Trenchless Pipe Installation Horizontal Directional Drilling
                     uni-bel l  t e c h n i c a l  Publ icat iOn
S u  S Ta I N a  b L E   P I P E   I N F R a  S T R u  C T u  
R E   –
I  T ‘ S O u  R R  E  S  P  O N S  I b I L  I  T  
y
PVC PIPE
THE RIGHT CHOICE
FOR TRENCHLESS 
PROJECTS
I N T R O D u  C T I O 
N
Construction in densely populated urban settings  
significantly increases real construction costs while 
greatly  impacting the indirect social costs that are 
These “no-dig” 
 procedures enable con-  associated  with interruptions to the flow of traffic and 
tractors to install pipe by  obstacles to  both businesses and the public. The 
tunneling or boring, thus  construction of new  underground infrastructure, or the 
greatly minimizing the  rehabilitation of old  infrastructure, presents the utility 
social costs associated with 
engineer and contractor  with the challenge of 
 the disruption to traffic,  
pedestrians, businesses minimizing the impact of these  disruptions on the 
and customers. surface, while making these needed  improvements 
underground.
While open-cut installation procedures  construction typically involves small  
continue to be the standard method  localized excavations from which the  
of construction for municipal piping  installation of pipe is completed by  
projects, various trenchless technology  either pulling or pushing of the pipeline 
developments are making these  through pre-drilled bore holes or the  
options  more economically viable and existing pipe. Similarly, it is also 
appealing.  These “no-dig” procedures possible  to rehabilitate deteriorating 
enable  contractors to install pipe by municipal  pipelines without digging up 
tunneling  or boring, thus greatly tlihne .e nTtihre  trenchless rehabilitation  
minimizing  the social costs associated processes can often restore both  the 
with the  disruption to traffic, structural integrity and the flow  
pedestrians,  businesses and characteristics of the pipe.
customers. Trenchless
2
T R E N C H L E S S T E C H N O L O G I E 
S W E L L S u  I T E D F O R P V C P I P E 
S
Sliplining, horizontal directional drilling (HDD), tight fit structural liner, and  
pipebursting are a few of the well-developed trenchless technology methods  
currently used for new construction and rehabilitation of pipelines. These  
construction techniques require piping products capable of withstanding large  
axial compressive and/or tensile forces. Through the development of several  
innovative joint designs, a number of PVC pipe producers offer pipe well suited  
for these trenchless pipe situations. The same properties that have made PVC  
the market leader among pipe materials for water and sewer applications in  
North america make PVC a material of choice in the performance of trenchless  
applications. The wide acceptance of PVC pipe among municipalities for open-
cut  construction also makes PVC pipe a preferred and familiar choice for 
trenchless  installations in capital improvement projects as well as rehabilitation.
T I G H T F I 
ST T R u  C T u  R a  L I N E 
L R
Tight fit structural lining with PVC is accomplished by expanding a specially  
formulated C900/C905/aSTM D2241 PVC that has been butt fused together in  a 
continuous length. It is inserted into the host pipe and then brought to tight  fit 
dimensions through a combination of heat and pressure. The lining maintains  
and/or increases flow capability by providing the C value of PVC that more than  
offsets the slight reduction in flow area.
3
P V C P I P E T R E N C H L E S 
SC O N S T R u  C T I O N O P T I O N 
S
There are four trenchless technology methods for which PVC pipes offer the  
best option. These are Horizontal Directional Drilling (HDD), Sliplining, Tight Fit  
Structural Liner and Pipebursting. Table 1 summarizes the common trenchless  
methods, their applications, the reference specifications and the corresponding  
PVC pipe products that are available.
Table 1: Construction/Rehabilitation Process and PVC 
Solutions
MethOd aPPlicat iOn S t a n d a r d
aSTM F 949
Segmental Gravity Piping System Rehabilitation aSTM F 794
Sliplining aSTM F 1803
aWWa C900/C905 
Continuous Pressure Piping System Rehabilitation  CSa b137.3  
aSTM D2241
aWWa C900/C905 
Horizontal Directional New Pressure & Gravity   CSa b137.3  
 Drilling (HDD) Piping System Construction aSTM D2241
aWWa C900/C905 
Pipe bursting Pressure & Gravity  CSa b137.3  
Piping  System aSTM D2241
Rehabilitation
Tight Fit  Pressure & Gravity  aWWa C900/C905 
Structural Liner Piping System Rehabilitation  aSTM D2241
Products utilize pipe that meet the referenced standard.
4
H O R I Z O N T a  
D I R E C T I OL N a  L D R I L L I N 
G
Horizontal directional drilling  
(HDD) is the most commonly
used trenchless process
for installing water pipe.
Traditionally these applications 
 were reserved for only 
roadway  and river crossings. Fig. 1a: Horizontal Directional Drilling (HDD) Method
Today,  HDD is employed for a 
mofy oritahder applications where the benefits of trenchless installation can be derived.
In recent years, developments in the precision of HDD machinery, specifically  the 
ability to monitor and steer the pilot bore with high levels of accuracy that  
maintain line and grade, has also enabled the installation of gravity sewer pipes.
Fig. 1b: Horizontal Directional 
 Drilling (HDD) Method
HDD, Figure 1a, is performed with a drilling rig, Figure 1b, and involves three  
essential steps. First a pilot bore is created, covering the distance over which the 
 pipe is to be installed. Highly sophisticated electronics enable the drilling rods 
to  be carefully guided and its direction of travel to be monitored. Reamers are 
then  pulled back to obtain a diameter large enough to accommodate the 
diameter of  the pipe. Simultaneously, drilling mud is pumped into the bore to 
stabilize the  boring and to prevent soil collapse. In the final step, the new pipe 
to be installed  is pulled back through the bore, Figures c & d.
Fig. 1d: Horizontal Directional 
 Drilling (HDD) Method
Fig. 1c: Horizontal Directional Drilling (HDD) Method
5
S L I P L I N I N 
G
Sliplining is a process outside diameter of the liner pipe is  
 for rehabilitating dete- less than the inside diameter of the  
host pipe, which leaves an annular  
 riorated large-
space between the two. In many 
diameter  gravity cases,  this annulus is filled with a 
piping systems  or for grout after  installation, particularly if 
the rehabilitating  of the host  pipe is in a high state of 
deterioration.  Grouting of the annular 
pressure distribution  space provides  additional support for 
and transmission lines. the liner pipe,  helps protect the liner 
Sliplining involves the pipe if the host  pipe is in structural 
 insertion of a new pipe distress, and stops  water infiltration 
Fig. 2b: Continuous Sliplining through the host  pipe annulus space. 
 inside the defective  The loss in cross-  sectional area is 
host pipe, either in  often offset by the  improved flow 
PVC slipliners are designed to provide 
segments or as a con-  characteristics of the  new PVC pipe. both structural support as well as an  
tinuous section of pipe. improved flow path to the deficient  
host pipe, and have been in wide use Continuous sliplining, Figure 2b,  with 
in  North america for over two PVC pipe is more prevalent in  the 
decades. rehabilitation of potable water  
Segmental sliplining, Figure 2a, is the  distribution and transmission 
least disruptive type of rehabilitation  pipelines.  In this process, the liner 
for gravity sewer lines. Profile-wall pipe, which is  manufactured to 
PVC  pipe, conforming to aSTM aWWa C900/C905  and aSTM D2241 
gravity pipe  standards, with smooth requirements, are  assembled in their 
joints (both  inside and outside), are entirety prior to  being pulled into the 
assembled in  segments at entry deteriorated  host pipe as a 
Fig. 2a: Segmented Sliplining
points along the  length of the continuous pipeline.  as with gravity 
deteriorated host pipe,  and inserted systems, grouting of  the annulus is 
directly into the host pipe  by either often employed to help  stabilize the 
pulling or pushing. a  section  of the pipeline and  increase  the life 
top half of the host pipe is often  cut expectancy of the line. When  
off to provide lead-in access. The required, taps are made after the pull-  
in of the new pipe into the host pipe.
6
P I P b u  R S T I N 
E G
The diameter of pipe being burst  Pipe bursting can be  
typically ranges from 2 to 30 inches,  applied on a wide range 
although pipes of larger diameters can 
 of pipe sizes and types  
 be burst. Pipe bursting is commonly  
performed size-for-size or one size  and in a variety of soil  
upsize above the diameter of the  and site conditions.
existing pipe. Larger upsize (up to  
three pipe sizes) has been successful, Fig. 3: Bursting Head
but the larger the pipe upsizing, the greater the force required to burst the  
existing pipe and to pull the new pipe and the greater the potential for ground  
movement (upheave).
This is another rehabilitation method of replacing both pressure and gravity  lines 
with new pipe and involves the breaking of an existing pipeline by brittle  
fracture, using mechanically applied force from within. While the deteriorated  
pipe fragments are forced into the surrounding ground, a new pipe of the same 
or  larger diameter is pulled in to replace the original pipe. Pipe bursting is 
performed  by the insertion of a conically shaped bursting head, Figure 3, into a 
deteriorated  pipe and causing it to shatter by pneumatic or hydraulic action, 
Figure 4.
Fig. 4: Pipe Bursting
7
P V C P R E S S u  R EP I P E S Ta N D a  R D 
FS O R T R E N C H L E S S C O N S T R u  C T I O 
N
PVC pressure pipes are routinely used for potable water distribution and  
transmission, as well as in sanitary sewer force mains. The hydrostatic design 
basis  (HDb) of PVC pressure pipe is the sustained hoop stress value from which 
the  long-term pressure rating of the material is established. HDb is the starting 
Specific information on 
point  for determining the pressure capacity of a given wall thickness. aWWa 
 available wall and aSTM  standards for conventional PVC pressure pipe require an HDb of 
thickness  and pressure 4000 psi.
class
Table 2: PVC Pressure Pipe Standards for Trenchless 
rating should be obtained Construction S t a n d a r d ava i lab le  d iaMeterS (in)
 from aWWa C900 4 - 12
aWWa C905 14 - 48
manufacturers.  
CSa b137.3 4 - 48
Products utilize  aSTMD2241 2 - 24
pipe that meet the
referenced standard.
There are currently four PVC pressure pipe standards to which products for  
trenchless technology are manufactured. Table 2 summarizes the size ranges  
available for each of these common standards. Pressure Ratings (and Classes) up  
to 315 psi are available for diameters up to 16 inches, 235 psi for diameters up to 
 24 inches, and 165 psi for diameters up to 48 inches.
8
P V C G R a  V I T y P I P E S T a  N D a  R D S
F O R T R E N C H L E S S C O N S T R u  C T I O N
Profile wall pipe generally fall into three categories – open  Non-pressure PVC pipes  
profile (OP), closed profile (CP), and dual wall corrugated   have been in use in the U.S.  
since the early 1960s. Today, 
profile (DWCP). OP pipe have their rib-enforcements  
 PVC gravity pipe is used in  
exposed on the outside of the pipe and are manufactured 
sanitary sewer, storm sewer  
to  meet the requirements of aSTM F794. CP pipe make and highway drainage and  
use of  a closed profile that provides a continuous outer culvert applications. There  
wall where  the wall sections are hollow and are often are two main groups of PVC  
described as an  I-beam or honeycomb (refer to aSTM gravity pipe --- solid wall  
and profile wall. For sliplin-  
F1803). DWCP pipe  have a smooth-wall waterway, braced 
ing, only profile wall pipes  
circumferentially with  an external corrugated wall (see are utilized. There are three  
aSTM F949 & F794). profile wall pipe standards  
While all PVC pressure pipe  is  12454 and 12364 (minimum tensile  for trenchless rehabilitation.
manufactured ONLy to cell strength of 6000 psi, minimum 
classification  12454 (tensile strength of modulus  of elasticity of 440,000 psi). • ASTM F794
7000 psi,  modulus of elasticity of Pipe  manufactured to either • ASTM F949
400,000 psi),  some sewer pipe formulation  performs very well for 
•
standards allow  manufacture of both sliplining  applications. ASTM F1803
cell classifications
Table 3: ASTM Gravity PVC Pipe Standards
S t a n d a r d   
SPecificatiOn W a l l  tyPe crOSS  Sect iOn
PerfOrMance  S t r u c t u r a l   JOining  
deS ignat iOn d iaMeter requireMentS c e l l  c l aSS SySteMS
12454/ Gasket- 
aSTM F794 DWCP Pipe Stiffness 4” - 48” PS = 46 12364  Joint
Gasket- 
aSTM F949 DWCP Pipe Stiffness 4” - 36” PS = 46 12454  Joint
Closed 12454/ Gasket- 
aSTM F1803  Pipe Stiffness 18” - 60” PS = 46 12364  Joint
Profile
D3034 Gasket/ 
 F679  butt  
(D2241 and  Solid Wall Pipe Stiffness 4” - 36” PS 46,115 12454 Fused  
aWWa sizes)* Joints
* Pressure Pipe
9
P V C P I P E : a  D V a  N T a  G E 
FS O R T R E N C H L E S S a  P P L I C a  T I O N 
S
Water Quality: PVC water • Corrosion Resistance /  Durability: PVC is inherently well suited for buried 
 pipe delivers water as  applications as it does not corrode internally or externally. This eliminates the 
 need to specify a corrosion protection method that adds costs and increase 
clean  and pure as it risks.  unlike other products, with PVC, long-term durability is not 
receives. compromised when  encasement bags are punctured or torn, or when thin 
coatings or linings are  damaged. PVC is corrosion resistant and not 
It imparts no taste or odor vulnerable to deterioration from  low resistivity drilling muds commonly used 
 to the water it transports,  with horizontal directional drilling  and other trenchless construction methods. 
System design and installation are  simplified with a homogeneous wall, and a 
PVC is not a source of lead  durable pipe material that doesn’t  require liners or coatings. For sanitary 
or other chemical contami-  sewers, PVC pipe is resistant to virtually  all the chemicals found in domestic 
and industrial wastewaters. In addition,  PVC is highly resistant to erosion or 
nants associated with metal 
abrasion wear.
 pipe, and does not react  • Strength: When properly designed and installed, PVC pipes can handle  
with even the most aggres-  external loads from over 120 feet of ground cover and are available with  
sive water. PVC’s smooth  internal pressure ratings up to 315 psi) with associated pipe stiffness of more  
than 800 lbs/in/in. PVC pipes are also able to bend or flex without breaking,  
non-biodegradable interior  making them ideally suited to handle ground movements caused by unstable,  
wall surface makes it more  shifting soils and earthquakes. because PVC pipe is stiffer (higher modulus of  
elasticity) than other thermoplastic pipes, it offers a much greater capacity for 
resistant to bio-film build-up.  maintaining grade and is less prone to ponding and sagging. In comparison  
to other methods of rehabilitation such as Cured-in-Place Pipe (CIPP), which  
do not necessarily provide structural renewal to the host pipe, sliplining with  
inserted PVC pipes adds structural renewal to the deteriorated host pipe.
• Hydraulics: PVC’s immunity to internal corrosion also eliminates 
tuberculation
-– the build-up of corrosion by-products that can reduce hydraulic capacity 
and  increase pumping costs. PVC pipe’s smoother internal wall surface 
minimizes  fluid friction and flow resistance. The need for cleaning and 
maintenance  are eliminated or reduced, thereby lowering operating costs. 
Numerous  experimental and real-life data provide testimony of PVC’s smooth 
internal  flow characteristics in its long-term performance. For PVC pressure 
systems,  a conservative Hazen-Williams “C”  factor of 150 is widely accepted 
and  used. This equates to a much lower lifetime pumping and maintenance 
costs.  Similarly, the accepted value of Manning “n”  for PVC gravity sewer 
pipes is
0.009. This is significantly lower than that of traditional piping materials such  
as clay or concrete.
10
P V C P I P E : a  D V a  N T a  G E 
F O R T SR E N C H L E S S a  P P L I C a  T I O N 
S
• Superior Strength-to-Weight Ratio: Fewer pounds of material are Longevity: PVC has been  
required  to manufacture a foot of PVC pipe versus a foot of metal or utilized since the 1950s as  
concrete pipe.  That weight advantage is quite significant. Not only does it 
make PVC more  economical on a per-foot basis, it also conserves resources, both a water and sewer  
lowers shipping  costs, simplifies and reduces the time needed for installation, main material, longer than  
and decreases  the number and severity of injuries for installation crews. 
Collectively, these  advantages result in lower installed costs. ductile iron and  
• Watertight Joints: PVC pipes for most water distribution applications and  polyethylene. PVC’s proven  
sanitary sewers are designed with gasket-joints. These reinforced gaskets  track record supports  
form a permanent seal. Water systems can expect zero leakage at joints.  
When used for sewers, watertight joints mean less chances of infiltration or  expectations of a very long  
exfiltration. Watertight joints significantly reduce the risks of a treatment  service life. An independent 
facility from becoming overloaded. Consequently, a lower volume of water to  
treat substantially reduces operating costs. Watertight joints also reduce the   AwwaRF research project  
likelihood that embedment soil will be washed away, potentially weakening  entitled LONG TERM  
the pipe or nearby structures such as paved roadways. PERFORMANCE  
• Crack Resistant Flexibility: PVC pipes also have an ability to bend or flex  
PREDICTION FOR PVC
when subjected to excessive loads. as a result, they develop fewer cracks  
and breaks – another source of leaks and a major entry point for tree roots  PIPES concluded that PVC  
surrounding embedment soils, two costly reasons why sewer systems get  pipes are capable of 100 + 
blocked and need extra maintenance. Water leaking into sewer pipes through 
 cracks and breaks can also increase the volume of wastewater that treatment  year performance.
 facilities must process. That, too, can drive up operating costs significantly.
• Maintainability: Due to the high acceptance of PVC pipe for water and 
sewer  applications, PVC maintenance equipment, repair parts, and 
appurtenances  are readily available in the utilities warehouse or at the local 
distributor. There  is no need to be concerned with having the proper 
materials for emergency  repairs or routine connections. Many alternative 
products require stiffeners  and other equipment that does not allow the 
utility to make a quality repair  or connection with standard off-the-shelf 
fittings properly sized for the pipe.  PVC’s coefficient of thermal expansion 
and contraction is four times less than  that of alternative thermoplastic pipe 
materials such as polyethylene (HDPE),  which minimizes concerns over proper 
restraint.
11
PVC PIPE
a  S S I S T a  N C 
The Erehabilitation of existing sewer and water infrastructure installation needs. If you would like more information or have   is a challenge faced by all utilities. PVC has a proven track  specific questions regarding the application of PVC pipes for  
record of long-term performance and leads the water and  various trenchless and/or rehabilitation needs, you are invited  
sewer industry in market share. utilities, design engineers,  to contact the uni-bell PVC Pipe association or its member  
and contractors are benefiting from the application of PVC  companies.
pipe products to their pipeline rehabilitation and trenchless
UNI-BELL MEMBER COMPANIES
 REGULAR MEMBERS  INTERNATIONAL AFFILIATE MEMBERS
CertainTeed Corporation  Contech Construction Products Amanco Group  Century Eslon Limited  
Diamond Plastics Corporation  Freedom Plastics, Inc. Interplast, Limited  Iplex Pipelines Australia 
 IPEX, Inc. JM Eagle Marley New Zealand Ltd.  PETCO S.A.
Lamson Vylon Pipe Company  National Pipe & Plastics, Inc.  Reliance Industries Ltd.  Vinidex
North American Pipe Corporation  Northern Pipe Products  Wavin Overseas B.V.
 Pipelife Jet Stream, Inc. Royal Pipe Systems
 ASSOCIATE MEMBERS  AFFILIATED ASSOCIATION
American Maplan Corporation Arkema, Inc.  The Vinyl Institute
 Cincinnati Extrusion, Inc. Cincinnati Milacron 
ColorMatrix Corporation  Corma, Inc. The statements in this publication are those of the Uni-Bell PVC Pipe Association and are not war-  
ranties, nor are they intended to be warranties. Inquiries for information on specific products, 
 EBAA Iron, Inc. Formosa Plastics Corporation  
their  attributes and recommended uses and manufacturer’s warranty should be directed to 
GPK Products, Inc.  Georgia Gulf Corporation  member  companies.
Holland Colours Americas Harrington Corporation  
 KibbeChem, Inc. Honeywell Specialty Chemicals  Although every attempt is made to assure factual accuracy, Uni-Bell and Rainmaker Advertising ac- 
Omya, Inc. Krause-Maffei Corporation   cept no responsibility for unintentional errors, other than printing a correction in a future issue.
Plastics Extrusion Machinery, Inc. OxyVinyls LP
 Rohm & Haas Company  Reagens, USA
Shintech, Inc. S & B Technical Products, Inc.
Specified Fittings, Inc. Theysohn Vinyl Extrusion Technologies, Inc.  
 Tigre USA, Inc. Underground Solutions
Westlake Chemical 
Corp.
uNI-Pub-11-07
Published by:
uni-bell PVC Pipe association
2711 LbJ Freeway Ste. 1000 •  Dallas, Texas 75234
Ph: (972) 243-3902 •  Fax: (972) 243-3907
www.uni-bell.org