SAES-Z-020.pdf

Engineering Standard SAES-Z-020 Design and Installation of Fiber Optic Cable Systems for Process Control Networks Process Control Standards Committee Members

24 October 2009

Khalifah, Abdullah Hussain, Chairman Assiry, Nasser Yahya, Vice Chairman Awami, Luay Hussain Ben Duheash, Adel Omar Bu Sbait, Abdulaziz Mohammad Baradie, Mostafa M. Dunn, Alan Ray Fadley, Gary Lowell Genta, Pablo Daniel Ghamdi, Ahmed Saeed GREEN, CHARLIE M Hazelwood, William Priest Hubail, Hussain Makki Jansen, Kevin Patrick Khalifa, Ali Hussain Khan, Mashkoor Anwar Mubarak, Ahmad Mohd. Qaffas, Saleh Abdal Wahab Shaikh Nasir, Mohammad Abdullah Trembley, Robert James

Saudi Aramco DeskTop Standards Table of Contents

1 2 3 4 5 6 7 8

Scope................. Scope............................. ......................... ............................... .................... 2 Conflicts and Deviations............... Deviations..... .................... .................. ........ 2 References......... References........................ ............................ ............................ ................. 2 Terms and Definitions............... Definitions..... .................... ..................... ........... 4 Design................ Design............................ ......................... ............................... .................. 5 Installation.......... Installation...................... ......................... ............................. ................ 12 Testing & Inspection................. Inspection...... ...................... ................... ........ 16 Safety Requirements................ Requirements..... ...................... ................... ........ 17

Annex A – Fiber Optic Optic Link Budget.................. Budget....... ............. .. 18 Figure 1 – Optical Link Budget Figure................ 20 Previous Issue: 16 April 2007 Next Planned Update: 15 April 2012 Revised paragraphs are indicated in the right margin Primary contact: Muammar, Rushdi Husain on 966-3-8747502 Copyright©Saudi Aramco 2009. All rights reserved.

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Document Responsibility: Process Control Issue Date: 24 October 2009 Next Planned Update: 15 April 2012

1

SAES-Z-020 Design and Installation of Fiber Optic Cable Systems for Process Control Networks

Scope This standard covers minimum mandatory requirements governing the design and installation of fiber optic cable infrastructure systems inside Saudi Aramco process p rocess plants for process control systems applications only. For telecommunications applications, refer to the applicable SAES-T series standards. All fiber cable infrastructure systems inside Saudi Aramco process plants are owned by the plants.

2

3

Conflicts and Deviations 2.1

Any conflicts between this Standard and other applicable Saudi Aramco Engineering Standards (SAESs), Materials System S pecifications (SAMSSs) Standard Drawings (SASDs), or industry standards, codes, and forms shall be resolved in writing by the Company or Buyer Representative through the Manager, Process & Control Systems Department of Saudi Aramco, Dhahran.

2.2

Direct all requests to deviate from this standard in writing to the Company or Buyer Representative, who shall follow internal company procedu re SAEP-302 and forward such requests to the Manager, Proces s & Control Systems Department of Saudi Aramco, Dhahran.

References The selection of material and equipment, and the design, construction, maintenance, and repair of equipment and facilities covered by this standard shall appl y with the latest edition of the references listed below, unless otherwise noted. 3.1

Saudi Aramco References Saudi Aramco Engineering Procedure SAEP-302

Instructions for Obtaining a Waiver of Mandatory Saudi Aramco Engineering Requirement

Saudi Aramco Engineering Standards SAES-B-008

Restrictions to Use of Cellars, Pits and Trenches

SAES-B-068

Electrical Area Classifications

SAES-J-902

Electrical Systems for Instrumentation

SAES-L-610

Nonmetallic Piping

SAES-P-104

Wiring Methods and Materials

SAES-Q-001

Criteria for Design and Construction of Concrete Structures

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SAES-Z-001


Process Control System

Saudi Aramco Materials System Specification 09-SAMSS-097

Ready-Mixed Portland Cement Concrete

Saudi Aramco Standard Drawings AB-036897 3.1

Buried/Underground Cable Route Marker Posts and Signs

Industry Codes & Standards The Instrumentation, Systems, and Automation Society ANSI/ISA-TR12.21.01

Use of Fiber Optic Systems in Class I Hazardous (Classified) Locations

National Fire Protection Association NFPA 115

Standards for Laser Fire Protection 2003 Edition

ANSI/NFPA 70

National Electrical Code (NEC)

International Telecommunications Union – Telecommunications Standardization Sector (ITU-T) G.651

Characteristics of a 50/125 µm Multimode Graded Index Optical Fiber Cable

G.652

Characteristics of a Single-Mode Optical Fiber Cable

G.653

Characteristics of a Dispersion-Shifted Single Mode Optical Fiber Cable

G.655

Characteristics of a Non-zero Dispersion Shifted Single-Mode Optical Fiber Cable

Electronic Industries Association (EIA) EIA/TIA-492

Detail Specification for 62.5/125 micron Class Ia Multimode, Graded-Index Optical Waveguide Fiber

EIA/TIA-492A

Sectional Specification for Class Ia Multimode, Graded-Index Optical Waveguide Fiber

EIA/RS-455

Standard Test Procedures for Fiber Series Optic Fiber, Cables, and Addendum

EIA/TIA-568

Optical Fiber Cabling Components

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EIA TIA-568A

Commercial Building Telecommunication Wiring Standard

IEC 60874-14

Sectional Specification for Fiber Optic Connector Type SCFOC/2.5

IEC 60874-10

Sectional Specification for Fiber Optic Connector Type BFOC/2.5

Building Industry Consulting Service International (BICSI)

4

TDMM

Telecommunications Distribution Methods Manual

COOP

Customer-Owned Outside Plant Design Manual

Terms and Definitions Attenuation: A measure of the decrease in energy transmission (loss of light) expressed in decibel (dB). In optical fibers, attenuation is primarily due to absorption and scattering losses. Coating: A layer of composite plastic material covering the fiber to provide mechanical protection. Core: The glass central region in an optical fiber that provides the means for transmitting light. Fiber Optic Cable: A cable that contains individual glass fibers, designed for the transmission of digital information, using light pulses. Fiber Node: is a location that contains the passive and/or active fiber optic components to interconnect the fiber feeder with the distribution point. Fiber Hub: a location with a single feeder cable from a fiber node and multiple fiber cables to outlying buildings. Fiber hubs are typically used if individual cables from the node to the buildings are either cost prohibitive or impractical. Hazardous (classified) location: a location in which fire or explosion hazards may exist due to an explosive atmosphere of flammable gases or vapors, flammable liquids, combustible dusts, or easily ignitable fibers. Multimode: A fiber that allows more than one optical mode to propagate. Minimum Bend Radius: The minimum radius a fiber may be bent before optical losses are induced.

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Operating Wavelength: The light wavelength at which a system is specified, normally expressed in nanometers (nm). Most single mode fibers can operate at 850 nm, 1300 nm or 1550 nm. Optical Link Loss Budget: Total losses allowed for satisfactory operation of an optical fiber system. Optical Time Domain Reflectometer (OTDR): A device used for characterizing a fiber, wherein an optical pulse is transmitted through the fiber and the resulting backscatter and reflections are measured as a function of time. Process Control Network (PCN): A proprietary process control networks provided as part of a vendor's standard process control system. Splicing: A permanent junction between optical fibers ma y be thermally fused or mechanically applied. Splice Loss: The amount of loss of light energy caused by angular misalignment, and/or fiber end separation, and/or lateral displacement of fiber ax es. Single Mode: A fiber that supports the propagation of only one mode.

5

Design 5.1

5.2

System Layout a)

Layout of a fiber optic cable system shall comply with SAES-Z-001.

b)

All fiber nodes within the plant shall provide five nines (99.999%) availability.

c)

Composite cable of power and fiber optic shall not be used unless approved in writing by the Process & Control Systems Department of Saudi Aramco.

d)

Aerial fiber optic cables shall not be used, unless approved in writing by the Process & Control Systems Department of Saudi Aramco.

Cable Routing a)

Multiple fiber optic cables between two locations shall be diversely routed to provide additional reliability and survivability.

b)

There shall not be more than one fiber hub between a destination location and its originating node.

c)

Multimode fiber cable runs shall not exceed 2 kilometers between the node and the final termination point.

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5.3

Cable Sizing a)

5.4


Fiber cables shall be sized with at least 50% additional strands above the initial strand requirements. The following minimum strand count shall also be applied: i)

24 strand count for cable run to a building or a facility that is not a node or hub.

ii)

12 strand count for cable run to small or temporary locations.

b)

Fiber strand count in all fiber cable shall be an even number.

c)

Spare fiber strands shall be spliced and terminated at the Fiber Distribution Panel (FDP), and marked as spares.

Design Documentation As a part of each telecommunications work order/project, detailed drawings and documents shall be prepared for each fiber optic cable system, showing the following information: 5.4.1

5.4.2

Fiber Cable Data a)

Cable manufacturer.

b)

Vendor number.

c)

Cable size (number of fibers).

d)

Cable type (filled or air core).

e)

Cable make-up (dielectric or non-dielectric).

f)

Type of fiber (multimode or single-mode).

g)

Dispersion shifted or non dispersion shifted.

h)

Fiber packaging (e.g., single fiber/loose buffer; multiple fiber/loose buffer; tight buffer, channel/groove or ribbon type, and color code, etc.).

Design Drawing a)

Cable route drawing (single line drawings)

b)

Cable schematic and detail drawings

c)

Wiring closet floor plans

d)

Equipment rack layout with distribution panels

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5.4.3

5.4.4


Other information 1.

Cable schematic and detail drawings shall identify support transitions, cable installation method on each section, building entrances and congested areas.

2.

Wiring closet floor plans and equipment rack layout shall identify cable routing inside the wiring closet and location of fiber distribution panels.

3.

At the completion of the project, cable route drawings, wiring closet floor plans, and equipment rack la youts shall be revised to reflect the "as built" conditions.

4.

Origin (normally node or hub) and destination of the cable.

5.

Fiber cable splice points with station location.

6.

Record the footage and/or meter markings on the engineering design construction drawings.

7.

Change in cable route.

8.

All substructures (pipes, utilities, etc.) with station location.

9.

Location of marker posts and signs.

10.

Cable Identification.

11.

Type of splice closures.

Link Loss Budget Requirements During the design stage a link loss budget shall be prepared and included with the project proposal and design packages. The link loss budget shall include: 1.

Total fiber attenuation (loss).

2.

Splice loss (including pigtail splices, if pigtails are used).

3.

Connector loss.

4.

A margin for light source aging as per manufacturer's specification.

5.

Link loss margin of 3 dB minimum for restoration splices. Commentary Note: See Annex A Fiber Optic Link Budget for detail calculation method.

The calculated dB loss cannot exceed the operating range of the terminal equipment that will be installed. Measured end-to-end loss should

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measure less than the calculated loss. Fibers that measure a higher loss than the link loss budget will not be accepted. 5.5

Optical Fiber All plant fiber optic cables for instrumentations and process control networks installations (intra or inter-building) shall be either; 

50 m (core)/125 m (cladding), MULTIMODE, GRADED-INDEX OPTICAL WAVEGUIDE FIBER (In accordance with the latest version of ITU-T G.651) Or



62.5 m (core)/125 m (cladding), MULTIMODE, GRADED-INDEX OPTICAL WAVEGUIDE FIBER (In accordance with the latest version of EIA/TIA-568 series) Or



 m (core)/125 m (cladding), STEP INDEX SINGLE-MODE OPTICAL FIBER (Dispersion-Shifted or Non-Zero Dispersion-Shifted) (In accordance with the latest version of applicable ITU-T-652, 653, 655) Commentary Notes: Selection of the specific fiber type shall depend on applications, speed, distance and future growth requirements. When MultiMode fiber is selected, 50 µm fiber shall be preffered over 62.5 µm fiber, since 50 µm offers better performance like lower signal attenuation.

All optical fibers shall be coated with one or mo re plastic materials or compositions to preserve the intrinsic strength of the glass. The COATING DIAMETER shall be at least 250.0 ± 15.0 micrometers. The optical fibers shall consist of a solid glass cylindrical core and cladding covered by Ultra Violet (UV) acryl ate or equivalent coating. 5.6

Optical Characteristics a)

The maximum attenuation of each fiber within a cable, when normalized to a length of 1 km shall be as per Table 1.

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Table 1 – Optical Signal Attenuation Fiber Type

Multi-Mode 50/125 m

Multi-Mode 62.5/125 m

Wavelength ( )

Max Attenuation (dB/km)

850 nm

4.0

1300 nm

2.0

850 nm

3.5

1300 nm

1.5

1310 nm

0.5

1550 nm

0.4

Single Mode

5.7

b)

Measurement of the attenuation shall be conducted at the wavelength specified for application and must be expressed in dB/km.

c)

The Numerical Aperture of Multimode fiber shall be 0.275 ± 0.015

d)

The minimum Bandwidth of the Multimode fiber cable shall be 160 MHzkm @ 850 nanometers and 500 MHz-km @ 1300 nanometers

e)

The Numerical Aperture of single mode fiber shall be at least 0.13

Cable Characteristics A.

Outdoor Cables 1.

All 'Outdoor Fiber Optic Cable' shall be loose-tube buffered.

2.

Cable shall be constructed of all dielectric materials. There shall be no metallic materials in the cable including the central strength member.

3.

Cable shall contain water-blocking material within the buffer tubes and the outside cable sheath.

4.

Cable shall contain 'Kevlar' threads to provide strain relief and protection of the buffer tubes.

5.

Cable construction shall be such that specified optical transmission properties are maintained when cable is installed and operated under manufacturer's specifications for loading, bend radius, and temperature.

6.

For an individual link, same type of cable shall be used to ensure same performance characteristics and to ensure compatibility of the geometrical parameters, attenuation and dispersion of the fiber.

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B.

C.


7.

Cable with 36 or fewer strands shall have six (6) fibers per buffer tube.

8.

Cable with 37 or more strands may have twelve (12) fibers per buffer-tube.

9.

All fiber optic outdoor cables shall be designed for a minimum temperature range of -5°C to 70°C at operating, placement, and storage conditions.

Indoor Cables 1.

Indoor cable shall be listed as being suitable for the intended purpose according to NEC classifications in article 770.

2.

Fan-out cables are acceptable for indoor use. Fan-out type must have each fiber strand contained in its own subunit with a dielectric strength member around the fiber.

3.

Each subunit shall have a jacket with a minimum outside diameter of 2.4 mm.

Fiber and Buffer Tube Identification The colors designated for identification of loose buffer tubes and individual fibers in multifiber tubes, slots or bundles shall be in accordance with BICSI COOP design manual. See the following table for details: Buffer Tube & Fiber No.

Color

1

Blue

2

Orange

3

Green

4

Brown

5

Slate

6

White

7

Red

8

Black

9

Yellow

10

Violet

11

Rose

12

Aqua

13

Blue/Black Tracer

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D.

E.


Buffer Tube & Fiber No.

Color

14

Orange/Black Tracer

15

Green/Black Tracer

16

Brown/Black Tracer

17

Slate/Black Tracer

18

White/Black Tracer

19

Red/Black Tracer

20

Black/Yellow Tracer

21

Yellow/Black Tracer

22

Violet/Black Tracer

23

Rose/Black Tracer

24

Aqua/Black Tracer

Fiber Jumpers 1.

Fiber jumpers for multi-mode fiber shall be orange and fiber jumpers for singlemode fiber shall be yellow.

2.

Fiber jumpers for routing inside cabinets shall be factory-built with each strand within its own subunit cable. Dual or Zipcord fiber jumpers are acceptable.

3.

Jumper cables shall be listed as being suitable for the intended purpose according to NEC classifications in article 770-50.

Fiber Distribution Patch Panel (FDP) 1.

Fiber Distribution Panels (FDPs) shall be designed so that the fiber optic cable enters from the rear of the FDP.

2.

FDPs shall be equipped with a mechanism to relieve strain on the cable.

3.

FDPs shall be designed so that, under normal installation, fibers are not subjected to bends radii less than the minimum recommended by the manufacturer.

4.

FDPs shall be designed to provide access only to individual pairs of fibers during installation of fiber jumpers or maintenance.

5.

FDPs shall have a means of protecting the individual fibers. Under normal access, the FDP shall not allow contact with the fiber cable or individual fibers terminated in the FDP.

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F.


6.

FDPs shall be designed with storage for excess slack of fiber jumpers in order to prevent multiple jumpers from becoming tangled with each other and exceeding their minimum bends radii.

7.

FDPs shall have an isolated partition to store splice trays and/or function breakout transition points.

8.

FDPs shall have a protective cover over its front. Cover shall be able to be modified so that a locking device can be added in the future.

9.

Fiber jumpers shall be accessible only from the front of the FDP.

Optical Connectors 1.

All fiber optic connectors shall comply with EIA/TIA-568. Only the ST and SC type connectors (as specified in IEC 60874-14 and IEC 60874-10 respectively) shall be used for terminate optical fiber cable.

2.

Each plant shall standardize on either ST or SC connectors. The preferred choice is the SC type. Commentary Note: For methods and guidelines on the proper installation and connection of optical fiber cabling, refer to EIA TIA-568A.

6

Installation 6.1

6.2

General 1.

Direct burial of fiber optic cables is prohibited.

2.

Conduit and/or Cable Tray systems shall be used for outdoor and/or indoor fiber optic cable installation. For details see section 6.1, and 6.2; respectively.

3.

Data links fiber optic cables, shall be specified and installed per system manufacturers' recommendations.

4.

When redundant data links are provided, the primary cable shall follow a different route from the back up cable.

5.

Fiber optic cable installation may use existing cable pathway (cable tray, and conduit system) provided that the existing pathway comply with this standard.

Conduit Systems 1.

Conduits shall be single bore, plastic (PVC) NEMA TC 8, Type DB or EB. Same type of conduits should be placed on any specific conduit section.

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2.

Conduits used in areas exposed to sunlight shall have built-in protection from Ultraviolet (UV) light or be treated as outlined in SAES-L-610.

3.

Conduits and associated junction boxes shall be permanently marked Fiber Optic Cable. Label should be in English and Arabic.

4.

The total number of conduits shall be designed to accommodate immediate and foreseeable future growth requirements. In all cases, at least one additional spare conduit shall be planned for maintenance and repair purposes. For conduits with sub-ducts (inner duct), an unused sub-duct may be used as a spare.

5.

The length of the conduit runs between two access points is limited mainly by the size of the cable which will be pulled into it and the number of bends it will contain. A maximum of equivalent two 90° bends are permitted in each section of the conduit runs. The minimum bend radius of the conduits shall be 36˝.

6.

For larger conduits designed for multiple fiber optic cables, sub-duct shall be used to assist in the future installation of additional fiber optic cables. Only longitudinally ribbed sub-duct shall be used in conduit runs over 150 meters (500 ft.) long.

7.

All underground conduit systems in plant areas shall be concrete encased for mechanical protection with non-structural concrete as per SAES-Q-001 and 09-SAMSS-097. The minimum amount of concrete shall be 75 mm along the top, sides and bottom of the conduit formation. a)

Underground conduit systems shall have Electronic Markers placed directly on top of the concrete.

b)

Electronic Markers shall be placed along the route of the conduit system at a maximum distance interval of 30 meters (100 ft.).

c)

Electronic Markers shall be placed at every change in direction, at the crossing of other utilities or lines, and at below-grade ac cess points.

d)

In plant areas, where vehicular traffic loads is expected, conduits should be located at least 760 mm (30˝) below surface grade. Plant areas, where vehicular traffic load is unlikely, conduits should be located at least 610 mm (24˝) below surface grade.

e)

A "yellow color" marker tape shall be placed above the conduit concrete encasement to provide early warning. The marker tape shall be located at a minimum of 300 mm above the upper surface of the conduit system.

f)

In plant area, underground manholes, hand holes, re-enterable splices, and access or service points are not allowed. All service and Page 13 of 20



access points shall be above ground. 8. 6.3

6.4

6.5

6.6

Installation of Fiber Optic System in Class I locations shall comply with NEC Article 501.

Cable Tray Systems 1.

Cable tray design, specification and installation shall be in accordance with SAES-J-902; Electrical Systems for Instrumentation; Section-9.

2.

Fiber Optic cables shall not be installed in cable trays sharing with high voltage transmission or distribution cables. High voltage cable is defined as cables that carry circuits operating at over 480 volts.

Transitions 1.

Fiber Optic cables shall be adequately supported (i.e., conduit or cable tray) at transitions from one type of installation method to another and also at transitions from one cable tray to another.

2.

Cables shall be adequately supported at transitions into equipment, cabinets and patch panels.

3.

Water seals must be used to prevent moisture entering in conduits where ever the conduits and sub ducts are exposed.

Cable Installations 1.

Fiber Optic cable installed for control networks shall not be used for any other applications or services, SAES-J-902 section 13.

2.

Do not install any other type of (copper or other metallic) cable other than non-metallic fiber optic cables in the same conduit.

3.

Because of the possibility of damaging existing cables, as well as the other uncertainties involved, pulling new cables through a partially filled conduit is generally not recommended.

Cable Bending Bending radius of fiber optic cable shall not be less than:

6.7

1.

Ten (10) times the cable diameter when the cable is not under tension

2.

Twenty (20) times cable diameter when the cable is under tension

Cable Splicing To keep future 'opening' of the new cable to a minimum, underground fiber optic cable splices shall be located at points where future branch splices will be

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required, in so far as it is practical to do so. 6.8

Cable Fill in conduits/sub-ducts The cross-sectional area of the cable should not exceed:

6.9

1.

28% of the inside cross-sectional area of the conduit sections or sub-ducts with two 90° bends;

2.

34% of the inside cross-sectional area of the conduit sections or sub-ducts with one 90° bend; and

3.

40% of the inside cross-sectional area of the straight runs (no bends) conduit sections or sub-ducts.

Cable Pulling Only cable manufacturers' recommended pulling tension, pulling methods and pulling equipment shall be used. Fiber Optic cables should always be pulled in a straight line. The cable shall never be bent or wrapped around hand or any other objects for pulling. In the absence of manufacturer's recommendation, the cable pulling tension shall not exceed 600 pounds.

6.10

Cable Protection During cable short and long term storage and cable handling, the cable shall be protected against environmental hazardous material and conditions that may be detrimental to the cable; like petroleum, petroleum based products, thermal, other chemical, mechanical, electrical conditions, etc.

6.11

Cable Entrances Fiber Optic Cables entering in buildings, control rooms or other indoor facilities shall comply with BICSI - TDMM (Building Industry Communications Services International - Telecommunications Distribution Methods Manual, Section-9). In addition, cable entry into control buildings or similar buildings in hydrocarbon processing plants shall also comply with SAES-P-104; Wiring Methods and materials, Section 15.4. The following guidelines shall be observed: 1.

Do not use power cable runways (AC and/or DC) to support optical cables.

2.

Install a new runway or conduit to support the planned optical fiber cable if the facility: i.

Is equipped with a cable grid only, and/or

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ii.

6.12

7


Does not have available existing cable troughs or race ways.

3.

Optical fiber cables may be routed with other high frequency (CXR) cable.

4.

Avoid a route that would stack future cables in excess of 225 kg/m on top of fiber cables.

5.

Do not exceed the fiber cable's minimum bending radius.

6.

Coil 10 meters of slack cable for restoration.

Fire Protection requirement 1.

All Fiber optic cables placed inside buildings, control rooms, offices, shall comply with the fire protection requirements in accordance with ANSI/NFPA 70, NEC Article 770.

2.

Outdoor fiber optic cables (non-fire rated) shall not be run exposed for more than 15.2 m (50.0 ft) within a building. If more than 15.2 m (50.0 ft) of cable is required between the building entrance point and the cable termination point, use rigid metallic conduit to enclose the cable to bring the exposed part of the cable to within 15.2 m (50.0 ft) or less of the termination. The metallic conduit must be grounded.

3.

Wrapping the outdoor cable with fire-rated tape as an alternative is not acceptable.

4.

Conduit and cable sealing, wherever are required, shall be installed in accordance with NEC Article 505.16.

Testing & Inspection 7.1

End-to-end testing shall be carried out on all outside plant fiber optic cable facilities (defined as the span of fiber from the transmitter to the receiver) and the overall optical loss shall be documented.

7.2

Acceptance Testing Requirements The following acceptance testing shall be conducted for all fiber optic cables: A.

End-to-end acceptance tests (typically conducted after completion of installation and splicing and before installing terminal equipment).

B.

Splice acceptance tests (individual splice insertion losses) shall be .05 dB average link splice loss with no single splice loss abov e 0.1 dB for fusion splices, and 0.1 dB average link splice loss with no single splice loss above .2 dB for mechanical splices; connectors shall hav e insertion losses of 0.3 dB or less).

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Commentary: Not required for patch cable.

8

C.

On-reel acceptance tests shall be performed on the cable to confirm the manufacturer's tests before the placing operation begins.

D.

Each link shall be tested for zero transmission error performance at the highest bit rate expected to be carried over the cable section. This test is to be performed with a transmission analyzer.

Safety Requirements Classified Area considerations 1.

Fusion splicing shall not be used in classified areas Commentary Notes: Note 1:

Fusion splicing process uses an electric arc to make optical splices which could cause fires and/or explosions.

Note 2:

All fusion splices shall be made outside the classified areas and at least 3 meters away.

2.

The Use of Fiber Optic Systems in Class I Hazardous (Classified) Locations shall comply with ISA-TR12.21.01-2004.

3.

Fiber Optic cables that are routed on trays in classified areas shall be specified per ISA-TR12.21.01-2004 and shall be marked on the outer jacket as suitable for tray application.

4.

Fiber optic cable used in hazardous (classified) locations must meet the fire resistance and smoke producing requirements of NEC Section 770.53.

5.

Fiber optic cable used in Class I locations must be sealed in accordance with the requirements specified in NEC Section 501.15 or 505.16, as appropriate.

6.

SAES-B-068 shall be used for electrical classification of plant areas where flammable gases or vapors, or combustible dust may be present in the air in quantities sufficient to produce ignitable mixture.

7.

SAES-B-008 governs restrictions for on-site below-grade trenches and other appurtenances where hazardous vapors may collect.

16 April 2007 24 October 2009

Revision Summary New Saudi Aramco Engineering Standard. Editorial revision to replace Standards Committee Chairman.

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Annex A Fiber Optic Link Budget This annex is included for information purposes

The following is a step by step methodology for designing the power loss budget of a fiber optic link (Fig-1): 1.

Calculate Transmitted Power: Generally, the transmitter power that is quoted by the manufacturer is the power into the fiber. If not, then the coupling loss must be determined. Power into fiber (dBm) = TX power (dBm) - coup ling loss (dBm)

2.

Calculate the System Gain Subtract the receiver sensitivity from the transmitted power. Both values must be in the same type of units (most common unit is dBm) and must be of the same measurement type (average power or peak power). The system gain will then be represented in decibels. System gain (dB) = TX power (dBm) - RX sens. (dBm)

3.

Determine the safety margin Calculate the safety margin for the fiber link. The safety margin is represented in decibels. Safety margin (dB) = Environmental factor (dB) + Aging factor (d B) + Dispersion factor (dB) + Jitter factor (dB) + Repair factor (dB) + Design error margin (dB) Commentary Note: The recommended safety margin is 4 dB.

4.

Calculate the link loss budget Determine the maximum allowable loss for the end -to-end optic fiber cable link section by subtracting the safety margin from the system gain. Link loss budget (dB) = System gain (dB) - S afety margin (dB)

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5.


Calculate the total connector losses Calculate the total connector losses in a link section of optic fiber by multiplying the number of connectors in that section by the loss per connector (in dB). Total Connector Losses (dB) = Connector Loss (dB) x number of connectors

6.

Calculate the total splice losses Calculate the total splice losses in a link section of optic fiber by multiplying the number of splices by the loss per splice (in dB ). Total Splice Losses (dB) = splice loss (dB) x nu mber of splices

7.

Calculate other possible losses Calculate other losses to the system by adding to gether losses due to passive components in the optic fiber route. For example: passive stars, combiners, splitters, etc.

8.

Calculate the maximum allowable cable attenuation Each section of fiber link should be analyzed to determine the maximum allowable fiber optic cable attenuation. This is calculated by subtracting the connector losses, splice losses and other losses from the link l oss budget. Allowable cable attenuation (dB) = Link loss bud get (dB) Connector losses (dB) - Splice losses (dB) - other losses (dB)

9.

Calculate the fiber loss for each cable section Calculate the expected signal attenuation from e ach section of optic fiber by multiplying the cable length for a section by the specified normalized cable attenuation of the chosen cable. Fiber loss (dB) = fiber length (km) x normal cable attenuation (dB/km)

10.

Calculate System Fade Margin Fade Margin= Link Loss Budget (dB) - fiber loss (dB) - connector losses (dB) - splice losses (dB) - other losses (dB) Commentary Note: Fade Margin shall be greater than zero. The recommended fade margin gain is 3dB.

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11.


Calculate the received signal level Determine the power level of the signal at the end of the fiber that is entering the receiver. This is calculated by subtracting all the losses along the cable section from the transmit power into the fiber. Received signal level (dBm) = transmit power (dBm) - fiber loss (dB) connector losses (dB) - splice losses (dB) - other losses (dB)

12.

Check dynamic range Ensure that the receive signal level at the end of the fiber section does not exceed the maximum permitted signal level allowed into the receiver. This is calculated by adding the dynamic range to the receiver sensitivity and ensuring that the receive signal level is less than this result. Receive signal level (dBm) < Receiver sensitivity (dBm) + Dynamic ran ge (dB) Commentary Note: Optical link budget calculation software tool the will calculate the entire link loss budget, is available in P&CSD website.

Figure 1 – Optical Link Budget Figure

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SAES-Z-020.pdf

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