Fibre Optic Splicing - Termination Safe Work Method Statement

Fibre optic technicians must complete laser safety training addressing Class 1, 1M, 2, and 3B laser hazards common in telecommunications environments. Active single-mode fibres commonly carry optical power levels of 0-10dBm (1-10mW) classified as Class 3B lasers capable of causing immediate retinal damage if directly viewed. Technicians must never look into fibre ends or connector ports without first verifying complete disconnection using optical power meters reading zero transmission. Laser safety glasses rated for telecommunications wavelengths (1310nm and 1550nm with optical density OD4 or higher) must be worn when working in areas where active fibre circuits exist. Even Class 1M laser sources considered safe to the naked eye become hazardous when viewed through optical instruments including magnifying glasses, microscopes, or visual fault locators. Implement written laser safety procedures including lockout/tagout for circuit disconnection, mandatory power meter testing before fibre handling, and immediate capping of all disconnected fibre ports preventing inadvertent viewing or contamination. Warning labels identifying laser hazards must be affixed to all equipment emitting optical radiation. Never use visual fault locators (visible red lasers) on fibres that may be connected to active equipment as the visible light can propagate through to active lasers causing interference or equipment damage.

Fusion splice quality depends critically on fibre cleanliness as contamination particles measuring micrometres in size cause splice loss and potential splice failure. Clean bare glass fibre sections using lint-free optical cleaning wipes dampened with 99% isopropyl alcohol in single-direction wipes from coated section toward fibre end. Never reuse wipe sections as this redeposits removed contamination. Allow alcohol to completely evaporate before cleaving - typically 30 seconds in normal conditions. Avoid handling cleaned bare glass with fingers or allowing contact with any surfaces. Maintain fusion splicer cleanliness by regular cleaning of V-groove holders and alignment mirrors using manufacturer-approved cleaning materials - typically lint-free swabs with isopropyl alcohol. Clean fusion splicer electrodes every 200-300 splices or when arc appearance indicates contamination visible as weak or erratic discharge. Some contamination originates from environmental sources including skin oils, airborne particles, and coating residue. Work in clean environments away from dusty conditions when possible. Use supplied dust covers on fusion splicers when not actively splicing. Store cleaned fibres in splice machine immediately after cleaving rather than leaving exposed to airborne contamination. For critical low-loss splicing such as long-haul telecommunications links, consider establishing clean-room conditions with filtered air and contamination controls. Regularly verify splice quality through OTDR testing - increasing splice losses despite proper procedures indicates cleaning protocol breakdown requiring investigation.

Atmospheric testing of telecommunications pits, vaults, and maintenance holes must occur before every entry using calibrated four-gas detectors measuring oxygen, combustible gases (LEL), hydrogen sulphide, and carbon monoxide. Testing sequence begins by removing pit cover and allowing natural ventilation for several minutes before introducing test equipment. Lower multi-gas detector into space using rope or pole positioning detector at multiple levels as gases stratify with heavier gases accumulating at lower levels. Test bottom, middle, and upper levels of space recording readings at each position. Oxygen concentration must be 19.5-23.5% throughout space - lower readings indicate oxygen-deficient atmosphere requiring forced ventilation before entry. Combustible gas levels must be below 10% of Lower Explosive Limit (LEL) preventing ignition risks. Hydrogen sulphide from adjacent sewers must be below 10ppm as higher concentrations are immediately dangerous to life. Carbon monoxide from vehicle exhausts must be below 30ppm. If any parameter exceeds safe limits, ventilate space using portable blower for minimum 15 minutes then retest before permitting entry. Maintain continuous atmospheric monitoring during occupancy using personal monitors with audible alarms. Set alarm levels at oxygen 19.5%, combustible gas 10% LEL, hydrogen sulphide 10ppm, and carbon monoxide 30ppm. Evacuate immediately if alarms activate or if technician experiences any symptoms including dizziness, headache, nausea, or difficulty breathing. Calibrate multi-gas detectors according to manufacturer schedules - typically quarterly bump testing and annual calibration verification.

Fusion splice loss acceptance criteria vary with fibre type, application, and network design margins. Single-mode fibre fusion splices should typically achieve less than 0.1dB loss with modern fusion splicers capable of consistently producing splices with 0.02-0.05dB loss when proper procedures are followed. Long-haul telecommunications networks may specify maximum single splice loss of 0.05dB to preserve optical power budgets over hundreds of kilometres. Multi-mode fibre splices exhibit slightly higher losses due to larger core diameters and alignment tolerances, typically 0.05-0.2dB depending on fibre grades being joined. Splicing dissimilar fibre types such as 50μm to 62.5μm multi-mode fibres produces inherently higher losses due to mode field diameter mismatch. Testing from both directions of dissimilar fibre splices reveals directional loss differences with higher loss in direction from larger to smaller core diameter. Mechanical splices exhibit higher insertion loss than fusion splices typically ranging 0.2-0.5dB due to air gaps between fibre ends and dependence on index-matching gel optical coupling. Network design must allocate splice loss budget based on expected number of splices, splice method, and application requirements. OTDR testing verifies individual splice losses enabling identification of outlier splices requiring investigation and potential re-splicing. Fusion splice losses exceeding 0.3dB for single-mode or 0.5dB for multi-mode indicate problems including contamination, poor cleaves, or parameter mismatches requiring corrective action. Document all splice losses as permanent record and for future troubleshooting reference. Elevated splice losses identified during testing should be investigated rather than accepted as marginal values compound across multiple splices degrading overall link performance.

Fibre optic splicing creates significant ergonomic challenges from sustained precision work requiring microscopic accuracy and awkward postures. Position fusion splicer on adjustable work surface at height allowing viewing of display screens at eye level without neck bending - typically 1000-1100mm work surface height depending on technician stature and whether sitting or standing. Use articulating monitor arms enabling positioning of splice machine display directly in front of technician minimising neck flexion and lateral bending. Ensure adequate lighting eliminates need for awkward positioning to view work clearly. Arrange all frequently used tools within primary work zone (450mm radius) preventing sustained reaching or twisting to access cleaver, cleaning supplies, and splice materials. Use adjustable seating with lumbar support for work requiring sustained sitting positions during splice machine operation. Implement micro-break schedules with 5-minute breaks every 45 minutes of continuous precision work. Use breaks for hand and wrist stretches, neck rolls, and eye focus relaxation looking at distant objects. Alternate between splicing work and other tasks including testing, documentation, and material preparation varying muscle group loading. On large splice projects, rotate personnel between splicing roles and support activities every 2-3 hours preventing sustained precision work exposure. Maintain neutral wrist positions during fibre handling and cleaving operations avoiding sustained flexion or extension. Use proper technique for cleaver operation with smooth controlled motion rather than excessive force. Consider environmental factors including temperature extremes which increase muscle tension and cold conditions which reduce finger dexterity requiring awkward compensation postures. Provide adequate workspace organisation eliminating clutter and optimising workflow reducing unnecessary movements. Training in ergonomic work practices combined with workplace design significantly reduces cumulative trauma disorder risk in fibre optic occupations requiring sustained precision work.