FIBER OPTIC PROJECT IMPLEMENTATION - IMT …imtcomputer.net/fiber/PROJECT IMPLEMENTATION.pdf · As to allow easily splice box installation and cable coils with respect of maximum

FIBER OPTIC PROJECT IMPLEMENTATION

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Fiber Project

Management

ADEJOLA JOHNSON Msc. CEO Imt computers Nig. Ltd

FOA Representative in Nigeria #718

www.imtfiber.com [email protected] 08039576767 Page

PROJECT IMPLEMENTATION

INTRODUCTION

TRENCHING

Trench making is one of the fiber project implementation process. It involves

removal of the topsoil or whichever terrain that is found at the location to a given

depth.

There are three basic trenches that is adoptable in most OFC Projects

Trench Type S1 or R1 – Filling the trench with the extracted

material from the soil. This trench type can be regarded as deep

trench of 1.2m deep ,as approved by the client. This type of trench is

achievable mostly in the backborne

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Trench Type S2 or R2 – Introduction of 20cm concrete layer

directly above the duct which will act as a shield protection




Trench Type S3 or R3 – Complete concrete encasement of the

entire trench.

Some of the terrain to come across during trenching include, but not limited to

ASPHALT CUTTING, CONCRETE BREAKING, THRUST BORING, PAVE

STONES, SWAMP AREAS, BRIGDE CROSSING




Where there is road crossing, the road must be backfilled and reinstated with

asphalt or any materials used for the constructed of the road before cutting. This

shall be done immediately after the installation of the ducts.

Not more than 100metres trench shall be left open overnight. Warning signs,

fencing, guards and watchmen are required where necessary.

The trench shall be dug in such a way that the minimum cover over the uppermost

layer of ducts is 100cm in carriageway and 45cm in footpaths. The bottom of the

trench shall be level and free from stones and debris, or other objects which may

damage the ducts.

MANHOLE WORK

Manhole, Handhole, JB or any other name it is called, is simply a concrete box

found on fiber project route mainly for accessibility, maintenance and securing the

enclosure.

As to allow easily splice box installation and cable coils with respect of maximum

bending radii, the dimensions of the manhole will not be less than:




W x H x L=1m x1.15m x 1.4m (urban manhole)

W x H x L =0.7m x 0.7m x 0.9m (suburban or rural manhole)

Lateral walls and covers will be resistant to a minimum of:

• 400 KN for manholes under roadways

• 250 KN for manholes buried in verges or sideways

The manhole cover is made of iron, but lately rubber lid are becoming prominent.

Whichever is used, the lid must have handle to lift it up and lock for additional

protection.

In order to ensure uniformity, the vendor must ensure that same manhole cover is

used across the network. This must be approved by the client

MAN HOLE COVER LID 400KN

Width =

1m

Height = 1.15m

Length = 1.4m

DUCT WAYS




TYPES OF MANHOLE

IN-SITU

These are man hole casted on-site, the form work and all other concrete material

are brought to the site for casting. This is not allowed except the man hole location

is a difficult terrain for Hiab movement and manhole installation. Such terrain

include swampy areas, no access area (residential compound)

PRE-CAST

These are the manhole that are casted in the construction yard meant for the project

(located very close to the project route. Aftyer the casting . it is expected to be

cured by wetting them regularly or subject them in to the curing oven for days.

After the curing process, the hiab will be engaged to take each manhole to their

respective and waiting manhole trenches. The lifting and the dropping of the

manhole need to be guided to align well.

MAN HOLE CASTING

MAN HOLE CURING OVEN

MAN HOLE INSTALLATION




MANHOLE DISTANCES & PLACEMENT

Manhole is one of the major civil work of the fiber implementation project.

As stated in the SOW , the distances of the manhole is already specified.

Metro project (project within the town) most of the time by standard is

250meters interval unless otherwise approved, while backbone or long-haul

installation have the manhole spacing as 950meters or 1000meters

NOTE: At every macro bend or sharp corner manhole must be inserted

irrespective of the distance of the last inserted manhole.

MH 1 MH 2 IN

MH 3

IN

MH 5 OUT

MH 4 OUT

MH 6 MH 7




Where bridges, streams or other obstacles require crossing, chambers should

be placed on either side of the obstruction.

Manholes should not be installed on steep banks or slopes.

The manhole construction must ensure the covers are well above the

footpath/ground level and also allow the cover to be raised or lowered to

accommodate changes in the footpath/ground level using conventional

manhole

MANHOLE TRACKING

Manhole numbering or labelling is very essential and crucial to preparation of the

AS-BUILT DRAWING.it is marked serially as MH 1, OR HH1, JB 1. This label

can be written on the MANHOLE itself or in a situation where no space to write it

, it can be outwardly inscribed on the wall or road divider or pole nearer to it or

better still perform what is referred to as internal TAGGING. Internal TAGGING

is mostly done inside Manhole that contains SPLICE ENCLOSURE




What is route marker? This is one of the project deliverables that indicates that a

telecom cable or underground telecom facility already passed through the route.

This is very essential for maintenance and more so for the new telecom company

to be guided while trying to trench same route.

NOTE: As rule of Thumb every underground facility sighted (be it water pipe,

telecom cable, electric cable etc.) must be given minimum of 1meter either side

before any other facility be installed.

The route marker must be placed at regular interval as stated by the client.

NOTE: in metro project of 250m Manhole intervals the route marker is also placed

in between manhole (hence route marker interval on a metro project is 250ms.

In a backbone or long-haul project where the manhole interval is 950m 0r 1000m

as the case may be, the route marker is also placed at such intervals, except at a

micro bend or sharp turning

ROUTE MARKER




Samples of route markers of Nigeria telecom companies

DUCTING & COUPLING

Galvanized Steel pipe of internal diameter of 100mm and normal length of 6m

shall be installed in areas requiring additional protection for optical fiber cable and

where the use of PVC duct is susceptible to damage. Also it shall be installed

where instances of road crossing. Steel pipe shall be used when crossing the

bridge, open sewer ditches, under railway and when crossing major roads.

Duct ends shall be closed during construction with rubber plugs to prevent dust and

water from entering

Suitable plug shall be provided and inserted into the end of each duct to prevent the

ingress of water and/or foreign matter




WHAT IS COUPLING

FOR THE CONTINUITY of the duct and sub-ducts there is need for joining

(coupling)

PVC (Polyvinyl chloride) COUPLING INVOLVE SETTING THE FEMALE

SIDE OF THE PIPE AGAINST THE MALE SIDE

(PVC Polyvinyl chloride) (HDPE: High density

polyethene) GI Pipe

Female end Male end




SUB-DUCT (HDPE) COUPLING

THE SUB-DUCT KNOWN AS HDPE (High Density Polyethylene) VARY IN

SIZES 33/40mm. It is uniform in size. Unlike PVC, it does not have male and

female sides. Joining requires a special coupler and techniques

BACKFILLING

Backfilling shall consist of sifted soil to a minimum depth of 100cm above the

uppermost duct layer. The backfilling shall be compacted so as to leave no voids

around or between the ducts. Where sifted soil is not readily available, sand may

be used. Normally the excavated materials may be used.

All backfilling must shall be backfilled in layers of 150mm to 250mm in the

reversed order to which they were excavated and thoroughly compacted.

SUB DUCT COUPLER




Warning tape is required here before total backfilling. Reinstatement only takes

place where major terrain such as asphalt cutting and concrete breaking take place

FIBER WORK

The optical network is to be constructed using quality optical cable that is suitable

for the underground environment. The cable is provided by the Client most of the

time.

The performance of the cable to use is prescribed by the client (the cable types,

cable wavelength and cable attenuation, all these are specified in the SOW

Cable installation must comply with international standards

Bend radius during installation should not be less than 20x outside diameter of

cable while the minimum bend radius after installation should not less than 10x




outside diameter of cable. Cable slack shall be provided as 5meter within the

Manhole and 10meters at termination points. A minimum of 0.5m is required as

slack within the termination enclosure.

The major Fiber work after ducting is pulling of the cable into the duct which

involve inserting of the fiber optics cable into the sub-duct from manhole to

manhole to the end of the cable drum or cassette.

Equipment such as the calibration rope, stager, hand and blowing machine can be

deployed to achieve this stage

STAGGER AIR COMPRESSOR




FIBER CABLE TERMINATION

After the installation of the cable into the ducts, termination into the optical

connection accessories such as patch panel, splice enclosure, pigtails will begin.

Expected loss during termination is an issue to take into cognizance. There is

standard for this from the industry, but nevertheless the client dictate what she

wants here concerning the termination, fiber cords and pigtails, fiber distribution

panels, optical fiber splice etc

Connectorization and splicing

Mechanical and fusion splicing are the major type of splicing that can be deployed

anywhere.




Fiber optic cable splicing procedure (How to splice fiber optic cable)

1. 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.

2. 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.

3. Clean cable gel. Carefully clean all fibers in the loose tube of any filling gel

with cable gel remover.

4. 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.

5. 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.

6. Place the fusion splice protection sleeve. Put a fusion splice protection sleeve

onto the fiber being spliced.

7. 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.




8. Fiber cleaving. With a high precision fiber cleaver, cleave the fiber to a

specified length according to your fusion splicer’s manual.

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

be spliced.

10. Fusion splicing. Place both fibers in the fusion splicer and do the fusion splice

according to its manual.

11. 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.

12. 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.

13. Perform OTDR test. Perform a OTDR test of the splice and redo the splice if

necessary.

14. Close the splice tray. After all fibers have been spliced, carefully close the

splice tray and place it into the splice enclosure.

15. Bidirectional OTDR test (or power meter test). Test the splices with an

OTDR or power meter from both directions.

16. Mount the splice enclosure. Close and mount the splice enclosure if all

splices meet the specifications.

TESTING

Fusion splicers are used to create long cable lengths by splicing multiple cable

segments. Although the splicer will give an estimate of the splice loss, the only




way to test it is with an OTDR. Since OTDRs have directional errors, testing may

be required from both directions and averaged. Generally long concatenated cables

are tested with an OTDR and traces kept for documentation in case of restoration.

OPTICAL POWER- POWER OR LOSS? (“ABSOLUTE” VS.

“RELATIVE”)

Practically every measurement in fiber optics refers to optical power. The

power output of a transmitter or the input to recever is “absolute” optical

power measurements, that is, you measure the actual value of the power.

Absolute optical power levels are measured in dBm. 0 dBm is equivalent to 1 mW

of power, hence the “m” in dBm



http://www.thefoa.org/tech/ref/testing/OTDR/OTDR.html


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FIBER OPTIC PROJECT IMPLEMENTATION - IMT …imtcomputer.net/fiber/PROJECT IMPLEMENTATION.pdf · As to allow easily splice box installation and cable coils with respect of maximum