large diameter pvc pressure pipe for water and sewer applications in ...

LARGE DIAMETER PVC PRESSURE PIPE FOR WATER
AND SEWER APPLICATIONS IN NORTH AMERICA
Shah Rahman, Uni-Bell PVC Pipe Association, Dallas, Texas, U.S.A.
ABSTRACT
The introduction of polyvinyl chloride (PVC) piping standards four decades ago on the North
American continent has provided utilities and municipalities a solution to overcoming
common problems inherent in traditional piping materials such as corrosion, pipe cracking,
poor joint performance, and cost and difficulty of installation. A rise in the comfort-level of
utilities with the use of small diameter (4-inch through 12-inch) gasket-joint PVC pipe has
resulted in the rapid adoption of large diameters (14-inch and above) for both pressure and
gravity applications. In large diameters, gasket-joint PVC pipe has exhibited the best growth
prospects based on increased sanitary sewer and water distribution and transmission uses.
PVC pressure pipe standards commonly used in the U.S. and Canada include ASTM D2241,
AWWA C900, AWWA C905, AWWA C909, ASTM F1483, and CSA B137.2. As AWWA
C905 is the most commonly used large diameter PVC pressure pipe standard, it is the main
focus of this paper. Discussion on the standard’s design allowances as they apply to potable
water transmission and sewer force main applications are included. Recent research, which
has led to a new approach for determining the cyclic life of PVC pressure pipe, is discussed.
Several case studies are included from Uni-Bell’s PVC News magazine to illustrate the
steady growth of the large-diameter pressure pipe market in North America.
INTRODUCTION
The condition of buried underground piping infrastructure in North America, particularly in
the United States, has recently received much attention from the engineering community as
well as government entities. Some of the oldest piping systems have already surpassed their
hundred-year mark, while others are nearing a quarter or half century of their service lives, or
have already surpassed their expected design lives and are in dire need of rehabilitation.
More alarming are the metallic pipe installed in the past twenty to forty years, some less,
which have already failed due to environmental conditions such as corrosion. According to
annual surveys of the municipal water and sewer infrastructure in the United States,
conducted in early 2003 and 2004 by Underground Construction magazine, $1.2 billion and
$0.6 billion were spent in 2003 and 2004, respectively, for water system rehabilitation. For
sewer rehabilitation, $2.0 billion and $2.6 billion were spent in 2002 and 2003, respectively.
For new construction of water systems, $4 billion were spent in 2002 and $3.5 billion were
spent in 2003. New construction of sewers saw expenditures of $4.1 billion in 2002 and
$4.14 in 2003. Projections for 2004 expenditures are also given, figure 1 (1, 2). From the
data, it can be concluded that the impact of state budget cuts, plus just how stable tax and rate
bases were going to be, weighed heavily upon the minds of municipal planners. Pipe demand
in the U.S. is projected to grow 2.5 percent annually to 15.5 billion feet in 2007. Construction
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will account for 48 percent of all pipe used in 2007 due to widespread drain, sewer, water
distribution and other uses (3).
Amount ($ Billion)
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
Water and Sewer Construction and Rehab in U.S.
2002 2003
Year
2004
2
Water New Construction
Water Rehabilitation
Sewer New Construction
Sewer Rehabilitation
Figure 1: Water and Sewer Construction and Rehabilitation
PVC has been used in municipal applications since the early 1960’s. With its first use in rural
water systems and sewers, today PVC is the most installed piping material in North
American municipal applications. A 1999 study of the buried pipe market in North America
(diameters of 4-in and above) concluded that on a linear footage basis, PVC pipe held a
market share of over 65% in the drinking water market and over 70% in the sanitary sewer
market, figures 2 and 3 (4).
Pipe Material
North American (US & Canada) Drinking Water
Pipe Market - 1999 (4" Dia and Above)
Total Buried Pipe = 310 million feet
("Buried Pipe Markets in North America," Nov. '00)
Conc.
PE
DI
PVC
1%
3%
30%
66%
0 10 20 30 40 50 60 70
% Market Share
Figure 2: North American Potable Water Piping Materials Market (4)
(1, 2)

Pipe Material
Clay
Conc.
North American (US & Canada) Sanitary Sewer
Pipe Market - 1999 (4" Dia and Above)
Total Buried Pipe = 290 million feet
("Buried Pipe Markets in North America," Nov. '00)
DI
PE
PVC
2%
3%
11%
11%
3
73%
0 20 40 60 80
% Market Share
Figure 3: North American Sanitary Sewer Piping Materials Market (4)
Typically in municipal applications, diameter ranges of 4-inch through 12-inch is considered
small diameter, while large diameter pipe range from 14-inch and above. Both small and
large diameter solid and profile wall PVC gravity pipe are widely used in sanitary sewer
systems. The same is true for PVC pressure pipe use in water distribution, transmission and
sewer force mains. The early acceptance and a steady rise in the use of small diameter PVC
pressure pipe in water systems throughout Canada and the U.S. resulted in the rapid adoption
of large diameter pipe once it became available to the marketplace in the late 1980’s. Today,
large diameter PVC pressure pipe use continues its steady rise. In a report published in
February 2003, the Freedonia Group concluded “Large diameter plastic pipe demand will
benefit from attributes such as lower cost, lighter weight, inherent corrosion and chemical
resistance, durability and installation ease. PVC will exhibit the best growth prospects based
on increased sanitary sewer and water distribution uses” (5).
NORTH AMERICAN PRESSURE PIPE STANDARDS
North American PVC pressure pipe is made of either conventional PVC (uPVC or PVC-U),
or molecularly oriented PVC (PVCO). The latter is manufactured by one American producer,
using an off-line process (6). Conventional PVC is by far the most used piping material in
municipalities and utilities. There are currently five American pressure pipe standards
commonly used in municipal applications, written by ASTM and AWWA (American Water
Works Association):
• ASTM D2241: Standard Specification for Poly (Vinyl Chloride) (PVC) Pressure-
Rated Pipe (SDR PR Series)
• AWWA C900: Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings, 4
In. through 12 In. (100 mm through 300 mm), for Water Distribution
• AWWA C905: Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings,
Nominal Diameter 14 In. through 48 In. (350 mm through 1,200
mm), for Water Transmission and Distribution
• AWWA C909: Molecularly Oriented Polyvinyl Chloride (PVCO) Pressure Pipe, 4
In. through 24 In. (100mm through 610 mm), for Water Distribution

• ASTM F1483: Standard Specification for Oriented Poly (Vinyl Chloride), PVCO,
Pressure Pipe
The Canadian Standards Association (CSA) also has several PVC pressure pipe standards,
but the main one used in municipal applications is:
• CSA B137.2: Rigid Polyvinyl Chloride (PVC) Pipe for Pressure Applications
The hydrostatic design basis (HDB) of PVC pressure pipe is the hoop stress value from
which the long-term pressure capacity of the material is established. It is the starting point for
determining the pressure capacity of a given wall thickness. AWWA and ASTM standards
for conventional PVC pressure pipe require an HDB of 4000 psi. For PVCO standards, an
HDB in the 7100 psi range (or less) is required. All conventional PVC pressure pipe
standards are manufactured to a cell classification of 12454 ONLY, ensuring a tensile
strength of 7000 psi, and a modulus of elasticity of 400,000 psi. The stock pipe used in
PVCO manufacture is also manufactured only to cell classification 12454. Table 1
summarizes some of the properties of each of the ASTM and AWWA standards.
Table 1: U.S. PVC Pressure Pipe Standards
Standard HDB (psi)
Factor of
Safety
Surge
Allowance
Available Diameters
(in)
ASTM D2241 4000 2 NO 4 – 36 *
AWWA C900 4000 2.5 YES 4 – 12
AWWA C905 4000 2 NO 14 – 48
AWWA C909 7100 2.5 YES 4 – 24
ASTM F1483 6810 / 6040 2 NO 4 – 16
*
Diameters of 1/8-inch through 3.5-inch available with solvent-welded joints
While ASTM D2241 was, and still is, used primarily in the Rural Water market after its
introduction in 1964, AWWA C900 was the first widely specified PVC pressure piping
standard in larger, urban utilities. Introduced in 1975, AWWA C900 incorporated a higher
factor of safety than its predecessor, and also included a surge allowance. In the diameter
range of 4-inch through 12-inch, this standard is most widely used in water distribution
systems, hence the surge allowance and a higher factor of safety. C905 was published in
1988, and because of its diameter range of 14-inch through 48-inch, the standard was
designed for use in transmission and force main lines. Like ASTM D2241, it has a factor of
safety of 2.0 and no surge allowance. It should be noted that a factor of safety of 2.0 results
in an allowable design stress of 2000 psi, while a factor of safety of 2.5 gives an allowable
design stress of 1600 psi.
Since ASTM D2241 is rarely used in diameters greater than 12-inch, the remainder of the
discussion will focus exclusively on the AWWA C905 standard.
AWWA C905 DESIGN
First published in 1988, AWWA C905 provided a solution to those municipalities that
demanded larger diameter PVC pipe for their pressure applications. The first version of the
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standard included diameters of 14-inch through 36-inch. It was revised in 1997 to include
diameters of up to 48-inch. Due to the larger diameters designated in this standard, it was
primarily designed for use in water transmission lines, which are characteristically nonlooped,
with generally fewer valves. It was determined that a safety factor of 2.0 was
adequate and that surge should be based on actual design velocity changes. Consequently, no
predetermined surge allowance was built in. The pressure capacity, or Pressure Rating (PR)
of pipe manufactured to this standard is calculated using equation 1 (7). The PR
corresponding to various DR’s are listed in table 2
PR = (2/DR-1) X (HDB/F) (Equation 1)
Where:
PR = pressure rating, in pounds per square inch (psi), for sustained pipe
temperatures above 73.4 o F [23 o C]
DR = dimension ratio (DR = outside diameter/minimum wall thickness)
HDB = hydrostatic design basis (4000 psi)[27.58Mpa]
F = factor of safety (2.0)
Table 2: Pressure Ratings for AWWA C905
DR (Dimension Ratio) PR (Pressure Rating), psi [MPa]
51 80 [0.55]
41 100 [0.69]
32.5 125 [0.86]
26 160 [1.10]
25 165 [1.14]
21 200 [1.38]
18 235 [1.62]
14 305 [2.11]
The unique characteristic of thermoplastic pipe to handle a much higher pressure for short
durations than for long-term periods is taken advantage of in AWWA C905 design. In the
event of infrequent surge pressures, PVC offers higher short-term hoop strength of 6400 psi
(than the HDB of 4000 psi). The pressure that corresponds to this elevated hoop stress is
referred to as quick-burst or short-term strength (STS). STS, when divided by a factor of
safety of 2.5, will yield the corresponding short-term pressure rating (STR) of the pipe (8).
Table 3 lists both STS and STR values of AWWA C905 pipe.
When limiting positive pressure surges to the STR, a minimum safety factor of 2.5 is
maintained against the short-term strength of the material. The values of STR represent a
level approximately 25% above the pressure rating for each DR (9). STR values are used in
both water transmission and sewer force main design to account for high (and repetitive)
surges. Fisher (10) illustrates the design methodology for AWWA C905 for water
transmission, while the Handbook of PVC Pipe (7) contains examples for sewer force main
design.
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Table 3: STS and STR Values of AWWA C905
DR (Dimension Ratio) STS, psi [MPa] STR, psi [MPa]
51 256 [1.76] 100 [0.70]
41 320 [2.20] 130 [0.88]
32.5 406 [2.80] 165 [1.12]
26 512 [3.53] 205 [1.41]
25 533 [3.67] 215 [1.47]
21 640 [4.41] 255 [1.77]
18 753 [5.20] 300 [2.08]
14 985 [6.79] 395 [2.72]
CYCLIC LIFE OF PVC PRESSURE PIPE
Transient surges, which manifest themselves in the form of water hammer, are of a short
duration and can be described as an intermediate condition that exists in a system as it moves
from one steady state condition to another. The closing of a single valve can be used to
illustrate the phenomenon. Though transient surges may be repetitive, they are not cyclic in
nature. Cyclic surges occur on a regular basis, in a cyclic fashion, in the form of pressure
fluctuations. Cyclic surging has the potential to cause fatigue damage to any material,
including PVC, when the frequency and magnitude of the cyclic actions exceed the
material’s performance limit. This type of condition may require additional design
considerations such as sufficient allowance for cyclic surging for the duration of the system’s
design life (11).
For two decades, the PVC pipe industry in North America designed for cyclic fatigue using a
methodology recommended by Vinson (12). Then, Moser et. al. (13), through research
performed at the Buried Structures Laboratory at Utah State University, concluded that
Vinson’s method was too conservative as it took into account only peak stresses to predict
cyclic life. They recommend a more precise approach by considering both average stress and
stress amplitude, equations 2 and 3.
Where:
Where:
σavg = [(Pmax + Pmin) (DR-1)] / 4 (Equation 2)
σavg = required design average hoop stress, psi
Pmax = maximum design pressure, psi
Pmin = minimum design pressure, psi
DR = dimension ratio of pipe
σamp = [(Pmax – Pmin) (DR-1)] / 4 (Equation 3)
σamp = stress amplitude, psi
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Using the above information, figure 4 can then be used to predict the cyclic life of a PVC
pressure pipe in an application such as sewer force main design.
Mean Stress (psi)
3000
2500
2000
1500
1000
500
3000
2000
Figure 4: S-N Diagram to Predict Cyclic Life of PVC Pressure Pipe (13)
INSTALLATION AND TESTING
AWWA C605, Underground Installation of Polyvinyl Chloride (PVC) Pressure Pipe and
Fittings for Water, outlines all installation and testing methods. Topics such as tapping, pipe
bending, thrust restraints, and disinfecting are also included. For pressure testing, it is
recommended that the pipe be pressurized to 150% of working pressure, but not less than
125% of normal working pressure at the highest elevation, for a 1-hour duration. For leak
testing, 150% of working pressure is recommended for two hours. Working pressure is
defined as the maximum anticipated sustained operating pressure. It is also noted that in no
case shall the test pressure be allowed to exceed the design pressure for the pipe,
appurtenances, or thrust restraints. A third test, which combines both pressure and leakage
testing, is performed for a 2-hour duration, with 150% of working pressure being applied, but
not less than 125% of normal working pressure at the highest elevation.
SELECT CASE STUDIES
1500
Stress Amplitude (psi)
1000
700
Positive/Negative Line
0
1.E+3 1.E+4 1.E+5 1.E+6 1.E+7 1.E+8 1.E+9
Number of Cycles
Due to its wide usage, where millions of feet of large diameter PVC pressure pipe are being
installed throughout North America annually, it is not possible to accurately track every
water transmission and sewer force main project. The Uni-Bell PVC Pipe Association’s biyearly
newspaper, PVC News, periodically publishes case histories of installations in the
larger diameters performed by various Member companies. Table 4 lists a select number of
projects that were chosen from the PVC News. A short discussion of each project follows.
7
500
2000 psi Limit
300
200
150
100
50
20
Vinson
USU
Design
Space

Table 4: Case Histories of Large Diameter Installations from the PVC News
Location Application Standard Length and Diameters
Magrath, Alberta
Corpus Christi,
TX
Batavia, NY
Grand Strand, SC
Natchitoches, LA
Water
Transmission
Sewer Force
Main
Sewer Force
Main
Water
Transmission
Sewer Force
Main
CSA Standard 6.5 miles of 18-in and 20-in
ASTM D2241 4,600 ft of 24-in
AWWA C905 4,900 ft of DR 25 30-in
AWWA C905
Pueblo, CO Water Main UNI-B-11
Muleshoe, TX
Vancouver, BC
Loudon County,
VA
Industrial
Water Supply
Relief Sewer
Line
Sewer Force
Main
8
145,000 ft of DR 25 24-in,
and 44,000 ft of DR 25 20-in
PVC News
Issue
Summer
1984
Summer
1987
Summer
1989
Summer
1992
AWWA C905 25,000 ft of DR 32.5 30-in Spring 1994
5000 ft of DR 25 24-in, and
4000 ft of DR 25 20-in
AWWA C905 5 miles of DR25 30-in
AWWA C905
AWWA C905
4,500 ft of DR 41 30-in, and
300 ft of DR 41 36-in
10,000 ft of DR 32.5, 48-in,
42-in, 36-in
Summer
1988
Summer
2001
Summer
2002
Summer
2003
Magrath, Alberta: Installed in 1984, this was described as Canada’s first large diameter PVC
pressure pipe, and included 6.5 miles of 18-inch (0.693-inch wall thickness) and 20-inch
(0.770-inch wall thickness), Series 160 pipe. The transmission line provides each residential
tap a pressure of 50 to 70 psi. In Spring 2000, almost two decades later, the City of Magrath
reported that not a single failure of any kind had occurred since its installation.
Corpus Christi, Texas: Concerns about the ability of polyethylene lining on ductile iron
staying in tact was the reason this project specified large diameter PVC pressure pipe to
upgrade an 8-inch sewer force main in 1987. Several metallic pipe installed around the same
period have failed. In 2000, the City of Corpus Christi reported that the PVC line was doing
well, was “still alive” and that the City had “no regrets” in selecting PVC for the project.
Batavia, New York: Installed in 1989, this 30-inch AWWA C905, DR 25 pipe, 4,900 feet in
length, was described as America’s largest diameter PVC pressure pipe to date. The high
water table and corrosive soil areas reduced the life span of metallic pipe, and so PVC was
selected. In Spring 2000, the City of Batavia reported that the pipe was “performing 24-hours
a day, seven days a week,” with no problems to report.
Grand Strand, South Carolina: This 50-mile long water transmission project consisted of 34
miles of 24-inch and 20-inch AWWA C905, DR 25 pressure pipe. In Spring 2000, the Grand
Strand Water and Sewer Authority (GSWSA) reported “extremely positive” experience with
the PVC pipe. This success led to installation of an additional 25,000 feet of 36-inch, 23,000
feet of 30-inch and 50,000 feet of 20-inch AWWA C905 pipe.

Natchitoches, Louisiana: In 1994, 25,000 feet of 30-inch AWWA C905, DR 32.5 PVC
pressure pipe was installed in a sewer force main application. In Spring 2000, the City of
Natchitoches reported no problems and was pleased with its performance of transporting raw
sewerage from a lift station to the treatment plant.
Pueblo, Colorado: It will be noticed that this project involved the use of a standard that is no
longer in publication, UNI-B-11, Recommended Standard Specification for Polyvinyl
Chloride (PVC) Water Transmission Pipe (Nominal Diameters 14-36 Inch). This standard
was the precursor to today’s AWWA C905. In Spring 2000, the Pueblo Board of Waterworks
reported that the pipe had been untouched since installation and was performing well.
Muleshoe, Texas: This project was executed to provide cooling water to a power station that
provides power to over 52,000 square miles in areas of Texas, Oklahoma, New Mexico, and
Kansas. The 5 miles of 30-inch AWWA C905, DR 25 pressure pipe was installed in the
winter of 1998-1999. An average of 2000 feet of pipe was laid daily.
Vancouver, British Columbia: The Sewerage and Drainage Department of the Greater
Vancouver Regional District installed the large diameter DR 41 AWWA C905 pipe. One
unique aspect of the project was the use of fabricated PVC access tees on the 30-inch portion
of the line. Installation and testing were performed without any problems and the pipeline is
currently in service.
Loudon County, Virginia: The Loudon County project has been described as the first 48inch
AWWA C905, DR 32.5 project in the U.S. The 26 MGD design flow will provide sewer
service to two communities of approximately 2500 new homes. Burial depths vary from 10
to 15 feet.
It should be noted that in all of the above case histories, the large diameter PVC pipe was
selected in a competitive bidding process involving other piping materials such as ductile
iron and concrete. In every case, engineers named the ease of installation, resistance to
corrosion, long-term durability, and cost advantages of PVC as its strengths. In all cases,
contractors laid anywhere from 700 feet to 2000 feet of pipe daily. All the projects were
completed on time, most ahead of schedule. These case studies clearly highlight those
advantages of PVC, which have made it the market leader in the municipal piping
construction industry.
CONCLUSION
The use of large diameter PVC pressure pipe will continue its steady rise as municipalities
throughout North America expand their existing water and sewer systems and also
rehabilitate deteriorating buried piping infrastructure. At the time of the writing of this paper,
the author was working with the City of Tulsa, Oklahoma, in specifying their first PVC
sewer force main, AWWA C905, to replace a ten-year-old concrete line that had failed. This
has been a common scenario throughout North America. Thermoplastics such as PVC are
inherently suited to withstand both internal and external corrosion, while providing the level
of structural integrity that is expected of buried piping materials. On-going research and
innovation within the North American PVC pipe industry may make it even more cost
efficient and further enhance its physical/mechanical capabilities.
9

References
1. Carpenter, R., 6 th Annual Municipal Sewer and Water Infrastructure Survey,
Underground Construction Magazine, Houston, TX (February 2003), p.18.
2. Carpenter, R., 7 th Annual Municipal Survey: Making Sense of a Complex Market,
Underground Construction Magazine, Houston, TX (February 2004), p.22.
3. The Freedonia Group, Inc., Plastic and Competitive Pipe, Cleveland, OH (September
2003).
4. Buried Pipe Markets in North America 1999, Dallas, TX (2000).
5. The Freedonia Group, Inc., Large Diameter Pipe, Cleveland, OH (February 2003).
6. Rahman, S., Municipal PVC Piping Products: A State of the Art Review, Proc. Texas
Section - American Society of Civil Engineers Fall 2003 Meeting, Dallas, TX (September
2003).
7. American Water Works Association (AWWA), C905: Polyvinyl Chloride (PVC)
Pressure Pipe and Fabricated Fittings, 14 In. Through 48 In. (350 mm Through 1,200
mm), For Water Transmission and Distribution, Denver, CO (June 1997).
8. Uni-Bell PVC Pipe Association, Handbook of PVC Pipe Design: Design and
Construction, 4 th Edition, Dallas, TX (2001).
9. American Water Works Association (AWWA), Manual of Water Supply Practices M23:
PVC Pipe – Design and Installation, 2 nd Edition, Denver, CO (2002).
10. Fisher, C., New PVC Transmission Pipe Design Philosophy, PVC News, Vol. 26, No. 2,
Dallas, TX (Summer 2003).
11. Rahman, S., PVC Pressure Pipe: Cyclic Design Research, Proc. Texas Water 2003
Annual Conference, Corpus Christi, TX (April 2003).
12. Vinson, H.W., Response of PVC Pipe to Large, Repetitive Pressure Surges, Proc.
American Society of Civil Engineers (ASCE) International Conference on Underground
Plastic Pipe, ASCE, New York, NY (March 1981).
13. Moser, A.P., Jeffrey, J.D., Folkman, S.L., New Design Guidelines for Fatigue Failure in
PVC Pipe, Proc. American Water Works Association Annual Conference, Denver, CO
(2003).
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