Cellular glass is well known as a non-combustible thermal insulation, which is in Europe expressed as EUROCLASS A1. It says that this material does not contribute to fire at all because the organic content, expressed in %C is less than 0.1% for cellular glass.
However, this material on his own is not known as a fire resistant material because it cracks due to thermal shock during fire and allow in that way that gases, flames and radiation may pass through the cellular glass board.
But today, FOAMROX announces large fire resistant boards, based on cellular glass. Indeed, the large GLAPOR cellular glass boards seems to have a special coating. I guess a glass fibre mesh is used to take the tensile forces and to keep the board together in case of breakage. This fibre mesh is probably adhered with a mineral adhesive.
The website declares that an EI=60 is reached according to the following ISO-kurve.
This means that the system resists shortly 940°C which is above the foaming temperature of GLAPOR ware. In fact, we have here an intumescent. This is a substance which is swelling due to a temperature rise, which is interesting in case fire resistance is needed.
The boards have large dimensions 3.73m x 1.2m and 10.5 cm thickness. The 1.2m is the original GLAPOR dimension.
Which other products do we have with EI=60. Fermacell offers the following system 3S21A1 in the Fermacell-firepanel-A1 leaflet. The weight is 40 kg/m² to be compared with only 17 kg/m² for the FOAMROX board which has the same thickness 105 mm. It is also clear that much more manhour will be involved in the FERMACELL case, while still with a material cost above 20€/m².
Other systems combine lower (fire) quality gypsum boards with mineral wool, which will be much harder to dispose later on.
From the above, it is clear that the FOAMROX boards have a nice future.