Continental Trade Sp. z o. o.

Technical glass

Color glass - metallurgic and welding filters

Metallurgic filters - INFRAZOR glass

Metallurgic filters

We offer filters of materials for observation molten in smelting stoves.
INFRAZOR is a filter for observing materials melted in metallurgical furnaces, where there is high temperature. The filter guarantees necessary protection against harmful radiating which takes place in the process of melting materials. It absorbs harmful infrared radiation in the range of 780 – 2000 nm as well as UV radiation.

The filters are produced in various levels of protection, depending on the temperature in the furnace. Metallized INFRAZOR with a protection level of DIN 7 is used in furnaces, where the temperature reaches 1650°C. The filter thickness is 2.2 – 2.8 mm. 

 More information included in the section below.

INFRAZOR - glass for metallurgical filters
Transmittance of  metallurgic filter glass INFRAZOR

INFRAZOR is newly developed protective glass for heating and melting in glass industry and for steel industry for watching into the oven and another heat equipments. INFRAZOR protects you against dangerous IR radiation but also make you possible to resolve all details during melting and heating . Using other glasses does not guarantee proper eye protection against IR radiation. Using welding (green) glass give you the protection too, but you cannot see the details during the process.  The glass absorbs the dangerous IR radiation in the range on 380 up to 2000 nm and UV radiance. INFRAZOR we can offer you in shade 1.2 to 8 and metalized in shade 5 to 8 for temperatures from 1050 °C do 1800 °C. When using the metalized INFRAZOR, the heat ray is reflected from the glass , glass is heated to a limited extent and heat affects user much less as well.

Glass filters INFRAZOR protect eyes properly when gazing into furnaces and/or thermo-devices in foundries, steelworks, glassworks, ceramic plants and similar facilities, during process of melting or high temperature thermo-processing. INFRAZOR provides worker with proper protection that prevents his eyes against harmful radiance and ensures perfect distinguishability of details in a furnace.

The protective glass in certified according the norm EN 171.

INFRAZOR glass is produced in many degrees of shading (protection grade PG) depending on the temperature in the furnace:

Recommended capable of use acc. to EN 171
Temperature of radiance [°C] INFRAZOR
Glass thickness [mm]
standard metalized
1.2 1050 1.6 – 2.2 -
1.4 1070 1.6 – 2.2 -
1.7 1090 1.6 – 2.2 -
2 1100 1.6 – 2.2 -
2.5 1140 1.6 – 2.2 -
3 1210 1.6 – 2.2 -
4 1290 1.7 – 2.3 -
5 1390 2.2 – 2.8 1.6 – 2.2
6 1500 2.3 – 2.9 1.7 – 2.3
7 1650 2.4 – 3.0 2.2 – 2.8
8 1800 2.6 – 3.2 2.3 – 2.9
9 1990 - -
10 2220 - -

Glass with a level of protection 5 - 8 can be metalized, which results in better reflection of infrared radiation (ie heat). 

Available screens:  INFRAZOR standard: 
INFRAZOR metalized:
PG 1.2 to 8
PG  5 do 8
Available shapes: round glasses
google prefabricated glasses
standard glass
metalized glass

max.700 x 300 mm
max.400 x 200 mm


  1. Using other glasses does not guarantee proper eye protection against IR radiation. Using welding (green) glass give you the protection too, but you cannot see the details during the process.

  2. Protective screen INFRAZOR is intended to be used only for gazing into furnace sand thermo-devices. lt is improper to be used for electric arc welding.

Welding filters

Welding filters

Welding filters are intended for employees performing welding work, electro-jet gouging and plasma jet cutting. These filters provide the necessary protection against the harmful effects of ultraviolet radiation (below   400 nm), and infrared radiation (780 - 2000 nm). Welding filters can be additionally metallized in a vacuum. Thanks to metallization, they reflect a significant portion of thermal radiation, which means that the welding filter glass itself heats up much less. This protects the eyes from overheating.

Welding filters are offered in different degrees of protection, depending on the type of welding.

More information is available in the tab below.

Welding filters
Transmittance of welding filters

Protective effects of welding filters against radiation

The human eye is endangered by the UV-radiation, i.e. the wave length under 400 nm, and by the IR-radiation,  i.e. the wave length above 800nm.

Ultraviolet radiation causes chemical changes in the cornea, in the white of the eye, in the eye lens and on the retina. The radiation  of the wave length under 320 nm causes conjunctivitis, whereas the long­ wave UV-radiation produces an eye fluorescence which reduces the contrast. UV-radiation of 300 nm and shorter irritates the skin and kills bacteria. The most harmful ultraviolet radiation for a living organism is about 260 nm, where it is absorbed by nucleic acids in the cellular nucleus. The cells necrotise and proliferation is originated. The UV­ radiation endangers the skin up to 0,6 mm deep, it means naturally also the skin of eye-lids and the eye front surface. These tissues become swollen.

Infrared radiation causes heat changes in the cornea, in the eye lens and on the retina. IR-radiation induces cataracts.

The protective welding  filters protect against the above mentioned harmful radiation and make possible a sufficient distinction ability during operation because their major transmittance is in the wave length range of 560-565 nm, i.e. the maximal susceptibility of the human eye.

Protection against radiation during welding

Welding eye protection is intended for employees performing welding work, electro-jet gouging and plasma jet cutting. There are 23 filters with different light transmission coefficient (various obscuration): 1,2; 1.4; 1.7; 2; 2.5; 3; 4; 4a; 5; 5a; 6; 6a; 7; 7a; 8; 9; 10; 11; 12; 13; 14; 15 and 16. Protections can be used with filters of one grade, i.e. with constant darkening or with two grades, i.e. with two different blackout states: one for the bright zone used to look at the electrode when applying it to the weld and ignite and the other for the dark zone used to observe the welding process. The difference in levels between the light and dark zones should not exceed five.

When selecting specific filters, the following factors must be taken into account:

  • flow through the burner (for gas welding and related techniques such as brazing and oxygen cutting);
  • current intensity (in electric arc welding, electro-ridges gouging and plasma jet cutting);
  • type of arc and parent metal (for arc welding);
  • setting the operator - depending on whether the operator bends over the workpiece or takes a position with outstretched hands, it may be necessary to change the filter by at least one level;
  • room lighting.

The recommended filter designations for each type of work are given below, assuming that the welder's eye distance from the weld pool is 50 cm, the average light intensity is around 100 lx, and the operator has no vision defect. If these conditions are changed, a filter with the next lower or higher grade may be used.

For gas welding and brazing, where q is the flow rate of acetylene in liters per hour:

  • q ≤ 70 l / h - filter 4;
  • 70 <q ≤ 200 l / h - filter 5;
  • 200 <q ≤ 800 l / h - filter 6;
  • q> 800 l / h - filter 7.

For oxygen cutting, where q is the oxygen flow rate in liters per hour:

  • 900 ≤ q ≤ 2000 l / h - filter 5;
  • 2000 <q ≤ 4000 l / h - filter 6;
  • 4000 <q ≤ 8000 l / h - filter 7.

For arc welding, electroporation gouging and jet cutting plasma, depending on the current intensity expressed in amperes [A], the recommended filter designations are presented in table below.

Filter selection for electric welding

Filter selection for electric welding
Warming of standard and metallised welding filter

Welding glass with a vacuum coating of metallic oxides.

Coated protective glass for welders is coated with a metal layer, which is perfectly connected with glass. The coating reflects thermal rays well. The products is suitable mainly for welding works carried on inside or for brilliant vessels, for extreme currents, for MIG, MAG, TIG and plasma welding.

The metal coating, reflects thermal rays, which are otherwise absorbed by protective glass and welding glass is not heated. Long thermal rays using of uncoated welding glass in extreme conditions makes danger of overheating of eye in top that is harmful. Richness in colour of welding glass and spectral transmission curve are not changed, if we use welding glass with vacuum coating of metaling of metallic oxides.

Suitability of application and protective properties are legalized by certified testing laboratory.

Colour filters for CCTV

Colour filters for CCTV

Filters for CCTV - available in the colors green, red and opal (white).

Colored glass filters are used to improve the legibility of TV observation of liquid level gauges (elimination of light reflection from the sight glass). When selecting the color and size of the filter, user should be guided by the recommendations of the manufacturer of liquid level indicator.

While every attempt has been made to verify the source of the information, no responsibility is accepted for accuracy of data.

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