Organic binder burn-off: resin-bonded mineral wools contain a few percent phenolic binder that pyrolyses around 200–250 °C, producing visible smoke and odour on first commissioning — alarming, usually harmless to the product, but plan ventilation and warn the fire watch. It happens once per heat-affected zone. Binder-free products (needled glass mat, wired mat with minimal binder) skip it — one of the reasons needle mat is the standard core inside removable covers fitted to hot equipment in service.
Compute your own case: free heat-loss calculator · materials library: 12 datasheets · related: How much heat does a flat hot surface lose?
