Palletizing of cellular glass boards

logo_smallThis topic is maybe not the most challenging, but it is very important. According to the Swiss ECO-scarcity method (UBP), the transport of raw materials and cellular glass is responsible for  20 % of the total damage to the environment due to production, transport and installation of the cellular glass. In other words, 20% of the UBP is caused by transport. It is clear that efficient packing becomes very important.

Forty years back, 40mm cellular glass boards were the standard while today 140mm is the most popular thickness. Transporting 40 mm boards horizontally is a risky operation while this seems logic for 140mm boards. As a consequence, the cellular glass world started to transport vertically. The internal trailer height is maximum 3m with 2.45m internal width to be used with exchangeable EUR-pallets or thinner single use versions. A typical trailer has a floor for 33 pallets, which can be double stapled in the case of cellular glass.


epal-europaletteIn case of vertical stacking, the boards have a width of 450mm (height when stacked) and 600 mm length (half pallet length). Six parcels have than a total height of 2.70m which should become 2, 984m  theoretical total height with two EUR-pallets (144mm height)  to be installed in trucks with internal height between 2.85 and 3m. This is not possible and for that reason thinner and weaker pallets are used for this application to gain about 10 cm tolerance. However, these pallets cannot be exchanged because they are not designed to carry 1500 kg. In case of horizontal stacking, exchangeable EUR-pallets can be used because height is not critical anymore. Two pallets stacked  have to respect a 2.80 m limit to allow loading the trailer. This means that a trailer can be maximally loaded with 79m³ cellular glass.

In case of vertical transport, the pallets have a fixed height  with thinner pallets and I assume that slightly more cellular glass can be loaded, improving the UBP-score due to transport with I guess 4%. But using single use pallets instead of exchangeable EUR-pallets is responsible for an increase of 3.5% UBP. On the other hand, a width of 450 mm (vertical transport) instead of 800mm induces more  joints  after installation and so a decreased thermal resistance. Joints between 0.6 x 0.45m boards are responsible for 5% heat leak , which means that 0.8 x 0.6m boards should leak 3% in the joints.

At the end, vertically stacked or horizontally stacked boards are nearly equivalent if we speak about ecology. The choice depends on the requested dimensions and it looks that larger dimensions (thickness and length) are becoming more popular. Therefore, I guess that horizontal transport with EUR-pallets will be the future on the condition that the EUR-pallets are not covered by hot bitumen on the roof.


ECOINVENT data for building products

logo_smallECOINVENT is a database which contains for many products production data which are important for the environment like the use of primary energy, raw materials, etc. This means that during development of a new product which is based on other products, the developer is able to obtain all data of the products he is using for his invention.

For example, if somebody is using celllular glass besides other materials for the construction of a house, ECOINVENT allows to calculate how much the environment suffered from this construction.

downloadBELGLAS could obtain the public report  about building materials, which is used to generate the ECOINVENT database. Although public, this report could not be found by Google and for that reason, it is included in this post.

On page 456, a very detailed description is given about the production of cellular glass based on a special glass composition. All used raw materials are listed together with their function in the process.

inventThe report mentions the following:

  • Electric melting furnace with molydenum electrodes at 1250°C
  • Grinding with corondum cylinders
  • Steel moulds coated with clay and aluminum hydroxide
  • The use of 10 kg one way pallets instead of 22kg EURO-pallet

In a following post, we will calculate the production cost of cellular glass with the numbers of this ECOINVENT report.

An old but interesting German patent

logo_smallAbout 50 years ago, an invention was made and patented in the VEB Schaumglaswerk Taubenbach, East-Germany. I give the abstract hereunder.

A process for making foam glass wherein mixtures of sulfur trioxide-containing glass and active carbon are first sintered in a pure steam atmosphere having a partial pressure above 200 mm. Hg and subsequently heated at a temperature ranging from 800° to 900 °C to form a foam structure.

steamGlass powder is sintered in a steam atmosphere before foaming. The glass powder is a mixture of a sulphate containing glass and active coal. Due to this steam atmosphere, a better foaming behaviour is obtained and the cells contains up to 11% H2S instead of less than 1%.

It seems that this procedure allows to foam a lower density with improved thermal conductivity.

All cellular glass green roofs with boards and gravel

logo_smallOriginally, gravel was not meant to be used in roofs. But the Kaluga plant produces 300000m³ cellular glas gravel, which is almost completely used for flat roofs. Typically, the upper layer of green roofs is soil, which is needed for the plants but can also serve as ballast.

gravelIn case ballast is present, we have the choice between a warm and an inverted roof. And if an inverted roof is accepted, we can indeed use cellular glass gravel. In case gravel is used under the concrete slab (floor insulation), the gravel is compacted to obtain a large compressive strength. This seems not be necessary for the roof, but this is a wrong statement.

In the roof, the warm side is under the gravel and convection is possible (contrary to the floor). An interesting paper about the thermal conductivity of gravel shows with calculation and experiment that compacted gravel has a lower thermal conductivity than uncompacted gravel.


However, even with compaction, there is always the risk that sudden cold rain water reaches the bottom of the gravel, creating condensation inside the building at the ceiling. This is precisely the effect where the inverted roof got its bad reputation. This can be avoided by installing 40mm GLAPOR cellular glass boards under the water proofing membrane. The  following figure shows such a roof, with a thin layer cellular glass boards to avoid any condensation problem.


By using tapered GLAPOR insulation, drainage is also installed. The water proofing membrane is protected against UV, thermal changes , humidity changes and mechanical damage. In our opion, this is the best roof possible in winter and summer for a very sharp price.



A Trumpian question: Is a passive house ecologic?

I could imagine that President Trump should put this question  and even answer it with no, it is not. Indeed, it is clear that too much thermal insulation takes more from the environment that the energy saved during the life time of the building brings back to the environment. Or in other words, which thickness is the break even point? We answer the question for GLAPOR cellular glass

 Passive houses have generally two requests:

  • The building envelope has to be airtight
  • The U-value should be between 0.15 and 0.1 W/m²K 

GLAPORlogoIt is clear that large GLAPOR cellular glass boards are the most ideal thermal insulation to obtain airtightness. But for an U-value of 0.15 W/m²K, we need 36cm GLAPOR PG600 boards, which is acceptable as wall thickness. Today, value down to U=0.12 W/m²K are already requested in Europe at some places. But is this ecologic? We answer this question with the UBP-system of Switzerland


ubp_passive housegrundschema_der_methodederoekologischenknappheit

For U=0.15 W/m²K, we need at least to use the house 13.5 years to pay back the environment for the production of the thermal insulation. For U=0.1 W/m²K, we have already 30 years. In Sweden for the roof, I found the following on Wikipedia: 

In Sweden, to achieve passive house standards, the insulation thickness would be 335 mm (about 13 in) (0.10 W/(m²·K)) and the roof 500 mm (about 20 in) (U-value 0.066 W/(m²·K)).

For U=0.066 W/m²K, we need already a lifetime of 70 years, while except GLAPOR, thermal insulation manufactureres does  not give a lifetime more than 50 years. And the UBP for all other thermal insulation boards is worse than GLAPOR, saying that even more than 70 years are needed with these materials even up to 150 year. 

trumpThis is a nice example of eco-fundamentalism, when laws forces people to demolish the the environment. Small U-values can only be approved  with thermal insulations with a very long life time and we should ask ourselves: Is this needed? In my opinion, below U=0.05 W/m²K (125 years), Trump should be right. 


Press release: AeroAggregates Doubles Production Capacity of Foamed Glass Aggregates with Installation and Start-up of Innovative New Kiln

New Production Fills Critical Need for Foamed Glass Aggregates in Sustainable U.S. Building, Highway Construction and Landscape Architecture Applications

logoEddystone, PA (January 15, 2019) – AeroAggregates, the first vertically-integrated  manufacturer in North America to produce ultra-lightweight, closed cell foamed glass aggregates (FGA), has completed installation and is now operational on its second kiln, doubling production capacity to meet growing U.S. demand.

The kilns at AeroAggregates use 100 percent post-consumer recycled glass to produce a building aggregate that is lightweight, non-combustible, insulating, free-draining, non-absorbent, and resistant to chemicals, rot and acid. This makes FGA superior for construction, lightweight embankments, load distribution platforms and insulating subgrade, as well as lateral load reduction behind retaining walls and structures. Foamed glass aggregates also possess a highly frictional surface which makes it ideal as a lightweight backfill.

“Our ultra-lightweight FGA can solve the challenges of today’s infrastructure projects, especially for those that require fill to be placed over soft compressible materials, weight-bearing structures or over areas with sensitive underground infrastructure,” explained Archie Filshill, CEO and Co-Founder of AeroAggregates. “We’re excited to fire up our second kiln in order to meet increased demand from the civil engineering and construction markets that require sustainable, lightweight materials due to specialized design and constructability requirements.”

With the addition of the new AeroAggregates kiln, the equivalent of more than 140 million recycled curbside glass bottles (or 32,000 tons) will be diverted each year, bringing relief to municipal recycling operations. According to a recent study, municipal recycling programs spend approximately $150 million annually to dispose of unwanted glass. The FGA manufacturing process employed by AeroAggregates can utilize mixed color glass and due to its advanced cleaning system is unaffected by small amounts of residual paper and other contaminates.

The new 60-foot foamed glass kiln was imported from Europe where, for many years, FGA technology and manufacturing have been used heavily by the civil engineering market. A recent report by market research firm BauInfoConsult found that the European architects they surveyed intend to use more natural insulating materials (wood wool, hemp, cork and granules such as FGA) in upcoming residential and commercial construction projects reducing their use of polystyrene, polyurethane and polyisocyanurate. Unlike the non-combustible nature of FGA, materials like expanded and extruded polystyrene, commonly used when lightweight construction materials are specified, are falling out of favor in the industry due to their flammability.

The company’s unique FGA manufacturing process, obtained through an exclusive license from a Europe-based firm, starts with curbside recycled glass powder which is then mixed with a foaming agent. The mixed powder is sent through a kiln and softened by temperatures reaching 1,800 degrees Fahrenheit. During this process, the foaming agent creates bubbles within the softened glass, which ultimately creates foamed glass aggregates. The output produced is a remarkable material that creates a superior building product offering many sustainability benefits.

About AeroAggregates

logoAeroAggregates is the first vertically-integrated company in North America to produce ultra-lightweight closed cell FGA from 100 percent recycled glass. The company’s manufacturing capabilities include the ability to make several types of foamed glass including both open and closed cell aggregates. The founders of AeroAggregates realized the need for a sustainable solution for lightweight construction materials due to increased design or constructability requirements. Today’s civil engineering challenges include construction on soft soils, lateral load reduction behind retaining walls and structures, insulating subgrade and backfill, and the protection of underground utilities. AeroAggregates provides an answer to many of these challenges by supplying a lightweight material with a high friction angle that is also insulating, free-draining, non-absorbent, non-combustible, and resistant to chemicals, rot and acid. Its manufacturing plant is located in Eddystone, PA, a brownfield redevelopment site that was formerly the location of Baldwin Locomotive Works. Visit for more information.

Eco-scarcity (UBP) ranking of thermal insulation

logo_smallUBP is the German abbreviation of Umweltbelastungspunkte, which is a result of  “Methode der ökologischen Knappheit”. The method is invented in Switzerland , which explains the use of the German language. In English, we speak about the  Ecological Scarcity Method (which has no Wikipedia page).

SES_Umweltbelastung_2013-600x487An EPD gives you for the production of each product how much CO2 is generated, how much fossil energy is used, etc. These 8 numbers don´t say a lot to the common consumer. The UPB combines the impact of all these emissions and material-energy use on the environment, the future of the raw materials and our health in only ONE number. The method is defined in a paper by the Swiss government and also Volkswagen has sponsored a publication. But for the standard consumer, I have the following table with the quantity of products for 1000 UBP.


This method is also applied for thermal insulations on the Swiss market which can be found in this spreadsheet.

GLAPORlogoGLAPOR communicates 690 UBP per kg cellular glass board for production in Germany and delivery in Switzerland, which is lower than any thermal insulation except foamed glass gravel (also a GLAPOR product) like shown in the following figure. The improved value compared with “Schaumglas” is due to the fact that GLAPOR foams directly recycled glass without melting a special composition. In case production should be in Switzerland, the UBP lowers to 552 UBP/kg.



For a fair comparison of thermal insulations, we have to work with UBP/m² for a certain thermal resistance (R=5 m²K/W) to be obtained. This table is given in the following:


GLAPORlogoIt is clear that according to the UBP system in Switzerland, GLAPOR cellular glass boards are the most ecologic thermal insulation which can take a compressive load of 600 kPa with a safety factor = 2.5. This is a consequence of the direct foaming of recycled glass. Standard cellular glass is made from a special glass composition involving an energy intensive melting step. In case cellular glass gravel is used, it is needed to use the RDS-system of GLAPOR to keep the gravel dry in order to have the best ecological solution.



The smart cellular glass plant operator

Every cellular glass factory has his “temperature curve expert”. These experts observe a cellular glass foam and know in a lot of cases how it can be improved by changing temperatures, foaming agents, …. . Their knowledge and availability have a strong influence on the quality and production yield of a factory.

In the past, managers have tried to describe their knowledge in a ISO9000 system or another system with procedures. This has never worked properly because the “book” knows always less than this person. This was always clear when this person was not present in the factory, the yield drops temporarily.

Ten years ago, we needed Kitt in Knight Rider to see a self driven car, but today Tesla and many others have converted this fiction into reality. And I guess that this “machine learning” technology will enter the (cellular) glass factories soon. I expect that neural networks will do the job, because the data for input and output are already available.

Neural networks (NN), programmed in Python, based on Numpy are a good candidate because they are open source and will be fast further developed. Indeed, the NN can be trained with the massive amount of data from the past and present. To obtain a new quality, the NN will find a new solution with data from the past like today the operator is doing by using his experience. Moreover, the NN of collaborating factories can be coupled and the operator experience will not be lost after retirement.

Europe goes for natural and mineral thermal insulation

I was very nice surprised about how architects in Europe are looking into the future of thermal insulation. The enquiry was done  by BauInfoConsult with 1600 architects in 8 countries in Europe. 

The tendency is clear:polymer (plastic) thermal insulation like EPS, XPS, PIR and PUR are decreasing while natural  and mineral insulation will increase. Of course the last tendency is interesting. We further have to explain the customer that in case a certain mechanical stability is needed, a cellular structure is more appropiate than a fibrous structure. And if humidity and air tightness are a issue, cellular glass is the only option. 

Once cellular glass is choosen, we have to explain that direct foaming of recycled glass in a continuous system is the cheapest and most ecologic solution. This technology is invented and developed by GLAPOR. After a life in cellular glass, I feel that the future is great without limits. 

Popular post: Mineral wool versus foam

Some years ago, we wrote a post about a comparison between mineral wool and cellular glass. And suddenly during the last months, this post became popular like shown hereunder. 

It is not clear which (GOOGLE or WORDPRESS) mechanisms are eventual repsonsible and I assume that some people are just interested. Like explained in this previous post, it is not clear why engineers should choose for fibrous structures when mechanical stability is involved. A cellular glass structure is obviously better for this kind of applications. On top of that, cellular glass with closed cells cannot have any issue with humidity due to internal condensation and water absorption. In that case, you think that the price is the reason to choose for mineral wool. 

As an example, we have taken the data from FLUMROC in Switzerland, a company producing mineral wool since 1950. We consider the three types with a mechanical stability. FLUMROC PRIMA , 341 and MEGA are mineral wool boards with different densities and allowabel loads. The properties and price are listed hereunder. 

For comparison, GLAPOR cellular glass PG600 has an allowable load of more than 250 kPa at 130 kg/m³ and can be bought for 280€/m³ without negociation. This is 6 times the one of FLUMROC MEGA ,160 kg/m³ density priced 438€/m³. After correction for the thermal conductivity (0.045 W/mK) to be compared with 0.054 W/mK for GLAPOR PG600, we arrive at 365€/m³ to be compared with 280€/m³ for GLAPOR cellular glass with 6 times higher stability. 

GLAPOR PG600 involves grinding and foaming at 800°C of 170kg recycled glass while FLUMROC MEGA needs minimum 160 kg basalt and recycled glass, melted at 1600°C and again reheated at 200°C for the binder. It is logic that mineral wool with a 6 times lower stability is more expensive than cellular glass. But is is not logic that people prefer mineral wool with a lower stability, humidity risks and even more expensive unless the acoustic absorption is needed. It seems that some types of cellular glass have a serious marketing problem.