Damage (other than fire) to the boiler or pressure vessels and to other property of the Insured

Liability of the Insured at law for damage to property not belonging to the Insured,

Liability of the Insured at law for fatal or non-fatal injuries to any persons other than the Insured's own employees or workmen or members of the Insured's family,

caused by and solely due to explosion or collapse as hereinafter defined of any boiler or pressure vessel described in the Schedule whilst in the course of ordinary working.

Boiler - shall mean any fired closed container or a combined container piping system in which steam is generated under pressure. The term "boiler" shall include fittings, built-in superheaters and economizers but shall not include steam or feed-water piping or separate economizers.

Vessel - shall mean any unfired closed container under steam or air pressure.

Explosion - shall mean the sudden and violent rending or tearing apart of the structure of a boiler or vessel, or any part or parts thereof by force of internal steam, air or fluid pressure, causing bodily displacement of said structure accompanied by the forcible ejection of its contents.

Flue Gas Explosion: "Explosion" shall also mean any damage to the structure of a boiler by force of the sudden and accidental combustion or explosion of ignited furnace or flue gases.

Collapse - shall mean the sudden and dangerous distortion of any part of a boiler or vessel caused by the crushing stress of external steam or fluid pressure, whether attended by rupture or not; it shall not mean any slowly developing deformation due to any cause.