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.