BS/EN 50411-3-4-2019 pdf download.Fibre management systems and protective housings to be used in optical fibre communication systems — Product specifications Part 3-4: WaIl box for splice to patchcord connections, for category C and A.
5.3 Cable anchoring
The outer cable sheath and central strength members shall be attached to the hardware of the box. The cable anchoring shall not be disturbed when adding or removing cables. Small diameter drop cables, cords or microduct tubes are typically attached by mechanical clamping on the outer cable sheath. The design of the cable clamps shall not cause any optical performance degradation of the cables.
5.4 Fibre management system
The FMS provides means to control, protect and store splices, connectors, passive optical components and fibres from incoming to outgoing cables. The fibre management system in the box shall be compliant with the requirements of EN IEC 61756-1.
Fibre circuits may be separated to an appropriate separation level SC. SE, SR. ME and MR. This will limit the risk of interruption to traffic in those fibres belonging to the same group of circuits.
The minimum storage radius of fibres in an FMS depends on:
— required failure probability target (location in the network):
— length of fibre to be stored:
— fibre type;
— longest transmission wavelength;
— maximum allowed attenuation increase (macro bending loss).
NOTE 1 The families of FMS covered in this document are listed in Annex C.
NOTE 2 Definitions of fibre separation levels SC, SE, SR. ME and MR are listed in Clause 3.
NOTE 3 EN IEC 61756-1 provides recommended storage radii for singlemode and multimode fibres.
For fibre types other than EN 60793-2-10 category Al and EN IEC 60793-2-50 sub-category B-652 and sub-category B-657, the minimum storage radius shall be 30 mm.
5.5 Patchcords and pigtails
Patchcords and pigtails with optical connectors are used in fibre management systems where frequent reconfiguration is expected. The fibre management system shall provide the means to manage the related over-length in an orderly manner (I.e. controlled bend radius, accessibility, limited amount of crossover).
5.6 Adapters
Adapters are typically mounted on an adapter plate or mounted on the modules containing the passive optical components. Each adapter shall be clearly and uniquely identifiable by a label or by their position in the adapter plate.
5.7 Passive optical components
Passive optical components may be installed in FMS splice trays, or in separately mounted modules or cassettes. Typical passive optical devices include splitters, wavelength division multiplexers (WOM) and fan-outs.
5.8 Materials
All materials that are likely to come in contact with personnel shall meet appropriate local health, safety and environmental regulations.
All components of the box shall be resistant to solvents and degreasing agents that are typically used to clean and degrease fibres and cables.
For category A boxes, the exposed polymeric materials shall be UV light and fungi resistant.
The performance of metallic parts shall not be affected by the corrosive influences they may encounter during the lifetime of the product.
All materials shall be halogen free for category C boxes as specified in Clause 10. These requirements are valid for all the materials that the box is made of as well as all components that are installed in it (during assembly and at a later time).
5.9 Marking and identification
8 Tests
8.1 Sample size
Separate test samples for sealing performance and optical evaluation may be used. For the purpose of this standard, a sealing test sample is defined as a box installed with several cable ends.
Optical test samples shall be constructed as described in 8.2.3. Due to their complexity, consecutive testing on the same optical sample is allowed.
The minimum recommended sample sizes are given in Annex B.
8.2 Test sample preparation
8.2.1 Fibre type for test samples
The fibres selected for the optica’ test samples depends on the product variant XXa. The fibres for the optical test samples with 30 mm fibre storage radius are covered in Annex A – Table A.1. The fibres for the optical test samples with 20 mm fibre storage radius are covered in Annex A – Table A.2.
Once the box is qualified for singlemode it can be considered as qualified for muttimode fibre.
8.2.2 Sealing performance test samples for boxes
Sealing performance test samples shall be installed to maximum capacity with cables and/or tubes. The length of the cables and tubes extending from the boxes shall be long enough to perform the tests (typically 1 m). The open ends of the cables and tubes shall be sealed. Cables with minimum and maximum diameter as specified by the manufacturer shall be represented in the test program
8.2.3 Optical performance test samples for boxes
Optical test samples for boxes shall be constructed in such a way that they will cover all allowed functions of a box. The samples are constructed by building optical circuits for each relevant fibre separation level (SC, SE, SR. ME or MR splicing).
Both extremities of a looped cable are terminated in the box (see Figure 6). The length of the looped cable is chosen to be longer than the dead zone of an OTDR. Typically, a cable length of 25 m to 50 m is used, allowing location of the potential causes of optical losses and to distinguish whether a change in signal is induced by the fibre management system in a single location or is distributed evenly over the whole circuit length.BS/EN 50411-3-4-2019 pdf download.