Developments in field coating used in new Dutch pipelines

Ir. A.M. Dam,

29th February 2012

Content

Introduction

Types of pressings and drillings

Coating approach and choices

Tests and experiences

Developments and improvements

Summary and Conclusions

Introduction [1]

Introduction [2] North – South project

600 km 48 inch pipeline

2 Compressor stations

Investment >2.000 mln euro

Owner: Gasunie

Construction: 2010-2013

Introduction [3]

pressing

drilling

0

20

40

60

80

100

120

140

5 15

25

35

45

55

65

75

85

95

10

5

11

5

12

5

13

5

14

5

15

5

16

5

17

0

length ranges [m 5m]

nu

mb

er

[/

]

Pressings.

Total: 476

≥

±

0

2

4

6

8

10

12

14

32

5

37

5

42

5

47

5

52

5

57

5

62

5

67

5

72

5

77

5

82

5

87

5

92

5

97

5

10

25

10

75

11

25

11

75

12

25

12

75

13

25

13

75

14

25

length ranges [m 25 m]

nu

mb

er

[/

]

Drillings.

Total: 63

±

Types of drillings and pressings [1]

• Open front end pressing

pushing (avegaar)

impact ramming

• Cutter head conventional pressing

Horizontal Directional Drilling (HDD)

pilot drilling + roaming (conventional)

push and pull with “Pipe thruster”

cutter head (“Direct pipe”)

Pressings length most < 100 m

Drillings length > 2750 m and increasing

Types of drillings and pressings [2]

Pushing and pulling:

• on steel => conventional

• on coating

Coating approach and choices [1]

Mill coating.

General => multi-layer coatings

– Anti-corrosion layer

– Mechanical protection layer

Mill coating => 3-layer coatings: chosen by Gasunie:

– Line pipe => PE

– Pressings & drillings => PP with additional thickness:

– ≤ 20”: min. 4.5 mm (3.0 mm on weld seams)

– > 20”: min. 6 mm (4.0 mm on weld seams)

Approval:

– According ISO 21809-1 => PQT, PPT, “production”

– NO standard on mill coating for pressings & drillings

Coating approach and choices [2]

Field coating (1).

General => multi-layer coatings

– Anti-corrosion layer

– Mechanical protection layer

Field coating => options given by Gasunie, choice by contractor

– Line pipe

– Anti-corrosion layer: epoxy or visco-elastic material

– Mechanical protection layer: shrink sleeve

– Fittings

– Visco-elastic material + tape

– Butyl rubber based material + PE-tape

Approval:

– According ISO 21809-3 => PQT, PPT, “production”

Coating approach and choices [3]

Field coating (2).

– Drillings and pressings => options given by Gasunie:

– PP Flame Spray

– Canusa GTS PP

– PUPPlining

Remark: NO GRE / epicoat / wavistrong

Approval:

– NO standard on field coating for pressings & drillings

Tests and experiences [1]

Material Resin : Epikote 828 Hardener : Euredur 43 Glass : Woven, 10 cm wide, 280 gr/m2 360 gr/m2 580 gr/m2 Non woven KH1603

Laminate instructions for steel welded joints for pipe diameter: 16" – 40”

Tests with GRE / epicoat / wavistrong :

Tests and experiences [2]

Experiences with GRE / epicoat / wavistrong:

Tests and experiences [3]

Experiences with PP Flame Spray:

Tests and experiences [4]

Experiences with Canusa GTS PP:

Tests and experiences [5]

Experiences with PUPPlining:

steel

PP mill coating

PP plate

polyurethane

PP “weld”

fibers

Tests and experiences [6]

Tests with PUPPlining:

Test: • 18 m pipe 36” • filled with water => total weight 17.5 ton • length test track app. 1000 m

Tests and experiences [7]

Impressed current tests:

Criterion, where A [m2]:

0 – 1000 m2: Imax = A *0.001 [mA] 1000 – 5000 m2: Imax = 1 + (A-1000)*0.00005 [mA]

DCVG (Direct Current Voltage Gradient) • directly after burial • within 1 year (guaranty period)

0,0

1,0

2,0

3,0

4,0

5,0

0 500 1000 1500

length [m]

cu

rren

t d

en

sit

y [

uA

/m

2]

0,0

0,2

0,4

0,6

0,8

1,0

0 500 1000 1500

length [m]

cu

rren

t d

en

sit

y [

uA

/m

2]

Tests and experiences [8]

steel

PP mill coating

flush

Experiences with HDD’s & pressings (@ e.g. 48” diameter).

steel

PP mill coating

Experiences with HDD forces.

0

100

200

300

400

500

600

700

800

900

0 200 400 600 800 1000 1200 1400

Pipe diameter [mm]

Fo

rce [

kN

]

Loose clay / peat

Stiff clay

Normal sand

Hard sand

R = 800 – 1000 * diameter [m]

R

Tests and experiences [9]

Scratch tests on mill and field coatings (1):

Tests and experiences [10]

Scratch tests on mill and field coatings (2):

y = 0,0003064x

R2 = 0,9943897

y = 0,0002401x

R2 = 0,9845693

0

1

2

3

4

5

6

0 3000 6000 9000 12000 15000

scratch load [N]

red

ucti

on

coati

ng

th

ickn

ess [

mm

]

6 mm PE

6 mm PP

Lineair (6 mm PE)

Lineair (6 mm PP)+ 28 %

0

1

2

3

4

5

6

7

0 3000 6000 9000 12000 15000 18000 21000 24000

scratch load [N]

red

ucti

on

coati

ng

th

ickn

ess [

mm

]

PE mill coating

PE field coating

PP mill coating

PP field coating

8 mm thickness4,5 & 6 mm thickness

Results PE versus PP (6 mm mill coating)

Results mill versus field

Tests and experiences [11]

Scratch tests on mill and field coatings (3): Results PE versus PP (mill & field coating)

0

3000

6000

9000

12000

15000

8:09:36 8:24:00 8:38:24 8:52:48 9:07:12 9:21:36 9:36:00 9:50:24

time [hh:mm:ss]

scratc

h f

orce [

N]

0

3000

6000

9000

12000

15000

8:09:36 8:24:00 8:38:24 8:52:48 9:07:12 9:21:36 9:36:00 9:50:24

time [hh:mm:ss]

pu

ll f

orce [

N]

y = 0,45867x

R2 = 0,37718

y = 0,57257x

R2 = 0,40737

0

3000

6000

9000

12000

15000

0 3000 6000 9000 12000 15000

scratch force [N]

pu

ll f

orce [

N]

PP

PE

Lineair (PP)

Lineair (PE)

diff. 25%

Developments and improvements [1]

Repair:

Developments and improvements [2]

Wehocoat:

Summary and conclusions [1]

• Gasunie is expanding its network with pipelines in 48” size. • the amount and length of drillings and pressings is large and increasing. • there are new methods for drillings: “Pipe thruster” and “Direct Pipe”. • PP is a stronger (± 25%) coating material than PE for use in drillings & pressings. • in the “North-South” project an existing and a new PP field coating system are successfully used. • those field coating systems have the same strength as the PP mill coating. • after some start-up problems the performance of those field coating systems is excellent now. • drillings with increasing pipe diameter give an increase in load on the coating. • the amount of load, a coating can coop, increase with increase in coating thickness. • drillings and pressings with large diameter (eg 48”) pipe require “flush” field coating systems. • the height of weld caps (round, seam or spiral) in steel pipe or pipe connection reduces the effective coating thickness.

Summary and conclusions [2]

• new repair methods for coatings are successfully introduced in the field and which originate from the “plastic industry”. • a new field coating system is under investigation. • the human factor is important and often decisive for the quality obtained especially in the field. • quality checks like “impressed current test” and “DCVG” work very fine. • contrary to line pipe, the pipe in a HDD can NOT be excavated and repaired. A high level of coating quality is compulsory in a HDD !