requested for each type of gas:

· Air or Argon-width of aluminum or PVC distance lath 16 mm
· Krypton- width of distance lath 10 mm
· Xenon-width of distance lath 8 mm
· SF6 gas-width of distance lath 8 mm

Aluminum profiles are mostly used for production of frames forming interspaces of IZO glass, although we use zinc-coated profiles as well as plastic material profiles, combinations of Aluminum and PVC, and recently some INOX profiles but not so often. In most of cases we use aluminum profiles. Speaking of profiles, it is very important that they are bend-resistant, so the original shape during the process of production and installation into IZO glass could be preserved.

Molecular –basic function of molecular id to dry humidity in the space between two glasses during the process of IZO glass production. Also, the molecular should ensure low level of humidity during IZO glass lifetime, which may penetrate the inner space due to various influences. Granulated molecular is being sued for aluminum or INOX distances, but powder molecular is to be mixed with polymer in order to create polymer distance.

Butyl-first kit serves for internal insulation (first barrier) of IZO glass. Butyl ensures low penetration of humidity, steam and gasses, and is age resistant, cracking and thermal stability. Butyl is the short term for polyisobutyl and is being polished, while warm, onto distance aluminum lath, before distance lath is glued onto the glass surface. Butyl can be easily joined with the glass, aluminum, INOX, etc.. Characteristics of good butyl are as follows:

1. Great age resistance due to influence of photo-chemical and thermal elements
2. Low penetration of steam and gas in/out of space
3. Powerful gloominess of surfaces
4. Good compatibility
5. Good crack-resistance while being transported
6. Good thermal stability
7. No evaporation
8. Greta resistance to deformations
9. Fast polishing by appropriate machine

Butyl is not resistant to water and water steam and therefore must be protected from atmosphere influences. For that reason, sealing gasket or another kit is being used.

Silicone-Second kit-usually silicone sealants or polysulfide (two –component kit) are to be polished onto IZO glass after the glass had been washed and squeezed out in the press machine. May be used as one-component kit hot –melt with excellent physical and chemical characteristics and very good resistance to high and low temperatures. Hot-melt can be easily vulcanized and is used only in situations when in short period of time, we must produce IZO glass for installation.

IZO glass

Specific mass of FLOAT glass is  2,5 g/cm3.It is used for calculation of weight of specific glass. For example, the lass which is 1 mm thick and covers 1 m2, weighs 2,5 kg.

IZO glass 4+16+4 of 1 m2 size weighs cca 22-24 kg

Low E glass

What is Low- E glass?
Low E glass reduces heat los for 60-70% in comparison to standard IZO glass. The cause of this is a micron thin, but efficient and functional layer of metal which in IR area, acts as a reflector. There are two types of low- E glass, or low emission glass. Hard-coating is the type of Low –E glass where during glass production, steel oxide is coated on the surface of FLOAT glass. Soft—coating is the type of Low-E glass where after the production of glass, several layers of steel oxide are coated in a highly vacuumed device.

Low-E glass significantly reduces U values of the glass, by blocking passage of IR rays but reflecting sin light. If we want to block the loss of thermal energy from the room, inner side of IZO glass must be of Low-E type and that is when we allow penetration of sun lighting which increases room heating. If we want to prevent sun heat to come into the room, than the Law-E glass should be installed onto the outer side of IZO glass. Low-E glass allows penetration of short waves, nut reflects long waves .We should point out that the metal oxide is always coated inside IZO glass.

A result of measuring of temperature on the surface of the inner glass, under conditions of outer temperature -10  °C  and inner temperature +20 °C

IZO glass
Sound insulation  34 dB
U= 2.5 W/m²K

Low –E glass
Sound insulation 34 db
U= 1.1 W/m²K

Three layer glass
Sound insulation 36 db
U= 0.8 W/m²K

All rights reserved. ŠU-MA Plast D.o.o.