calculation of negative buoancy for pipelines

8/3/2019 Calculation of Negative Buoancy for Pipelines

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CALCULATION OF BUOYANCY PREVENTION

BY CONCRETE SADDLE WEIGHTS WITHIN SABKHA AREAS

MOG DOCUMENT NO.

SOC DOCUMENT NO.

CLIENT:

PROJECT NO.: 520 01 20880

30" GAS & 12" CONDENSATE TRUNK LINES

EROMATTAHADDYTO KM 91,5

PROJECT TITLE:

I~'i 2

1

'ev.

ISSUED FOR CONSTRUCTION-!

ISSUED FOR CONSTRUCTION -

ISSUED FOR SOC APPROVAL-

Description of Revision

BUOYA104



1.1 Basic Data for Calculation of Buoyancy Prevention of 30" Gas Trunk Line

[0.0.[tp]

[Wp]

[wcs]

[VT]

[Vp]

[YC]

[YW]

[tRs]

[8]

762,0 mm

9,53 mm

176,3 kg! m

2158 kg

0,959 m3

0,634 m3

2250 kg! m3

1050 kg! m3

10 mm

~ 1,3

Pipe outlet diameterWall thickness

Weight of pipe (30" x 0,375")

Weight of concrete saddle for 30" pipe

Total volume of concrete saddle

Part volume of conc. saddle below water

Minimum concrete density

Maximum water density

Thickness of REGUPOL- Rock Shield

Safety factor against buoyancy

1.2 Calculation of Single Weights

Concrete saddle weight and total weight according to a max. centre distance of

~ 9 feet / appro 2,75 meter.

WConcrc!e=0,9593

2,25.9,81.10 =21167,5 N respect.7697,2N/m

Total Weight (1729,5 + 7697.2) = 9426.7 Nt m

1.3 Calculation of Buoyancy of Pipe and Concrete Saddle

3[,05.9,81.10B Concreteaddlepartial) = 0,634 =6530,0 N respect. 2374,7 N/m

Total Buoyancy (4697,4 + 2374,7) = 7072,1 Nt m

1.4 Safety Factor against Buoyancy



3 Dimension, Volume and Weight of Concrete Saddle

011I

L

REGUPOO-ROCK $HIEOO. $=10 mm~ --

Length of Concrete Saddle:

Concrete Quality:

L = 1,0 m

according DIN 1045 (B25)

dI

(mm]L~

950

f

~400

275

h(mr1]l

Volume

~m31

Pipelinefinch 1

b

{!!!!!!)400

275

e

~250

200

9!!!!!!!J250

200

a!IE!IJJ381

162

c

J!!.)!!]l350

150

10g0 1- g.9590"12" 625 0,482

Weight

[Kg]

2160i

jQ85 I



f

PROJECT NUMBER

TP-1326AT

PIPELINE SYSTEM AnAHADDY-BREGAGAS TRAN$MISSION LINE KM 91.5 - BREGA

SIRTE OIL COMPANY: I

I

~ r B o n a t t jSheel 1 of 15 i ! SPC NUMBER JOB 83301

A 0 1

Rev. r

1 0005'97 M.G.

o 3003197 M.G.

A 200:Y97 M.G.

REV DATE BY

INDEX i PLANT SEQUENCE

~ LD1. i 31 C1-9004...

. !

III i

. - I:ij

SPECIFICATlON

FOR

PIPE CONCRETE WEIGHT eOATING

'.. r-cI

I!

REVISED VI/Il1-l SOC COMMENTS AND ISSUED FOR IMPlEMENTATION

ISSUED FOR IMPLEMENTATION

ISSUED FOR APPROVAL IREPlACES SPEC. lB-E-S0041

i DESCRIPTION

SPC. No.

31-C1-9004

Ii 'GM 'MG II GM PI.M

CHK'd APfYd

THIS SPECIFICATION IS NOT BE USED FOR

CONSTRUCnON OR FOR ORDERING

MATERIAL UNTIL CERTIFIED AND DATED

CERTIFIED

DATE



._-I

PROJECT NUMBERI

SIRTE OiL COMPANY ~ r B o n a t t iT P ~ 1 3 2 6 A T I

I

Sheet 2 of 15 SPC NUMBER JOB B3301

INDEX PLANT SEQUENCEA 0 1 SPC. No.

Rev. LD1 31 C1-9004 31-C1-9004

. l INDEX

1. INTRODUCTION

1.1 Scope

1.2 Definitions

1.3 Codes and Standards

2. BASIC DESIGN OF CONCRETE COATING

2.1 Line pipes

2.2 Coating method2.3 Bases of design

3. MATERIAL3.1 Concrete Mix Design3.2 Cement3.3 Fine aggregates3.4 Coarse aggregates

3.5 Mixing water

3.6 Steel wire mesh'I

4. APPLICATION OF COATINGI

4.1 General I4.2 Placement of steel wire mesh

4.3 Placement of Concrete CoatingI .

4.4 Cut-back i

4.5 Stripping .14.6 Curing of ConCrete

M ·k ·14.7 arlng .. :1j;1

5. REpAIRS 1'(55.1 General jl

5.2 Permissible r ~ p a i r s to Concrete Coating

5.3 CUring of RepairsI

6. INSPECTION ANDiTESTING

6.1 - General I6.2 Inspection ofianti-corrosion coating

6.3 Concrete strength6.4 Electrical insl,Jlation of reinforcement

6.5 Concrete co*ing diarneter6.6 Weight control arid Negative- Buoyancy

6.7 Data recording

7. HANDLING

8. DOCUMENTAtiON

8.1 Design documents

8.2 Pre-prod:uction documents8.3 Production data dossier



I.

PROJECT NUMBER I

SIRpE OIL COMPANY rBonatti7P-1326AT

Sheet 3 of 15 SPC NuMBER JOB 83301


Rev. LD1 31 C1-9004 31-C1-9004.

1. INTRODUCTION

·i1.1 Scope !:

This specification defines the minimulTj requirements for materials, application, inspection and repairs

of concrete weight coating to be a p ~ l i e d onto the 36" line pipes which will be laid in the swampy

sections of the New Gas Transmissiop line Attahaddy - Brega.

1.2 Definitions

Owner: Company or organization who will own and/or run the facility for which the coated pipesare intended. In tl:lis case, Sirte Oil Company (libya)

Company: same as "Owner" above

Purchaser: Company or organization who awards the Purchase Order for coating the pipes. In thiscase,BonattiSpA -

Contractor: Company which is aWarded of the above Purchase Order and has the responsibility forthe coating application.

Supplier: The Company which supplies the Contractor with the coating materials.

;"

Inspector: Person or Company a p p o ~ n t e d by Purchaser tor carrying out inspections.

1.3 Codes and Standards

The following Codes and Standards, latest edition, are applicable. to the Work and are referenced in

this specification.

ASTM CiS0, or as 4027Specification for Portland Cements

ASTM C33Specification for Concrete Aggregates

ASTM A641 M

Specification for zinc-coated carbon steel w ~ r e

ASTM AgO

Test Method of coating on zinc-coated steel articles

ASTM A185Specification for Welded Steel Wire Fabric for Concrete Reinforcement

ASTM A82Specification for Cold-Drawn Steel Wire tor Concrete Reinforcement

ASTM C171

Specification for Sheet materials for Curing Concrete



- .

PROJECT NUMBER

S RTE OIL COMPANY ~ r B o n a t t iTP-1326AT

",

't! ., :

Sheet 4 of 15 SPC NUMBER JOB 83301

INDEX PLANT SEQUENCE,A 0 1 SPC, No,

Rev. LD1 '"31 C 1 ~ 9 0 0 4 31-C1-9004

ASTM C192. C31, 8S 1881 Pt 108

Method for making Concrete Test'Specimens

A.C.!. 318

Method for Concrete Hardness Test

2. BASIC DESIGN OF CONCRETE COATING

Line pipes

The line pipes to be coated are a portion (about 9200 Meters) of the 36" pipes, API 5L X-eO, 0.344"w.thk. The exact amount to be established during the detail design of the line. Pipes intended for

concrete coating will be provided of a FBE external anti-corrosion coating, 700 micron thick.

2.2 Coating Method

The concrete coating will be applied By Contractor with the impingement method, in his shop area.Contractor shall submit a detailed written description of the coating equipment, procedures and

materials for Purchaser's review.

Bases of design

The purpose of the concrete coating is to provide the pipe with a negativj3 buoyancy adequate tc-

ensure stability to the pipeline in the swampy sections of the R.O.W.

The theoretical Negative Buoyancy of the empty pipe shall be calculated·as per following formula:

8N =Wc -8

We = Wp + TC· te(D + te)y e + W R ( 1 - ~ )- YR

B= ~ ( D + 2 . t e ) 2 Y LI 4

where:

BN =We =B =Wp =te =0 =WR =Ye =YL =

YR =

Negative Buoyancy per unit length of concrete coated pipe (kg/m).'- I

Weight (in air) per unit l e n g t ~ of concrete coated pipe (kg/m)

Buoyancy of the concrete coated pipe (kg/m)Weight (in air) per u n i l l e n g t ~ of steel pipe FBE coated (kg/m)

Thickness of the concrete ~ J a t i n g (m) ..

Outside diameter of the steel pipe, FBE coated (m)

Weight of reinforcement pJr! unit length of pipe (kg/m)

Specific weight of water s a : t ~ r a t e d concrete coating (kg/m3)

Specific weight of fluid (kg1m3)

Specific weight ofr e i n f o r c ~ m e n t

(kg/m

3)

I



/.---- . - - - -

PROJECT NUMBER

SIRTE OIL COMPANY ~ r B o n a t t iTP-1326AT

,



Rev.LOt 31 C1-9004 31-C1-9004

The specified Negative Buoyancy and specific weight of fluid are as follows:

BN =101 kg/m

yL = 1025 kg/m3

based upon the following parameters:

lc=0.125 m Yc=2410 kg/m3

Contractorshall design the concrete Iihing such as to attain the above specified Negative Buoyancy

BN with the specified specific weight of fluid YL' Contractor may establish design concrete thicknessand specific weight different from the !above reference ones, provided that they meet said Negative

Buoyancy BN· _ IJ.! . _

1.1 'I!

3. MATERIAL fil3.1 Concrete Mix Design

Contractor shall design the mix using approved aggregates and materials and shall determine the

material proportions to give the rsquired concrete density and strength. Required compressive

strength after 28 days curing shall bJ not less than 25 N/mm2

(tested on cubic specimen). .

The mix design specification shall be approved by Purchaser prior to commencement of the coating

operations. The specification shall be supported by.certificates of tests carried out by an approved

laboratory. Full details shall be provided by Contractor with regard to:

a) the Supplier's certificates of the cement

b) the chemical/physical analysis of the aggregates

c) the water analysis '

d) the grading of the various aggregates, with combined grading curves as necessary

e) the water/cement ratio and the proportions of the components

f) the types and specifications o,f admixtures, if any

All component of concrete shall oe resistant to slurry condition of "Sabka" (salty marsh) environment.

Cement

BS 4027 type 32.5R s u l p h a t ~ resisting Portland c ~ m e n t shall be used, or equivalent cement

according to ASTM C 150 a p p r ~ v e d by P u r c h ~ s e r .3.2.4 Cement that has hardened, become partially set or has become lumpy shall be rejected and removed

from the site by Contractor.

3.2.5 The cement shall be stored in a manner which will provide satisfactory weather protection



' ~ " , '- ,.F' .........-.

P ~ O J E C T NUMBER

SIR1TE OIL COMPANY ~ r B o n a t t i-' TP-1326AT ,"

..

-'- SPC NUMBER JOB 83301Sheet 6 of 15I

INDEX I PLANT SEQUENCEA 0 1 SPC. No.

Rev.LD1 31 C1-9004 31-C1-9004

Manufacturer's cement chemical analysis certificates shall be collected by Contractor and transmittedto Purchaser as follows: '

_Included in the "Concrete Mix Design" for the first shipment delivered to shop (copy)

-Included in the final documentati?n for first and any additional material delivered to shop (originals).

Fine aggregates

Fine aggregate shall consist of natural sand, manufactu'red sand or a combination thereof and shall

conform to the requirements ot:ASTM C33. Grains shall be clean, hard, strong, durable free from

other foreign and deleterious substance. ' "1 '

sand grading shall conform to ,standard ranges indicated in ASTM C33, with reasonable tolerances.

Deviations in the sieve analysis' will be allowed, provided they are supported by positive results oftests.

Sand shall be stored in a manner to avoid contamination from soil or other foreign matter.

3.4 Coarse a g g r e g a t ~ s

Coarse aggregates shall consist of gravel, crushed gravel or crushed stone and shall conform to

requirements of ASTM C33. The materials shall be clean and free of any injurious amount of

c ~ e m i c a l compounds, organic materials, or solids Which may impair the strength and durability of theconcrete.

Tl:1e maximum size of coarse aggregate shall be compatible with the size of the mesh reinforcement.

Aggregate grading shall con(orin to standard ranges indicated in ASTM C33, with reasonabletolerances. Deviations in the sieve analysis will be allowed, provided they are supported by positiveresults of tests. .,

3.4.4 Aggregate shall be stored sep,arately from sand and suitable provisions shall be made to prevent

contamination with soil and other foreign matter.

3.5 Mixing water

3.5.1 Mixing water shall be fresh water, clean and free from injurious oils, acids, alcohols and organicmaterials. Water containing more than 2,000 ppm of silt or suspended particles shall not be used.

3.5.2 The follOWing maximum contents of dissolved solids are a l l o ~ e d :

Sodium and Potassium carbonates and bicarbonates

Sodium chloride and sulphate

Calcium and Magnesium carbonates

Iron saltsSalts of Manganese, Tin, Zinc, Copper and Lead

Sodium sulphide

Sugar

pH

1,000

10,000400

40,000

500

100

0.02

~

ppm

ppm

ppmn

ppm

ppm

ppm%wt



PROJECT NUMBER

SIRTE OIL COMPANY ~ r B o n a t t i..$

TP-1326AT

Sheet 7 of 15 SPC NUMBER JOB 83301-


Rev. LD1 31 C1-9004 31-C1-9004..

r) as bicarbonate ion,

Water having contents of substances exceeding the above limits may be used for mixing concrete if

they produce mortar cubes having 7 and 28 day strength equal or exceeding the 90% of strength of

similar specimens made with water of known satisfactory quality. The strength comparison shall bemade on mortar identical, except for mixing water.

Water analysis certificate, when drinking water is not used, shall be transmitted to Purchaser as

follows:

- Included in the "Concrete Mix Design" for the firSt water used (copy).

- During construction and included in the final documentation for any used water source (originals).

3.6 Steel wire mesh

Reinforcement shall consist of three concentric layers of galvanized wire mesh type Bekaert "NewLight Armapipe" or approved similar.

3.6.2 Welded wire mesh shall conform to ASTM A 641M, ASTM A 90, ASTM A 185 and ASTM A 82.

Contractor shall submit reinforcement application details for Purchaser's review prior to starting of the

coating operations.

;, '

4.

4.1

4.1.1

4.1.2

4.1.3

APPLICATION OF COATING

General. ,

Concrete shall be applied with the impingbment method. Contractor shall provide expressly designed

system, suitable for this purpose and for arational and efficient application..1

Contractor shall make sure that t h s U r f ~ c e of the pipe FBE coating is clean, undamaged and freeI

from holidays before commencing concrete coating application. F8E repair if any will be carried out

immediately by the repairing gang. '

"" II.1

Contractor shall provide as a minimum al\ ;plant and facilities necessary for the following:

"." a) Storage-of all uncoated pipes and materials in a proper manner

b) Handling of pipes and materials - Ic) Batching and mixing of all concrete to produce a consIstent and homogeneous mix

d) Uninterrupted transportation of mixed, concrete to the point of application in a manner avoiding

segregation and premature hardening ,- . .

e) Application of concrete by i m p i n g e ~ e n t unit that spray a quantity of material on the entire

circumference of the pipe that rotate alongwith buggies movement.

f) Application of mesh reinforcement on the entire circumference of the pipe that rotate alongwith

buggies movement. , '

g) Weighing of concrete coated pipes: i.h) Storage of concrete coated pipes i



TP-1326ATSIRTE OIL COMPANY ~ r B o n a t t i


INDEX PLANT SEQUENCEA 0 SPC. No.

Rev. LD1 31 C1-9004 31-C1·9004

b) Data sheet and drawings, i f applicable, showing the established dimensions of the coating, in

particular the thickness consistent.'f. 'ith the aimed density, the calculation of the Negative

Buoyancy, the details of wire mesh application, if any, etc...

These documents may be incorporated in a revised issue of this specification. .

8.2 Pre-production documents

The following dQcuments shall be submitted by Contractor to Company review prior to starting the

production:

a) Description of the coating facilities, including a lay-out of the yard, the list of equipment and test

instruments, the drawings of the moulds for concrete casting, etc...

b) Certificates of lifting equipment

c) Certificates and/or calibration certificates of testing equipment and instruments

d) Pipe stacking procedure

e) Curing method statement

f) Quality plan, including the description of the tesVinspection procedures, the relevant forms and the

traceability procedure

8.3 Production data dossier

C ~ n t r a c t o r shall gather in an ordered file the data and information relevant to the production,

including but not limited to the following ones:

a) Daily production of coated pipes (With individual pipe numbers)

b) Daily report of repaired pipes ..c) Reports of all tests and inspeCtionsd) General remarks covering operation of eqUipment, weather conditions (including ambient

temperature), testing, pipe stacking, etc...



" ' t ~ . ,_ . _ ~ -

: ~ ' ; ; ' PROJECT NUMBER

SJRTE OIL COMPANY ~ r 8 0 n a t t i~ ~ - y,.,. _...\TP-132GAT- ' ~ " - 1 .!

..t .

.J -

Iheet 14 or 15 SPC NUMBER JOB 83301.; INDEX PLANT SeQUENCE

A 0 1SPC. No.

Rev. LD1 31 C1-9004 31-C1-9004

,"rrrI

F

The Negative Buoyancy BN must be found to be equal to the design one (i.e. 101 kg/m) within the

following tolerances:

a) On a single pipe length: :

b) On the average of the daily production:

-25 kg/m

-10 kg/m

+40 kg/m

+15 kg/m

G.7 Data recording

-Contractor shall establish suitable procedures for recording the results of all tests and inspections,

together with the most important data/information, and for having them f i l ~ d in a rational manner. Allinspection and test reports shall be traceable to the original pipe identification number assigned bythe pipe mill.

A written description of these procedures, including details of data to be recorded and samples of the

forms proposed for this purpose, shall be submitted to Purchaser prior to starting the coating activity.

7. HANDLING

7.1 The handling of pipe shall be performed in a manner preventing damages to the pipe and its coated

surfaces.

7.2 Pipe shall "not be dragged but shall be picked up bodily using fork lift with SUitably padded forks or bymeans of crane and non-metallic slings. Alternatively, i f end hooks are to be used, they shall be

suitably radiused and lined with plastic or similar material. A spreader bar shall be used between

lifting lines. During handling,Jhe pipe shall not be subject to impacts or jars. Any pipe SUffering impact

or jars shall be immediately marked for subsequent repair, when applicable.

7.3 After coating the pipes shall be SUbjected to minimal handling until concrete is set and SUfficiently

hardened. Concrete coated pipe shall not be placed on skids or racks until the coating has hardened

SUfficiently to prevent flattening.

As a general rule, concrete coated pipes shall not be handled or stacked until the concrete has

achieved.a compressive streQ9th of at least 16 N/mm2.

Pipe shall be stacked in such a manner so as to prevent damage to the pipe and coating. Contractor

shall submit proposed-stacking arrangement, including stacking heights.

8. DOCUMENTATION

8.1 Design documentsi

Contract;r shall submit the following documents to Company's approval, at latest one month prior to

the starting of production: I -

a) Concrete mix design specificatiorl, supported by the certificates of all tests carried out for proving

that the proposed material and the mechanical characteristics and density of the concrete are

suitable for the purpose and fulfil lhe requirements of this specification.The mix design specification shall include the data sheets and/or technical bulletins of the

products that Contractor i n t e n d s ~ to use for the fabrication.I!I i



,.lfl!i ' "----- -- -

PROJECT NUMBER. , ;,

SIRTE OIL COMPANY ~ r B o n a t t i.!J

TP-1326AT


INDEX PLANT SEQUENCEA 0 1 SPC, No,

Rev, LD1 31 C1-9004 31-C1-9004

I

Concrete coating diameter

The Nominal Diameter of the concrete coating is defined as the sum of the outside diameter of the

FBE coated pipe (916 mm) and twice the concrete thickness, which shall have been established by

Contractor on the basis of the actual mix design and concrete density. ' ,

Five (5) girth tape measurements equally spaced along the pipe shall be taken after concrete coating

application. Each one of the five measured diameters must be equal to the Nominal Diameter of the

concrete coating with a tolerance of: -7 mm I +10 mm.

6.5.3

6.6

6.6.1

6.6.2

The Average Diameter of each concrete coated pipe is defined as the arithmetic mean of the five

measured diameters, as specified under 6.5.2 above, The Average Diameter so detel]]1ined must be

equal to the Nominal Diameter of the concrete coating with a tolerance of: -4 mm I +6 mm.

Weight control and Negative Buoyancy

!Each pipe length shall be weighed immediately after stripping. Weighing shall be performed using a

sui table weighing device having an ~ c c u r a c y of one-half of percent (0.5%). Calibration of the

weighing device shall be checked everY. day of production., .

Tpe Negative Buoyancy per unit l e n g ~ ~ of concrete coated pipe shall be calculated with the following

formulae: I ;

CBW =Wp .(L-Le)

/lwc--= MW - CBW._

: Lc, 1t 2B=4".DA 'YL

where:

CBW = Weight of the steel pipe protruding at the cut-backs (kg)

Wp = Weight (in air) per unit ',ength of steel pipe FBE coated (kg/m)L = Measured length of the'steel pipe i9int (m)

Lc

= Measured length of the' concrete coating (m)

We = Weight (in air) per unit length of concrete ~ o a t e d pipe (kg/m)

MW = Total actual weight of Coated 'pipe (kg), measured as specified under 6.6.1 above

B = Buoyancy of the concrete coated pipe (kg/m)

DA = Average diameter of the concrete coating (m), as defined under 6.5.3 above

= Design specific weight of fluid (=1025 kg/m 3)

= Negative Buoyancy per unit length of concrete coated pipe (kg/m)



~ l *' PROJECTNUMBER S I R ~ ~ OIL COMPANY ~ r B o n a t t if lP-1326AT

Sheet 12 of 15 i SPC NUMBER JOB 83301

INDEX I i PLANT SEQUENCEA 0 1

SPC. No.

Rev. LD1 . 31 C1-9004 31-C1-9004

-,

6.2 Inspection of anti-cor;osion coating

Contractor shall carry out visual and Holiday tests on the FBE coating of each pipe length, prior to

proceeding with the concrete lining. Procedure for holiday test shall be as specified by the F8E

Manufacturer. In case holiday(s) are detected, the defective section of coating shall be identified and

repaired in accordance with procedure recommended by the FBE coating Supplier/Applicator and retested.

Concrete strength

The compressive strength of the corcrete coating shall be determined by testing concrete c u b ~ s (150mm size), prepared with fresh material taken before to enter in the mixer of impingement unit.Each cube will be marked with the date of sampling, the cube number and concrete batch No.Test samples of eight (8) cubes shall be taken during each shift production.

Two cubes will be--weighed after the specified period and the dry density will be calculated. The

acceptable tolerance on concrete dry density shall be + 5% - 2% to those measured during concrete

mix design. Two additional test will be carried out on two extra cubes in case of test failure bothcubes shall meet the requirement.

The first couple of cubes will be crushed after 28 days. The second couple of cubes shall be crushed

to determine the strength if the pipe are to be moved for shipment.

The minimum compressive required at 28 days test is 25 N/mm2 on cubic specimen..

Two extra cube will be prepared and tested in case of failure of any cube.

6.3.2 In the event that concrete cubes do not meet the minimum compressive strength requirements of this

specification, additional tests'of the suspect pipe coatings shall be made by schlerometer. (as perA.C.1. 318) in order to decide about the suitability of the pipe joints coated with the concrete from the

same batch. Schlerometer shall be calibrated prior to use.

6.4 Electrical insulation of reinforcement

6.4.1 Measurements shall be made on coated pipes, after curing, in order to make sure that there is no

electrical contact between the reinforcement and the steel pipe.

Tests shall normally be done on one pipe every len (10) coated pipes. Should any test fail, all pipes

of same day's production shall be tested.

6.4.2 The test shall be carried out when concrete coating is sufficiently dry. One measure shall be taken of

the electrical resistance between the steel pipe and the reinforcement prior to be cutted (para 4.2.4)

--

6.4.3 -The measurement is carried out using a megaohmmeter providing 500 Volts d.c. The electrical

resistance, measured between the reinforcement and the pipe, shall'not be less than 100 kW. When

the megaohmmeter gives values below 100 kW , the pipe section being t ~ s t e d must be put aside andthan inspected by C o i n p a n y ~ s Representative who, after furthertestsand checks, shall decide on the

corrective action to be taken.



~ ' ' ' , ~ "".

.I!.i .' PROJECT NUMBER

S I ~ T E OIL COM·PANY. j i ~ · ~ r B o n a t t i~ ~ " ~ TP-13215AT"'!.l''', .- .


INDEXA 1

PLANT SEQUENCE0

SPC. No.Rev. LD1 31 C1-9004 31-C1-9004

4.

5.2.2 Cracks

Cracks due to bending stress do not,need repair when their width is less than 2 mm (3 mm after site

transportat ion). Annular cracks exceeding 2 mm width (3 mm after site transportation) shai l' be

repaired if theyextend over 1800

of pipe circumference. Longitudinal cracks exceeding 2 mm width (3

mm after-site transportation) shall be repaired if they extend over 300 mm.

Repair shall be made by chiselling the crack out to a width of at least 25 mm throughout its length or

anyway up to a width compatible with size of aggregates used in the repair concrete.

Voids shall be filled using the methods outlined in Section 5.2.1 of this Specification.

5.3 Curing of repairs

All repairs shall be allowed to mOist cure for a minimum of 36 hours before the pipe is handled.

The resulting repair shal l be similar to the originally appl ied coating in uniformity, strength and

density.

6. INSPECTION AND TESTING

6.1 General

6.1.6

6.1.3

6.1.4

6.1.5

6.1.1 Contractor shall establish, before commencing production,-an identification procedure such that test

results can be clearly identified and associated to the appropriate pipe length.

Contractor shall have a field laboratorY available. The laboratory's equipment shall aI/ow the routine

quality tests performed during the concrete coat operations.

Special care shall be paid to m a i n t e n ~ ! 1 c e and correct sett!!lg of electrical/electronic equipment used

for inspection and testing. ' . ;

Current certification and/or calibratioh certificates..for all testing equipment shall be submitted for

Company's review prior to use. IContractor shall make available, and'where - ~ e q u i r ~ - d supply copies of .. all documentation required to

enable Company to determine that! t,he coating material and ·application and inspectioFl procedures

comply with the requirements of thi! ~ p e c i f i c a t i o n .

If, after-examination 'or testing, a coated pipe(s) is foundllot complying with the requirements of this

specification, all material defective 9r improperly applied shall be removed and the pipe(s) re-coated.

!All tests and inspection will be carried out by Contractor's Q.C. personnel. Purchaser has the right to

witness some or all tests, however production shall not be hold in case of absence of Purchaser's

representatives.

f; ~ ~ .

'-



.. ttl.

~

4vROJECT NUMBER

. ~ TP-1326AT SIRTE OIL COMp·ANY ~ r B o n a t t i

I

Sheel 10 of 15 SPC NUMBER JOB 83301

0 1INDEX PLANT SEQUENCE

ASPC. No.

Rev. LD1 31 C1-9004 31-C1-9004

5. REPAIRS

5.1 General

Repairs shall be made either using c o n c r ~ t e with the same proportion of constituents as the original

coating (a slight iRcrease in water content' is acceptable for hand repairs) and shall be performed assoon as possible after discovery of the damage.

The concrete-shall be placed by either jehing or trowelling. such that the surface is continuous with

the level of the undamaged coating a r o u n ~ the repair. All repairs shall be visually inspected to ensurethat the finished coating complies with thi,s specif icat ion.-

All rejected sections of pipe coating, to be subsequently re-coated. shall have the concrete carefullyremoved. After the removal of the defective concrete coating, the anti-corrosion FBE coating shall beexamined for damage and tested by Ho!iday Detector. All damaged anti-corrosion coating shall berepaired in accordance with procedure recommended by the FBE coating Supplier/Applicator and retested before subsequent re-coating with concrete.

5.2 Permissible repairs to Concrete Coating

The following repairs shall be permitted for concrete coating defects or damages during har.dling or

st,prage.

5.2.1 Spalling

Spalling due to compression or shearing caused by impact against other objects will be handled as

follows: :

a) Spalling which causes a loss of no more than 20% (25% after site transportation) of the total

thickness of the coating in an area of less than 300 cm 2, where the remaining concrete is soundwill be accepted without repairs.:

b) Spalling which causes a loss of more than 20% (25% after site transportation) of the coating

thickness or which affects an area larger than 300 cm 2, but having a dimension not exceeding 1/6

of the pipe circumference, shall be repaired.The damaged concrete shall be removed such as to expose the sound concrete. The resultingcavity will then be filled by the mix used for the repair. Before pouring, the cavity surface shall be

brushed and wetted with a mortar prepared with one part cement and two parts sand.

c) In case the dimension of damaged area is larger than 1/6 of the pipe circumference, the coating

shall be completely removed on an annular portion exceeding the dimension of the damaged

area. A new coating shall be applied on this portion, including the steel reinforcement. if al]y, using

a metallic sheet as a formwork. such as to obtain the requiredcoating thickness. Before casting.

the surface of the adjacent concrete shall be brushed and wetted with a mortar prepared as per

previous item b). '



L ,"

49ROJECT NUMBER

SIRTE OIL COMPANY ~ r B o n a t t iTP-1326AT

Sheet 9 of 15 : SPC NUMBER JOB 83301


Rev. ,., LD1 31 C1-9004 3i-C1-9004

.t.

.;

The uncoated portion of the pipe and the bevels shall be kept clean and free from concrete spatter,

oil, grease, etc. : :I : '

4.5 Stripping

Coated pipes shall be removed from impingement unit, and shall be laid on sand berms. Particular

care shall be taken in pipe picking up and handling in order to prevent any damage to the freshI

concrete.! - .I

Curing of Concrete

Concrete coatings may be cured by any of the two following methods (see next art!. 4.6.2 and 4.6.3)

but, whichever is used, the concrete shall not be allowed to dehydrate and the temperature of the

concrete coat shall not be allowed to fall below 2 °C during the initial 24 hours of curing.

.-

If water curing method is adopted, curing shall commence not later than two hours after stripping and

shall comprise keeping the coating continuously moist for a period of not less than seven days. This

maybe accomplished by water spray, application ofJutefgunny bags spreaded over the pipes. or any

other approved mean. Use of curing compound, that may be proposed by Contractor in his curing

procedure, can reduce the above specified watering period. Contractor shall submit details of the

rl)ethod to Company for approval.

Water spray curing shall not be allowed when ambient temperature falls below 5°C.

If any s h ~ e t or. film is used for concrete curing, i t shall comply with ASTM C17i. Samples 9f thematerialshall be taken and tested to ensure conformity with ASTM C171, unless Manufacturer's test

results are available.

4.6.4 Pipes shall not be removed from their first curing site nor handled for transportation until a time has

elapsed from casting equal to the time required by concrete to attain a compressive cube strength of

16 Nfmm2.

4.7 Marking

4.7.1 Care shall be taken by Contractor to preserve the original pipe marking by pipe mill and the marking

applied by tbe FBE coating Applicator.

4.7.2 The date of casting and the pipe number shall be stencilled using indelible paint on the external

surface of the co,,!cretecoating.-



. .. . '-"0_- ..

PROJECT NUMBER

SIRTE OIL COMPANY ~ ' B o n a t t i' TP-1326AT.:

Sheet 8 of 1S SPC NUMBER JOB 83301


Rev.LD1 31 C1-9004 31-C1-9004

,.Contractor shall take all necessary measures to prevent any damage to FBE pipe coating and to pipe

bevels and to avoid any entrance of concrete into the pipe during coating operations.

4.2 Placement of steel wire mesh

Three concentric layers of galvanized steel wire mesh shall be applied. The Contractor shall propose

a positioning of the reinforcement l ~ y e r s for Purchaser approval..

The distance from anti-corrosion coating to the inside of the reinforcement shall be a minimum"ofi5

mm and 20 mm between the mesh and the outer surfaceof

the concrete. <1>

Overlap for reinforcing shall be not less than 25 mm.

4.2.4· The wire mesh at the end shall be cut in a such way that shall be covered by at least of 15 + 20 mm

of concrete. <1 >

Placement of Concrete Coating

The constituent parts of the concrete mix shall be weight-batched using a batching plant daily

c9librated.

A water gauge accurate to within 2 of the indicated values shall be used for adding water to themix. :1' -.

Ii

,!.The accuracy of the weight device fot:weight batcher shall be 2%, calibrated prior to production and acalibration chart issUed to Purchaser; ,The weight-batcher and water gauge shall be regularly checked

'. 'Ifor accuracy (at least once a month).;:

,II:The dry materials shall be batch mixed with the required quantity of water to make a homogeneous

mix using a mechanical mixer. The concrete shall then be transferred to impingement unit an than

impinged upon the pipe within amaximum of 30 minutes from the time of mixing water.! .

In case fresh concrete needs to be.applied after an interruption the surface of the previously placed

concrete shall be cleaned and wetted in order to obtain a good bond between the fresh and thepreviously placed material. i .

Each joint of pipe shall be coated in a continuous operation, the time allowed between the first coat

and the last coat shall not exceed one hour.. '

Concreting shall not take place if temperature of pipe, or of reinforcement or of concrete . ~ i x is lower

than5°C.'

4.4.1

4.4 Cut back

The concrete coating shall be applied to within 350 ±10 mm from the ends of each length of pipe. The

ends of the concrete coating s h ~ 1 I be square cut back and in accordance with paragraph 4.2.4. <1>

calculation of negative buoancy for pipelines

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