Abstract: In connection with installations comprising articles housing or conducting corroding material, or in connection with substantially pipe- or hose-shaped articles which are to be protected against fire, for example a propulsion motor in a vehicle, it is in accordance with the present invention suggested, rather than using steel pipes and/or steel containers, to use plastic articles which by nature is corrosion resistant. Plastic articles which preferably are pipeshaped (1) are insulated by means of a combination of a light thermally insulating material (2) which normally cannot stand exposure to fire (approximately 800.degree. C. and higher), and a fire resistant material (3) which is provided around said insulating material (2), and which at high temperature (approximately 800.degree. C. and higher) renders a ceramic stable fire protecting phase.