United States
                    Environmental Protection
                    Agency
                                  C1"

		_.. _..	
                    Research and Development
EPA-600/S2-83-064  Sept. 1983
&EPA         Project Summary

                    Demonstration  of  Sewer
                    Relining  by the  Insituform
                    Process,  Northbrook,  Illinois
                    F. T. Driver and M. R. Olson
                      A full-scale study was undertaken of
                    the Insituform process for lining sewer
                    pipes to seal leaks and thereby prevent
                    the infiltration of groundwater through
                    leaky joints, cracks, and breaks. Such
                    infiltration can add significantly to the
                    amount of flow to sewage treatment
                    plants.
                      The study was done at the village of
                    Northbrook, Illinois, with two consec-
                    utive, 12-in.-diameter (31-cm) vitrified
                    clay pipe sanitary sewer segments that
                    were badly cracked. One was 150 ft (46
                    m) long, and the other was 432 ft (132
                    m) long.
                      Before the pipes were lined, average
                    groundwater infiltration was 19,500
                    gpd (74 mVday); after lining it was 100
                    gpd (0.4 mVday). The rate of exfiltration
                    was 3,800 gpd (14 mVday)  before
                    lining  and 270  gpd (1.0  mVday)
                    afterward. The  Manning coefficient
                    after lining was 0.008 to 0.009. These
                    values are comparable to other plastic
                    such as PVC.  Measurements  of  the
                    physical properties of the lining material
                    were also similar to those of PVC. A
                    realistic cost estimate cannot  be  ob-
                    tained directly from Northbrook because
                    this installation was a demonstration
                    project that limited the total length to
                    be lined and increased installation time
                    and cost for sewage bypass. But based
                    on cost data developed from previous
                    installations, the cost for Northbrook
                    would be $55/ft ($166/m).

                      This Project Summary was developed
                    by EPA's Municipal Research Labora-
                    tory, Cincinnati. OH. to announce key
                    findings of the research project that is
                    fully documen ted in a separate report of
the same  title (see  Project Report
ordering information at back).

Introduction

  The  infiltration of groundwater into
sanitary sewers through leaky joints and
cracks and breaks in sewer lines can add
significantly to the amount of flow to
sewage treatment plants, especially
during periods of elevated groundwater
levels  caused by  wet weather.  Also,
during wet weather an inflow of water
into sanitary sewers can occur from roof
leaders and other types of drains. As a
result  of  infiltration and inflow (I/I),
treatment  plants  are  overloaded and
operate less effectively.
  Infiltration would  be measurably
reduced with a rehabilitation technique of
reasonable cost that could seal  all
unwanted  openings in the pipe wall.
Such a method was conceived in England
more than a decade ago, but it has only
recently been introduced to the United
States, known commercially as "Insitu-
form,"* this method has a good potential
for completely  sealing all leaks.  Since
most installations can be made through
existing manholes, installation time,
traffic  upsets, and  surface disturbances
are reduced considerably.
  To assess the effectiveness of Insitu-
form, a full-scale evaluation was under-
taken at the Village of Northbrook, Illinois.

Insituform Concept

  The  concept of the Insituform process
involves the use of a long tube or bag of

"Mention of trade names or commercial products
 does not constitute  endorsement or recommenda-
 tion for use

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partially polymerized thermosetting resin
impregnated on a felt backing and closed
at one end  This tube is inverted into the
pipe to be  lined  by filling  it with cold
water. The  felt tube has a thin film  of
                                      polyurethane on what  is initially the
                                      outside. Upon inversion of the tube into
                                      the pipe, the polyurethane film forms the
                                      pipe surface, which is very smooth. This
                                      film also provides a leak-proof barrier to
               the water being used for inversion. Aftf
               inversion,  hot water is pumped into tr
               tube to cure the liner by  completing
               polymerization. The important installation
               steps  are outlined  in Figure  1.  After

The lining material is threaded
down the inversion bag
                                                                        The end of the lining material is
                                                                        opened up. turned inside out, and
                                                                        clamped onto the steel 1/4 bend.
              Manhole


ane



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1
                                                                                  Wood Bracing
                                                                        Stainless
                                                                        Steel Clamps
               Pipe to be lined-
        Water is pumped into the inversion
        bag, and as the water pressure builds
        up, the lining material starts to
        turn inside out into the pipe to be
        lined.
                                                              W
                                                            A 1
                                                           •^ J|
                                                              ^1
As the end of the lining material
disappears into the inversion bag,
layflat hose is attached to its end.
This hose is pulled right through
the pipe, and is used to circulate
hot water

                                                                                         Layflat Hose
                                                                     Water
                                        «4r-
                                                                                                    - 1
                                                                                                        /
       When the lining is fully cured, the
       downstream end of the bag is
       pierced to allow the hot,
       circulating water to drain.
                                                                 The ends of the lining material are
                                                                 cut off 2 in. beyond the end of
                                                                 the pipe. The pipe is air -tested using an
                                                                 expanding stopper developed for the purpose.
                                                                 The section of pipe that was removed is
                                                                 trimmed to the correct length and joined
                                                                 into the pipe using  a resin, felt, and glass-
                                                                 fiber bandage.
       Pierce in Downstream
       Manhole
                                          'l
                                                                                     I f*
                                                                                           Downstream M.H
                                                                                                                    /
                                                                                                                    0
 Figure  1.    Steps in lining with Insituform.

                                       2

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installation, the end of the tube is cut off
with a power saw, and the wall of the
manhole near the pipe is finished with a
sand-resin mixture. Reconnection  of
service laterals is carried out with a rotary
cutter  .For pipes  that are too small  to
enter,  a  remote-controlled  television
camera-cutter combination  has been
developed.


Installation at Northbrook

  At Northbrook, two consecutive 12-in.-
diameter (31-cm) vitrified  clay pipe
segments were lined  Segment lengths
were 150 ft (46 m) and  432 ft (132 m).
Manholes we re located at the entrance to
the  first  segment, between  the  two
segments, and at the outlet of the second
segment. Two 6-in.  (15-cm) service
laterals  entered the first pipe segment
The sewer was a sanitary sewer installed
in 1962 and had many offsets  and radial
and  longitudinal cracks. Some sections
were deteriorated to the point of not being
circular
  Before  lining, the sewer segments
were cleaned well, since any remaining
debris would  not be forced out during
inversion but  would increase the rough-
ness of  the lining,  reduce flow capacity,
and reduce strength. Very sharp protru-
sions could break the liner and interfere
with curing.
  The felt tube was built up from two  3-
mm  layers of densely needled polyester
fiber. (Thickness  can  be increased by
adding 3-mm layers). Impregnation was
conducted at the site by filling the liners
with the appropriate  amounts of a
catalyzed, thermosetting, isophthalic-
acid-based resin and passing the liner
through a system of conveyers and rollers
to wet a II of the felt thoroughly. Inversion
was carried out using a 19.7-ft (6-m)
static head. The two pipe segments could
have been lined with one length of liner
and one inversion, but two were used on
successive days to accommodate a large
number of interested observers.
  The desired curing temperature for the
chosen  resin  was approximately 180° F
(82° C). The  curing cycles for the two
segments are listed in Table 1.  Consider-
able time was required to heat the water
to curing temperature. Cooling was
purposely slowed to an hour or more  to
prevent  rapid contraction, which might
cause separation  of the liner from the
pipe. Small  thermocouples placed be-
tween the original pipe wall and the liner
at both  ends  of the lengths being lined
were used to determine  whether curing
temperature was being reached through
the total  thickness of  the liner.  The
Table 1 .    Resin Curing Cycles

           Temperature Range
                                 PC)
                                  Curing Time
                                      (hr)
   Upper pipe segment:
   55-160
   160-185
       185
   185-100
13-71
71-85
85
85-38
0.75
0.5
2
1
                                              Total
                                                                     4.25
Lower pipe segment'
55-160
160-185
185
185-10O


13-71
71-85
85
85-38
Total

1.25
0.75
2
1.5
5.5
conditions  listed  in Table  1  would be
typical of most installations.

Results

  The success of the lining process was
tested  by observing both the infiltration
into the upstream pipe segment and the
exfiltration from the downstream segment
just before and after lining. The infiltration
test  was  carried  out  by plugging the
upstream manhold and measuring  flow
over a weir at the downstream end of the
pipe segment. Groundwater levels were
approximately 14  in. (35 cm) above the
crown at the outlet. The average value of
infiltration was 19,500 gpd  (74 mVday)
before  lining  and  100 gpd (0.4 mVday)
afterward. The small amount of inflow
after lining is believed  to have resulted
from leakage at the upstream manhole,
since television inspection  of the  pipe
showed no breaks in the lining.
  The exfiltration test was carried out by
plugging the line just above the manhole
at the upstream end of the pipe and the
line just below the downstream manhole.
The pipe segment was then flooded to 3 ft
(91 cm) above the crown at the upper
manhole The rate of fall of the water was
measured. Before  lining,  the  rate of
exfiltration was 3,800 gpd (14 mVday),
and  after lining  it was  270  gpd  (1.0
mVday). The small amount of exfiltration
after lining is believed to have occurred in
the manholes.
           An indirect measure of the effectiveness
         of lining was an obvious increase in the
         leakage into  the adjacent manholes
         through cracks in their  walls.  This
         observation confirms the experience with
         sewer  grouting methods,  in  which
         leakage appears after grouting at points
         that did  not formerly leak. The cause is
         ascribed to a  higher groundwater level
         resulting from  elimination  of the most
         significant  leaks. Where the condition of
         manholes is questionable, their rehabili-
         tation should also be considered.
           One of the advantages claimed for the
         Insituform  lining of sewers  is the in-
         creased  smoothness, with  regard to
         carrying  capacity. The Manning coeffi-
         cient was  0.008 to 0.009  after lining.
         These values are comparable with those
         for other  plastic pipe such  as PVC.
         Accurate values for the Manning coeffi-
         cient were not obtainable before lining, so
         a comparison of maximum water-carrying
         capacities before and after lining was not
         possible  at Northbrook.
           A number of physical properties of the
         lining material used at Northbrook were
         measured and compared with PVC (Table
         2).
           This comparison indicates that the two
         materials are very similar in their physical
         characterstics.
         Insituform Costs

           Approximate costs for relatively  long
         length installations of Insituform are
Table 2.    Properties of Insituform Compared with PVC

            Property                      Insituform
                                       PVC
Tensile strength (psi)*
Modulus of elasticity (psij
Flexural strength (psi)
Compressive strength (psi)
Coefficient of thermal
expansion (cm/ cm °C)
5,420
475.000
9,320
15,000

5.96 x 10~5
7,200
400, OOO
1 1,000
9,000

52 x ;o~5
"To convert psi to kN/m}, multiply by 6.895

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   shown in Table 3. These figures include
   the fabrication and  installation  of the
   liner and cutting of openings to service
   laterals Additions for pipe cleaning and
   inspection  and for  bypass pumping of
   sewage must  be  made as  shown in
   footnote in  Table 3. In addition, there are
   other relatively small costs for setting up
   of equipment (mobilization) and for traffic
   control
     A  realistic cost  estimate cannot be
   obtained directly from Northbrook because
   this  installation was a demonstration
   project that limited the total length to be
   lined and increased installation time and
   cost for sewage bypass. But an estimate
   can be made  for Northbrook based on
   Table 3 information. For lining the two
   pipe segments (with $1,500 estimated for
   mobilization and traffic control), the cost
   would be approximately $55/ft ($ 166/m).
   This estimate assumes that other sewers
   in the  area would be lined at the same
   time to take advantage of the large-order
   prices in Table 3.
        Table3.
Insituform Costs*
Sewer
(cm)
155

31

47

61

Diameter
(m.)
6

12

18

24

Liner Thickness
(mm)
3
6
6
12
6
12
9
15
Cost Per
Linear Foot
($)
33
39
47
55
57
66
74
86
Cost Per
Linear Meter
($)
108
128
154
180
187
217
243
282
        * Add $1.900 per line for bypass pumping Add $1.90 for 6-to 15-in.pipe,and$2.50for15-to30-m.
        pipe per foot for preliminary cleaning and inspection.
         At  Northbrook,  the condition of the
        pipes was too poor to consider specific
        point repair and grouting. Where the pipe
        is severely deteriorated grouting cannot
        be  used. Had grouting been practical, it
        would have been a cheaper alternative.
        Grouting is not as effective as Insituform,
        and in a number of documented cases it
        has been essentially ineffective. The cost
                               effectiveness  of  grouting in terms of
                               actual I/I reduction can therefore be very
                               low.
                                 The  full report  was  submitted in
                               fulfillment of Grant No. R-806322 by the
                               Village of Northbrook, Illinois, under the
                               sponsorship of the U.S.  Environmental
                               Protection Agency.
                                              F. T. Driver and M. R.  Olson were with Driver. Olson and Degraff Associates,
                                                Rockford. IL 61104.  F.  T. Driver is now with Insituform of North America,
                                                Memphis, TN 33118; and Mr. Olson is with Thomas I. Simmons & Associates.
                                                Rochelle. IL 61068.
                                              Richard Field and Robert Turkeltaub are the EPA Project Officers (see below).
                                              The complete report, entitled "Demonstration of Sewer Relining by the Insituform
                                                Process, Northbrook, IL." (Order No. PB 83-245 878; Cost: $7 7.50, subject to
                                                change) will be available only from:
                                                      National Technical Information Service
                                                      5285 Port Royal Road
                                                      Springfield,  VA 22161
                                                      Telephone: 703-487-4650
                                              Richard Field can be  contacted at:
                                                      Municipal Environmental Research Laboratory
                                                      U.S.  Environmental Protection Agency
                                                      Edison,  NJ 08837
                                                                                            ftUS GOVERNMENT PRINTING OFFICE 1983-659-017/7173
United States
Environmental Protection
Agency
Center for Environmental Research
Information
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