Abstract: A process for protecting a metal, wood or plastics substrate exposed to fire risk from hydrocarbons, comprising coating the substrate with an intumescent composition comprising a polydimethylsiloxane (A) of degree of polymerisation at least 300 siloxane units, said polydimethylsiloxane containing reactive hydroxyl or hydrolysable groups bonded to silicon, and a crosslinking agent (B) containing hydrolysable groups reactive with the reactive groups of (A) in the presence of moisture, expandable graphite and a titanate catalyst for the reaction between the reactive hydroxyl or hydrolysable groups of polydimethylsiloxane (A) and the crosslinking agent (B).