Self-ignition in stone wool insulation contaminated with fatty acid (fundamentals, case study, analysis methodology)

• A model for simulation of self-heating/self-ignition process in porous structures (insulation) wetted with fatty acids is presented.
• Different methodologies to determine qualified simulation data (heat transfer, formal kinetic) from experiments are shown.
• Comparison of experiments and simulation show the possibility to simulate the transition from self-heating to self-ignition.
• Different methodologies for determination of self-ignition temperature are proposed.
• Suggestions for model improvement are made.

A combination of a residual film of flammable organic substance, air and porous structures like insulation material (e.g. stone wool) may result in a fire. The initiating self-heating process depends on the substance (reactivity, volatility), amount of accumulated liquid, volume and temperature. Specific information is given for application and extension of the Thomas criterion with a 2nd order reaction. The experimental part includes new experimental techniques to determine heat transfer and formal reaction kinetic data. The applied self-ignition temperature (SIT) simulation model relies on liquid film volume and not on liquid film surface reaction. As a further result of the studies detailed working procedure of three simplified methodologies for estimation of SITs in technical scale are presented. New techniques to determine parameters necessary for SIT prediction, especially in combination with Methodology III, have the power to reduce the costs for estimating the SIT up to 80%.