Recent patent about facades thermally insulated without cold bridges

Installation of very light thermal insulation with a rendering on a new facade can in principle be done with an adhesive. However, most people don’t trust this because it depends on the state of the facade (wet by rain, contamination due to traffic, etc.). At that moment, they want mechanical fixings, which are anchored in the facade.

Large cold bridge fixation

In case of a ventilated surface with more heavy thermal insualtion like cellular glass and with a heavy cladding, an improved mechanical fixing is needed.The patent of Willy Trittenbach, once a collegue is a nice example of such a very stable fixings. But stainless steel has thermal conductivity of 15 W/mK and GLAPOR cellular glass about 0.05 W/mK or a factor 300. This means that a 6mm screw cinducts the same amount of heat as a cylinder GLAPOR cellular glass with a diameter of 100 mm, which is a huge cold bridge. Besides the screw, also the legs are passing the cellular glass. The patents mention at least one fixing in every boards 450 x 600 or a cold bridge of about 10% of the thermal insulation. To remove this cold bridge, a new patent was taken.

This new patent eliminates works with a double layer insulation, separated by a board, which is fixed on the walls. In this case, there is no direct connection by a long screw between the surface of the thermal insulation and the wall.

Small cold bridge fixation

However, in Germany ventilated facades have to be insulated with thermal insulation with melting point above 1000°C according to DIN 4102-17. Check the German product datasheet before ordering the thermal insulation in case of Germany.

Tribute to the father of cellular glass: Professor Isaak Ilyich Kitaygorodskiy

In 2022, it is 90 years ago that Professor Ilya I. Kitaygorodsky presented cellular glass at the All-Union conference on standardization and production of new materials in Moscow. Therefore, BELGLAS BV conducted some research about this man, with which we share a common respect for cellular glass.

Professor Isaak Ilyich Kitaygorodskiy

Professor Isaak Ilyich Kitaygorodskiy was the founder of the Department of Chemical Technology of Glass and Sitals at the D. Mendeleev University of Chemical Technology of Russia. In the following, I copy a part of an interview with Vladimir Nikolaevich Sigayev.

The Department of Glass is a legendary one. It was founded almost 90 years ago, in 1932, by the famous Soviet scientist, technologist #1 in the field of glass, Isaak Ilyich Kitaygorodskiy. Suffice it to mention that the ruby stars of the Moscow Kremlin were created on the basis of his developments related to glass coloring processes. I should remind you that the towers of the Kremlin were originally decorated with two-headed eagles. The builders of communism got to them only in 1937, and the eagles were replaced by metallic stars, which, however, were not visible at night and did not make a good impression at all. Therefore, it was decided to replace them by ruby-colored glass stars which fitted perfectly well into the architectural appearance of the Kremlin. It was a very beautiful design that complemented the brilliant work of Aristotle Fioravanti. 

Let us return to the foundation of the department. 1932 was a landmark year not only in the context of its founding. It was the same year when the famous article by William Zachariasen, the largest scientist of crystal chemistry, who laid the foundation for the theory of the glassy state structure, was published. By the way, this two-page work remains the most cited article in glass science to date. 

Kitaygorodsky, the founder of the department, worked as a chief engineer at a glasswork in Zaprudna near Moscow before the events of the 1917 revolution. Kitaygorodsky set up the production of light bulbs at this, judging by the preserved photographs, quite ruined facility. In fact, as they say today, he started the process of import substitution, and beginning from 1913 Russia has been using domestic light bulbs. After 1917, when the entire country was electrified under the GOELRO plan, they began to be called “Ilyich bulbs,” referring not to Isaac Ilyich, but to Vladimir Ilyich, which I find a major historical injustice. 

Later, the activity of the department covered all the variety of glass technologies, including all the new challenges coming from the needs of instrumentation, medicine, and ecology. The main challenge was related to the improvement of sheet glass and organization of its multitonnage production (95% of all glass production is oriented on the creation of window sheet glass, i.e., glass used in architecture). The problem of sheet glass production was finally resolved with the aid of the so-called float technology, which makes it possible to obtain nearly perfect glass sheets up to six meters wide by melting the glass mass into liquid tin. In Russia, this problem has been solved when foreign companies came to the Russian market such as “AGC,” “Guardian,” “Pilkington,” etc. It is difficult to overestimate the contribution of Kitaygorodsky and his students in the development of sheet glass, electrovacuum, medical glass, foam glass, and seals.

The Russian university where Professor Ilya I. Kitaygorodskiy teached

Today, a lot of research about cellular glass is again performed in Russia. I guess that our spiritual father will be pleased.

The rebirth of the inverted cellular glass roof

The inverted roof has the thermal insulation on the waterproofing membrane. A better but less known name is the Protected Membrane Roof (PMR). Another contraction was IRMA (Inverted Roof Membrane Assembly), which was once a registered trademark of the Dow Chemical Company. Moreover, Dow Chemcial company had once a patent on the inverted roof. It was filed in 1965, which means that there was no absolute freedom to install this type of roof in the USA untill 1985.

The patent describes that the thermal insulation has to be watertight and should not absorb humidity. It is a surprise that this patent showed up 24 yeasr after the invention of the XPS. The patent mentions also cellular glass in its introduction: The thermal insulating layer, employed in the practice of the present invention, beneficially is a closed cellular material which is substantially water impermeable. Particularly beneficial and advantageous, for use in the pres ent invention, are cellular plastic foams of a closed cell configuration including styrene polymer foams, styrene acrylonitrile copolymer foams, styrene-methylmethacry late copolymer foams, polyvinyl chloride foams, poly ethylene foams and other water impermeable materials available in cellular foam form which are well known to the art. Foam glass is particularly advantageous when it is desired to omit a protective layer over the thermal in sulating material. A protective layer beneficially is employed when synthetic resinous organic cellular thermal insulating layers are utilized. Such organic materials are generally subjected to decomposition when exposed to weather and more particularly when exposed to Sunlight.

Cellular glass can not be used in freezing countries because freezing water in the open cells on the top surface will induce cracking and water absorption. For that reason, cellular glass was only used under the water proofing membrane like shown in the many applications of GLAPOR cellular glass. However, if your are able to solve the problem of open cells at the surface of cellular glass, the way is open to use cellular glass in an inverted roof. The advantages in these sustainable times are clear.

Since less than one year, a patent was published, which claims to solve this problem. This patent from a Belgian inventor works with a mineral protective coating on the cellular glass surface.

Hytherm CG inverted roof with cellular glass

This patent does not refer to the original inverted roof patent but is on the other hand very extended. It describes a few detailed methods how to prepare a mineral protective coating on the cellular glass. All these coatings are based on alkali silicate solutions with mineral fillers and even some testing in a climatic chamber for facades is included. The coating is proven to be resistant to UV, higher temperatures and freezing water. I guess that a mineral coating, based on hydraulic lime could also be suited. I used it once for a “sculpture” and it survives already 15 years in a Belgian climate, even the horizontal part.

Choosing between a warm roof (thermal insualtion under the water proofing membrane) or an inverted roof is choosing between the risk for damage / wear at the thermal insulation or damage / wear of the water proofing membrane. I guess that the second risk is at least more acute. An inverted roof needs ballast on the thermal insulation, which makes the roof construction more expensive. But Germany is going in the direction to make ballast on the water proofing membrane an obligation for every flat roof.

If the roof construction can bear ballast and cellular glass with a mineral coating is available, an inverted roof with loose-laid cellular glass is the most durable solution. Indeed, the life time of the membrane will be very long (no UV, stable temperature and no mechanical damage) and recycling at the end of the roof life (building life) will be much easier. These coated cellular glass blocks can be found at Hytherm CG and I guess other suppliers of cellular glass will follow. In the UK, non-combustible thermal insulation is an issue since the incident with the Grenfell Tower, while the inverted roof with the combustible XPS was very popular there. Mineral coated cellular glass is there a big opportunity today.

In my opinion: “The warm roof is dead, hurray the inverted roof”

In the mean time, we learn the above patent has been aborted.

3D printed house with GLAPOR cellular glass

Recently, a nice YouTube-movie appeared about full printing a 3D-house. The house was put on GLAPOR cellular glass gravel, while the flat roof was insulalted with GLAPOR-boards.

The movie shows the use of cellular glass gravel and the printing of the house, layer by layer. In fact, the house was printed by only two people and a huge cement mortar printer. The challenge was to develop a mortar, which allows printing but which does not flow after printing.

On the flat roof, GLAPOR cellular glass boards were installed with bitumen. Although, the main target was to use only mineral materials, bitumen, as an exception on the rule, was used to have a firm adherence to resist important wind loads.

More information about the printing can be found in another YouTube movie.

Old patent study foaming glass in a mold

The following patent US 2377076, filed in 1943 by Walter Ford, is such a nice piece of work in a former great company. The patent describes two shapes of molds wherein the glass is foamed at high temperature. Both shapes have been applied although without top cover like seen in the pictures hereunder.

Foaming in demountable mould
Foaming in non-demountable mould

The patent mentions that the demountable mold does not need a short heatup to release the foam during stripping.

Further, the patent gives a recipe for a coating, which is needed to release the foam from the mold without damaging the mold or the foam. The basic substance should release gas between 600°C and 900°C to facilitate parting. Hydrated Alumina (Al(OH)3) is such a substance found in Bauxite or Clay (Kaolinite) or which can be bought pure. Dextrin is added to improve adherance on the mould.

The first cellular glass producer in Iran

Cellular glass in Iran

The company Jahan Ayegh Pars in Isfahan, Iran started with the production of cellular glass due to its unique properties and because it is was hard to get in Iran. I am a little bit surprised about the name because they must be aware about Pittsburgh Corning.

Just like IZOSTEK , STESS and GLAPOR, a family take the initiative to develop a process and build the production facility. Further, they organize succesfully a sales environment. In this case, the company already produces mineral wool, ceramic wool and PIR industrial technical insulation.

In this case, I also measured the gas composition in the cells to check for closed cells and to estimate the thermal conductivity, which is not published. The cells are indeed 100% closed and I estimate the thermal conductivity to be 0.046 W/mK for the 115 kg/m3 density and 600 kPa compressive strength. Although recycled glass is used without remelting, JAP achieved a low H2 content below 3%. In view of the low energy cost, labour cost and recycled glass use, I estimate the production cost of this material between 50 and 70 €/m3. In the Middle East, such a producer can be a game changer. A chromatogram is given hereunder.

We are 100% sure that we hear much more about this porducer in the near future.

Glass literature

To understand fully the unique properties of the different types of cellular glass, it makes sense to read some more didactic books for glass science. I found these books on the Internet and I guess I am allowed to mention them.

The first work I like to advise is the under graduate student book of James E. Shelby. I got sympathy for the book by its definition of a glass: A glass can be defined as “an amorphous solid completely lacking in long range, periodic atomic structure, and exhibiting a region of glass transformation behavior”. Any material, inorganic, organic, or metallic, formed by any technique, which exhibits glass transformation behavior is a glass.

The second work is a little bit more academic. About glass is a shorter but more difficult version of the above one. 

Cellular glass can be foamed from different glass compositions. The history of the glass composition is the perfect introduction how the world evolved from colored glass beads to optical fibers. This topic is interesting because cellular glass is the best method to recycle all kinds of glass. 

Linux on an USB-stick

Knoppix is well known as a live-LINUX in Germany, which allows to taste LINUX on a CD or DVD, without writing on the hard disk of your PC. Any possible damage on your Windows-system is excluded. Klaus Knopper started in 1998, already 23 years ago as a LINUX and open source software consultant. He also developed his own LINUX, KNOPPIX on a live CD/DVD and later on a USB-flash drive. Since USB 3.0, such a flash drive is fast enough for a gentle opeation.

Knoppix logo

This standard KNOPPIX USB-drive (XTRA-PC) is delivered by SoftwareFair for 23.85€ in Germany, delivery included within 2 days. After plugging into an (old) PC and booting for the US-drive, the LINUX system runs. The orginal PC-XTRA does not allow writing on the USB-flash drive, which means that extra installed programs are lost after shutdown. For that reason, you will find on the desktop a button to make a copy of the USB-flash drive with an overlay up to maximum 65GB. Once booted with the new USB-flash drive, all work and installed programs will be saved on the USB-flash drive. This USB-flash drive can be used on any Windows of Mac computer, every where on the world, even without internet connection with all your work included.

Libre office alternative of Word, Excel,Powerpoint, Drawing and Access

The USB-flash drive system contains a preinstalled an enormous amount of open source software. Libreoffice (Office replacement), GIMP (Photoshop replacement), a terminal emulator, Chromium webbrowser and a File explorer are a few examples. I included a FORTRAN compiler, which allows to run all my old programs, Texmaker (to work with Latex to write my book), YAD to generate a graphical interface and Anydesk to be able to take over PC’s of my customers all over the world. All this software is easily loaded from the Debian site but don’t forget to run first the “sudo apt update” command before installation.

Texmaker editor

As a service, BELGLAS sells this USB-flash drive with possibly all the FORTRAN programs, with and without source, I have written about cellular glass annealing, foaming, thermal shock, pipe thermal insulation, … . By nature, when your PC is booted with this USB-flash drive, all the programs will run for sure.

At last but not at least, I like to thank Klaus Knopper, who developped this valuable tool.

Klaus Knopper


WSL: Linux during Windows

logo_smallIn a previous post in 2016, we already reported on this move of Windows. At that time, a real BASH – shell was available. In this application, only text based programs without GUI could be run. Today, we have WSL2 (Windows Subsystem for Linux), which works with a real Linux-kernel and allows to call GUI-programs from the command line.

storeWSL-Ubuntu can be run as in a terminal of  (as an example) MobaXterm. The X-server of MobaXterm (free for home-use) makes the GUI possible. We have succesfully installed and used

  • Mousepad and Gedit editors
  • GNUplot to show our data
  • LibreCad to make 2D drawings
  • Qpdfviewer to show pdf-files
  • Krusader to search and navigate in the filesystem.
  • Zenity to write BASH scripts with GUI

krusader-twinpanel-thumbIt is possble to enter the Windows filesystem, which is mounted under /mnt and in this way, Linux and Windows-applications can be run on the same files. A C-complier and Python2 and python3 interpreters are already standard availbale with WSL-Ubuntu. The ordinary scientist has everything for his standard scientific work with this WSL-Ubuntu.

DownloadWe may speculate about Windows 11. Will it be totally based on LINUX and in that way make all other LINUX-distros unnecessary? I would not be surprised. In the mean time, I enjoy the feeling that a community of free of charge working programmers clearly influence the decision of a large multinational.



FORTRAN: An old but new language in memoriam of Prof. Dr. Olav Verbeke

logo_smallThe first time I met FORTRAN (and programming) was as a part of a numerical analyis course at the University in 1981. We had to “write” the program with punch cards. It was FORTRAN77 and we did not speak about structured programming at that time. During my PhD-time, I worked with FORTRAN 77 with my adviser Olav Verbeke. In that time, there were already rumours that in further versions, we should have to decalere all variables and we should forget the equivalence statement.  Later on, I learned C at one employer and then again I used FORTRAN77, with a lot of GOTO´s at another one. I moved from UNIX to LINUX, introduced there the GNU FORTRAN compiler and  used him to compile succesfully the old HP-FORTRAN77 programs.

fortran_bannerI made some new programs myselves and I found out that structured programming without GOTO, COMMON, … statements is very wel possible with FORTRAN90 for all our typical numerical programs. Structures of different types of variables can be described while subroutines can be collected in modules. C-functions can be merged in a FORTRAN program. Moreover, object oriented programming and parallel programming is also possible in FORTRAN 2003 and 2008, but I do not use that for the moment. Recently, also a GUI is available in order to make the program userfriendly with buttons and graphs. In case only a graph is needed, including GNUplot in the program is a fast and neat way to go.

imagesSome time ago, I was considering Python but the slowness of this interpreter is sometimes a problem. A direct competitor is C++, which is as fast as FORTRAN with splendid GUI possibilities but is complicated to learn. I decided to continue with my “old” FORTRAN and to wrap the subroutines in Python, if a GUI is needed. In fact, a lot of the Python modules in Numpy and Scipy are wrapped FORTRAN routines.

220px-John_Backus_2A lot of free FORTRAN source is available with the Numerical Recipes for FORTRAN 77 and FORTRAN 90, where the routines are well explained. Today, I program with CODE:BLOCKS IDE under Raspbian LINUX . I thank John Backus and his team for this wonderful job. John was the first one, who realized that developing a higher level language above assembler would speed up programming a lot. But he did not only have the idea, he also realized his idea at IBM. The name of his child was FORTRAN.