European Machine Directive 89/392 requires the installation of appropriate audible and visual warning devices as an essential safety requirement for the operator in industrial environments. • European norms EN 457 and EN 842 (machine safety: audible and visual danger signalling) specify the technical, design and functional characteristics the audible and visual signal must have to be effective, i.e. audible or visible, distinguishable and unequivocal. • SIRENA acoustic (electric and electronic sirens, bells and industrial horns) and luminous devices (continuous, blinking, rotating and flashing beacons) conform in every aspect to the technical and functional requirements of Norms EN 457 and EN 842. • The installation of Sirena’s range of audible and visual products onto machines conforms in every way to the safety standards set out in current norms.