Detail of GB/T 7247.2-2024

Introduction of GB/T 7247.2-2024

GB/T 7247.2-2024 Safety of laser products - Part 2: Safety of optical fibre communication systems (OFCSs) 1 Scope 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 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. Note 1: Throughout this document, a reference to 'laser' is taken to include LEDs and optical amplifiers. 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. 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 2: 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). 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60825-1:2014 Safety of laser products - Part 1: Equipment classification and requirements 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60825-1 and the following apply. 3.1 accessible location part or location within an OFCS at which, under reasonably foreseeable events, human access to laser radiation is possible without the use of a tool 3.2 automatic power reduction; APR feature of an OFCS whereby the accessible power is reliably reduced to a specified level within a specified time, whenever there is an event which could result in human exposure to radiation Note 1 to entry: The term "automatic power reduction" (APR) used in this document encompasses the following terms used in ITU-T Recommendation G.664: ——automatic laser shutdown (ALS); ——automatic power reduction (APR); ——automatic power shutdown (APSD). Note 2: The term automatic laser shut off (ALSO) has also been used by some manufacturers in the industry. Note 3: A fibre-cable break is an example of an event which could result in human exposure to radiation. 3.3 end-user person or organization using the OFCS in the manner the system was designed to be used Note 1: The end-user cannot necessarily control the power generated and transmitted within the system. Note 2: If the person or organization is using the OFCS for a communications application in a manner other than as designed by the manufacturer, then that person/organization assumes the responsibilities defined in this document applicable to a manufacturer or installation organization. 3.4 hazard level level of potential hazard at any accessible location within an OFCS Note: It is based on the level of laser radiation which could become accessible in a reasonably foreseeable event, e.g. a fibre cable break. It is closely related to the laser classification procedure defined in 5.3 in IEC 60825-1:2014. The meaning of hazard level is clarified in Annex B. 3.5 hazard level 1 hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 1 as defined in 4.7.2 a) and 4.7.3, will not exceed the accessible emission limits of Class 1 in IEC 60825-1 for the applicable wavelength and emission duration, with additional constraints as defined in 4.7.2 a) Note: "Additional constraints" refers to additional and stricter constraints that 4.7.2 a) of this document places on the values specified in IEC 60825-1:2014 for the accessible emission limits of Class 1 in the wavelength range 1200 nm to 1400 nm. 3.6 hazard level 1 M hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 1 M as defined in 4.7.2 a) and 4.7.3, will not exceed the accessible emission limits of Class 1 in IEC 60825-1 for the applicable wavelength and emission duration, with additional constraints as defined in 4.7.2 a) Note: "Additional constraints" refers to additional and stricter constraints that 4.7.2 a) of this document places on the values specified in IEC 60825-1:2014 for the accessible emission limits of Class 1 in the wavelength range 1200 nm to 1400 nm. 3.7 hazard level 2 hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 2 as defined in 4.7.2 b) and 4.7.3, will not exceed the accessible emission limits of Class 2 in IEC 60825-1 for the applicable wavelength and emission duration 3.8 hazard level 2M hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 2M as defined in 4.7.2 b) and 4.7.3, will not exceed the accessible emission limits of Class 2 in IEC 60825-1 for the applicable wavelength and emission duration 3.9 hazard level 3R hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 3R as defined in 4.7.2 c) and 4.7.3, will not exceed the accessible emission limits of Class 3R in IEC 60825-1:2014 for the applicable wavelength and emission duration, with additional constraints as defined in 4.7.2 c) Note: "Additional constraints" refers to additional and stricter constraints that 4.7.2 c) of this document places on the values specified in IEC 60825-1:2014 for the accessible emission limits of Class 3R in the wavelength range 1200 nm to 1400 nm. 3.10 hazard level 3B hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 3B as defined in 4.7.2 d) and 4.7.3, will not exceed the accessible emission limits of Class 3B in IEC 60825-1: 2014 for the applicable wavelength and emission duration 3.11 hazard level 4 hazard level at which, under a reasonably foreseeable event, human access to laser radiation (accessible emission), evaluated by the measurement conditions for hazard level 4 as defined in 4.7.2 e) and 4.7.3, will exceed the accessible emission limits of Class 3B in IEC 60825-1 for the applicable wavelength and emission duration Note: This document is applicable for the operation and maintenance of OFCS. In order to achieve an adequate level of safety for persons who might come into contact with the optical transmission path, hazard level 4 is not permitted within this document. It is permitted to use protection systems, such as automatic power reduction, to achieve the required hazard level where the transmitted power under normal operating conditions (e.g. no fault exists in the fibre path) exceeds that permitted for a particular location type. For instance, it is possible for accessible parts of an OFCS to be hazard level 1 even though the power transmitted down the fibre under normal operating conditions is Class 4. 3.12 installation organization organization or individual that is responsible for the installation of an OFCS 3.13 controlled location location with controlled access accessible location where an engineering or administrative control is present to make it inaccessible, except to authorized personnel with appropriate laser safety training Note: For examples, see D.2.1 a). 3.14 restricted location location with restricted access accessible location that is normally inaccessible by the general public by means of any administrative or engineering control measure, but that is accessible to authorized personnel who might not have laser safety training Note: For examples, see D.2.1 b). 3.15 unrestricted location location with unrestricted access accessible location where there are no measures restricting access to members of the general public Note: For examples, see D.2.1 c). 3.16 manufacturer organization or individual that constructs or modifies OFCSs by assembling or incorporating optical devices and other components Note: Typical components in OFCSs are shown in D.2.2. 3.17 operating organization organization or individual that is responsible for the operation of an OFCS 3.18 optical fibre communication system; OFCS engineered, end-to-end assembly for the generation, transfer and reception of optical radiation arising from lasers, LEDs or optical amplifiers, in which the transference is by means of optical fibre for communication and/or control purposes 3.1 9 reasonably foreseeable event event whose occurrence under given circumstances can be predicted fairly accurately, and the occurrence probability or frequency of which is not low or very low Note 1: Examples of reasonably foreseeable events might include the following: fibre cable break, optical connector disconnection, operator error or inattention to safe working practices. Note 2: Any intentional act to create a hazard is not considered as a reasonably foreseeable event.

Contents of GB/T 7247.2-2024