Termination of Fiber Optic Cables

This fiber optic installation method statement covers the termination of fiber optic cables with patch panel, network distribution cabinet NDC and door junction box but can be applicable for any kind of network installations.

Roles and Responsibilities:

The electrical manager shall be responsible for the overall implementation of this method statement, and to ensure that section engineer and general foremen are well informed of its requirements.

He is responsible for:

Providing all required resources in terms of Manpower, Equipment and Materials.

Controlling the coordination between all involved parties to ensure Safety, Quality and schedule requirements are met.

Section Engineer and General Foreman in-charge shall be responsible for:

Control and ensure the construction work is carried out to the required contract specification and approved shop drawings.

Implement the PTW as required by project HSE procedures.

Accompanying the client engineers for ongoing inspection and obtain his approval to proceed.

Quality Manager shall be responsible for:

Clearing all non-conformances relevant to that activity.

Ensuring that all activities subject to inspection are recorded and cleared.

Controlling and organizing the inspection works.

Ensuring that inspections are carried out in a timely manner.

Quality control engineer shall be responsible for:

To inspect and ensure the construction work is carried out to the required contract specification and approved drawings

Informing the consultant via work inspection request when his presence is required to carry out the inspection as per the approved ITP.

Accompanying the client for inspection to release the hold points.

Necessary Tools and Equipment

Below is list of necessary tools and equipment for fiber optic installation activities:

• Optical Power Meter for estimating the overall loss of FO cable.
• Cabling Punching tools
• Screw drivers
• Wire cutters
• Crimping tools
• Hand Gloves, Fall protection equipment’s
• Portable Power Outlet
• Tracers
• Fluke testing tools
• Drilling tools.
• Measuring Tape / Permanent Marker

Safety requirements tools such as safety shoes, safety helmet, safety glasses, fluorescent vest, safety gloves and dust mask when required to ensure maximum achievement of safe work.

Health and Safety Requirements

Prior to commencement of fiber installation, all activities shall be coordinated with the Project Safety Officer and PTW holder, who will assess the associated risks if any, and monitor the implementation of the work as per the Project Safety Plan and liaise with the construction team to ensure a safe working environment.

The concerned Supervisor/Foreman or Gang Leader shall ensure that all workers are equipped with their PPE throughout the construction work.

Safety Officer in charge in coordination with the construction manager shall study, organize and control the traffic flow during the operation of this working procedure.

Construction Manager, in coordination with the Safety Officer, Store/Time keeper and Labor Camp Boss shall conduct induction sessions for all staff and workers involved with this particular operation to ensure every person is well aware of his obligation, work distribution and role.

Safety officer / in-charge shall organize and conduct necessary periodic toolbox meetings for supervisory staff and manpower, to ensure the construction team are well aware of safety requirements.

Ensure adequate lightings are provided as required and as per manpower schedule shifting incase the works went beyond the normal working hours.

Make sure that individual water bottles are provided to all the work force and appropriate capacity of Water Thermos are available in the work area during the summer / hot weathers.

Prerequisites To Start Work

PTW must be secured before starting the work.

Install the necessary barricades and safety signages.

Ensure that the work area is ready and safe to start the Termination of Fiber Optic cables with Patch Panel.

Makes sure that the approved wiring diagrams is available.

Ensure adequate lightings are provided as required and incase the works went beyond the normal working hours i.e. night shifts.

Work shall be carried out by the site staff under strict supervision and guidance of the concerned Supervisors / Engineers.

QA/QC Engineer shall ensure latest approved IFC drawings are used in the construction works.

QA/QC Engineer shall coordinate and arrange inspection for installation to the Client.

Patch Panel, NDC and Door Junction Box Termination

Check that the laid segment of the fiber optic cable sheath has no deep cuts.

Perform an OTDR test on this segment to ensure continuity of all the strands.

Label the laid segment as per the proper numbering scheme that should indicate the starting point and the finish point of that segment.

Document the results of the OTDR test before clearing the fiber optic cable laid as clear for termination.

Prepare the cable and store it within the equipment cabinet to keep it ready for the final routing and termination.

Strip fiber cable jacket

Strip back about 3 meters of fiber cable jacket to expose the fiber loose tubes or tight buffered fibers.

Use cable rip cord to cut through the fiber jacket.

Then carefully peel back the jacket and expose the insides.

Cut off the excess jacket.

Clean off all cable gel with cable gel remover.

Separate the fiber loose tubes and buffers by carefully cutting away any yarn or sheath.

Leave enough of the strength member to properly secure the cable in the splice enclose.

Strip fiber Tubes: For a loose tube fiber cable, strip away about 2 meters of fiber tube using a buffer tube stripper and expose the individual fibers.

Clean cable gel: Carefully clean all fibers in the loose tube of any filling gel with cable gel remover.

Secure cable tubes:

Secure the end of the loose tube to the splice tray and lay out cleaned and separated fibers on the table.

Strip and clean the other cable tube’s fiber that is to be spliced, and secure to the splice tray.

Strip first splicing fiber:

Hold the first splicing fiber and remove the 250um fiber coating to expose 5cm of 125um bare fiber cladding with fiber coating stripper tool.

For tight buffered fibers, remove 5cm of 900um tight buffer first with a buffer stripping tool, and then remove the 5cm of 250um coating.

Fusion splice protection sleeve: Put a fusion splice protection sleeve onto the fiber being spliced.

Clean the bare fiber: Carefully clean the stripped bare fiber with lint-free wipes soaked in isopropyl alcohol. After cleaning, prevent the fiber from touching anything.

Fiber cleaving: With a high precision fiber cleaver, cleave the fiber to a specified length according to your fusion splicer’s manual.

Prepare second fiber being spliced: Strip, clean and cleave the other fiber to be spliced.

Fusion splicing: Place both fibers in the fusion splicer and do the fusion splice according to its manual.

Heat shrink the fusion splice protection sleeve: Slide the fusion splice protection sleeve on the joint and put it into the heat shrink oven, and press the heat button.

Place splice into splice tray: Carefully place the finished splice into the splice tray and loop excess fiber around its guides. Ensure that the fiber’s minimum bending radius is not compromised.

Close the splice tray: After all fibers have been spliced, carefully close the splice tray and place it into the splice enclosure.

Checking a terminated Segment of the Fiber Optic Cable

Check that all the cable strands are contained in the right place.

Terminated/spliced strands are mounted in the patch panel and the spare strands are kept within a proper storage.

Perform an OTDR test on the terminated fiber to ensure that it is properly terminated.

Ensure that the OTDR figures are not exceeding the permissible dB loss figures as per the specifications and applicable standards.

Save the above test results of all the fiber strands in OTDR device.

Close and mount the splice enclosure if all splices meet the specification.

Document the results of the OTDR test clearing the fiber optic cable as Ready for Service.

Procedure for Fiber Optic splicing

There are two types of splices, fusion and mechanical.

Fusion splicing is most widely used as it provides the lowest loss and least reflectance, as well as providing the strongest and most reliable joint.

The fusion splicing machines are available in two types that splice a single fiber or a ribbon of 12 fibers at one time.

Virtually all single mode splices are fusion.

Mechanical splicing is mostly used for temporary restoration and for multimode splicing.

FUSION SPLICING METHOD

In fusion splicing a machine is used to precisely align the two fiber ends then the glass ends are “fused” or “welded” together using some type of heat or electric arc.

This produces a continuous connection between the fibers enabling very low loss light transmission. (Typical loss: 0.1 dB)

Four basic steps to completing a proper fusion splice:

Step 1: Preparing the fiber:

Strip the protective coatings, jackets, tubes, strength members, etc. leaving only the bare fiber showing.

The main concern here is cleanliness.

Step 2: Cleave the fiber:

Using a good fiber cleaver here is essential to a successful fusion splice.

The cleaved end must be mirror-smooth and perpendicular to the fiber axis to obtain a proper fiber optic splice.

NOTE: The cleaver does not cut the fiber! It merely nicks the fiber and then pulls or flexes it to cause a clean break.

The goal is to produce a cleaved end that is as perfectly perpendicular as possible.

Step 3: Fuse the fiber:

There are two steps within this step, alignment and heating.

Alignment can be manual or automatic depending on what equipment is used.

Once properly aligned the fusion splicer unit then uses an electrical arc to melt the fibers, permanently welding the two fiber ends together.

Step 4: Protect the fiber:

Protecting the fiber from bending and tensile forces will ensure the splice not break during normal handling.

A typical fusion splice has a tensile strength between 0.5 and 1.5 lbs. and will not break during normal handling but it still requires protection from excessive bending and pulling forces.

Using heat shrink tubing, silicone gel and/or mechanical crimp protectors will keep the splice protected from outside elements and breakage.

Evaluating Splices – Good Splices

Visually inspect splice after the program has run, using both X and Y views.

Some flaws that do not affect optical transmission are acceptable, as shown below.

Some fibers (e.g. fluorine-doped or titanium coated) may cause white or black lines in splice region that are not faults.

Evaluating Splices – Bad Splices

Some flaws are unacceptable and require starting the splicing process over.

Some, like black spots or lines, can be improved by repeating the ARC step, but never more than twice.

For large core offsets, bubbles or bulging splices, always redo the splicing.

Mass (Ribbon) Fusion Splicing

Many high fiber count cables today are made from ribbons of fibers, usually 12 fibers per ribbon.

Splitting all those fibers out to splice individually would be time consuming, so ribbon fusion splicers, also called mass fusion splicers, can splice entire ribbons at one time.

Ribbon splicers look similar to single fiber splicers and work in much the same way, except the ribbons are treated as one assembly, stripped, cleaved and spliced by special tools while held in a special holder.

Special ribbon fiber holder is used.

The holder is inserted in a special stripper that uses heat to make stripping easier.

After stripping, the holder is placed in a special cleaver that will cleave all 12 fibers at once.

The fixture with all the cleaved fibers is placed in the splicing machine.

When the second ribbon is prepared, the unit is set for automated splicing.

Tips for Better Splices

Thoroughly and frequently clean your splicing tools.

When working with fiber, keep in mind that particles not visible to the naked eye could cause tremendous problems when working with fiber optics.

“Excessive” cleaning of your fiber and tools will save you time and money down the road.

Properly maintain and operate your cleaver.

The cleaver is your most valuable tool in fiber splicing.

Within mechanical splicing you need the proper angle to insure proper end faces or too much light escaping into the air gaps between the two fibers will occur.

The index matching gel will eliminate most of the light escape but cannot overcome a low quality cleave.

Fusion parameters must be adjusted minimally and methodically (fusion splicing only).

If you start changing the fusion parameters on the splicer as soon as there is a hint of a problem you might lose your desired setting.

Dirty equipment should be your first check and then continue with the other parameters.

Fusion time and fusion current are the two key factors for splicing.

Different variables of these two factors can produce the same splice results.

High time and low current result in the same outcome as high current and low time.

Make sure to change one variable at a time and keep checking until you have found the right fusion parameters for your fiber type.