i
_' ASSESSMENT OF SEWER SEALANTS
by
Richard H. Sullivan
William B. Thompson
t
American Public Works Association
K.-./2-- ._C.hi.?ago,._Illinois_606.37
Grant No. R806567 \
j
j
i ,s
Project Officer
Richard P. Traver \
j Storm and Combined Sewer Section
Wastewater Research Division
Municipal Environmental Research Laboratory (Cincinnati)
Edison, New Jersey 08837 I
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
i U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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--DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use. j
11
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...FOREWORD ..
The U. S. Environmental Protection Agency was created because of in- j
creasing public and governmental concern about the dangers of pollution to j
the health and welfare of the American people. Noxious air, foul water, and
spoiled land are tragic testimony to the deterioration of our natural en-
vironment. The complexity.of that environment and the interplay between i
its components require a concentrated and integrated attack on the .problem.
1 <
Research and development is that necessary first step in problem solu- ;
tion and it involves defining the problem, measuring its impact, and j
searching for solutions. The Municipal Environmental Research Laboratory i
develops new and improved technology and systems for the prevention, treat-' ,
ment, and management of wastewater and solid hazardous waste pollutant
discharges from municipal and community sources, for the preservation and
treatment of public drinking water supplies and to minimize the adverse
economic, social, health, and aesthetic effects of pollution. This pub- I
lication is one of the products of that research; a most vital communica- . j
tions link between the researcher and the user community. !
This report describes performance attributes for a sewer sealant. In
addition, tests for use by the manufacturer and user are provided to allow
insight to be gained as to what application and use characteristics a new
sewer sealant might exhibit. It is hoped that several products will be made
available from the private sector which will be usable for infiltration i
control. Hopefully, such new products will be capable of being applied j
without the need for major retrofitting of the estimated 800 sewer sealant ,
units now owned by sewer service contractors and local governmental agencies.
: j
An investigation was also conducted to determine possible methods to j
improve systems to seal house service lines. Cost effective technology is ',
needed in this area. . i
Francis T. Mayo
Director
Municipal Environmental
Research Laboratory
111 .
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ABSTRACT
The control of infiltration into sanitary sewers is a major element of
local governmental agencies' pollution control program. In 1978 the major
product used for small diameter sewers was withdrawn from production. A .
study was conducted to develop performance attributes of a sewer sealant i
which could be used with existing sewer sealing equipment. ]
A series of laboratory, soil box, and field evaluation studies were
also devised to assist in the testing of new products.
Manufacturers .in the United States jand throughout the world were con- ,
; tacted to determine if there were additional chemical formulations which
, could be used or if there was interest in developing a product.
Present methods for sealing building sewers were also investigated
and suggestions ..for new methods developed.
i This report is in partial fulfillment of the U. S. Environmental Pro-
! tection Agency Grant No. R806567-. Work was completed in August, 1980.
IV
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ACKNOWLEDGMENTS
The American Public Works Association (APWA) conducted this study with the
assistance of the National Association of Sewer Service Companies (NASSCO).
Project Director for APWA was:
Richard H. Sullivan
Associate Executive Director
Director for NASSCO was:
'-« ^ J-1/i" "William B.-Thompson
: ! Executive Director
Consultant - Testing: j
c:-1-'">" Reuben H. Karol (Ph.D)
; ' Consulting Engineer
Members of the project steering committee were:
A. B. Colthorp :R. L. Nolte
Penetryn System, Inc. Metro Sewer District
Knoxville, Tennessee :St. Louis, Missouri
James Conklin 'Elton Smith
NASSCO , Department of Sanitary Sewers
: Winter Park, Florida ,Tampa, Florida
(Chairman, Safety Committee)
Kenneth Guthrie William B. Thompson
Cues, Inc. 'NASSCO
Orlando, Florida .Winter Park, Florida
Lonnie McCain Richard P. Traver, USEPA
Cherne Industries, Inc. 'Municipal Env'l Research Lab
Edina, Minnesota Edison, New Jersey
James Monaghan James Witt
Gelco Grouting Service Naylor Industries
Salem, Oregon Baton Rouge, Louisiana
(Chairman, Equipment Committee)
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ACKNOWLEDGMENTS (continued)
For their assistance to the study, we would also like to thank -
Richard M. Berry
Penetryn System, Inc.
Knoxville, Tennessee
Will Jacques
Avanti International
Houston, Texas
(Chairman, Testing Committee)
James W. Johnson
3M, Chemical Resources
St. Paul, Minnesota
Patsy Sherman
3M Chemical Resources
;St. Paul, Minnesota
William J. Clark
Geochemical Corporation
Ridgewood, New Jersey
VI
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CONTENTS
Page
SECTION I Overview and Recommendations 1
SECTION II Performance Specifications - Sewer Sealants 4
SECTION III Testing of Potential Sewer Sealants 13
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SECTION IV Sewer Pipe Joint Grouting Equipment 22
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SECTION V Building Sewer (House Lateral) Repairs 31
SECTION" vi" Glossary'.' .~" T 7~Y".~ 7 ~. T 7~. T"." T ~ T".". T 7~.~4i
SECTION VII References; 42
SECTION VIII -. Appendix , 43
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! FIGURES
NO.
1. Attributes of Specifications for Chemical Sewer
Sealant Systems 6 j
2. Gradation of Sand for Test Cylinders 15
3. Closed Circuit TV Equipment . .' 24
4. Remote Sealing Equipment. . . 24 j
5. Packer Devices 25 j
6. Preinspection of Sewer 26 |
1. Sewer Joint Sealing 27
8. Building Sewer Joint Sealing 38 ,
9. Building Sewer Exfiltration Sealing 38;
' TABLES
1. Steps in Life of Chemical Sealant 5
2. Limits and Measures of Sewer Sealant Characteristics. ........ 7
3. Sealing of Building Sewers 33,:34,35' .
4. Range of Costs for Repair of Building Sewers [. . . . 36 j
5. Insituform Method , 40 j
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Vll
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SECTION I
OVERVIEW AND RECOMMENDATIONS !
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In recent years the need to reduce infiltration from sanitary sewer j
systems has become recognized as one of the means available to reduce the \
hydraulic loading of wastewater treatment facilities. Without infiltration,
treatment plants may serve additional customers without expansion or allow ;
construction of smaller facilities. In addition untreated overflow of
infiltrated flow and sewage are also minimized.
; t ' ; -
Sealing of defective joints in sewers has been a recognized method Jto J
reduce or eliminate infiltration for many years. Where the pipe is struc- ;
turally sound and equipment can be inserted into the pipe, sealant materials
can be injected into a joint and a seal achieved.
Although many types of chemicals have been used for grouting, the
major material used in this country and throughout the world was an acrylamide
monomer manufactured by American Cyanamid. In 1978, production of this pro- .
duct was discontinued. By 1979 a similar product was available from Japan. !
The price has almost tripled. j
In recent years a urethane foam grout sealant was .developed by the \
3M Company. Though the product is used in small diameter sewers, its major
use has been in sewers where physical access by workers can be obtained.
Concern was expressed by the USEPA, local government, and sewer
service contractors over the high cost and dependence upon a single foreign
manufacturer. A study was therefore undertaken to determine if there were
alternative products available; to develop performance specifications for a
sewer sealant; to assist manufacturers considering entering the market; to
develop a series of tests to evaluate new products; and to evaluate methods
available or which appeared possible for sealing building sewers. Building
sewers have not generally been rehabilitated because of the high cost of
current technology.
1 ,
The American Public Works Association (APWA) in conjunction with the
National Association of Sewer Service Companies (NASSCO) established an
advisory committee of local governmental and Federal and industry officials.
The committee reviewed products and made recommendations throughout this
study.
During the course of the study, several manufacturers announced new i-
products of their intention to do so in the near future. A list of all I.
currently available products is contained in Section VIII. I
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In an effort to broaden the search,letter contact was made to major
United States chemical companies and nations with domestic chemical
industries. This search proved futile. As a result of the letter inquiry
no new chemical products were suggested for use as a sewer sealant.
A one-day meeting was held to brief representatives of chemical
companies as to what was needed and the environment in which a_sealant _ _ /
system must function. Several companies were present, and some have indi-
cated that they are developing and testing products to be introduced to the ;
market. : ;
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A set of sewer sealant performance attributes was developed as ex- i
plained in Section II. In conjunction with the limitations of existing i
equipment used for sewer sealing described in Section IV manufacturers now ;
have an overview of what characteristics a product should have to be con-
sidered for sewer sealing. . I
Section III sets forth a series of tests by the manufacturer and tests
which might be conducted by a user to evaluate a product. To speed the j
evaluation and possible acceptance of new products^ a framework for"field ' "*
evaluation of new products also was developed. '
Section IV provides an overview of the existing equipment and its
delivery capabilities and limitations.
Existing and proposed methods of sealing building sewers are des- ;
cribed in Section V. Existing methods are very costly and generally not
cost effective. Difficulties of access to the small pipe used makes sealing
of this portion of the sewer system very difficult.
RECOMMENDATIONS " \, ..''.,.
1. The study has made it clear that several manufacturers have
developed chemical sealing systems which may be used in
sanitary sewers. Acceptance by consulting engineers, local
government, and sewer service companies of such new sealants
would be stimulated if a controlled field demonstration were
conducted. The availability of an unbiased, third party
report on the performance of the sewer sealant products is
desirable to allow consideration by local governmental
agencies, sewer service companies, and consulting engineers and
would allow a broader understanding of conditions specific to the
use of each sealant tested.
It is recommended that USEPA sponsor a field demonstration program
for at least four of the sealants deemed to have the characteristics
most likely to provide a superior product with minimum retrofit of
existing equipment, or a probable low cost product compared to
others available, if such a product has also developed usable
application equipment. The field demonstrations should be conducted
in various climates under various soil and groundwater conditions,
types of pipe materials, and size of pipe. The evaluation should
include observations and testing over at least a one year period.
2
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2. The importance of economically and effectively eliminating
infiltration from building sewers has become apparent in recent
years. (2,4) Present methods, depending upon access from a
surface excavation, are costly. There has been relatively little
private research and development effort reported.
. It is recommended that USEPA sponsor a symposium to be attended by
other Federal agencies, consultants, local government, sewer service
contractors, and industry to review the findings and suggestions of
this report and such other work as may be available, and suggest to
USEPA what technologies are available from other areas to provide a
sealant system for the building sewer and the direction that USEPA's
Research and Development effort should take.
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; SECTION II '.
PERFORMANCE SPECIFICATIONS - SEWER SEALANT
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.- To assist users of sewer grouting materials and manufacturers who are s=i
considering the development of new products, a performance specification has
been developed. The performance attributes of a sealant have been detailed.
These attributes may or may not be applicable to a particular chemical system
due to the chemistry of the particular system used. !
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Experience with sealing sewers over a 20-year period has indicated many ;
desirable features of a system depending upon how the sealant is to accomplish
its primary task of not allowing infiltration into the pipe. In addition, i
there are several requirements which must be met due to the normal processes [
of shipping, handling and work safety. i
i
At the beginning of this study two methods were in use for sealing a
sewer joint: 1) form a new gasket in the joint, and 2) build up an imperme-
able band of material around the outside of the joint. The nature and
quantity of material is generally different for the two methods. % ;
A third method, bonding the pipes together (3), was tried several years
ago. However, due to trench conditions, loadings and placement problems,
the concept does not appear workable.
Two major" constraints adopted by this study were: 1) the sealant must
be capable of being applied internally with remote controlled equipment in '
small diameter pipes, 15 cm (6 in.) to 76 cm (2.5 ft); and 2) the application
of the sealant should be accomplished with existing equipment in use by local
.governmental agencies and sewer service companies or with only minor retro-
fit costs. Existing equipment for the purpose of this study has been defined
as that sewer sealing equipment presently in use by the public and private :
sectors to internally seal small diameter sewers. Minor retrofit cost has
been defined as the cost which, when capitalized over the remaining life of : -,'..'.! C
the equipment and if used with a particular product, would be cost effective. ' '*:""- ""''
Thus the cost would vary with the ultimate cost of the installed joint and . ~ - '^''~J'C
would be influenced by both the cost of the material and the cost of applica-" '^ '^\^'~'':.
tion. ^A,';..,',/):;:
Table 1 lists the steps in the life of a chemical sealant from manu-
facture to conditions which may be found at the site of placement. These
steps provide a quick screening of the major conditions which dictate the
necessary specifications for a sealant.
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BY
Manufacturer
Manufacturer
Common carrier
Distributor
Common Carrier
Applicator
Applicator
Applicator
Applicator
Applicator
Applicator
Applicator
Applicator
Applicator
Applicator
Applicator
TABLE 1
STEPS IN LIFE OF CHEMICAL SEALANT
STEP
1. Formulate components and package
2. Warehouse storage
3. Transport to distributor
4. Warehouse storage
5. Transport to applicator
6. Warehouse storage*
7. Transport to field
8. Field storage*
9. Transport to job site
10. Mix batch*
11. Pump to application
12. Mix with catalyst/activator
13. Force into/through joint
a. sand c. water e. voids
b. grease c. bedding
14. Remove excess grout from pipe barrel*
15. Clean equipment
! OUTSIDE
16. Subject grout to
a. freeze-thaw*
b. submergence
c. wet-dry*
d. chemicals*
e. flexure
f. pressure head
*may not always be required
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J
1 1. Flexible
I
4. impervious
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B. Not rendered
ineffective by
pipe cleaning
I
..Low viscosity
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3. Variable react*
lime
1 PREVENT INFILTRATION WHEN PROPERLY APPLIED ;(
A. Have Desirable Physical B. Applied by c. Hut Acceptable
Characteristics in Place Enisling Equipment Sa'ety and Health
| 2. Non shrinking
5. Compression
Strength
1 1
3. Nogroundwiter
contamination
1 1
6 Non-soluble 7. Long-term
in place chemical stability
1
9. Resist rodent 10. Durable
and roach attacks
" ' 1 i.Acceotabie
1. Special Handling 2. Shipped by ' Toxicology
""""""' "*"""
1 2. Acceptable
1 Handling
1 Properties
11 3. Acceptable
I Salety
_ll Properties
3. Long shell lile 4. Immune to olfocl
ol outdoor
.
1 1 1
[ (.Bacteria | B Scour/Abrasion | c. Acid-Base
d.Freeze/Thaw | e. Dry/Saturation j
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D Have Desirable E. Easily shipped f other
Application Characteristics . end handled
on
I
5. Easily rerm
equipment
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2. Controlled
variable viscosity
II sealant goesbeyc
1
4. Predictable viscosity
until gelation begins
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, '
1 1 I
. . .. 1. II mixed 2. Low I.Noelleclon 2. Noellecl
.id pipe wall ( ( retrofit cost w.W. Treatment on pumping
1a) Low precision 1B> Form 'rue
required soiuiion/stable
II biological effect
1 n cl Resist hiah sheet lri)Lonatnt lelfinartm.* -
wed from 6. Excess easily removed 7. Full reaction
(clean-up) from barrel In moving water
1 mixing equipment lile time
. r-
Figure 1 Attributes of Specifications for Chemical Sewer Sealant Systems
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The performance specifications are intended to develop a "picture" of -
-.the desirable.characteristics and the physical, conditions and restraints by ]
which the sealant's performance will be evaluated.
A variety of materials with regard to performance and manufacture is
desirable to allow competition, meet the needs of specific application
problems, and decrease dependence upon only one or two sources. Described
is what is necessary, rather than how to obtain the desired objective. This
is particularly important as systems based upon several families of chemi-
cals may be found to be usable.
Although any given chemical sealant may not meet all of the performance
specifications and physical standards, it may still be a viable material.
The applicator would "trade off" advantages, total _cost, or_superior per-_ ..
formance for deficiencies. Thus the specifications developed are for
general guidance and in most instances are not absolute.
i
Both functional and physical characteristics of sewer sealants must be
considered. Figure 1 is a chart which arrays the various attributes re-
quired of a sealant. Those in the "A" and "B" groups are thought to be of
primary importance to the grouting application and rely upon the inherent
characteristics of the material. Other groups are dependent upon the
manufacturers or the application system developed to use the product.
Table 2 lists the limits for the various factors shown in Figure 1.
TABLE 2 "
ATTRIBUTES OF SEWER SEALANT CHARACTERISTICS
(amplifies information outlined in Figure 1) \
A. Have Desirable Physical Characteristics in Place
1. Flexible; deflect pipe 1° to 5° without cracking or losing seal
through temperature range of -7° to 38° C (20° to 100° F.)
2. Non-shrinking: no adverse shrinkage that could cause loss of
seal.
3. No groundwater contamination .
4. Impervious: not allow infiltration of groundwater or roots
through the material.
5. Compression strength; withstand a 2.1 kg/sq cm (30 psi)
hydraulic pressure without damage to or loss of seal in place.
6. Non-soluble in place: will not dissolve in ambient groundwater \
or sewage flow over the life of the material.
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liable 2 continued j
7. Long-term chemical stability; no loss of desirable character- j
istics due to long term chemical change in place. j
8. Not rendered ineffective by pipe cleaning; in place the :
1 materials or.seal will not be rendered ineffective by sewer ,j
cleaning equipment. ; |
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9. Resist rodent and roach attacks: material will not be affected :
by roaches and rodents. j
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10. Durable: i 1
a. bacteria: non-biodegradable. j
b. scour/abrasion: 1.5 m/sec (5 ft/sec) of flow in pipe with '
grit load. ; j
c. acid/base: not rendered ineffective by acid/base in normal
I concentrations. :
__d.' freeze/thaw:_ not rendered ineffective by repeated freeze-
, thaw cycles. : """"j
e.: dry/saturation: not rendered ineffective by repeated '
;' cycles of dry and saturated environment. j
f. organic solvents: not rendered ineffective by repeated
~.-,-exposure to organic solvents.
11. Long life; material in place, should have a useful life of 20
years.
B. Applied by Existing Equipment .
If mixed: ;
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1. Low precision required; no special equipment or precise
measurements required for mixing of 'components and/or additives.
2. Form true solution/stable dispersion: once mixed, the materials
shall not settle out or separate from solution for a minimum of
24 hours.
3. Resist high sheer mixing equipment: material will be unaffected
when mixed with blades or paddles.
4. Long pot life: minimum 5 days.
5. Short mix time: maximum 15 minutes.
C. Have Acceptable Safety and Health Properties
1. Acceptable toxicology: material should not be harmful or
cumulatively toxic in amounts likely to be transmitted by
finger-to-mouth contact or by smoking. Skin contact absorp-
...tion should not be toxic or..cumulatively toxic. Components
__ ..._.. 8 '' ' ' ._.
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"Table 2 continued "
j
of spills or unreacted components drained from equipment j
should not cause damaging effects to wastewater treatment '
plants or receiving waters when washed into sanitary or
J~" storm sewers at a dilution of 1,000/1. Unreacted components
^n smaii amounts~diluted by groundwater-1000/1 should "not ;
form an identifiable pollutant with a life of more than 48 |
hours. Manufacturers Material Safety Data Sheets (MSDS) i
OSHA Form-20 and Standard Ratings for Toxic Substances :
(LD 50|)lreports should be available.
2. Acceptable handling properties: skin contact, as well as i
; dust or fumes, should not cause burns, blisters, peeling, ;
dermatitis, or allergic reaction. Accidental eye contact
should not cause permanent eye damage. Concentrated and ;
unreacted components should have a solvent for cleaning :
the materials from skin and/or equipment. The solvent should i
.;. have acceptable toxicology, handling, and safety properties. ~ -'^
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}
3. Acceptable safety properties; the materials should not be 1
so corrosive as to require special packaging and plumbing. i
The material, as well as dust or vapor, should not be ,
dangerously combustible. Flash point should be above '
working temperature 40° C (100° F), and preferably above
; a possible storage temperature of 60° C (140° F). The ;'
sealant components should not be hypergolic, i.e., (ignite :
spontaneously) with common materials, e.g., rags, oil,
gasoline. ;
D. Have Desirable Application Characteristics ;
' i
1. Low viscosity at point of application: materials which i
perform by grouting of the soil generally must have a i
viscosity of 1 to 30 cps over temperature range of from
-1° to 50° C (300 F to 120° F). Materials must be }
capable of being pumped 150 m (500 ft) in hoses of j
1.2 to 1.9 cm (0.5 to 0.75 in.) / j
: I
2. Controlled variable viscosity: with additives, increase
the viscosity from 1 to 10 times.
3. Controlled variable reaction time: from 5 seconds to
15 minutes.
4. Predictable viscosity until gelation begins: once
mixed and during placement the viscosity remains
essentially constant until gelation begins.
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3. No long-term biological effects; will not break down,
leach, or release any toxic materials.
Additional background information concerning safety criteria and
existing equipment should be considered by the manufacturers of grouts.,
Table 2 continued -
5. Easily removed from equipment; clean equipment in 30
minutes or less without special equipment or toxic,
flammable solvents.
6." Excess easily removed from pipe barrel'; excess "material
removed with the packer.
7. Full reaction in moving water; unconfined groundwater
flowing at 2.5 cm (1 in.) per second.
E. Easily Shipped and Handled
1. Special handling not required; meet DOT regulations. \
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2. Shipped by common carrier; meet DOT regulations. \ \
.;. . 3., -Long shelf life;--Minimum of 6 months; 1 year desired. I" -"'1
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4. Immune to effect of temperature over normal range; un- !
affected in temperature ranges of -1° to 50°C (3Qo F to !
120° F). i !
5. No danger if mixed with other chemicals, etc.; will not >
cause explosion, fire, or poisonous gases or fumes if | i
accidentally mixed with other chemicals that might \ :
commonly be found at a sewer line rehabilitation site. \ '
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6. Labeling;
a. labeling should be easy to read.
b. contain instructions for handling damaged materials.
c. contain instructions for cleanup of spillage and
disposal of excess materials and packaging.
F. Other ; )
1. No effect on wastewater treatment plant; excess material ;
or material's components will have no negative effects on
the performance of wastewater treatment plant operations. \ !
2. No effect on pumping; excess materials will not clog or j
damage pumps used for the transportation of sewage. !
10 ;
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".Table 2 continued
Safety '
Sewer sealants are handled and applied by construction-type
workers using truck-mounted equipment. Operations are per-
' formed in the field (away from warehouse or yard) under all
weather conditions. Sewer sealant materials are carried on
the truck in concentrated form (powder or liquid) and the
components may be dissolved/diluted/mixed/blended, as required,
at the work site. The components, in liquid form,are then
pumped through 155 to 215 m (500 to 700 ft) of hose to the point \
of application in the sewer where final mixing/catalyzation/ \
reaction of the components takes place and affects seal.
Worker Exposure - Regardless of preferred procedures for
handling, mixing, and applying chemical sealants, workers
can (and will) occasionally be exposed to the sealant com-
ponents.
For example; i
,
- Containers (bags, drums, pails) will receive rough hand-
ling in the field. There will be breakage and spills from
time to time. . '
!
- Equipment and plumbing (tanks, pumps, hoses, fittings)
will be disassembled for repair/replacement.
Diluting/mixing, blending of the concentrated components
may 'cause airborne dust, mist, or vapor. There may be
spills and residuals.
- Manual access sealing of large pipes and manholes will
expose workers to the components at the point of applica-
tion.
Safety Equipment
Workers will have and use approved respirators, gloves, goggles,
aprons, and such for protection when mixing and handling the
chemicals. Use of such personnel protection gear cannot be
assured at all times.
Wash Facilities
Workers will not generally have shower, hand wash, or eye wash
facilities available at the job site.
11 ',
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Table 2 continued
Desired Safety and Health Properties
It would be ideal to have a chemical sealant system which was
non-combustible, non-corrosive, non-toxic, non-irritating,
1. non-allergic, etc. In -all-probability, however,- it would
also be non-effective.
Moderate and tolerable levels of undesirable properties
may exist. The important thing is to rule out materials
having highly dangerous and cumulatively toxic properties.
12,
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SECTION III
TESTING OF POTENTIAL SEWER SEALANTS
To evaluate the potential usefulness of a material proposed for use as
a sewer sealant, at least four levels of testing appear needed. "These are: ^
1) basic tests by manufacturer and bench tests to determine essential
characteristics of the material as related to the desired performance
attributes; 2) soil box tests to evaluate the application characteristics of
the material and its potential ability to seal the sewer under various con-
ditions; 3) controlled field applications to determine long-term stability
and application factors; and 4) examination of sealed joints after a period
of service.
Many testing requirements for new chemical formulations have been im-
posed by the Federal government. Such tests are not discussed in this
report. Rather, tests which will allow a user to evaluate a product for
particular applications are outlined. Inasmuch as the tests were not de-
veloped for a specific sealant, they must be evaluated for applicability to
a specific product considered. Manufacturer tests have not been developed
in detail by the project inasmuch as material specific tests should be
provided and these may vary widely, based upon product base materials.
This chapter sets forth a series of simple specific measurements or
bench tests. ,. These may be made of candidate materials for sewer grouting
work by the manufacturer and individuals interested in using these
materials for sewer sealing.
It is important to keep in mind that sewer joint sealing is only a
segment of the overall pressure grouting field in its broadest sense.
Pressure grouting might be defined as the introduction of material into
remote areas to obtain a changed condition. Over the years pressure :
grouters have probably worked with almost every material which may be made
to flow. Under ordinary conditions pressure grouters are working through
pumps, pipes, and hoses, and injecting liquified materials into below-
ground structures. In addition to sewer lines, pressure grouting techniques
are commonly applied in mines, tunnels, dams, shafts, and foundation soils
primarily to control the movement of water.
The tests described herein enumerate the characteristics of an "ideal
sewer sealant." Several materials in common use today for sewer sealing do
not pass all of these tests at their maximum or most ideal levels. There is
no "pass or fail" for a sealing material. It is entirely possible, and
perhaps even to be expected, that some new sealant would earn itself a very
comfortable place in some of the market for which it was not originally
intended but was ideally suited. Acceptance by the end-user is, after
all, the ultimate test.
13, _.. ....__. __
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MANUFACTURER TESTS
The manufacturer should provide detailed test results and product com-
position information. Depending upon the method by which the product j
effects a seal, the following types of tests should be reported. By 1981, ;
it is expected that ASTM Committee D-18 on Soil and Rock for Engineering
purposes will promulgate various standards, some of which may be appropriate
for sewer sealants. . ;
j
It is important that grouts be stable. The use of a suitable unconfined
compressive strength test before and after the various tests will indicate .
if stability is being maintained. : ]
Unconfined : For sealants to be used in cohesive soils, ASTM
Compressive ' D-21.66 can be used with low strength chemical
Strength ' grouts. A standard filler of #5 silica sand can
be used. This sand has a DJQ of 0.39 mm. Figure
2 is a plot of the percent of the sand mixture by
" size. A minimum sample appears to be a 5 cm
(2 in.) - diameter/cylinder, 10 cm (4 in.) long.
ASTM D 1056 might be adapted for use with flexible
cellular materials such as urethane foam grouts.
Identify all known toxic components of the grouting
materials together with their individual and com-
bined toxicity, flammability, and/or other hazards
prior to, during and after placement. From these
statements extrapolate the potential for:
1. Groundwater contamination.
2. Personnel hazards.
3. General environmental hazards.
If chemicals not supplied by the manufacturer are 'I
needed, similar information should be provided.
USEPA toxic material register numbers or status
of listing should be provided. j
Mix and react the product in all of the configurations
which may be recommended for field use including ad-
mixtures or additives which might be employed to
change the characteristics of the product. Report
and comment on the minimum, average, and maximum
product reaction times (gel times) and report the
Toxicology
Product Reaction
Characteristics
Variability
14
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0.01!
0.1
0.2; 0.3[ 0.4', 0.5 0.6
Particle size (mm)
1.0
Figure 2 Gradation of Sand for Test Cylinders
15
-------
Predictable
Viscosity
Adhesion
Solubility and
Chemical
Reaction
Biodegradation
Flammability
Acid/Base
Reactions
results, including physical appearance or perfor-
mance characteristics over the gel time range.
Report all physical properties of the cured
material.
React five samples of the product at a minimum of
each of the minimum, average, and maximum gel times.
Measure, by any appropriate standard viscosity
measurement technique, the viscosity of the pro-
duct (and particularly changes in the viscosity
of the product) between the time of product
mixing and product gelation. Draw the viscos-
ity curve for the product from the time of
product mixing to product set for gelation.
If the seal depends primarily upon adhesion, tests
results should be provided to demonstrate the
ability of the product to adhere to the various
pipe materials under conditions of cleanliness
"which can be expected within a sewer. ~ "'
Solubility tests should be made on the cured material
for reaction in or with alcohol, ketones, hydro-
carbons, and metal salts. Response of the cured
material to solutions up to 10 percent strength of
sulfuric acid and caustic sodium hydroxide should
be determined. Compression tests should be made
after these tests.
Report on the constituents of the cured grout material
both separately and in combination and extrapolate
from the information the possibilities of decompo-
sition of the cured grout from:
1. Bacterial activity.
2. Consumption by rodents and/or insects.
Flash point information in accordance with DOT regu-
lations for shipping.
Components. ;
Comment on the effects of and the range of acid- or \
base-mix waters.] Comment on the effects of the
cured grout sample (the mixed product) in place or
during placement as to toleration of acids/base
contact with in-place solutions prior to final
product reaction. Prepare cured samples of grout i
with standard buffer solutions of pH 5 and pH 9.
Compare physical properties of the cured grout
made with pH 5 and pH 9 buffer solutions with those
of cured grout prepared with distilled water (control),
16
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Permeability
Final Product.
Prepare 27 cured samples. Precisely weigh and
measure each sample and record these measurements
along with the physical appearance of each sample.
Then immerse three of the samples in separate
containers of pH levels of 4, 7, 10. Let all
samples stand for 24 hours at ambient temperature.
Remove the samples. Measure and weigh each and
report their physical appearances and conditions.
Compression tests should be made after these tests.
Report on the permeability of the product under
varying pressure heads of up to 2.1 kg/sq cm
(30
BENCH LEVEL TESTING
The following tests are also suggested for initial product testing by i
the manufacturer. Product users and applicators may wish to use bench level
testing to confirm reported test results by conducting their own analyses.
Note:
Flexibility
For all tests except flexibility and permeability
samples to be 5 cm (2 in)-diameter cylinders,
10 cm (4 in.) long. As an alternate, samples |
5 x 2.5 x 2.5 cm (2 x 1 x 1 in) may be used.
Samples to be mixed with proportions specified
by manufacturer. Samples should be cast with
and without the #5 silica sand and the test re-
sults reported separately.
Cast a sample of grout material 30.5 x 2.5 x 2.5 cm
(12 x 1 x 1 in.)
Take an object with a smooth curved surface and a
radius of 10 cm (4 in). Place one end of the
sample against the curved surface and gently se-
cure the end against any movement. Grasp the
opposite (unsupported) end of the sample and
deflect it around the mandrel toward a maximum of
180° at a rate of not less than 1° per minute.
Record: \
1. Degree of deflection at formation of first
noticeable surface crack.
2. Degree of deflection when material ceases to
conform fully to the mandrel surface curvature.
3. Degree of deflection when crack formation in
the material extends one-half the way through
sample.
4. Degree of deflection when material fails
17
-------
Shrinkage
Permeability
Environmental
Cycling
completely, as evidenced primarily by extension of
the crack more than 90 percent through the sample.
Prepare a minimum of five cured samples. Weigh each
sample carefully and record the weight. Place all
samples in 50 percent relative humidity at 38° C
.,(100° .F) for 24 hours. ..Remove.the samples .and
after allowing them to cool to ambient temperature
and report their physical appearance. Then weigh
and measure each sample and report before and
after test results. Repeat test using the standard
sand filler. Observe cracking. Immerse dried
samples in water at room temperature, 18 to 23° C
(65 to 75 F), for 48 hours and observe condition of
samples and measure reswelled weight and dimen-
sions. Compare with original weight and dimen-
sions. :
Cover one end of a 5 cm (2 in.)-diameter cylinder^ _
38 cm (15 in.) long with a small mesh screen. Cast
a 2.5 cm (1 in.)-thick sample of cured grout in the
bottom (screened) end of the cylinder wall. Add
water to the cylinder to a height of 30.5 cm (12 in.)
above the cured grout. Collect and measure the
amount of water permeating through the cured grout.
Although permeability is not desired, rates of
10~8 cm/sec would indicate a very impervious
material for use as a sewer sealant.
Freeze/Thaw
Use 50 cured samples. Precisely measure and record
the weight and volume of each sample, then freeze
all samples so that each sample reaches a temperature
of -18°C (0° F) for 24 hours. Then remove and let
stand and allow the samples to thaw gradually to
room temperature. Repeat this series for five com-
plete cycles.
Select five samples from the group after each
cycle and report their physical appearance. Then \
precisely measure the weight and volume of each
sample and report that data in comparison to their
original weights and volumes.
Wet/Dry
Take a minimum of 30 cured samples and precisely
measure their weights and volumes. Place the
samples in a 50 percent relative humidity environ-
ment at approximately 21 C
(70° F)
for 24 hours.
IS'
-------
Organic
Solvents
Component
Storage
Pot Life
Remove the samples and immerse them in water at
21
for three complete cycles. \
° C (70° F) for 24 hours. \Repeat the procedure
At the end of each cycle interval of 1) 50 percent
relative humidity and 2) immersion, remove five of
the samples_and report their physical appearance; _
then precisely measure their weights and volumes
and report that information as compared to the
original weight and volume for each sample.
Prepare a minimum of 15 cured samples and precisely
measure their weights and volumes. Immerse five
samples in separate containers containing a minimum
of 165 ml (6 oz) acetone in closed cups. Let all
samples stand for 24 hours at about 21° C (70° F).
Remove the samples and clean off any liquid ob-
viously clinging to the sample. Dry the samples
in a dessicator for 30 minutes and report their
physical appearances and precisely measure and
report their weights and volumes. Repeat the test
with 165 ml (6 oz) of methyl alcohol. Repeat
the test with 165 ml (6 oz) of toluene.
Take a minimum of six samples of each component of
the chemical grout system to be used in the field.
Place each sample in a container which most closely
approximates the probable shipping container for
each component. React two of the samples to obtain
the grout end product and set aside for comparison.
Freeze the remaining samples to a sample temperature
of -18° C \(0° F) for 24 hours. Remove the samples.
Let them stand and allow them to thaw to ambient
temperature, than heat samples to 49° C (120° F) \
for 24 hours. Remove the samples, let stand, and
allow to cool to ambient temperature.
At each interval of 1) ambient temperature after ,
-18° C 1(0° F), 2) ambient temperature after 49° C
(120° F); react two samples of the product. Record
the reaction characteristics as compared to the
original controls and report the product appear-
ance prior to each test and after each test..
For materials which must be mixed with other mater-
ials prior to placement, prepare a minimum of twelve
samples of each grout component in a container which
most closely resembles the probable on-job container
for each component immediately prior to grout place-
ment. Allow these samples to stand for 24 hours.
19'
-------
Then take two samples, open their containers, mix
the product and take a gel time test. Repeat the
test each day for five days.
Compare the results of the daily tests for con-
. sistency.
Viscosity Measure the viscosity of the components in their
form immediately prior to pumping to the point of
application at temperatures of -1° to 40° C
(30 to 100° F).
SOIL BOX TESTING \
Any sealant material which emerges from bench testing with acceptable
characteristics would be further evaluated under simulated use conditions
to obtain some knowledge and understanding of the material's more subjec-
tive characteristics. Such tests would be performed in a "soil box" and
behavior of the material would be reported for the following condition-
variables as follows:
1. concrete and clay pipe 20 cm (8 in.)
2. hydrostatic pressure 9 m (30 ft)
3. large and small joint leaks
4. laminar water flow outside of pipe
5. fine sand, pea gravel, 5 cm (2 in.) stone, and cohesive soils
6. joint deflection :
7. "pumpability"
8. compatability with existing equipment
9. ease of excess material removal from pipe barrel
10. resistance to cleaning equipment
11. resistance to scour and abrasion
12. ease of product handling :
13. batch time preparations
Proper conduct of these tests would require construction of at least
two well-built soil boxes capable of full closure and pressurization to
achieve a 9 m (30 ft) head pressure. Each sealant material would require
approximately one week of such soil box testing.
20 \ ... ._.. .... ._- -
-------
Due to the subjective nature of this phase of testing, actual test
work on all sealant material should be performed at the same location and
under the same supervision. Careful documentation by written records, audio
visual equipment, and photographic equipment would be necessary.
_.. Major items of equipment required for such tests might be listed as
-follows: soil box quantity -_two at $5,000 each; packer .or grout ejection .....
system; pump system; hose; mix tanks; agitators; miscellaneous; total cost \
$25,000. (1980 price estimate) i
In addition it would be desirable to employ an outside testing labora-
tory during this phase of test work. Such a lab could perform independent
tests of such variables as unconfined compression, cohesion, extrusion, and
other variables as applicable. A final report and synopsis would also be
necessary. The total variable cost for such soil box testing might approxi-
mate $15,000 per sealant tested.
FIELD APPLICATION ' \ \ \
Following these soil box tests, actual field application could be .'
recommended for a sealant showing an acceptable mix of characteristics. !
Ideally, four locations would be selected from separate areas of the United
States and test sections in each area would be tested and sealed for each
of two pipe size diameters - 20 cm (8 in.), and 61 cm (24 in.).
The test sections would be critical to the proper evaluation of the
material handling characteristics for the following variables: clay pipe,
concrete pipe, hot climates, wet conditions, dry conditions, sandy soil, j
silty soil, clayey soil, northern winter climates, southern summer climates,
rock backfill,- sealing above the groundwater table, sealing below the ground-
water table, "salt water in the soil, large leaks, small leaks. ;
t
A sealant, such as acrylamide grout which has given satisfactory service
over a long period of time, should be used for reference purposes. After
application, the joints should be tested as well as visually inspected.
i
i
i
EXCAVATION OF JOINTS ' ' \ - !
i
After at least one year in place, representative joints should be !
excavated for physical inspection. Such inspection should include a visual
inspection for cracks and failures as well as evidence of root attack, ;
biodegradation, or solubility problems. !
21
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SECTION. IV,.,, ,-
SEWER PIPE JOINT GROUTING EQUIPMENT ;
Initially sewer pipe joint grouting equipment were products of spec- \
ialty contracting firms building and using such equipment within their own
organizations. Equipment configurations varied widely depending upon the
specific process and needs of the individual contractor. It wasn't until
the early sixties that the sewer grouting process had developed suffic-
iently to attract manufacturers to build equipment for use with the various
sealant materials available. Through the years, equipment manufacturers
have refined the technology and equipment that is in use today. ;
i
During"the' early sixties " commercial ~equipme"nt~was" designed and manu- 1
factured for the placement of an acrylamide base grouting material (low <
viscosity) as acceptable alternative grouting materials were not available.
When urethane foam grout was introduced in the early 1970's, suitable ;
equipment was likewise developed.
At the present time there are two distinct types of grouting equipment
being manufactured: that for placing an acrylamide base material; and that
for an urethane grouting compound. It is anticipated, however, that equip-
ment of the future may be designed to accommodate placement of a variety of
grouting materials.
PRESENT DAY SEWER GROUTING EQUIPMENT \ :
In an effort to review existing sewer grouting equipment, the following
two categories have been established based upon the viscosity of the chemi-
cals as they are pumped to the packer:
Category "A" - Equipment designed for the placement of
1 to 50 centipoise materials (low viscosity \
delivery system)
Category "B" - Equipment designed for the placement of
; 1 to 700 centipoise materials (high viscosity
delivery system)
These two categories will encompass 95 percent, if not all, of the
equipment available for the placement of sewer sealants at the present time.
All of the equipment is designed to functicn effectively in a minimum of
sewer line sizes ranging from 15 to 76 cm (6 to 30 in.) diameter. In all
cases the "in-line" equipment is manufactured with sufficient tolerances
to accommodate the normal deviations of size, alignment and obstructions
normally found in a sewer pipe. ._ .
22
-------
'. From a process point of view, there is little difference between the ....
two equipment systems. Each system utilizes closed circuit t.v. equipment
as shown in Figure 3 for visual monitoring of the remote sealing process.
A hose and reel combination as shown in Firgure 4 for transporting the sealant
material from above ground to the point of placement is included. A packer
device shown in Figure 5 is utilized for controlling the injection of sealant
j-ntp the sewej|^jDipe__J:ault.
The basic process steps may be described as follows:
1. Precleaning of the sewer line from manhole to manhole
to remove debris that could interfere with the move- !
ment of the television and grouting equipment
through the line.
2. Preinspect the sewer line by pulling closed circuit
television equipment from manhole to manhole to de-
termine the general condition of the sewer line and
if it is groutable as shown in Figure 6.
3. Place the joint sealing packer equipment into the
sewer line with the closed circuit television
equipment. ;
4. Move the combined equipment through the line to each
joint. ;
5. Using the closed circuit television equipment, posi-
tion the center of the packer adjacent to the joint
to be tested. . \
6. Inflate the packer to isolate the joint to be tested
from the remainder of the sewer line as shown in
Figure 7. |
7. Test the joint in accordance with the equipment and
medium available. If it holds water or air pressure,
j move to the next joint and repeat steps 4, 5 and 6
until a joint is reached which will not hold pressure.
8. For joints which fail the pressure test, inject the
sealing materials into the joint until a successful
seal is achieved.
9. Retest the joint to determine if it will pass a
pressure test.
10. Deflate the packer and move to the next joint or
remove the equipment from the sewer line, which-
ever is appropriate. j
Differences that do exist between the two defined categories of equip-
ment result from the materials they are designed to handle. As previously
23
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Figure 3 Closed Circuit TV Equipment -courtesycue.me
Figure 4 Remote Sealing Equipment -courtesycheme, me.
24
-------
Packer Device (for 10 to 61 cm (4 to 24 in.) diameter) -courtesycues,me
Sleeve Packer (for 10 to 30 cm (4 to 12 in.) diameter) - courtesy cheme, inc.
Figure 5 Packer Devices \
25
-------
.<4ir 000
Figure 6 Preinspection of Sewer - courtesy cues, i
26
-------
to
AIR LINE-
(FRONt SEALING'
UNIT) / '
//
CHEMICAL LINES
(FROM SCALING UNIT)
''/
STAINLESS STEEL CABLE
RUPTURED SEWER LINE BELL
Figure 7 Sewer Joint Sealing Positioning of Packer - courtesy Peneiryn systems,
Inc.
-------
described, Category "A" equipment generally is designed to pump low
viscosity (1 to 50 cps)\materials, which, when injected pass through the
faulty sewer joint into the surrounding soil to form a watertight barrier.
High viscosity (1 to 700 cps) [materials pumped by Category "B" equipment
when injected, form a new joint gasket and may or may not penetrate into
..the surrounding soil areas.
Basic characteristics of the two categories of equipment are detailed
as follows:
Category "A" (low Viscosity Delivery Systems)
i
1. Chemical Pumping System: Most of the equipment in
this category are equipped with pressure tanks used
;to pump the sealant from the grouting unit to the
point of repair and are commonly referred to as the
"air over" system. In practice, the chemical con- ;
stituents are mixed in two pressure tanks. Once ;
mixed, the tanks are closed and compressed air is *
r .._ _ .... £ntro .-^' '.
Alternate to the "air over" method is a dual 1 to 1
positive displacement pump system where the chemical - :
constituents are mixed in two non-pressure vessels !
. and are pumped to the point of repair. This method " '
would also allow placement of category "B" materials. :
\
With both systems, the chemical fluids are pumped '
through a dual hose system to the packer where they ;
are mixed at the point of injection.
2. Operating Pressures: The "air over" system operates
at a maximum of 8.8 kg/sq cm I(125 psi) tank pressure
and is thus limited in its pumping capability. The
pump systems, by contrast, have the capacity of devel-
oping pump pressures in the range of 35.15 to 70.30
kg/sq cm!(500 to 1,000 psi) and therefore have the
ability of pumping a broader spectrum of materials.
3. Chemical Delivery System: The chemicals are pumped,
with either of the two systems described, to a grout
control panel where the flow rate of each material
may be varied as required and monitored by flow rate
gauges. From the control panel the fluids are pumped
through 150 m (500 ft) of a 1.2 to 1.9 cm (0.5 to
0.75 in.) diameter dual hose system to the packer in
the sewer line. At the point of injection, the two
materials are combined for placement. In line check
28 .
-------
valves located at the packer are used to avoid
combining of the chemicals other than at the point
of injection.
Category "B" (High Viscosity Delivery Systems)
. Chemical Pumping System: .All of the.__equipment .in
this category are equipped with pumps. None of the
systems are of the "air over" type. The dual pump ;
system is of a positive displacement type and pumps
in a ratio of 1/1 to 1. With some modification the
pump ratios may be changed. -Chemical concentrate is i
either pumped directly from the shipping containers
or from non-pressurized storage vessels through a :
clual hose system to the point of repair in the
sewer line.
i
2. Operating Pressures: Normal pump operating pressures j
are in the area of 42.18 kg/sqjcm (600 psi);/however, ;
"~ ""the pump system has the "capacity to pump a~t pressures "" .
in the range of 70.30 kg/sq'|Cm (1,000 psi). Generally, i
with the type of material being pumped, pressures of
a 70.30 kg/sq cm\(l,000 psi) are not reached.
3. Chemical Delivery System: Unlike the low viscosity ,
equipment, this system pumps the sealant materials
directly from containers, through 150 m (500 ft) of
1.2 to 1.9 cm (0.5 to 0.75 in.) diameter dual hose
to the packer in the line where mixing occurs at the
point of injection. The ratio of fluid pumped is '
. fixed with only the flow rate being variable based
on the operating speed of the pumps. Check valves :
incorporated in the packer device are used to avoid j
contamination of the separated materials in the hose ;
line. \
It is obvious that there are differences between the two categories of
equipment. However, there are similarities as well: in packaging and :
auxiliary equipment. Both types of equipment are mounted in van trucks or
trailers. One hundred and ten (110) VAC power is available from either self-
contained power supply units or from 5,000 to 6,500 watt generators mounted
within the vehicle. Small air compressors are also standard equipment.
COMPONENT SYSTEMS \ :
Generalized description of three portions of the sealant delivery sys-
tem are provided for general information. Each is essential to an operating
system but may need modification to accept the use of a new product.
29 -.-
-------
Flow Control Systems \ -~
About 50 percent of the systems route the chemical through a
panel that contains flow meters with flotation device to measure
flow rates. The panels are also equipped with flow control valves to
activate chemical movement and pressure gauges to monitor back pressure.
Other gauges monitor packer inflation pressure and compressor receiver
pressure. Most of the remaining systems do not use flow meters. However,
they do incorporate pump pressure gauges, pump .controls, packer inflation
pressure gauges, and compressor receiver gauges.
Reels and Hoses \
Virtually all of the systems incorporate a hose reel with
rotary passage joints. The reels allow for passage of two to
three fluids and one or two air lines. About half of the hoses
~ are triline "systems with two chemical and one air line.
Quad line systems have two chemical, and two air lines. The
chemical hose sizes range from 1.2 to 1.9 cm (0.5 to 0.75 in.)
and the air lines range 0.95 to 1.2 cm (0.375 to 0.5 in.). The
hose lengths normally range from 122 to 183 m (400 to 600 ft)
with the standard being 150 m (500 ft). Over 50 percent of the
hose ends are equipped with quick disconnects. About the same
percentage of hose ends are fitted with check valves.
Packers
Some are equipped with two inflatable rubber elements stretched
over a cylinder, and fitted into a center casting. The center
casting contains two openings to exit the chemical into the void
areas after element inflation. Mixing chamber may or may not be
incorporated into these packers.
Other packers are' equipped with three inflatable elements
stretched over mandrels. Chemical exits from the openings
between the elements after the end elements are inflated.
The center element can be inflated to extrude most of the
remaining chemical from the void. Some mixing occurs prior
to exit from the portal. Some other packers are used incor-
porating a long or single sleeve stretched over a cylinder
or pipe. The chemical exits from one or two openings passing
through the rubber sleeve. Some of these packers are equipped
with a mixing chamber.
30
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.SECTION V .
BUILDING SEWER (HOUSE LATERAL) REPAIR
For many years, the effect of leaking building sewers on the collection
system and treatment facilities was considered insignificant. This theory
was built around the concept that most of the building sewer would be above .
the water table and therefore would only be subject to leakage during per-
iods of excessive rainfall or exceedingly high groundwater levels. These
sporadic conditions were not viewed as "serious" when compared to other j
collection system problems.
...Therefore, during the early development of internal pipe-joint grouting
processes, little attention was given to the building sewer. It wasn't
until the late 1960's that serious attempts were made to repair building
sewers by a means other than by excavation and replacement. Shortly, three
primary processes emerged and were used in varying degrees throughout the
country. Each of these processes required some excavation and proved to be
cumbersome and expensive. Therefore, wide acceptance and use of these' pro-
cesses was never achieved. \
Today, however, the recognition of the need to repair building sewers
is much greater. Expanded awareness of the impact of building sewers on
the collection system and treatment facilities has developed from the current
on-going I/I program. Research studies sponsored by the USEPA (4) indicate /
that a significant percent of the infiltration found in many collection
systems is being contributed by the building sewers. In addition, it is now
realized that building sewers that are left unattended may become a major
source of renewed infiltration, through water migration, after the street
sewers have been repaired. ,
Current technology is not considered to be generally effective or '
economical in addressing the building sewer infiltration problem. The
industry is left usually with only one remedy, the expensive and sometimes
impossible task of building sewer excavation and replacement. The need to ;
develop new and more effective processes is well known. The following will
provide further understanding of the current processes available for the
repair of building sewers. In addition, two new concepts have been developed
and are presented. These concepts, though untried, are felt to be sound
with each having the potential of being developed into successful and
economical processes.
THE BUILDING SEWER
The building sewer is the extension of the waste drain system of a
31 , _
-------
'building or other waste producing facility which is extended to the public
right of way for conveyance in the collection sewer to the wastewater treat-
ment facility. The building sewer may be as small as 10 to 15 cm (4 to 6 in.)
diameter and varies in length from 4.5 m (15 ft) to 30 m (100 ft) or more.
The line is usually laid at a minimum self-cleansing grade from the build-
ing to the immediate vicinity of the collection or street sewer. At this --.
.'location there may be an abrupt change in grade in order for .the flow to
descend to the collection sewer. The building sewer may enter the collection
sewer at an angle of 30 to 90 degrees from the axial5, flow direction and at a
verticle angle of 0 to 90 degrees.
The building sewer may have been built with any one of several common ;
products including clay, plastic, concrete, asphalt impregnated paper, or
cast iron. Inspection of the construction has generally been described as .'.
minimal. The trench for the pipe and the backfill used may act as a french
drain and allow more rapid movement of groundwater than would be typical of
undisturbed ground. ; i
i ;
Few systems provide for access at the property line. Some systems
where basement flooding has been prevalent have required a relief overflow '.
point outside of the foundation.draining to the surface. Overall, such points
for access must be considered as the exception. Access from within the
building for sealing equipment is not considered feasible due to the problems
of access to the pipe and the type of equipment required as well as the
incovenience to the occupants.
EXISTING PROCESSES
\
As a requirement of this study, current methods for the sealing of
building sewers were identified and evaluated. Incremental costs have
been developed and are presented for each method.
Pump full method
Sewer sausage method
Camera-packer method
Each is discussed in detailed step procedures that must be accomplished
for a successful application. Costs associated with each step of the pro-
cedure is also given. Note that the cost of excavation has not been given
in the tables. Rather, excavation costs have been included in a cost range.The
The sewer sausage and camera-packer methods are both patented processes. \ ;
A fourth method, in-situ lining has been used to a limited extent in some1 : .)
foreign countries and work has been initiated in this country to determine . >'
the cost and applicability to conditions of United States practice. Generally,
the street sewer must be cleaned for access of equipment. Cost of cleaning has
not been included in the price estimate.
32 \i
-------
;Pump Full Method
This concept is one of injecting a chemical sealant through a conven-
tional sealing packer from the street sewer up the building sewer to a
point where access has been gained through excavation and plug installed.
As the sealant is pumped under pressure, it is forced through the pipe
.faults into the surrounding soil area where a seal is effected after gela-
tion of the sealant occurs."""After the sealing has been accomplished, the
excess sealing material is removed from the building sewer and it is re-
turned to service. The steps; required to accomplish the work are listed
in Table 3 A.
Table 3 '
(SEALING OF BUILDING SEWERS)
A Pump Full Method
1. Locate building sewer at property line.
2. Clean street sewer. \
3. Set-up and move camera/packer unit
into position in the street sewer
4. Install pipe plug in the downstream
end of the building sewer at a point \
of access.
5. Inflate packer in street sewer and
inject sealing materials. :
6. Remove camera/packer from the street
sewer and the plug from the building
sewer. : <
7. Remove excess sealing materials from
the building sewer.
8. Re-clean the street sewer to remove
excess sealing materials.
COSTS ($)
Equip-
- Labor ment
Mater-
ials "
20
90
40
40
40
150
30
45
20
20
20
50
50
150
Subtotal $410 $205 $150
TOTAL COSTS
a. without excavation $765
b. if excavation required Up to $1615
Note: Cost estimated as $6.60/kg ($3/lb) material
Average labor cost $20/hr (includes supervision)
33
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Sewer Sausage Method
This method is similar to the pump full method in that it requires
access to the building sewer, the use of a camera/packer unit in the street
sewer and the injection of a sealant from the street sewer up the building
sewer to effect a repair. The primary difference is the use of a tube in-
serted into the building sewer prior to sealing to reduce the quantity of
sealant used and minimize"the cleaning requirement~after the sealing has been
completed. The sealant is pumped under pressure around the tube, up the
building sewer and through any pipe faults into the surrounding soil areas
where the seals are effected after gelation of the materials occurs.
Table 3 B lists the steps and estimated costs to accomplish the sealing of
a building sewer.
Table 3
B Sausage Method
Steps
1.
2.
3.
9.
10.
Locate building sewer at property line.
Clean the street sewer.
Set up and move camera/packer unit
into position in the street sewer
Install tube from the point of
excavation down to the street
sewer. .. .
Install pipe plug in the downstream
end of the building sewer at the
point of excavation
Inflate packer in the street sewer and
inject sealing materials.
Remove camera/packer unit from the
street sewer
Remove plug and tube from the build-
ing sewer.
Remove excess sealing materials from
the building sewer.
Reclean street sewer to remove any
excess sealing materials
Subtotal
Labor
20
90
20
60
40
40
40
30
COSTS($)
Equip-
ment
45
20
20
Mater-
-,
xals
20
20
50
10
$ 55
'34 '
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Steps continued
TOTAL COSTS
a. without excavation $610
b. if excavation required Up to $1510
Note: Cost estimated as $6.60/kg ($3/lb) material - _
Average labor cost $20/hr (includes supervision) '
Camera-Packer Method ' :
Unlike the other methods described this method does not require the
placement of equipment in the street sewer. It also differs in concept, as
only faults discovered by the television camera would be repaired. This
process also requires access to the building sewer. Through the access,
a miniature television camera and specialized sealing packer are inserted.
Using a tow line, previously floated from the building sewer access to
the downstream manhole of the street sewer, the camera packer unit is
pulled into the building sewer. The camera/packer unit is then slowly
pulled back out, making repairs to faults that are discovered by the
television camera. Thus, the deepest leaking joints are sealed first.
The repairs are made similarly to the conventional methods used for sealing '
joints in street sewers. Once the repairs have been completed, the equip- ;
ment is removed and the building sewer returned to service. The steps and
costs are described in Table 3 C. .
: Table 3
C Camera - Packer Method !
Steps Labor
1. Locate building sewer at the property
line. 20
2. Clean the building sewer 30
3. Clean the street sewer. 90
4. Float line from access in the building
sewer to the downstream manhole of
the street sewer. 20
5. Insert special camera/packer unit
into the building sewer 40
6. Pull camera/packer unit down to the
street sewer. 30
7. Retrieve camera/packer unit, making
repairs as detected by the tele-
vision camera. 110
COSTS ($)
Equip-
ment
10
45
Mater-
ials
15
55
120
35
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continued
COSTS ($)
Equip-
Labor ment
8. - Remove equipment from the building sewer. ...40
9. Flush the building sewer to remove
excess sealing materials. . 20 5
10. Remove the tow line from the down-
stream manhole of the street sewer. " 10
11. Reclean the street sewer. 30
Subtotal ; : $440 \ $145 $120
TOTAL COSTS i
_ _ a._without excavation _' $_^Q5; ..
b. if excavation required Up to $1615
Note: Cost estimated as $6.60/kg ($3/lb) material
Average labor cost $20/hr (includes supervision)
The costs shown above do not reflect many of the difficulty factors
that can be encountered when repairing building sewers. As an example, there
are no allowances for difficult site access and excavation dewatering, etc. ,
It is also assumed that the street sewer size would range from 20 to 30 cm !
(8 to 12 in.). Shown in Table 4 is a range of costs that could be en-
countered when repairing building sewers with the methods described.
Table 4
Range of Costs for Repair of Building Sewers :
Method Cost Range (1980) !
Pump Full Method $765 - $1615 :
Sewer Sausage Method $610 - $1510
Camera Packer Method $705 - $1615
NEW CONCEPTS \
Two concepts for the sealing of building sewers are presented, each
concept is different with regards to the development required. One concept
utilizes existing sealing materials, but requires the development of mechani-
cal capability. The other concept is based on the use of existing mechani-
cal equipment, but requires the development of suitable sealing material.
Both concepts have the singular objective of avoiding the primary disadvant-
age, of existing methods for sealing of building sewers; namely, the necessity
36 ,
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of gaining access to the building sewer by excavation either at the property .
line or at the structure being served. The following describes these two
concepts in general terms as specific details would be determined during
development.
1. Building Sewer Joint Sealing (Figure 8) - This method is based on __
using existing sealing materials to seal faulty pipe joints within the
building sewer and without the need for surface access to the building
sewer. Envisioned with this method is a device of a cylindrical shape
(1) that could be pulled through the existing street sewer (6) to the
location of the building sewer connection (7) as viewed by a television
camera. Once in place, shoes (2) on either end of the device would
expand to the wall of the pipe (6) to hold the device in place. The
center barrel of the device (1) would be rotated to orient the chute (3)
for the self-powered tractor (4) and sealing packer (5) opposite the
building sewer opening. The tractor (4) would travel along the chute (3)
and into the building sewer (7) pulling the sealing packer (5) with it.
Once in the building sewer, the sealing packer (5) would be stopped at
predetermined intervals and the pipe tested and sealed if necessary.
2. Building Sewer Exfiltrtetion Sealing (Figure 9) - Based on the use of
existing equipment, this concept also does not require excavations to be
made for the purpose of providing access into the building sewer.
Rather, it would involve the pulling of a standard sealing packer device
(1) into the street sewer (3) and locating it so that the center is ad-
jacent to the building sewer opening (4) as viewed by a television cam-
era. Once in place, the end elements (5) of the packer would be in-
flated to isolate the building sewer (4) from the remainder of the street
sewer (3). Then the first component of a staged chemical sealant would
be injected through the injection ports (2) and up the building sewer (4).
After sufficient time to allow the sealant to migrate through each of the
pipe faults into the surrounding soil areas had elapsed, the packer and
elements (5) would be deflated and the excess material allowed to flow
out of the building sewer (4). The end elements (5) would be reinflated
and the second stage of the chemical system would be injected in the
same manner as the first stage. The second stage material would be held
in place for sufficient time to insure proper chemical curing. After
cure the packer end elements (5) would be deflated and the sealing
operation would be complete.
An estimate of the developmental cost of either system is beyond the
resources of this study. The key elements of a cost effective system appear
to be:
1 1. Use of minimum amount of material.
2. Achieve access to the building sewer from street sewer for a
distance of 20 to 60 m (60 to 180 ft).
3. Equipment able to rise almost vertically and make a 90 bend.
4. Equipment able to enter building sewer from any angle from the
vertical and from flow direction.
37
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Cylindirical shaped device
Shoes
Chute/
Self-powered tractor!
Sealing packer
Pipe wall
Building sewer connection
Figure 8 Building Sewer Joint Sealing Concept |"
Standard sealing packer device
Injection ports
Street sewer
Building sewer opening
Packer end elements
(§>
Figure 9 Building Sewer Exfiltration Sealing Concept
38
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5. Equipment able to go from 20 cm (8 in.) street sewer to 10 to 15 cm
(4 to 6 in.) diameter building sewer.
Television cameras have been developed of a diameter small enough to
enter a building sewer. However, their length may preclude traversing the
abrupt vertical angle in the pipe. Radar technology is available for in-
"specting water coolant pipes in nuclear reactors, and the use.of such equip-
ment might provide a suitable alternate for visual inspection. ;
The Insituform Method . :
Limited experience has recently been gained with a building sewer lining
method to eliminate infiltration. The Insituform method of lining building
sewers not only eliminates infiltration, but provides a degree of renewed
structural integrity to the existing pipe. The Insituform method introduces,
via inversion, a 3 mm thick polyurethane coated polyester liner which is
saturated with & thermal setting, dual catalyzed isothalic resin. This
method requires an entry point at the property line. The liner is then i
inverted through the building sewer and is terminated.upon .its. entry .into the
the main line. The water used for inversion is then connected to a heat ;
exchange unit which will heat the water in the liner to approximately 71 C
(160 F). The thermal setting resin cures and the once pliable liner be- ;
comes a structurally sound continuous, i.e., no joints, pipe. The end of \
the liner is opened by excavation or via a remotely controlled cutting device
placed in the main line; the hookup at the property line is completed;
the excavation pit backfilled and service to the building sewer is restored.
The Insituform method has been used on main line sewers in Europe for
the last 10 years. Now the same principles are being applied to rehab-
ilitation of small diameter building sewers.
The steps and costs are described in Table 5.
39 ''
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Table 5
Insituform Method
Costs
1. Locate building sewer at the property line $ 10
2. Remove one length of pipe from building sewer 10
3. Clean the building sewer 30
4. Televise the building sewer - 30
5. Materials: chemicals, liner material, special equipment 1,250
6. Cut open liner at main sewer via remote control cutter 150
7. Labor: TV, cleaning, liner saturation and lining^' 300
8. Replace section of building sewer 30 i
.Total Costs: , .
a. Without excavation $1,810 '
b. If excavation required $2,710
All costs based on a 10 cm (4 in.) diameter line, 12 m (40 ft) long and
located 1.5 to 2.1 m (5 to 7ft) below a grassy surface at the property
line. Also, the main line and the building sewer to be lined has no
sharp turns nor does it enter the main line via a stack.
(2)
This price is based on Insituform's best estimates. Insituform is
presently entering into a building sewer lining program and feels this
price can be lowered with on-job experience; also daily production
volume will lower the price as well. The above price is based on a
one line a day production.
(3)
Average labor cost $20/hr (includes supervision).
40
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SECTION VI
GLOSSARY OF PERTINENT TERMS
Bench Level Testing - A series of tests which might be conducted by the
manufacturer, applicator or owner to screen or evaluate the character-
istics of a product prior to additional testing.
Building Sewer - also house lateral, house connection, or house service
line. The portion of the sewer system which connects the building
to the collector sewer in the public right-of-way. The building
sewer is usually of small diameter, on both public and private
property and may be laid with rather abrupt changes in grade.
Access to the bulidng sewer from the overlaying ground surface
usually is not available without excavation.
Existing Equipment - All equipment owned by the private and public sector '.
used for the internal sealing of small diameter sewers. Such equip-
ment may have been fabricated by a major manufacturer of equipment or
assembled from separately purchased components by the owner. The
equipment may or may not be in regular use at this time and may be >
limited to use with only one type of chemical system.
Infiltration - The flow of groundwater into a sewer through open joints,
cracks or other defects in the sewer pipe or its appurtenances.
, . '
Retrofit Cost - A cost to convert an existing internal sewer sealing equip-
ment unit to allow the use of a different chemical system. The minimum
retrofit cost becomes the cost of such retrofitting with consideration
of the cost of the amount of chemical required to effect a seal, and
the cost of manpower and equipment to achieve the seal, all compared to
the cost of sealing with the chemical system for which the equipment
was designed.
Sewer Sealant - A chemical system which can be applied with appropriate
equipment to internally stop the infiltration of groundwater into
joints of sewers.
Soil Box Tests - A series of tests conducted to evaluate a sewer sealant
under controlled laboratory tests prior to field testing. Such tests
allow rapid evaluation of its ability to handle the chemicals and to
effect a seal under various soil bedding and hydrostatic head
conditions.
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SECTION .VII ...__
REFERENCES
1. American Public Works Association, "Control of Infiltration and Inflow
into Sewer Systems," 11022EFF12/70, U.S. Environmental Protection \
Agency, NTIS PB 200 827, 1970.
2. Sullivan, R., et al, "Sewer System Evaluation, Rehabilitation and New
Construction," EPA-600/2-77-017d, U.S. Environmental Protection Agency, '.
NTIS PB 279 248, 1978. \
3. The Western Company, "Improved Sealants for Infiltration Control," :
11020D.IH06/69, U. S. Environmental Protection Agency, NTIS PB 185 951,
1969.X
4. Conklin, Gerard F., "Evaluation of Infiltration/Inflow Program -
EPA Project 68-01-4913, U.S. Environmental Protection Agency,
Municipal Construction Division, Washington, D.C., July 1980. '
42
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Trade Name
SECTION VIII
APPENDIX
List of Presently Available or
Announced Chemical Systems of
Internal Sealing of Small Diameter Sewers
1. AV-100
2. AC-400
3. Chem G-9
4. CR-202
5. CR-250
6. Injectite-80
7. Q-Seal
Base Manufacturer/Supplier
acrylamide Avanti, International ]
monomer _ _Houston,_Texas ...^
organic Geochemical Corporation
monomer ; Ridgewood, New Jersey ;
acrylamide Polymer Corporation <
monomer : Ft. Lauderdale, Florida
urethane Minnesota Mining and Manufacturing
foam (3M) St. Paul, Minnesota
urethane Minnesota Mining and Manufacturing
3M) St. Paul, Minnesota
poly- Cues, Incorporated ;
acrylamide Orlando, Florida
acrylamide Cues, Incorporated
monomer Orlando, Florida :
43
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