PE pressure pipes made from PE 100-RC - hessel … · PE pressure pipes made from PE100-RC ......

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HESSEL Ingenieurtechnik

PE pressure pipes made from PE100-RC

Plastic Pressure Pipes 05.-07.October 2009 | HESSEL-Ingenieurtechnik GmbH

PE pressure pipes made from PE 100-RC

Design and calculation of gas- or water pipelines

for a minimum service life of 100 years

Dipl.-Ing. Sven Nonhoff

Dr.-Ing. Joachim Hessel

HESSEL Ingenieurtechnik GmbH

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We offer SOLUTIONS

ŁŁŁŁ for engineering applications of thermoplastics,

ŁŁŁŁ by quick and comprehensive tests of raw materials,

ŁŁŁŁ to matters concerning design and fabrication.

Accredited Testing Laboratory according to

DIN EN ISO/IEC 17025 by DAP GmbH (DAP-PL-3760.00)

We are an officially approved testing, inspection and certification

facility (NRW 37). raw materials / pipes / shafts

HESSEL Ingenieurtechnik GmbH

Am Vennstein 1a ■ D-52159 Roetgen

Phone: +49-2471-92022-0 ■ Fax: +49-2471 - 92022 -19

E-Mail:[email protected] ■ Internet: www.hessel-ingtech.de

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Contents

1. Overview on Failure Modes

2. Progress in raw material development

3. Requirements of PAS 1075

4. Thermal Ageing

5. New creep rupture curves for PE 100-RC

6. Conclusion

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Failure Modeslo

g σ

[N/m

m²]

log t [h]

ductile

brittle

thermal ageing

Ø failures through

stretching of material

Ø failures through

stress cracking

àààà Relevant for service life

Ø failures independent of

stress level

Ø Onset of thermal ageing

at 80 °C after 1 year*


* DVS directive DVS 2205-1, sup. sheet 19

flat ‘branch’

2 nd‘branch’

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Full-Notch Creep Test

Test fluid – e.g. ARKOPAL N-100

F

circumferentialnotch

F

FNCT

dead load

rupture record

constant fluid

temperature


Test to detect stress cracking resistance: FNCT

Advantage:

Ø The results out of FNCT

correlate with results out of

pipes under internal pressure

Ø Test time reduction by using

surface active solutions

(VA 2.1-4, ISO 16770; DIN EN 12814-3 (2005-10), Anhang A.1; DVS 2203-4)

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Influence of medium


log

σ [N

/mm

²]

log t [h]

water

gas

Same slope but different rupture times

surface active solution

(e.g. 2% ARKOPAL N-100)

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10

100

1.000

10.000

Rupture Time in Hours

Test temperature 80 °C

tensile load 4 N/mm²2 % Arkopal N-100

F


F

FNCT

14460 14835

PE 100-RC

Increasing rupture times


4

11

PE 63

1960

338 359491

643832

2.041

10462

PE 100

1999

31

51

259

1980

PE 80

Specimens show brittle failure

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Requirements to PE 100-RC raw material (PAS 1075)


> 8760 h

Notch Test on full

walled piping

(DIN EN ISO 13479)

> 100 years @ 20 °CThermal ageing test

> 8760 h (> 1 year) at 80 °C

4 N/mm², in 2 % Arkopal N-100

Point loading test on

full walled piping

> 8760 h (> 1 year) at 80 °C


Stress cracking test (FNCT)

RequirementTest

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> 8760 h (> 1 year) at 80 °C

4 N/mm², in 2 % Arkopal N-100FNCT ⇒⇒⇒⇒ no brittle failure until 1 year⇒⇒ ⇒⇒

onset of thermal ageing after 1 year at 80°C in water *



log t [h]

log

σ [N

/mm

²]

4 N/mm²

> 1 year

thermal ageing

F


F

FNCT

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> 8760 h

Notch Test on full

walled piping

(DIN EN ISO 13479)

> 100 years @ 20 °CThermal ageing test

> 8760 h (> 1 year) at 80 °C


Point loading test on

full walled piping

> 8760 h (> 1 year) at 80 °C


Stress cracking test (FNCT)

RequirementTest

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4. Thermal ageing

Influencing variables for thermal ageing

ü Oxygen concentration

ü Temperature

ü Flow rate of medium

ü Stabilization package

ü Local strain situation

NOT taken into account in ISO 9080

⇒ values are too optimistic

⇒⇒⇒⇒ For PE 100-RC materials thermal ageing has to be tested additionally

weekly exchange

of medium

Circulating

medium

Point loads

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4. Thermal ageing

Extrapolation of results àààà Arrhenius-Diagram

log t [h]

Re

cip

rocal a

bsolu

te t

em

pe

ratu

re [

1/K

]

80 °C

90 °C

100 °C

20 °C

> 100 years

reciprocal slope of regression curve is proportional to activation energy EA for thermal ageing

~ EA

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4. Thermal ageing

Minimum required activation energy for thermal ageing

1. Requirement: no failure until 100 years @ 20°C

Minimum required activation energy for thermal ageing:

EA ≥ 67 kJ/mol

log t [h]

Re

cip

roca

l ab

so

lute

te

mp

era

ture

[1/K

]

80 °C

90 °C

100 °C

20 °C

> 100 years

~ EA

> 1 year

2. no failure until 1 year @ 80°C *


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PE 100-RC exceeds standard creep rupture curveslo

g σ

[N/m

m²]

log t [h]

flat ‘branch’

steep ‘branch’

the

rma

l age

ing

?1 year at 80 °C

PE 100 according to DIN 8075

PE 100-RC5 N/mm²

1000 h

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1

10

100

1.000

10.000

100.000

1.000.0002,5

3

4

5

6

7

8

9

10

11

12

13

14

15

Rupture time [h]

Ho

op

str

es

s [

N/m

m²]

1 10 100 Jahre

20°C

40°C

60°C

80°C

1

10

100

1.000

10.000

100.000

1.000.0002,5

3

4

5

6

7

8

9

10

11

12

13

14

15

Rupture time [h]

Ho

op

str

ess

[N

/mm

²]

1 10 100 Jahre

20°C

40°C

60°C

80°C


New creep rupture curves for PE 100-RC in PAS 1075

Creep rupture curves

according to PAS 1075Creep rupture curves

according to DIN 8075

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6. Conclusion

Conclusion

• PE 100-RC - thermal ageing becomes the relevant failure mechanism

• PE 100-RC exceeds standard creep-rupture curves

• PE 100-RC are raw materials with very high stress crack resistance

⇒ High chemical resistance

⇒ Extended application àààà alternative installation techniques

• PE 100-RC - New creep rupture curves have been established in

PAS 1075

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Thank you for your attention !

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PE pressure pipes made from PE 100-RC - hessel … · PE pressure pipes made from PE100-RC ......

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