Conditions of sales


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CE perfornamce declaration

Please find our CE performamce declaration:  Download

GMB Solarglas SINA

The microstructure of GMB solar glass SINA is characterised by specially designed forming rollers on both glass surfaces. The surface of SINA is a non-geometrically aligned structure with a typical roughness height (Rz) of approx. 15 μm (taken from a measuring length of 15 mm). The structure demonstrates a high “density” (number of bumps and holes per unit of length) in order to limit direct reflection and hence reduce dazzling to a minimum. The consistent appearance of the glass is guaranteed in so far as the reflection characteristics of the glass are constantly monitored in our in-house laboratory and corrected as appropriate.

The SINA structure with its geometry as explained – besides a high solar rate of transmission for perpendicular solarisation – minimum reflection losses when a higher variation of the solarisation angle from the perpendicular (higher angle factor also called “Incident Angle Modifier” or IAM). Until today, no structured glass has been found which beats these characteristics for the application in conventional flat collectors and PV modules. The excellent angle factor forms the basis for high annual output.

GMB solar glass SINA has been certified as class 1 solar glass by the Institute for solar technology SPF at the HSR Hochschule für Technik Rapperswil (Switzerland).




GMB Solarglas CONE

Solar glass CONE has two differently structured surfaces. One surface has a geometric, pyramid formed structure (see diagram). The other surface exhibits the same microstructure as GMB solar glass SINA. The side with the pyramidal structure is usually oriented towards the absorber. The advantages of the CONE structure are the significant reduction of dazzling effects and the considerably poor view into the inside of the collector. Small shortcomings in the absorption surface (fingerprints, etc.) can therefore be concealed. The angle-dependent transmission of CONE glass lies comparatively lower than SINA glass. Therefore the annual output of collectors which are equipped with CONE glass is somewhat lower than when SINA glass is used. The lower angle factor also shows itself in the appearance of CONE glass in collector fields. From a few metres away, CONE glass collectors appear light grey. Collectors fitted with SINA glass appear much darker, from dark blue to black, depending on the absorption coating.




GMB Solarglas ASTRA


GMB solar glass ASTRA has a rough, non-geometric structure similar to SINA on the one side but with a significantly larger roughness height (Rz) of approximately 60 μm (taken from a measuring length of 15 mm). The other surface has the same microstructure as GMB solar glass SINA. ASTRA glass exhibits a similarly high angle factor (IAM) as SINA glass and, therefore is also ideal for use in collectors with the highest performance. The advantages of ASTRA glass also lie in minimal reflection or dazzling and the very poor view into the inside of the collector. As such, small visual blemishes (such as fingerprints) are easily concealed.

Various collector manufacturers use ASTRA glass for the purposes of product diversification and to provide a recognisably visual difference to a collector fitted with SINA glass.





Table of technical Data



 Dimensions width [mm]; length [mm]

 dimensions raw glass

 200 – 2200; 200 – 3300

 dimensions tempered glass

 500 – 1650; 700 – 3000


 3.0 mm ‐ 6.0 mm



Thermal collectors

300 nm -2500 nm (AM 1.5)

Solar transmission

3.2 mm

Solar transmission

4.0 mm

Solar transmission

6 mm


91.6 %

91.3 %

91.2 %


91.4 %

91.2 %



91.6 %

91.4 %



Sensitivity on the eyes

D 65

Visual transmission

3.2 mm

Visual transmission

4.0 mm

Visual transmission

6 mm


92.1 %

91.9 %

91.7 %


91.8 %

91.7 %



92.0 %

92.1 %




Directions to GMB:


GMB Glasmanufaktur Brandenburg GmbH, Spremberger Strasse 4, D-03130 Tschernitz, Germany



Coming from the Northwest from Berlin, A13


-          At the Spreewald intersection, take the A15 towards Cottbus

-          Take exit no. 6 Roggosen and turn right onto the L48 towards Döbern

-          Follow the road (L48, L482, B115) until the town-exit Döbern

-          Approx. 1.7km after the outskirts of Döbern turn right towards Tschernitz

-          Drive through Tschernitz until the B156, take a right at this crossing

-          Turn right into the factory premises after about 700m


Coming from the Southwest from Dresden, A4


-          At the intersection Dresden-Nord, take the A13 towards Berlin

-          Take exit no. 14 Großräschen and turn left onto the B96 towards Großräschen/Spremberg

-          At the T-junction, turn right onto the B169 and then left onto the B156 towards Spremberg

-          At the T-junction in Schwarze Pumpe, turn left towards Spremberg

-          Stay on the B156 in Spremberg towards Bad Muskau

-          Turn left into the factory premises after 18km


Coming form the Northeast, from Zielona Góra


-          Follow the A15 towards Cottbus

-          Take exit no. 7 Forst, turn right onto the B115 towards Döbern

-          At the T-junction, turn left towards Döbern (stay on the B115), until the town-exit  Döbern

-          About 1.7km after the town limits of Döbern, turn right towards Tschernitz

-          Drive through Tschernitz until the B156, take a right at this crossing

-          Turn right into the factory premises after about 700m


Coming from the Southeast, from Warsaw, A4


-          Take the A4 towards Dresden after crossing the border

-          Take exit no. 93 Kodersdorf, turn left onto the B115 towards Niesky/Bad Muskau

-          Follow the B115 until Krauschwitz, turn left after about 800m (at the Penny Markt) onto the S123 towards Döbern

-          Go straight ahead at the crossing with the B156 (at the restaurant “Gasthof Zur Linde”)

-          B115/B156 towards Döbern

-          About 4km after Jämlitz Hütte, turn left onto the B156 towards Spremberg

-          Turn right into the factory premises after 2km



We ask all visitors to pay attention to massive speed controls in the whole region!



Interfloat Corporation


Structured high performance solar glass from quartz sand to ready-to-install finished product

Interfloat Corporation has been a supplier of the European solar industry since 1982. Delivery reliability, superior glass quality as well as the continuous improvement of our products is the hallmark of the company. As the first European importer of solar glass from the USA, Interfloat invested in the research and development of innovative solar glass. Among the most important issues are coating technology and novel structures. Interfloat Corporation has now evolved from a long-term trading partner for the solar industry to a producer and reliable investor in Brandenburg. A highly modern production facility for solar glass has been created on the site of a former television screen factory in Tschernitz/Niederlausitz. GMB Glasmanufaktur Brandenburg GmbH took up production in 2008. The functions of giving advice, sales and after sales service for GMB’s solar glass products are exclusively carried out by Interfloat.

GMB Glasmanufaktur Brandenburg GmbH produces high quality low iron solar glass exclusively for Interfloat 365 days a year. In contrast to existing production facilities, all the machinery at the factory has been specifically designed and constructed to fulfil this purpose. In contrast the procedure of batch manufacture (the alternate production of “ordinary” ferrous glass followed by solar glass and vice-versa), the high performance of the product can be guaranteed by GMB with 100 % assurance. The purity of the glass, as the basis for the minimal absorption of damaging substances such as iron oxide is constant at all times.





  • Production of innovative solar glass of the highest quality with minimal environmental burden in the heart of Europe

In contrast to a number of competitors – the glass processing industry – we do not buy any glass from the Far East (with the social and ecological dumping which goes with it), instead we produce glass ourselves in Germany. We pay German wages and comply with the federal law on emissions!

  • Energy efficient smelting process

The dual heating with gas using the oxy-fuel system (pure oxygen instead of air) together with the targeted application of electrical energy reduces energy consumption and emissions at the same time.


  • Innovation is at the fore

The design of the glass surface – be it macro- or microscopic – has a significant influence on the output of the finished product. For this reason, we are constantly working on innovative structures and coatings.

  • In-house expertise from raw material to the implementation of the finished product

The know-how required for the manufacture of our products is onsite. Our quality management system extends from raw materials to the finished glass. In-house laboratories check all the relevant aspects of the individual manufacturing steps on a daily basis. No delivery takes place without an accompanying transmission certificate – the customer receives a performance receipt for the goods obtained.


  • Customer oriented logistics and packaging

Timely dispatch to meet the customer’s requirements is an important part of our service. The loading of the vehicle according to the customer’s wishes is also part of this service. In addition, each product demands the most suitable package – we adapt to meet our customers’ needs. Our packaging concepts also aim to minimise waste. The majority of our packaging (made of metal and wood) are used again.

  • Security and reliability of deliver are the basis of the long term partnership with our customers

The customer receives the tailor-made solution to securing uninterrupted supply. With the help of a store of more than 30'000 m² in size, we can maintain security storage stocks of individual customer’s finished goods – the customer determines the extent of this security stock itself.

  • Completely independent of conglomerates and guaranteed focus as supplier of the solar industry

Interfloat is not part of a large conglomerate but rather an independent medium-sized company with a long history. In contrast to our competitors, we do not produce PV modules of thermal collectors – we do not compete with our customers!



Facts and figures on GMB Glasmanufaktur Brandenburg GmbH





  • Production of low iron solar glass (< 140 ppm FexOy)
  • Production capacity: 300 tonnes/day or approximately 10'000'000 m² gross/year
  • Glass thicknesses: 2.0 mm to 6 mm
  • Maximum tempered glass size: 1.65 m * 3 m
  • Solar transmission factor 3.2 mm glass: > 91.5 %
  • Structures: SINA (matt-matt), CONE (pyramidal-matt), ASTRA (rough texture-matt)
  • New: customers specific structures for exclusive products




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