This Recommendation refers to passive optical nodes in outdoor environments. It deals with the design of the closure housing as well as the fibre organizer or fibre management system, taking into account mechanical and environmental characteristics as well as the characteristics of the optical fibre organizer. The following new elements are added in this revision: -a new clause 5.3 on closure materials with detailed test requirements for UV-light exposure and fungus resistance of polymer materials and a material test requirement for the ageing of polymer materials by humidity; -a new clause 5.5 on cable attachment and termination with recommendations for electrical grounding of metallic elements of the cables; -a test program for the performance evaluation of sealed optical closures in ground level (OG) environment. The following changes were made to harmonize the performance tests with [IEC 61753-1]: -Sealing tests are done with 20 kPa overpressure for ground level (OG) and above ground (OA) closures; -Pass-fail criteria of pressure loss during test are added to mechanical sealing tests for ground level (OG) and above ground (OA) closures; -Reduced loads cable axial tension test for small diameter cables and microduct tubes; -Reduced loads for cable axial compression test for small diameter cables; -The duration of the cycles in cable torsion and cable bending test is added; -Location for impact test added for rectangular shaped closures; -Free fall test is removed (it is covered by a more reproduceable shock test); -In the assembly and disassembly test the duration is reduced to 5 cycles; -Resistance to solvents and contaminating fluids: added immersion in diesel with duration of 1 h and 24 h drying time and added immersion in petroleum jelly for 5 days. Kerosene is removed; -Duration of the change of temperature is reduced to 12 cycles; -Water immersion test at 1 m for 7 days for ground level (OG) closures.

References "[ITU-T G.Suppl.59] ITU-T G-series Recommendations- Supplement 59 (2018), Guidance on optical fibre and cable reliability" and "[EN 590] EN 590 (2009), Automotive fuels. Diesel. Requirements and test methods" were moved from Clause 2 to Bibliography of the LC text.