Fire resistance is determined in order to assess the performance of a given building element, when subjecting his sample to specific conditions of heating and pressure. The fire resistance of a test piece is expressed in time, by which the relevant classification criteria are met.

Fire resistance test
This standard defines, among other things, the basic criteria for fire resistance and so accordingly:
• fire tightness, is the ability of a test piece separating an element of a building structure to prevent the passage of flames and hot gases and to prevent the appearance of flames on an unheated surface,
• fire insulation, is the capacity of a trial element separating an element of a building structure, exposed to fire on one side, to limit the temperature-rise of the unheated surface below certain levels,
• smoke tightness, is the ability of a test piece to limit the passage of hot and / or cold gases or smoke from one side of the test piece to the other, below certain levels.

The concept of a trial element appearing in the above definitions should be understood, as an element (or part of) building structure or device provided to determine either its fire resistance, or its contribution to the fire resistance of another building element. Fire resistance is sometimes determined, expressed in full minutes, through which the sample element maintains its features appropriate for a given criterion during the test.

Temperature course during the fire test, conventionally called standard temperature / time curve. The heating conditions defined in the above curve are related to the conditions, which occur in real fires, however, they are not the definition of a "medium" fire, which can be used universally. In practice, in some cases, fire scenarios that deviate significantly from the standard conditions are possible.

Alternative and additional procedures ". Examples of fire scenarios, to which the standard temperature / time curve is not applicable:
• fires of open liquid fuel tanks – a hydrocarbon curve is used,
• slowly developing fires – heat-activated products – a slow heating curve is used,

• walls and perimeter elements of the building exposed to external fire or flames from windows – the outer curve is used.

Certain aspects of fire resistance testing relate to actually only the specific test method for a given device or component, e.g. smoke tightness test of the cut-off damper, therefore they are defined in a specific test method, corresponding to the type of device.