I've been asked to look at a steel framed building constructed in the 1970's. The frame incorporates load bearing steel trusses which are provided with a form of fire protection which appears to be mineral wool and vermiculite. The vermiculite forms a "particle board" structure and is applied to the horizontal sections at the base of the truss.
The diagonal sections of the trusses have been covered with a grey "cotton wool" like substance which is almost granular in form (looks like blown mineral wool, but the clumps are very small <5mm diammeter). This substance is held to the truss elements by what appears to be a woven nylon cloth held in place with steel banding. Over the years some of the supporting cloth has torn and otherwise become damaged allowing the contents to spill out.
At the time of construction I would have been in infant school and my teachers negligently omitted the important lessons on construction methods that should have followed colouring within the lines and counting without using fingers!
I'm hoping that some of the knowledgeable chaps here that went to better schools than I did can help me out and clarify the accepted methods of structural steel protection at the time this building was constructed.
