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HDPE Pressure Pipe
Occasional and Recurring
Surge Design Considerations
Mark Knight PhD, P. Eng.
University of Waterloo
Camille George Rubeiz, P.E.
Plastics Pipe Institute
Larry Petroff, P.E.
Plastic Pipe Consultant
Developers of Industry Leading Design Tools
BOREAID
Full commercial licenced HDD design tool Fall 2013 a Vermeer
Product
free web based HDD PE pipe design tool limited version of
BOREAID
free web based HDPE and PVC pressure pipe calculator that
follows ASTM and AWWA standards
Disclaimers
I am a product independent academic and
researcher
I am not paid to represent any pipe manufacturers
or suppliers
Confused Plastic Pipe Industry
Different terminology for HDPE and PVC
Pressure Class (PC) vs Pressure Rating (PR)
DIOD, CIOD, IPS, DIPS
HDPE vs PVC marketing
Lack of industry understanding of ASTM
and AWWA design methods
HDPE and PVC
Pressure Pipe Design Standards
ASTM
F714
AWWA C901
AWWA
C906
AWWA
C900/C905
PE3608
PE 4710
@ 1000 psi
PE3608
PE 4710
@1000 psi
PE3608
PE4710
@800 psi
PVC12454
PVC12454
@ 2000 psi
PVC12454
HDPE Pipe Resin = PE3608 and PE4710
PVC Pipe Resin = PVC12454
Plastic Pressure Pipe Design
PIPE Design Input Properties
Velocity
Min ID
Flow
Pressure
Disinfectant
Complete Operational Design
Working and Surge Pressure Analysis
Complete Life Cycle Design Analysis
Fatigue Determine No. of cycles to failure over design life
Working Pressure Design
Hydrostatic Design Stress (HDS)
HDPE
ASTM
F714
PE4710
PE3608
PVC12454
AWWA
C901
1000psi
PVC
AWWA
C906
AWWA
C900/C905
800psi
800psi
2000psi
Pressure Class (PC) @ 73oF
PC = 2 HDS/(DR-1)
HDS = Hydrostatic Design Stress
DR = Dimension Ratio = OD/tmin
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Allowable Pressure Design
PVC
AWWA
C900/C905
HDPE
AWWA M55
WPR
PC x FT
WPR + Pos
2.0 x PC x FT
1.6 x PC x FT
WPR + PRS
1.5 x PC x FT
PC x FT
WPR = Working Pressure Rating
POS = Occasional Surge
PRS = Recurring Surge
Temperature Factors (FT)
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Temperature Factors (FT)
HDPE
AWWA M55
FT
1.0
0.9
0.8
PVC
AWWA
C900/C905
Continuous Long-Term
Temperature
< 81oF
81 90oF
91-100oF
80oF
90oF
100oF
FT
0.88
0.75
0.62
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Allowable Design Pressure Example
PC = 2 HDS/(DR-1)
HDPE
DR-17
ASTM
F714
PE 4710
PE 3608
PVC
12454
AWWA
C901
125 psi
AWWA
C906
PVC
DR-18
AWWA
C900
C905
100 psi
100 psi
235 psi
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Surge Design (Wing Flex Design)
What are the major design Issues for Wing design?
TypicalPressureFluctuationfrom
SuddenValveClosureinDR11Pipe
Pressure
(bar)
LoadRate~120psig/sec
Time(seconds)
G.P.Marshall,S.Brogden,M.A.Shepherd(1998)EvaluationoftheSurgeandFatigueResistanceofPVCand
PEPipelineMaterialsforuseintheU.K.WaterIndustry,
PlasticsPipeX,Goteburg,Sweden
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Surge Design
Design system such that it can withstand the
highest expected surge load event over its
design life
While a full transient analysis is recommended,
a full flow stoppage at the max. flow velocity
provides a good basis for considering surge
events.
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Surge - Analysis
Joukowsky Equation:
Ps = a(V/2.31g)
Ps = surge (psi)
a = wave velocity (ft/s)
V = change in velocity (fps)
g = acceleration due to gravity (32 ft/sec2)
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What are Typical
Network Water Velocities?
Jana Lab survey of 51 water utilities determined:
Average Maximum Design Velocities for Normal Flow
Average Maximum Design Velocities for Fire Flow
Jana Lab Water Velocity Survey
http://plasticpipe.org/pdf/mid-fatigue-plastic-water-pipe-01-12-12
Maximum Design
Velocity for Normal Flow
(fps)
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Average = 6.7 fps
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10
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51
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Fatigue Design
Recurring surges:
frequently occurring surges caused by
normal pipe operations like opening and
closing of pumps and valves, AWWA PE M55
may occur up to millions of times in a
piping systems lifetime AWWA PVC C905-10
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Fatigue Design
Occasional surges:
Caused by emergency operations
Often the result of a malfunction, such
as a power failure or system component
AWWA PE M55
failure
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PVC Fatigue Design
PVC design fatigue life is determined using AWWA
C900 and C905 Appendix B.
Well established method but not well understood in
the industry.
Often not performed due to analysis complexity
and lack of industry understanding
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PVC Fatigue Design
HDPE Fatigue Design
Fatigue surge pressure analysis in AWWA M55
Fatigue life method is not in current AWWA M55
(typically, not a limiting factor)
Fatigue life method will be implemented in revised
AWWA M55
PE 3608 / PE 4710 design fatigue life can be
determined using fatigue curves provided in
Marshall, G.P., Brogden, S: Final report of Pipeline
Innovation Contract to UKWIR, 1997.
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HDPE Fatigue Design
PPI-PACE methodology implemented from:
AWWA M55-2005, PE Pipe Design and Installation
Jana Lab, 2012, Fatigue of Plastic Water Pipe: A
Technical Review with Recommendations for PE4710
Pipe Design Fatigue
PE4710 fatigue S-N curves data from:
Resistance of PE4710 Piping to Pressure Surge Events
in Force Main Applications, PP XVI, Barcelona, 2012
UK Water Industry IGN 4-37-02 Design Against
Surge and Fatigue Conditions for Thermoplastic
Pipes
PE4710RecurringSurgePipeTests
(cycles0to1.5xPC)
Test Specimens
Cycles at 1.5 x PC
(Recurring Surge)
Status
11,213,023
Straight Pipe
10,038,073
6,754,833
Pipe with buttfused joint
10,952,363
No
Failures
11,017,153
TestsconductedbyJanaLabsSeeCrabtreeetal.,PPXVI,2012
Aftercompletionpipescycledfrom0to2xPC
for2739to6665cyclesnofailures Showslotsofliferemaining
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NumberofCyclestoFailure
StressforPE4710at1.5x PC=1500psi(10.34MPa)
Jana4tests
4thGenerationPE
at1500psi
1450psi
1st GenerationPE
G.P.Marshall,S.Brogden,M.A.Shepherd(1998)EvaluationoftheSurgeandFatigueResistanceofPVCandPE
PipelineMaterialsforuseintheU.K.WaterIndustry,
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PlasticsPipeX,Goteburg,Sweden
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http://ppipace.com/
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PPI-PACE: Purpose
1. Developauserfriendly,free&onlinepipesoftware
2. Provideprelim.calculationsforoperatingpressure,
surgepressureandfatiguedesignlife.
3. Assistdesignersandownersintheevaluationofplastic
pipeforwaterdistribution,transmissionandforcemains
4. Implementexistingstandardsandmethods:AWWA
C900/C901/C905/C906,M55andASTMF714/D2241.
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PPI-PACE Defaults
Recurring Surge
Velocity
Occasional Surge
velocity
Working
Pressure
Anticipated
Surges per day
Temperature
Min. Design Life
Default
5 fps
Allowable Range
4 8 fps
8 fps
5 - 15 fps
70 psi
40 psi (min.)
55 cycles
57 oF
100 years
40-100 oF
50 (min.)
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UNI-BELL and PPI-PACE
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Design Example
18 inch DIPS/CIOD
160 psi Operating Pressures
4.0 fps Recurring Flow Velocity
7 fps Occasional Flow Velocity
57oF Temperature
100 Year Design Life
55 cycles/day = approx. 2 million cycles/100 yrs
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Uni-Bell Design Example
1. Why HDPE DR 7.3? DR 13.5 (PC 160) is OK
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PE 4710 DR
13.5 (PC 160)
OK
PE 3608 DR
13.5 (PC 128)
NG
PVC DR 14
(PC 305) NG
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PE 4710 DR 13.5 (PC 160) OK
PE 3608 DR 13.5 (PC 128) NG
PVC DR 14 (PC 305) NG
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Summary
HDPE and PVC are both good materials
According to existing approved design standards
HDPE has much fatigue life than PVC
PPI-PACE provides a simple, easy to use plastic
pipe design tool that follows existing design
standard methodologies
