Describes a method for determining the following: - ability of fire dampers installed in ventilation systems to prevent the spread of fire and heat through designated fire divisions; typical ratings are given in ISO 13702:1999, Table C.5. - fire damper operational reliability in the petroleum, petrochemical and natural gas industries, particularly offshore installations; - ability of fire dampers installed in ventilation systems to withstand blast overpressures that may result from the explosion of a flammable gas.