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How do the different standards define 'Surge Cycles'?
Answer

Definition 1
AWWA C906-07 for PE PIPE

The allowance for recurring positive surge pressure included in the pressure class rating is applicable to current PE materials described in this standard. This allowance assumes that the total number of surge events the piping will experience over its intended service life will not exceed one million. Some PE materials provide greater fatigue endurance and permit the use of larger effective allowances. The manufacturer should be consulted for more detailed recommendations.

Definition 2
AWWA M55-06 for PE PIPE- First Edition

Number and magnitude of cyclic loading events in a pipeline Lifetime

Design lifetimes for piping systems vary. However, it is increasingly common for pipeline owners and designers to establish 50 to 100 year service life expectations for municipal potable water systems. Long service lives require significant resistance to fatigue, even if the daily number of surges is relatively small. Table 1 was newly created to show the cumulative surge events for 50 and 100-year service lives for multiple hourly and daily surge events.

Table 1. Pressure Surges in a 100 year Service life
Surges
[per day]		 Surges
[per hr]		 Surges
[per 50 years]		 Surges
[per 100 years]
1 0.04 18,263 36,525
10 0.42 182,500 365,00
40 2 730,000 1,460,000
75 3 1,368,750 2,737,000
150 6 2,637,500 5,475,000
250 10 4,562,500 9,125,000
300 13 5,478,750 10,957,500


The actual number of surge events experienced by a pipeline is dependent on the specific pipeline design and operating conditions and varies even within a given pipeline system. Resistance to cyclic loading must, therefore, consider the total number of expected surge events based on an analysis of the specific system.

Definition 3
AWWA C900-07/C905-10 for PVC PIPE

It is stated that recurring surge pressures may occur up to millions of times in a piping system’s lifetime.

Design Examples state:
Number of cycles: Anticipated # of cycles = (# cycles/day) × (365 days/year) × (Design Life in Years). 55 cycles/day (PPI PACE default) result in 1 million cycles over 50 years or 2 million cycles over 100 years. The PPI PACE default is reasonable and realistic.

Definition 4
AWWA M23 for PVC PIPE – Second Editon

Page 59 states:
"The application of PVC pressure pipe for water transmission mains differs greatly from that of a distribution main. There are virtually no cyclic stresses, velocities may be higher, and surges in general are very occasional."

Page 66 states:
"When transient pressures of noticeable magnitude occur on a frequent basis, cyclic stresses may be imposed upon the pipe material. If the cyclic stresses occur frequently enough at a sufficiently high magnitude, fatigue failure is a possibility in a thermoplastic pipeline, such as PVC.

Cyclic stresses are found more commonly in sewage force mains or turf irrigation lines than in water mains. Smaller-sized distribution mains do generate cyclic surges; however, the generously large safety."

What are some typical values for 'Surge Cycles'?
Answer

Typical Surge Cycles

The design of a piping systems requires engineers and systems owners to set an acceptable design pipe life. Typically a water pipe design life is set between 50 to 100 years. For PVC and PE pipes the cumulative number of fatigue cycles will determine the pipe design life. PPI-PACE defaults to 55 cycles per day and allow values greater than and equal to 55 cycles per day. PPI-PACE defaults values are reasonable and realistic for most watermain and forcemain designs.

Where do these typical values for 'Surge Cycles' come from?
Answer

Datum Source Reference Comments
55 cycles/day ANSI/AWWA C900-07 Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings, 4in. Through 12In. (100mm through 300 mm), for Water Transmission and Distribution Appendix B Recurring (Cyclic) Surge-Figure and Design Example Page 23 Section B.2: Design Example Anticipated cycles per day = 55
54 cycles/day AWWA C905-10 Appendix B Recurring (cyclic) Surge - Figures and Design Examples Section B.2: Design Example Page 27 Total # of cycles = factor of safey *(# cycles per day) * (365 days/year) = 2 *54*(365*50) = 2 million cycles in 50 years Note: 54 cycles per day
48 - 192 cycles/day Charlotte Mecklenburg Utilities Wastewater Pumping Station Standard Specifications Section 2.04 Cycle and Pump Run Times A 2 page 6 Pumps shall be designed to operate between two and eight times per hour at a design daily flow
96 - 120 cycles/day Charlotte Mecklenburg Utilities Wastewater Pumping Station Standard Specifications Section 2.04 Cycle and Pump Run Times A 2 page 6 with a strong preference for 4 to 5 cycles per hour
116 cycles/day Uni-Bell 2012 Fifth Edition Handbook of PVC Pipe Design and Construction Page 5.44 Example 5.5 14in. AWWA Force main page 5.47 N=58 starts+ 58 stops = 116 cycles/day
96 cycles/day Performance Pipe Bulletin PP402-4710 1 cycle every 15 minutes = 96 cycles/day

How do the different standards define 'Recurring Surge Pressure'?
Answer

Definition 1
AWWA C906-07 for PE PIPE

Recurring (cyclic) Surge Pressure (PRS): Recurring surge occur frequently and are inherent in the design and operation of the system (such as normal pump startup or shutdown, and normal valve opening or closure).

Definition 2
AWWA M55-06 for PE PIPE- First Edition

Recurring (cyclic) Surge Pressure (PRS): recurring surge occur frequently and are inherent in the design and operation of the system. Recurring surge pressures may be caused by normal pump start-up or shut-down and normal valve opening or closure. PRS is the allowance for recurring surge pressures.

Definition 3
AWWA C900-07/C905-10 for PVC PIPE

Recurring (cyclic) Surge Pressure (PRS): Surge pressures that occur frequently and are inherent to the design and operation of the system (such as normal pump startup or shutdown and normal valve opening or closure). Recurring surge pressures may occur millions of times in a piping system’s lifetime.

Definition 4
AWWA M23 for PVC PIPE – Second Editon

"Surges may generally be divided into two categories: transient surges and cyclic surges. Transients may best be described as the intermediate conditions that exist in a system as it moves from one steady-state condition to another. The closing of a single valve is a typical example. Cyclic surging is a condition that recurs regularly in time. Surging of this type is often associated with the action of equipment such as reciprocating pumps and pressure-reducing valves. Small oscillatory surges can grow rapidly in magnitude and can become damaged if the frequency is at or near the natural resonant frequency (harmonic) of the piping system. Any piping material including PVC may eventually fatigue if exposed to continuous cyclic surging at sufficiently high frequency and stress amplitude."

What are some typical 'Recurring Surge Velocities'?
Answer

Typical Recurring Surge Velocities

The design of PVC and PE pressure pipe requires the system recurring surge flow velocity or normal systems operational flow. The design Recurring Surge pressure is estimated using the change in water velocity resulting from sudden stoppage of the operational (normal) design flow. Graphs and Tables below summarize available water design guides and reports, water design standards, and utility and forcemain specifications, which provide guidance on realistic recurring surge flow velocities.

  • WATERMAINS

    Normal water flow velocities are shown to range from 3 to 10 ft/sec. Most flow velocities range from 5 to 7 ft/sec. PPI PACE considers flow velocities from 4 to 8 ft/sec. This range is reasonable and realistic.

  • FORCEMAINS

    Normal water flow velocities are shown to range from 2 to 10 ft/sec. The data indicate the mean flow velocity is approximately 6 ft/sec. PPI PACE considers flow velocities from 4 to 8 ft/sec. This range is reasonable and realistic for most forcemain designs where fatigue should be considered.

Where do these typical 'Recurring Surge Velocities' come from?
Answer

Note: Click the columns of the graph to drill down to the specific data.
Note: Click 'Back to Data' on the graph to return to the averaged data.

SOURCE DATA FROM DESIGN REPORTS

SOURCE DATA FROM DESIGN STANDARDS

SOURCE DATA FROM UTILITY SPECIFICATIONS

SOURCE DATA FROM FORCEMAIN SPECIFICATIONS

Datum Source Reference Comments
8.0 fps PE UPC (Max) An American National Standard IAPMO/ANSI UPC 1-2012 Installation Standard for Polyethylene (PE) Cold Water Building Supply and Yard Piping Page 359 Water flow velocity shall not exceed 8 ft/Sec
8.0 fps PVC UPC (Max) An American National Standard IAPMO/ANSI UPC 1-2012 Installation Standard for PVC Cold Water Building Supply and Yard Piping Page 361 Water flow velocity shall not exceed 8 ft/Sec
7.8 fps ANSI/AWWA C901-08 (Ex) Polyethylene )PE) Pressure Pipe and Tubing, 1/2 In. (13 mm) Through 3 In. (76 mm), for Water Service APPENDIX A Example Page 22 an acceptable recurring surge in this example is 100/12.8 = 7.8 ft/sec
3.0 fps AWWA C906-07 (Ex C.1.1) Appendix C Working Pressure Rating and Pressure Class Page 33 Watermain design Examples C1.1
5.0 fps AWWA C906-07 (Ex. C.1.2) Appendix C Working Pressure Rating and Pressure Class Page 35 Watermain design Examples C.1.2
5.0 fps ASTM F645-13 Section 5.1 Page 488 Surges likely to be encountered at water flow velociites up to 5 ft/sec.
Datum Source Reference Comments
10.0 fps City of Palo Alto, CA, US Part III- Water Distribution System Section 2660 - Page 14 maximum design flow velocity in any residental or commerical water service shall not exceed 10 ft/sec
7.0 fps City of Palo Alto, CA. US Part III- Water Distribution System Section 2660 - Page 13 maximum design flow velocity in any water main shall not exceed 7 ft/sec
10 fps San Joaquin County, CA, US Water System Design Standard (Draft 2012) Section C Layout and Sizing of Mains 2(a) Page 68 Maximum velocities shall not exceed 10 ft/sec
5.0 fps Logan City, UT, US Section 21 Pipe Specification Page 21-2 Peak flow water velocity of 5 ft/sec shall be used I the hydraulic engineering analysis
5.0 fps DC Water, DC, US Peak flow water velocity of 5 ft/sec shall be used in the hydraulic engineering design
6.0 fps Polk County Utlilites, FL, US Utilitites Standards and Specification Manual, Rev December 2012 Section 610 page 2 Mains shall be sized so velocities do not exceed six feet per second under maximum daily flow conditions
7.5 fps Western Municipal District, Riverside, CA, US Revised Standard January 2001 For all cases, mainline water velocities are not to exceed 7.5 ft/sec
Datum Source Reference Comments
10.0 fps EPA (Peak) Wastewater Technology Fact Sheet Sewers and Forcemain EPA 832-F-00-071 September 2000 Maximum force main velocity at peak conditons is recommended not to exceed 10 ft/sec
6.0 fps EPA Low Lift (Min) Wastewater Technology Fact Sheet Sewers and Forcemain EPA 832-F-00-071 September 2000 Low lift recommended design force main velocity is 6 to 9 ft/sec
9.0 fps EPA Low Lift (Max) Wastewater Technology Fact Sheet Sewers and Forcemain EPA 832-F-00-071 September 2000 Low lift recommended design force main velocity is 6 to 9 ft/sec
2.0 fps EPA Lift Station (Min) Wastewater Technology Fact Sheet Sewers and Forcemain EPA 832-F-00-071 September 2000 Forcemains from the lift station are typically designed for velocities between 2 to 8 ft/sec
8.0 fps EPA Lift Station (Max) Wastewater Technology Fact Sheet Sewers and Forcemain EPA 832-F-00-071 September 2000 Forcemains from the lift station are typically designed for velocities between 2 to 8 ft/sec
2.64 fps Uni-Bell 2012 (Ex. 5.5.1.4) Fifth Edition Handbook of PVC Pipe Design and Construction Page 5.44 Page 5.44 to 5.46 Example 5.5 14in. AWWA Forcemain Maximum flow velociy is 2.64 ft/sec on page 5.46
Datum Source Reference Comments
3.5 fps 1st Ed. AWWA M55 (Calc) PE-Design and Installation Calculation page 43
4.4 fps 1st Ed. AWWA M55 (Ex. 1) PE-Design and Installation Example 1 Page 46
5 fps 1st Ed. AWWA M55(Ex. 2) PE-Design and Installation Example 2 Page 46
2 fps 2nd Ed. AWWA M23 2002 (Calc) PVC Pipe Design and Installation page 59 Ps = surge for 2 ft/sec velocity, psi
1 fps 2nd Ed. AWWA M23 2002 (Ex.) PVC Pipe Design and Installation page 59 Ps' = 17.4 psi (from Table 5-6)
1 fps 2nd Ed. AWWA M23 2002 (Calc) PVC Pipe Design and Installation page 60 Ps′ = one ft/sec surge pressure, psi—from Table 5-6
2 fps 2nd Ed. AWWA M23 2002 (Ex.) PVC Pipe Design and Installation page 65 A flow of 2 ft/sec is suddenly stopped in 6-in. Pressure Class 150 (DR 18) PVC Pipe
1 fps 2nd Ed. AWWA M23 2002 (Table) PVC Pipe Design and Installation page 66 Table 5-6 Page 66
3.5 fps AWWA M23 2010 Errata (Ex) PVC Pipe Design and Installation Page 61 Example Velocity of 3.5ft/sec
4.5 fps AWWA M23 2010 Errata (Ex) PVC Pipe Design and Installation Page 68 Example Velocity =4.5 ft/sec
4 fps Jana (Min) TECHNICAL REPORT Fatigue of Plastic Water Pipe: ATechncial Review With Recommendations For PE4710 Pipe Design Fatigue Page 10 Figure 4.2 Typical minimum watermain value for survey of 51 Water Utilities
8 fps Jana (Max) TECHNICAL REPORT Fatigue of Plastic Water Pipe: ATechncial Review With Recommendations For PE4710 Pipe Design Fatigue Page 10 Figure 4.2 Typical maximum watermain values for survey of 51 Water Utilities
6.7 fps Jana (Avg) TECHNICAL REPORT Fatigue of Plastic Water Pipe: ATechncial Review With Recommendations For PE4710 Pipe Design Fatigue Page 8 Average watermain value for normal flow is 6.7 ft/sec for survey of 51 Water Utilities
5 fps 2013 AWWA Book Normal Operation (Max) Water Distribution Operator Training Handbook Fourth Edition by William C Lauer The limit for normal operations should be about 5 ft/sec
7 fps University of Florida (Ex) Circular 828 February 1994 Water Hammer in Irrigation Systems Page 3 Water velocity of 7 ft/sec in a Class 160 (SDR 26) PVC conduit
5 fps University of Florida (Min) Circular 828 February 1994 Water Hammer in Irrigation Systems Page 4 General recommendations are to limit maximum operating velocities to 5 ft/sec. In no case should the velocity exceed 10 ft/sec.
10 fps University of Florida (Max) Circular 828 February 1994 Water Hammer in Irrigation Systems Page 4 General recommendations are to limit maximum operating velocities to 5 ft/sec. In no case should the velocity exceed 10 ft/sec.
5 fps 2003 AWWA (Max) Third Edition AWWA Water Transmisson and Distribution Page 12 Velocities should normally be limited to about 5 ft/sec
5 fps 2007 AWWARF Report (Design) Leakage Management Technologies IWA Publishing Page 126 Design 5 ft/sec for pipelines
5 fps 1995 AWWA Book (Max) Modeling, Analysis and Design of Water Systems by Lee Cesario Page 138 The maximum allowable velocity is most commonly 5 ft/sec for pipelines
7.5 fps Journal of Water Resources Planning and Management Planning Unidirectional Flushing Operations in Response to Drinking Water Distribution System Contamination Vol 136, No. 6 November 1, 2010 Page 654 Table 4 Summary of Hydraulic and Operational characterististics for Eight analyzed cases from the Valcourt network and 8 from the TV Network.
2 fps Performance Pipe (Min) Bulletin PP402-4710 Most systems operate at velocities operate at velocities of 2 to 4 ft/sec. Velocities will vary throug
4 fps Performance Pipe (Max) Bulletin PP402-4710 Velocities will vary throughtout ta piping system. Prudent engineering suggests using the highest velocity that may occur.
5 fps Plastic Pipe Institute (Ex) PPI TN-27/2009 Frequently Asked Questions HDPE Pipe for Water Distibution and Transmission Applications Page 4 and 5 Q.13 At a daily recurring average surge velocity of 5 ft/sec
6 fps Uni-Bell 2012 (Ex) Fifth Edition Handbook of PVC Pipe Design and Construction Page 5.34 Example 5.3 8in. AWWA PVC water distribution pipe Maximum flow velociy is 6.0 ft/sec

How do the different standards define 'Occasional Surge Pressure'?
Answer

Definition 1
AWWA C906-07 for PE PIPE

Occasional Surge Pressure (POS): Occasional surge are caused emergency operations. Occasional surge pressure is usually the result of a fire flow or a malfunction, such as a power failure or system component failure, which includes pump seize-up, valve-stem failure, and pressure-relief-valve failure.

Definition 2
AWWA M55-06 for PE PIPE- First Edition

Occasional Surge Pressure (POS): Occasional surge are caused by emergency operations. Occasional surge pressures are often the result of malfunctions, such as a power failure or system component failure, including pump seized-up, valve-stem failure, and pressure-relief valve-failure. POS is the allowance for occasional surge pressure (Eq. 4-5).

Definition 3
AWWA C900-07/C905-10 for PVC PIPE

Occasional (emergency or transient) surge pressure (POS): Surge pressures caused by emergency operations, usually the result of a malfunction (such as power failure, sudden valve closure, or system component failure).

Definition 4
AWWA M23 for PVC PIPE – Second Editon

The following is stated for transmission lines. "The application of PVC pressure pipe for water transmission mains differs greatly from that of a distribution main. There are virtually no cyclic stresses, velocities may be higher, and surges in general are very occasional.

For distribution lines the following is stated. "When transient pressures of noticeable magnitude occur on a frequent basis, cyclic stresses may be imposed upon the pipe material. If the cyclic stresses occur frequently enough at a sufficiently high magnitude, fatigue failure is a possibility in a thermoplastic pipeline, such as PVC.

Cyclic stresses are found more commonly in sewage force mains or turf irrigation lines than in water mains. Smaller-sized distribution mains do generate cyclic surges; however, the generously large safety factors in the pressure class design terminology are thought to eliminate any fatigue failure concerns. For transmission piping, cyclic surges, if they occur at all, typically would be at such infrequent intervals that cyclic design is not warranted in the vast majority of cases. Should the designer wish to investigate the effects of cyclic surges, reference should be made to the Handbook of PVC Pipe published by the Uni-Bell PVC Pipe Association.

The design process should involve consideration of each parameter discussed in this chapter. Because the nature of transmission pipelines permits interactive analysis, the designer can minimize costs without sacrificing sound engineering judgment.”

What are some typical 'Occasional Surge Velocities'?
Answer

Typical Occasional Surge Velocities

The design of PVC and PE pressure pipe requires the system Occasional surge flow velocity. The design Occasional Surge pressure is estimated using the change in water velocity resulting from sudden stoppage of the design flow. Graphs and charts below summarize available water standards, design guides, design reports and water utility specifications, which provide guidance on realistic occasional surge flow velocities.


  • WATERMAINS

    Normal water flow velocities are shown to range from 4.5 to 15 ft/sec. Most flow velocities range from 5 to 10 ft/sec. PPI PACE considers flow velocities from 5 to 15 ft/sec. This range is reasonable and realistic.

  • FORCEMAINS

    Forcemains are normally designed to have recurring surges only. For this reason no occasional surge design data is reported in standards, design guides, design reports and water utility specifications.

Where do these typical 'Occasional Surge Velocities' come from?
Answer

Note: Click the columns of the graph to drill down to the specific data.

SOURCE DATA FROM DESIGN REPORTS

SOURCE DATA FROM DESIGN STANDARDS

Datum Source Reference Comments
14.1 fps ANSI/AWWA C901-08 Appendix Ex. Polyethylene (PE) Pressure Pipe and Tubing, 1/2 In. (13 mm) Through 3 In. (76 mm), for Water Service APPENDIX A Example Page 22 an acceptable velocity for occassional surge iint this example is 180/12.8=14.1 ft/sec
10.0 fps 2013 National Fire Protection Association (NFPA) Min. NFPA 24 Standard for the Installation of Private Fire Service Mains and Their Appurtenances 2013 Edition Underground Piping Section 10.10.2.1.3 page 24-17 10 ft/sec minimum flow stated in Table 10.10.2.1.3
7.0 fps ANSI/AWWA C900-07 Ex. Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings, 4in. Through 12 In. (100mm through 300 mm), for Water Transmission and Distribution Appendix B Recurring (Cyclic) Surge-Figure and Design Page 23 Example Water anticipated occasional surge pressure = 7 ft/sec
7.0 fps AWWA C905-10 Ex. Appendix B Recurring (cyclic) Surge - Figures and Design Examples Section B.2: Design Example Anticipated occassional instantaneous change in flow velocity 7 ft/sec (determined by design engineer)
6.0 fps AWWA C906 (2007) Ex C1.1 Appendix C Working Pressure Rating and Pressure Class Page 33 Watermain design Examples C1.1
5.0 fps AWWA C906 (2007) Ex C1.2 Appendix C Working Pressure Rating and Pressure Class Page 35 Watermain design Examples C1.2
Datum Source Reference Comments
15.0 fps Jana Max. TECHNICAL REPORT Fatigue of Plastic Water Pipe: ATechncial Review With Recommendations For PE4710 Pipe Design Fatigue Figure 4.3 page 10. Typical minimum watermain fire flow value for survey of 51 Water Utilities
11.6 fps Jana Average TECHNICAL REPORT Fatigue of Plastic Water Pipe: ATechncial Review With Recommendations For PE4710 Pipe Design Fatigue Page 8. Average watermain value for occassional fire flow is 11.6 ft/sec for survey of 51 Water Utilities
10.0 fps 1st Ed. AWWA M55 Ex. 3 PE-Design and Installation Example 3 page 46
7.0 fps Uni-Bell 2012 Design Value Technical Note October 30 2013 Occasional Surge Pressure for HDPE and PVC Pipe: Advantage PVC Design value is 7 ft/sec
6.0 fps Uni-Bell 2012 Ex. 5.3 Fifth Edition Handbook of PVC Pipe Design and Construction Page 5.34 Example 5.3 8in. AWWA PVC water distribution pipe Maximum flow velociy is 6.0 ft/sec
5.0 fps Jana Min. TECHNICAL REPORT Fatigue of Plastic Water Pipe: ATechncial Review With Recommendations For PE4710 Pipe Design Fatigue Figure 4.3 page 10. Typical minimum watermain fire flow value for survey of 51 Water Utilities
4.5 fps 2nd Ed. AWWA M23 2002 (Ex.) PVC Pipe Design and Installation page 68 V = 8.91/1.98 = 4.5 ft/sec