A method of performing a static test on a safety line, the method comprising the steps of: a) mounting on a building structure a safety line comprising a first and a second supporting device spaced between them and a connection cable connecting said two supporting devices, at least the first of said supporting devices having a main body stiffly fixed to the building structure and an anchoring body provided with a constrained end integrally fixed to the main body and a free end opposite to said constrained end, the free end being bound to said connection cable, wherein the anchoring body has at least a first and a last sub-portion said method being characterized in that said anchoring body of step a) is structured for plastically deforming due to a tensile force greater than 2 kN applied to said free end, so that the last sub-portion plastically changes its position with respect to the first one; b) mechanically constraining the first and last sub-portion of said first supporting device so as to prevent the last sub-portion from plastically changing its position with respect to the first when a tensile force greater than or equal to 3 kN, preferably greater than or equal to 4 kN, is applied to said free end; c) after step b), applying to the connection cable a tensile force greater than or equal to 3 kN for a determined period of time, said tensile force having a value that does not cause a plastic deformation of the mechanically constrained anchoring body of the first supporting device of step b); d) after step c), reducing said tensile force to a value less than or, preferably, equal to 2 kN; e) after step d), releasing said first and last sub-portions of said anchoring body of the first supporting device from said mechanical constrain of step b) so as to allow the aforesaid plastic deformation. a) mounting on a building structure a safety line comprising a first and a second supporting device spaced between them and a connection cable connecting said two supporting devices, at least the first of said supporting devices having a main body stiffly fixed to the building structure and an anchoring body provided with a constrained end integrally fixed to the main body and a free end opposite to said constrained end, the free end being bound to said connection cable, wherein the anchoring body has at least a first and a last sub-portion said method being characterized in that said anchoring body of step a) is structured for plastically deforming due to a tensile force greater than 2 kN applied to said free end, so that the last sub-portion plastically changes its position with respect to the first one; b) mechanically constraining the first and last sub-portion of said first supporting device so as to prevent the last sub-portion from plastically changing its position with respect to the first when a tensile force greater than or equal to 3 kN, preferably greater than or equal to 4 kN, is applied to said free end; c) after step b), applying to the connection cable a tensile force greater than or equal to 3 kN for a determined period of time, said tensile force having a value that does not cause a plastic deformation of the mechanically constrained anchoring body of the first supporting device of step b); d) after step c), reducing said tensile force to a value less than or, preferably, equal to 2 kN; e) after step d), releasing said first and last sub-portions of said anchoring body of the first supporting device from said mechanical constrain of step b) so as to allow the aforesaid plastic deformation.