This document provides requirements and specific guidance for the safe operation and maintenance of optical fibre communication systems (OFCSs). In these systems optical power is possibly be accessible outside the confines of the transmitting equipment and/or at great distance from the optical source. This document requires the assessment of hazard level at each accessible location of the OFCS as a replacement for product classification according to IEC 60825-1. It applies to the installed OFCS as an engineered, end-to-end assembly for the generation, transfer and receipt of optical radiation arising from lasers, light-emitting diodes (LEDs) or optical amplifiers, in which the transference is by means of optical fibre for communication and/or control purposes. Individual components and subassemblies that fall under the definition of a laser product are subject to the applicable subclause(s) of IEC 60825-1. This document is applicable to individual components and subassemblies intended to be installed within OFCSs. This document does not apply to optical fibre systems primarily designed to transmit optical power for applications such as material processing or medical treatment. Throughout this document, a reference to laser is taken to include LEDs and optical amplifiers. In addition to the hazards resulting from laser radiation, OFCSs possibly give rise to other hazards, such as fire. This document does not address safety issues associated with explosion or fire with respect to OFCSs deployed in explosive atmospheres. NOTE The hazard presented by optical radiation emerging from a fibre is determined by the wavelength and power emerging from the fibre and also by the optical characteristics of the fibre itself (see Annex A). The objective of this document is to: protect people from optical radiation emitted by OFCSs; provide requirements for manufacturers, installation organisations, service organisations and operating organisations in order to establish procedures and supply information so that proper precautions can be adopted; ensure adequate warnings are provided to individuals regarding the potential hazards associated with OFCSs through the use of signs, labels and instructions. Annex A gives a more detailed rationale for this document. The safety of an OFCS depends to a significant degree on the characteristics of the equipment forming that system. Depending on the characteristics of the equipment, it is necessary to mark relevant safety information on the product or include it within the instructions for use. Where required by the level of potential hazard, this document places the responsibility for the safe deployment and use of these systems on the installer or end-user / operating organisation or both. This document places the responsibility for adherence to safety instructions during installation and service operations on the installation organisation and service organisation as appropriate, and operation and maintenance functions on the end user or operating organisation. It is recognised that the user of this document may possibly fall into one or more of the aforementioned categories of manufacturer, installation organisation, end-user or operating organisation.