A system for limiting the risk of forming an explosive atmosphere in the furnace of a continuous metal strip heat treatment line, the sections of which are under an atmosphere consisting of a mixture of inert gas and hydrogen, the hydrogen content of which is between 5 and 100% by volume, said system being equipped with a rapid induction heating section and a rapid cooling section, wherein it comprises:
- a chamber maintained under inert gas, at the inlet of the rapid heating section of the furnace and at the outlet of the rapid cooling section, the pressure in the chamber being above atmospheric pressure when the heating of the furnace is operating normally;
- an inlet device at which the strip enters the chamber from the atmospheric air;
- the atmosphere-separating inlet device via which the strip enters the heating section of the furnace from the chamber under inert gas, this device being fitted with a gas take-off;
- an atmosphere-separating outlet device via which the strip exits the rapid cooling section of the furnace, this device being fitted with a gas take-off;
- and
- an outlet device via which the strip exits the chamber into the atmospheric air.