FTN design & development specification (D&D)

SP FTN (D&D) 012

Optical Fibre Tail Cable Assemblies

Issue 1, Sep 2003 · FTN D&D specs & typical drawings

Product spec for FTN optical pigtails and patchcords: the buffered and ruggedised tail cable they are made from, the SC/APC and FC/PC connectors, and the acceptance and production tests a supplier must pass.

Clause map — what each clause deals with

1	Introduction	Background: new FTN for GSM-R and operational circuits.
2	Abbreviations	Acronyms (FC/PC, SC/APC, MBR, MTBF, SU, ZHLS).
3	Glossary	Definitions of pigtail, patchcord, tail cable, buffering, ruggedising, primary/secondary coating, uniter.
4	Scope	Covers tail cable assemblies only; terminations and accessories are in SP/FTN(D&D)/011.
5	Optical Pigtails and Patchcords	Network Rail free-issues the buffered fibre so all assemblies use the same fibre.
5.1	Optical Pigtails	Pigtail construction, supplied length and tolerance, and how they are cut when pre-loaded in trays.
5.2	Optical Patchcords	Patchcord construction (SC/APC one end, FC/PC other) and the table of standard lengths with tolerances.
6	Optical Fibre Tail Cable	Two tail cable types: secondary coated (buffered) and ruggedised.
6.1	Secondary Coated Optical Fibre Tail Cable	Buffer material and diameter, fibre to SP/FTN(D&D)/010 with tightened geometry limits.
6.1.1	Colour	Colour of buffered tail cable to distinguish it from other sources.
6.1.2	Free-issue	Buffered fibre is free-issued to assembly suppliers.
6.2	Ruggedised Optical Fibre Tail Cable	Ruggedised cable built from buffered fibre with strength members and ZHLS sheath; must pass sections 10 and 11.
6.2.1	Tightness of Ruggedising	Fibre must be able to move within the ruggedising to avoid macrobends at the connector; sheath curing requirement.
6.2.2	Peripheral Strength Members	Aramid yarn layers over the buffered fibre.
6.2.3	Outer Sheath and Cable Diameter	Sets ruggedised cable diameter, circularity and minimum sheath thickness.
6.2.4	Additional Requirements for ZHLS Sheath	Chemical groups excluded from the ZHLS sheath and the fire-safety code that defines trace levels.
6.2.5	Colour	Sheath colour options for patchcords to tell optical paths apart.
6.2.6	Sheath Marking	What must be printed on the patchcord sheath and how often.
6.2.7	Labelling	Site label for patchcords and the from/to identifier format it must carry.
7	Demountable Optical Connectors	Connector types on pigtails and patchcords (tuned SC/APC, FC/PC with ceramic ferrule) and proof of tuning.
8	Environment	Environmental classes the goods must suit.
9	Product Acceptance and Supporting Information	What the supplier must state and supply for product acceptance.
9.1	Product Acceptance	Product acceptance process and passing section 10 tests as a condition.
9.2	History of Use in a Railway Environment	Supplier to give railway track record.
9.3	MTBF	Calculated and actual MTBF data to be supplied.
9.4	Materials	Service life expectation for materials.
10	Product Acceptance Tests	Three groups of tests; IEC 60874-14-9 takes precedence on conflict.
10.1	Product Acceptance Tests for Optical Fibre Tail Cables	Tests on the tail cable itself.
10.1.1	Attenuation of Ruggedised Optical Fibre Tail Cable	Attenuation test methods, wavelength and the maximum loss per km.
10.1.2	Macrobend Performance	Mandrel wind test and allowed excess loss per turn.
10.1.3	Strength	Tensile loads, strain limits and residual effects.
10.1.4	Flexibility	Repeated flex test parameters.
10.1.5	Compressive Stress	Crush load test.
10.1.6	Impact	Drop-weight impact test parameters.
10.1.7	Tightness of Ruggedising	Pull-out test showing the buffered fibre slides freely within the ruggedising.
10.1.8	ZHLS Tests on Ruggedised Optical Fibre Tail Cables	Sheath material tests: insulation resistance, water absorption, smoke emission and flammability.
10.2	Product Acceptance Tests for Optical Connectors	Connector end-face geometry tests.
10.2.1	Connector End Face Eccentricity	Apex offset test method and limit.
10.2.2	Connector End Face Radius	Radius of curvature test and range.
10.2.3	Fibre Position Relative to End Face (Fibre Undercut)	Undercut/protrusion test and tolerance.
10.2.4	End Face Angle	APC angle measurement and tolerance, with reference ferrule parameters.
10.3	Product Acceptance Tests for Optical Fibre Tail Cable Assemblies	Tests on the finished pigtail/patchcord.
10.3.1	Attenuation	Insertion loss test method and limit per connector end.
10.3.2	Return Loss	Return loss test setup and minimum values for FC/PC and SC/APC.
10.3.3	Vibration	Vibration sweep parameters and allowed loss change.
10.3.4	Mating Durability	Repeated mating test, loss limits and microscope inspection.
10.3.5	Cable Pulling	Cable retention pull test, directions and pass criteria.
10.3.6	Cable Torsion	Torsion test load, mandrel and failure signs.
10.3.7	Shock	Shock pulse parameters, axes and pass criteria.
10.3.8	Drop	Drop test count, height and pass criteria.
10.3.9	Change of Temperature	Temperature cycling profile and allowed loss.
10.3.10	Attenuation of Randomly Mated Connectors	Random mating test method and maximum loss.
10.3.11	Visual Inspection	Microscope inspection magnification and defects that fail.
11	Production Tests	Routine tests the supplier runs to keep defect rate low; IEC precedence.
11.1	Production Tests on Optical Fibre Tail Cables	List of section 10.1 tests repeated in production.
11.2	Production Tests on Optical Connectors	List of section 10.2 geometry tests repeated in production.
11.3	Production Tests on Optical Fibre Tail Cable Assemblies	Visual, attenuation, return loss and random mating tests in production.
12	Packaging	Packaging and paperwork for assemblies.
12.1	Tail Cable Assemblies Supplied in Termination Trays	Pre-loaded tray protection, uniter ports capped, routing without stress, and accompanying documents.
12.2	Tail Cable Assemblies Supplied Separately	Connector caps (not tethered), transit protection and accompanying documents.
13	References	Referenced standards and FTN specs.
App A	Specification BR 967	Placeholder for the BR 967 environmental spec; pages are blank in this copy.

Clause map — what each clause deals with

Standards this one points to