Fire judgement
Fire assesment done by the institution for material testing of civil engineering at Braunschweig.
The potential of the oxygen share is to less and besides limited through mineral layers.
Fire by means of more then the oxygen share is not possible.
You can avoid that.
The hollow - space most not be higher than 200 mm.
The complete regulation you can get of following address:
Amtliche Materialpruefanstalt für das Bauwesen
Beethovenstr. 52
D-38106 Braunschweig