European standard NBN EN 12371

For this test pieces of natural stone are subjected to a repeated cycle of freezing and thawing. A measurement of the elasticity modulus determines whether or not the stone can be classified as frost-resistant.
Unfortunately, this European norm makes no comparison between the standard freeze-thaw test cycles and the actual conditions to which the natural stone will be subjected. In reality, every application of natural stone out of doors will experience differing levels of frost stress. For example, terrace tiles are normally in direct contact with a surface which can become frozen, whereas a ventilated cladding will undergo a much less severe frost regime. Various organisations are currently investigating whether or not alternative criteria, based on the European norms but more representative of actual conditions, can be devised.