ACI 350.1-10Reported by ACI Committee 350Specification for
Tightness Testing ofEnvironmental Engineering ConcreteContainment
Structures(ACI 350.1-10) and Commentary
Specification for Tightness Testing of Environmental
EngineeringConcrete Containment Structures (ACI 350.1-10) and
CommentaryFirst PrintingFebruary 2011ISBN 978-0-87031-418-6American
Concrete InstituteAdvancing concrete knowledgeCopyright by the
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ACI 350.1-10 supersedes 350.1-01, was adopted October 25, 2010,
and publishedJanuary 2011.Copyright 2011, American Concrete
Institute.All rights reserved including rights of reproduction and
use in any form or by anymeans, including the making of copies by
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1ACI Committee Reports, Guides, Manuals, and Commentariesare
intended for guidance in planning, designing, executing,and
inspecting construction. This document is intended for theuse of
individuals who are competent to evaluate thesignificance and
limitations of its content and recommendationsand who will accept
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American Concrete Institute disclaimsany and all responsibility for
the stated principles. The Instituteshall not be liable for any
loss or damage arising therefrom.Reference to this document shall
not be made in contractdocuments. If items found in this document
are desired by theArchitect/Engineer to be a part of the contract
documents, theyshall be restated in mandatory language for
incorporation bythe Architect/Engineer.Specification for Tightness
Testing of Environmental Engineering Concrete Containment
Structures(ACI 350.1-10) and CommentaryAn ACI StandardReported by
ACI Committee 350ACI 350.1-10These test methods give procedures and
criteria for tightness testing ofenvironmental engineering concrete
structures. They are applicable toliquid and gas containment
structures constructed with concrete or acombination of concrete
and other materials. This document includeshydrostatic, surcharged
hydrostatic, and pneumatic tests.These test methods may involve
hazardous materials, operations, andequipment. This document does
not purport to address all of the safetyproblems associated with
its use. It is the responsibility of the user of thisdocument to
establish appropriate safety and health practices anddetermine the
applicability of regulatory limitations before use.Keywords:
containment structures; hydrostatic; leakage; pneumatic;reservoirs;
tests; tightness; tightness criteria.CONTENTS(mandatory portion
follows)SPECIFICATIONSection 1General requirements, p.
31.1Scope1.1.1Work specified1.1.2Work not
specified1.2Definitions1.3Description1.4Submittals1.4.1General1.4.2Repair
procedures1.4.3Test reports1.5Quality assurance1.5.1Duties and
responsibilities of ContractorIyad M. Alsamsam Charles S. Hanskat
Daniel J. McCarthy Andrew R. PhilipSteven R. Close* Keith W.
Jacobson Andrew R. Minogue Risto ProticRobert E. Doyle M. Reza
Kianoush Javeed Munshi William C. ShermanAnthony L. Felder Ramon E.
Lucero Jerry Parnes Lawrence M. TabatCarl A. Gentry*Subcommittee
members who produced this specification.The committee would like to
thank David Poole, Paul Hedli, and Kyle Loyd for their
contributions to this specification.Satish K. SachdevChairJon B.
Ardahl*Vice ChairJohn W. BakerSecretaryA metric version of this
document (ACI 350.1M-10)is available at www.concrete.org
2 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.orgSection 2Hydrostatic tightness
test for open or covered containment structures, p.
42.1General2.1.1Scope2.2Products2.2.1Materials2.3Execution2.3.1Test
preparation2.3.2Hydrostatic tightness testPart 1:
Qualitativecriteria2.3.3Hydrostatic tightness testPart 2:
Quantitativecriteria2.3.4RetestingSection 3Surcharged hydrostatic
tightness test for closed containment structures, p.
53.1General3.1.1Scope3.2Products3.2.1Materials3.3Execution3.3.1Test
preparation3.3.2Surcharged hydrostatic tightness testPart
1:Qualitative criteria3.3.3Surcharged hydrostatic tightness
testPart 2:Quantitative criteria3.3.4RetestingSection 4Pneumatic
tightness test for closed containment structures, p.
74.1General4.1.1Scope4.2Products4.2.1Materials4.3Execution4.3.1Test
preparation4.3.2Pneumatic tightness testPart 1:
Qualitativecriteria4.3.3Pneumatic tightness testPart 2:
Quantitativecriteria4.3.4RetestingSection 5Combination
hydrostatic-pneumatic tightness test for closed containment
structures, p.
85.1General5.1.1Scope5.1.2Submittals5.2Products5.2.1Materials5.3Execution5.3.1Test
preparation5.3.2Hydrostatic tightness testingParts 1 and 2
andretesting5.3.3Pneumatic tightness testingParts 1 and 2
andretesting(nonmandatory portion follows)Notes to Specifier, p.
9General notesForeword to ChecklistsMandatory Requirements
ChecklistOptional Requirements ChecklistSubmittals
ChecklistCOMMENTARYSection R1General requirements, p.
11R1.1ScopeR1.1.2Work not specifiedR1.3DescriptionSection
R2Hydrostatic tightness test for open or covered containment
structures, p. 11R2.1GeneralR2.3.1Test preparationR2.3.2Hydrostatic
tightness testPart 1: QualitativecriteriaR2.3.3Hydrostatic
tightness testPart 2: QuantitativecriteriaR2.3.4RetestingSection
R3Surcharged hydrostatic tightness test for closed containment
structures, p. 13R3.1GeneralR3.3.1Test preparationR3.3.2Surcharged
hydrostatic tightness testPart 1:Qualitative
criteriaR3.3.3Surcharged hydrostatic tightness testPart
2:Quantitative criteriaR3.3.4RetestingSection R4Pneumatic tightness
test for closed containment structures, p. 14R4.1GeneralR4.3.1Test
preparationR4.3.2Pneumatic tightness testPart 1:
QualitativecriteriaR4.3.3Pneumatic tightness testPart 2:
QuantitativecriteriaR4.3.4RetestingSection R5Combination
hydrostatic-pneumatic tightness test for closed containment
structures, p. 15R5.1GeneralR5.3.1Test preparationR5.3.2Hydrostatic
tightness testingParts 1 and 2and retestingR5.3.3Pneumatic
tightness testingParts 1 and 2 andretestingSection R6References, p.
15(mandatory portion follows)
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 3American Concrete Institute
Copyrighted Materialwww.concrete.orgSPECIFICATIONSECTION 1GENERAL
REQUIREMENTS1.1Scope1.1.1 Work specifiedThis Specification covers
tightnesstesting of liquid and gaseous environmental
containmentstructures designed to resist liquid or gaseous loads.
Provisionsof this Specification shall govern except where other
provisionsare specified in Contract Documents.1.1.1.1 These test
methods are for the tightness testing ofconcrete environmental
engineering liquid and gaseouscontainment structures. The included
tests are:(a)Hydrostatic tightness test for open or covered
contain-ment structures.(b)Surcharged hydrostatic tightness test
for closedcontainment structures.(c)Pneumatic tightness test for
closed containmentstructures.(d) Combination hydrostatic-pneumatic
tightness test forclosed containment structures.1.1.1.2 The
tightness testing procedures and requirementscontained herein are
applicable to reservoirs, basins, andtanks constructed of concrete
or a combination of concreteand other materials. Preparatory items
indicated arerequired, unless otherwise specified, but the waiver
of suchitems shall not change the test criteria.1.1.1.3 Each cell
of multi-cell containment structuresshall be considered a single
containment structure and testedindividually unless otherwise
permitted.1.1.1.4 The hydrostatic tightness testing procedures
andrequirements herein are also applicable for tightness testingof
open concrete liquid transmission structures such as cast-in-place
concrete channels and conduits.1.1.1.5 The hydrostatic tightness
testing procedures andrequirements herein, where applicable, can be
used for tightnesstesting of concrete paved structures, such as
channels andimpoundments.1.1.2 Work not specifiedThese provisions
are notintended for hazardous material primary or
secondarycontainment structures, cryogenic storage structures,
high-pressure gas tanks, or miscellaneous precast concrete
structuressuch as culverts, pipes, and
manholes.1.2Definitionsaccepteddetermined to be satisfactory by
Archi-tect/Engineer.Architect/Engineerthe Architect, Engineer,
architecturalfirm, or engineering firm, developing Contract
Documents,or administering the Work under Contract Documents,
orboth.containment structurea basin, reservoir, channel, orconduit
to be tightness tested regardless of whether it has aclosed or open
top or is constructed partially or entirely ofconcrete.containment
structure, closeda containment struc-ture where the roof or cover
is used to prevent the escape ofthe contents, including gases
emanating from the contents, tothe outside atmosphere.containment
structure, covereda containmentstructure where the contents are
protected from exteriorcontamination by the presence of a cover or
roof over the topof the containment structure.containment
structure, opena containment structurewhere the top surface of the
containment structures contentsis exposed to the
atmosphere.Contract Documentsa set of documents supplied byOwner to
Contractor as the basis for construction; thesedocuments contain
contract forms, contract conditions,specifications, drawings,
addenda, and contract changes.Contractorthe person, firm, or entity
under contract forconstruction of the Work.environmental
engineering concrete structuresasused in this Specification,
concrete structures intended forconveying, storing, or treating
water, wastewater, or othernonhazardous liquids.fittingan object
that passes through the concrete or isembedded in the concrete to
facilitate a connection to thecontainment structure.Ownerthe
corporation, association, partnership,individual, public body, or
authority for whom the Work isconstructed.permittedaccepted by or
acceptable to Archi-tect/Engineer, usually pertaining to a request
by Contractor,or when specified in Contract Documents.Project
Drawingsgraphic presentation of projectrequirements.Project
Specificationsthe written documents that detailrequirements for the
Work in accordance with serviceparameters and other specific
criteria.Reference Specificationa specification that is intendedto
be a reference standard for Contractor to use in theconstruction of
the Work.reference standardsstandards of a technical
society,organization, or association, including the codes of local
orstate authorities, which are referenced in Contract
Documents.requiredmandatory in this Specification or
ContractDocuments.soap sudswater impregnated with soap or
syntheticdetergent used to indicate air passage through joints
ordefects by the formation of soap bubbles.submitprovide to
Architect/Engineer for review oracceptance.submittaldocument or
material provided to Archi-tect/Engineer for review or
acceptance.vacuum boxa box with a transparent top, openbottom, and
air sealing bottom edges used in conjunctionwith an air pump
capable of creating at least a 3 psi vacuumwithin the box.Workthe
entire construction or separately identifiable partsthereof
required to be furnished under Contract
Documents.1.3Description1.3.1 The structural adequacy of the
containment structureshall be verified for the test pressure or
pressures to beapplied. One type of test shall not be substituted
for anothertype of test without acceptance of the
Architect/Engineer.
4 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.org1.3.2 Unless specifically
allowed by the Architect/Engi-neer, the containment structure shall
not be tested before allof the structure is complete and the
concrete has attained itsspecified compressive
strength.1.4Submittals1.4.1 GeneralSubmittals required in this
Specificationshall be submitted for review and acceptance.1.4.2
Repair proceduresSubmit for acceptance theproposed repair methods,
materials, and modificationsneeded to assure that the Work will
meet tightness require-ments of Contract Documents.1.4.3 Test
reportsTest reports provided by theContractor shall include the
results of tightness testingperformed during the course of the Work
and shall besubmitted to the Architect/Engineer. Test reports
shallinclude test locations in the containment structure, dates
oftesting, water level measurements, amounts of precipitationor
evaporation (when applicable), measured temperaturesand volume
corrections (if any), retest results, correctiveactions taken, if
any, and final results. Final reports shall beprovided within 7
days of test completion.1.5Quality assurance1.5.1 Duties and
responsibilities of ContractorUnlessotherwise specified in Contract
Documents, the Contractorshall prepare and fill the containment
structure and provideaccess and equipment and make the measurements
andobservations for the required testing. The Architect/Engi-neer
shall have access to observe measurements and witnessobservations
included in the test reports, for verification.SECTION 2HYDROSTATIC
TIGHTNESS TEST FOR OPEN OR COVEREDCONTAINMENT
STRUCTURES2.1General2.1.1 ScopeThis section covers the hydrostatic
tightnesstest, which consists of two parts. Part 1 shall be a
qualitativecriterion. Part 2 shall be a quantitative criterion
expressed asthe maximum allowable percent volume loss per day.
2.1.1.1 The hydrostatic tightness test shall be the prelimi-nary
test for all other tightness tests as well as an individual
test.2.1.1.2 Containment structures shall be tested for
hydro-static tightness when required by Contract Documents.When a
hydrostatic tightness test is required and a particularcriterion is
not specified, the quantitative criteria shall be:2.1.1.3 No
measurable loss of water means the drop inthe water surface shall
not exceed 1/8 in. in 3 days whenadjusted for evaporation and
precipitation.2.2Products2.2.1 Materials2.2.1.1 WaterUse potable
water unless otherwisespecified.2.3Execution2.3.1 Test
preparation2.3.1.1 The exposed concrete surfaces of the
containmentstructure, including the floor, shall be cleaned of all
foreignmaterial and debris. Standing water in or outside of
thecontainment structure that would interfere with the
examinationof the exposed concrete surfaces of the containment
structureshall be removed. The concrete surfaces and concrete
jointsshall be visually examined by the Contractor for
potentialleakage points. Areas the Contractor believes are areas
ofpotential leakage shall be repaired before filling the
containmentstructure with water. Unless otherwise specified,
coatingsshall not be applied until after the hydrostatic
tightnesstesting has been completed.2.3.1.2 All openings, fittings,
and pipe penetrations inthe containment structure shell shall be
visually examined atboth faces, if practical.2.3.1.3 Liners that
are mechanically locked to thesurface during the placement of the
concrete shall beinstalled before the hydrostatic tightness
testing. Interiorliners shall be visually examined for pinholes,
tears, andpartially fused splices by the Contractor. Integrity
testing ofinterior liners, when required by the Contract
Documents,shall be performed and passed prior to hydrostatic
testing.Deficiencies shall be repaired.2.3.1.4 All containment
structure penetrations andinlet/outlets shall be securely sealed to
prevent the loss ofwater from the containment structure during the
test. If thecontainment structure is to be filled using the
containmentstructure inlet/outlet pipe, positive means shall be
providedto check that water is not entering or leaving the
containmentstructure through this pipe once the containment
structure isfilled to the test level.2.3.1.5 Containment structure
penetrations and pipe,channel, and conduit inlets/outlets shall be
monitored beforeand during the test to verify the watertightness of
theseappurtenances. Seepage at these locations shall be
repairedbefore test measurements. No allowance shall be made intest
measurements for uncorrected known points of seepage.The flow from
any underdrain system, if a system isprovided, shall be monitored
during this same period, andany increase in flow shall be recorded
and considered forinformation as a part of the hydrostatic
tightness testing.2.3.1.6 The ground water level shall be brought
to a levelbelow the top of the base slab and kept at that elevation
or ata lower elevation during the test.2.3.1.7 No backfill shall be
placed against the walls or onthe wall footings of the containment
structures to be tested,unless otherwise specified.2.3.1.8 The
initial filling of a new containment structureshould not exceed a
rate of 4 ft/h. Filling shall be continueduntil the water surface
is at the design maximum liquid level,or either 1 in. below any
fixed overflow level in coveredType of containment structureDefault
hydrostatic test quantitative criterionFully lined prior to
hydrostatic test No measurable lossRequired to have secondary
containment No measurable lossWith monolithically placed floors
designed to be shrinkage crack free 0.0125% of volume per dayOther
types 0.050% of volume per dayConcrete-paved reservoirs and
channels 0.100% of volume per day
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 5American Concrete Institute
Copyrighted Materialwww.concrete.orgcontainment structure or 4 in.
in open containment structure,whichever is lower.2.3.1.9 Unlined
concrete containment structures shall bekept full to the level
specified in 2.3.1.8 for at least 3 daysbefore Part 2 of the
hydrostatic tightness test described in2.3.3.2.3.2 Hydrostatic
tightness testPart 1: Qualitativecriteria2.3.2.1 The exterior
surfaces of the containment structureshall be observed in both the
early mornings and late after-noons during the 3-day period before
Part 2 of the test. If anywater is observed on the containment
structure exteriorsurfaces, including joints, repaired honeycombed
areas andcracks, where moisture can be picked up on a dry hand,
thecontainment structure shall be considered to have failed Part1
of the hydrostatic test.2.3.2.2 Wet areas on top of the wall
footing shall not because to fail Part 1 of the hydrostatic
tightness test, unless thewater can be observed to be
flowing.2.3.2.3 Although Part 2 of the test may begin prior
tocompletion of repairs for Part 1, all defects causing thefailure
of Part 1 of the hydrostatic tightness test shall berepaired before
acceptance of the containment structure.2.3.3 Hydrostatic tightness
testPart 2: Quantitativecriteria2.3.3.1 Part 2 of the hydrostatic
tightness test shall not bescheduled for a period when the forecast
is for a differenceof more than 35F between the ambient temperature
readingsat the times of the initial and final level measurements of
thewater surface. The test shall also not be scheduled when
theweather forecast indicates the water surface could freezebefore
the test is completed.2.3.3.2 The vertical distance to the water
surface shall bemeasured to within 1/16 in. from a fixed point on
thecontainment structure above the water surface. Measurementsshall
be recorded at 24-hour intervals.2.3.3.3 The test period for the no
measurable loss criterionshall be 3 days (72 hours). For other
criteria, the test periodshall be at least the theoretical time
required to lower thewater surface 3/8 in., assuming a loss of
water at themaximum allowable rate. The test period need not be
longerthan 5 days.2.3.3.4 The water temperature shall be recorded
at adepth of 18 in., unless otherwise specified, below the
watersurface at the start and end of the test. Volume corrections
fortemperature differences shall be included in Part 2 of the
test.2.3.3.5 In uncovered containment structures, evaporationand
precipitation shall be measured. Evaporation shall also bemeasured
in well-ventilated covered containment structures.2.3.3.6 The
containment structure shall continue to beobserved in both the
early mornings and late afternoons toverify compliance with Part 1
of the hydrostatic tightnesstesting during Part 2 of the
hydrostatic test.2.3.3.7 At the end of the test period, the water
surfaceshall be recorded to within 1/16-in. at the location of the
orig-inal measurements. The water temperature and the
evaporationand precipitation measurements shall be recorded.2.3.3.8
The change in water volume in the containmentstructure shall be
calculated and corrected, if necessary, forevaporation,
precipitation, and temperature. If the lossexceeds the required
criterion, the containment structureshall be considered to have
failed Part 2 of the test.2.3.4 Retesting2.3.4.1 A restart of the
test shall be required when testmeasurements become unreliable due
to unusual precipita-tion or other external factors.2.3.4.2 It
shall be permitted to immediately retest acontainment structure
failing Part 2 of the hydrostatic testwhen Part 1 is passed. If the
containment structure fails thesecond test or if not immediately
retested after the first testfailure, the interior of the
containment structure shall beobserved for probable problem areas
by the Contractor. Thecontainment structure shall only be retested
after the prob-able problem areas are repaired.2.3.4.3 Containment
structures shall be retested untilthey meet the required Part 1 and
Part 2 criteria. Repairs shallbe made before each retest.SECTION
3SURCHARGEDHYDROSTATIC TIGHTNESS TESTFOR CLOSED CONTAINMENT
STRUCTURES3.1General3.1.1 ScopeThis section covers the surcharged
hydrostatictightness test, which consists of two parts. Part 1
shall be aqualitative criterion. Part 2 shall be a quantitative
criterion andthe results shall be expressed as the maximum
allowablepercent loss per day of the test water volume, as
specified in2.1.1.2.3.1.1.1 Surcharged hydrostatic tightness
testing shall beconfined to containment structures that have been
designedand constructed to be filled with liquid to the underside
of theroof and surcharged. The surcharge test pressure at
theunderside of the roof high point shall be within the
specifiedpressure range.3.1.1.2 Containment structures shall be
tested forsurcharged hydrostatic tightness when required by
ContractDocuments. When a surcharged hydrostatic tightness test
isrequired and a specific criterion is not stated, the
quantitativecriteria shall be based on the containment structure
construc-tion type, as described in 2.1.1.2, except a
surchargedcontainment structure required to have no measurable
lossshall also have a monolithically placed roof (as well as
thefloor) designed to be shrinkage-crack-free.3.1.1.3 When no
measurable loss of water is specified orrequired for containment
structures subjected to asurcharged hydrostatic tightness test, no
measurable loss ofwater shall mean a drop in water surface in the
standpipe(refer to 3.3.1.8) indicating less than 0.01% loss of
containmentstructure water volume per day.3.2Products3.2.1
Materials3.2.1.1 WaterUse potable water unless
otherwisespecified.
6 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.org3.3Execution3.3.1 Test
preparation3.3.1.1 The exposed concrete surfaces of the
containmentstructure, including the floor, shall be cleaned of all
foreignmaterial and debris. Standing water in or outside of
thecontainment structure that would interfere with the inspectionof
the exposed concrete surfaces of the containment structureshall be
removed. The concrete surfaces and concrete jointsshall be visually
reviewed by the Contractor for potentialleakage points. Areas the
Contractor believes are areas ofpotential leakage shall be repaired
before filling thecontainment structure with water. Unless
otherwise specified,coatings shall not be applied until after
tightness testing hasbeen completed.3.3.1.2 All openings, fittings,
and pipe penetrations inthe containment structure shall be visually
examined at bothfaces, if practical.3.3.1.3 Liners that are
mechanically locked to thesurface during the placement of the
concrete shall be installedbefore the inspections. Interior liners
shall be visuallyexamined for pinholes, tears, and partially fused
splices bythe Contractor, and integrity testing of interior liners,
whenrequired by the Contract Documents, shall be performed
andpassed prior to hydrostatic testing. Deficiencies shall
berepaired.3.3.1.4 All containment structure penetrations
andinlet/outlets shall be securely sealed to prevent the loss
ofwater from the containment structure during the test. If
thecontainment structure is to be filled using the
containmentstructure inlet/outlet pipe, positive means shall be
providedto verify that water is not entering or leaving the
containmentstructure through this pipe once the containment
structure isfilled to test level.3.3.1.5 Containment structure
penetrations and pipe,channel, and conduit inlet/outlets shall be
monitored beforeand during the test to verify the watertightness of
theseappurtenances. Seepage at these locations shall be
repairedbefore test measurements. No allowance shall be made intest
measurements for uncorrected known points of seepage.The flow from
any underdrain system, if a system isprovided, shall be monitored
during this same period, andany increase in flow shall be recorded
and considered forinformation as part of the tightness
testing.3.3.1.6 The ground water level shall be brought to a
levelbelow the top of the base slab and kept at that elevation or
ata lower elevation during the test.3.3.1.7 After the containment
structure examinations havebeen completed, the pressure-relief
valve or valves shall beplugged and the top of the containment
structure vented tothe atmosphere. The containment structure shall
be filledwith water, at a rate not exceeding 4 ft/h, to the
underside ofthe roof while allowing all air to freely escape. The
waterlevel shall be kept near or at the top of unlined or
uncoatedcontainment structures for a period of at least 3 days
beforethe test.3.3.1.8 The containment structure vent at the roof
highpoint shall be replaced with an open-ended pipe to form
astandpipe. The diameter of the standpipe shall not be lessthan the
diameter of the vent it replaces nor more than sixtimes the vent
diameter. The top of the standpipe shall belocated to limit the
hydraulic surcharge to 1.25 times the designsurcharge at the high
point of the underside of the roof. Thestandpipe shall be slowly
filled to the point of overflow.3.3.2 Surcharged hydrostatic
tightness testPart 1: Qual-itative criteria3.3.2.1 The exterior
containment structure examinationsshall be in accordance with the
requirements of Part 1 of thehydrostatic test as described in
2.3.2.3.3.2.2 There is no numerical value for the allowableloss of
water during Part 1 of the surcharged hydrostatic test.No flow or
seepage of water from the containment structure,however, shall be
present on the exterior surfaces after thecontainment structure is
filled to the test level, as describedfurther in 2.3.2.3.3.3
Surcharged hydrostatic tightness testPart 2:Quantitative
criteria3.3.3.1 The duration of the test shall be 1 hour. The
watertemperature 10 ft below the bottom of the standpipe shall
betaken at the start and end of each test.3.3.3.2 The water level
in the standpipe shall be maintainedfor 1 hour. If the water level
starts to drop below the top-mostpoint of the standpipe, the
standpipe shall be refilled.Makeup water of a monitored volume
shall be added duringthe test to keep the water level near the top
of the standpipe.If the amount of makeup water required is higher
than theallowable, and is suspected to be due to water
temperaturechange, the containment structure shall be retested
after thewater temperature stabilizes.3.3.3.3 Once the amount of
makeup water has remainedwithin the allowable range in the
standpipe for the test periodof 1 hour, the water level shall be
kept in the standpipe untilanother close visual examination of all
visible containmentstructure joints and around hatches, manways,
nozzles, pipeconnections, and other openings and penetrations has
beenperformed.3.3.3.4 The water level shall then be lowered below
theinlets to the pressure relief valves, and the plugs shall
beremoved from the relief valves. The operation of the reliefvalves
shall then be checked by removing the standpipe, plug-ging the air
vent, and injecting air into the top of the contain-ment structure
until the pressure in the vapor space equals thedesign pressure. If
the relief valves do not start to release air atthe design
pressure, they shall be adjusted or repaired.3.3.3.5 Upon
completion of the test, the pressure in thecontainment structure
shall be released and the containmentstructure emptied. A thorough
visual examination shall bemade of both the inside and outside of
the containmentstructure. For a combination metallic-and-concrete
structure,particular attention shall be paid to any internal metal
ties,braces, trusses, and their attachments to the walls of
thecontainment structure.3.3.4 Retesting3.3.4.1 A restart of the
test shall be required when testmeasurements become unreliable due
to a sudden change intemperature or other external factors. If the
water level in the
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 7American Concrete Institute
Copyrighted Materialwww.concrete.orgstandpipe falls below the level
of the roof, or overflows thestandpipe during the test, the test
shall be restarted.3.3.4.2 If the water level fails to remain
within theallowable range in the standpipe, or the amount of
makeupwater exceeds the allowable rate, in the initial test or up
totwo retests, the containment structure shall be observed
forseepage on the exterior surface and then drained andreviewed for
defects that are suspected water loss locationsin the interior
surfaces. All defects or points of suspectedseepage shall be
repaired and the test repeated.3.3.4.3 Containment structures shall
be retested untilthey meet the required criterion. Repairs shall be
made to theprobable leakage areas before each retest.SECTION
4PNEUMATIC TIGHTNESS TEST FOR CLOSED CONTAINMENT
STRUCTURES4.1General4.1.1 ScopeThis section covers the standard
pneumatictightness test for closed containment structures and shall
beexpressed as the maximum allowable percent loss per day ofthe
test air volume. There shall be two parts to the pneumatictest for
closed containment structures. Part 1 shall detect airlosses from
visible surfaces. Part 2 (Section 4.3.3) isexpressed as the maximum
allowable percent loss per day ofthe test air volume.4.1.1.1
Pneumatic tightness testing shall be confined tocontainment
structures that have been designed andconstructed to be tested with
pneumatic pressure. Thepneumatic testing of containment structures
shall occur afterany lining or interior waterproofing membrane is
in place.Unless otherwise specified, coatings shall not be
applieduntil after the pneumatic tightness testing has
beencompleted. Pneumatic tests shall be limited to test
pressureswithin the specified pressure range.4.1.1.2 Containment
structures shall be tested forpneumatic tightness when required by
Contract Documents.When a pneumatic tightness test is required and
a specificcriterion is not stated, the quantitative criteria shall
be nomeasurable loss for containment structures that are enclosedor
partially enclosed in a building, and 2.0% per day forcontainment
structures that are surrounded by outside air. Nomeasurable loss
shall mean less than 0.5% loss of test airvolume per day after
correction for any changes in barometricpressure and test air
temperature.4.2Products4.2.1 Materials4.2.1.1 AirUse oil-free air
unless otherwise specified.4.3Execution4.3.1 Test
preparation4.3.1.1 The test preparations shall be in accordance
withthe requirements of 2.3.1.4.3.1.2 After the containment
structure has beenreviewed for potential sources of air loss, a
calibrated pressuregauge or manometer shall be connected to the
containmentstructure, and the pressure-relief valve or valves and
ventsshall be plugged. The containment structure shall then
beslowly filled with air to a pressure of 1.25 times the
designpressure or the maximum specified pressure the tank cansafely
withstand, whichever is smaller for Part 1 of thepneumatic
tightness test.4.3.2 Pneumatic tightness testPart 1: Qualitative
criteria4.3.2.1 Soap suds shall be applied to the exterior of
thecontainment structure. Joints and repaired concrete cracksshall
be tested with a vacuum box.4.3.2.2 The test pressure shall be held
until an examinationof all visible joints in the containment
structure and aroundmanways, nozzles, and other openings and
penetrations hasbeen performed. During such examinations, soap suds
shallbe applied to the surfaces, and vacuum boxes shall be
usedwhere applicable.4.3.2.3 If any leaks appear, the defects shall
be repaired,and the test repeated. Part 1 of the pneumatic test is
completewhen no leaks are found.4.3.2.4 All soap solutions shall be
thoroughly flushedand rinsed from the concrete and metal surfaces
after use.4.3.3 Pneumatic tightness testPart 2: Quantitative
criteria4.3.3.1 Air shall be slowly injected into, or releasedfrom,
the containment structure until the internal pressurereaches the
test pressure.4.3.3.2 After the test pressure is achieved, the
inlet shallbe closed and the containment structure kept pressurized
forat least 2 hours. The barometric pressure and pressurized
airtemperature at the start and end of the test period shall
berecorded. The gauge pressure drop and elapsed time betweenthe
start and conclusion of the test shall be measured, andvariations
in the barometric pressure and temperaturechanges of the test air
shall be corrected for the purpose ofcalculating the volume change
over a 24-hour period.4.3.3.3 If the containment structure does not
meet thetest criterion, the pressure shall be released slowly, and
theplugs shall be removed from the relief valves. The operationof
the relief valves shall then be verified in accordance withthe
manufacturers specifications. If the relief valves do notstart to
release air, they shall be adjusted or repaired. Thecontainment
structure shall be retested after repair of anyknown defect.4.3.3.4
Upon completion of the test, the pressure in thecontainment
structure shall be released and a thoroughreview made of both the
inside and outside of the containmentstructure. On combination
metal containment structures,particular attention shall be given to
all internal metal ties,braces, trusses, and their attachments to
the walls of thecontainment structure.4.3.4 Retesting4.3.4.1 It
shall be permitted to immediately retest acontainment structure
that does not meet the acceptancecriterion when no obvious sources
of pressure loss areknown. If the containment structure still does
not meet theacceptance criterion on the second test or if not
immediatelyretested after the first test, the containment structure
shall bereviewed to determine probable areas of air loss by
theContractor. The containment structure shall only be
retestedafter the probable areas of air loss are repaired or
isolated.
8 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.org4.3.4.2 Containment structures
shall be retested untilthey meet the required criterion. Repairs
shall be made to theprobable areas of air loss before each
retest.SECTION 5COMBINATION HYDROSTATIC-PNEUMATIC TIGHTNESS TEST
FOR CLOSED CONTAINMENT STRUCTURES5.1General5.1.1 ScopeThis section
covers the combinationhydrostatic-pneumatic tightness test and
shall be conductedin two combined parts. Part 1, the qualitative
criteria, is basedon Part 1 of the hydrostatic tightness test
criterion (Section2.3.2) and Part 1 of the pneumatic tightness test
criterion(Section 4.3.2). Part 2, the quantitative criteria, shall
be basedon Part 2 of the hydrostatic tightness test (Section
2.3.3),expressed as the maximum allowable percent volume loss ofthe
test water per day, and Part 2 of the pneumatic tightnesstest
(Section 4.3.3), which shall be expressed as the maximumallowable
percent loss per day of the test air volume.5.1.1.1 Combination
hydrostatic-pneumatic tightnesstests shall be limited to pneumatic
test pressures within thepressure range specified.5.1.1.2
Containment structures shall be tested for tightnesswhen required
by Contract Documents.5.1.1.3 When a combination
hydrostatic-pneumatictightness test is required and the specific
criteria are notstated, the quantitative criteria shall be based on
Sections 2and 4.5.1.2 Submittals5.1.2.1 Submit results of the
tightness testing in accordancewith 1.4.3.5.2Products5.2.1
Materials5.2.1.1 WaterUse potable water unless
otherwisespecified.5.2.1.2 AirUse oil-free air unless otherwise
specified.5.3Execution5.3.1 Test preparation5.3.1.1 Hydrostatic
tightness test preparation5.3.1.1.1 The exposed concrete surfaces
of thecontainment structure, including the floor, shall be
cleanedof all foreign material and debris. Standing water in
oroutside of the containment structures that would interferewith
the examination of the exposed concrete surfaces of thecontainment
structure shall be removed. The concretesurfaces and concrete
joints shall be visually examined bythe Contractor for potential
leakage points. Areas theContractor believes are areas of potential
leakage shall berepaired before filling the containment structure
with water.5.3.1.1.2 All openings, fittings, and pipe
penetrationsin the containment structure shell shall be reviewed at
bothfaces, if practical.5.3.1.1.3 Liners that are mechanically
locked to thesurface during the placement of the concrete shall
beinstalled before the hydrostatic tightness testing.
Interiorliners, when present, shall be observed for pinholes,
tears,and partially fused splices. Deficiencies shall be
repaired.5.3.1.1.4 Unless otherwise specified, coatings shall notbe
applied until after Part 1 of the tightness testing has
beencompleted.5.3.1.1.5 After all the joints have been examined
andall defective joints disclosed by such examinations havebeen
repaired, the containment structure shall be filled withwater to
the design water level. The top of the containmentstructure shall
be vented to the atmosphere during the fillingof the containment
structure to prevent pressurization bytrapped air. The rate at
which water is introduced into acontainment structure shall not
exceed 4 ft/h.5.3.1.1.6 The water in unlined or uncoated
containmentstructures shall remain at the design water level for at
least3 days. Pressure shall not be applied above the surface of
thewater before the temperature of the containment structureand its
contents are within 5F of each other. Parts 1 and 2 ofthe
hydrostatic test of Section 2 may be performed duringthis
time.5.3.1.2 Pneumatic tightness test preparation5.3.1.2.1 The
preparations for the pneumatic test shallbe in accordance with
4.3.1. All water used in the hydrostatictest shall be removed from
the containment structure beforethe pneumatic testing.5.3.2
Hydrostatic tightness testingParts 1 and 2 andretesting5.3.2.1 The
containment structure exterior shall beobserved in accordance with
the requirements of Part 1 of thestandard hydrostatic test as
described in 2.3.2. All defectsallowing water seepage shall be
repaired, and the containmentstructure shall be rechecked for
liquid tightness.5.3.2.2 For Part 2 of the hydrostatic test,
measurementsas described in 2.3.3 shall also be made before testing
thecontainment structure for gas tightness. The allowable
losscriteria, unless otherwise specified, shall be in
accordancewith 2.1.1.2.5.3.2.3 Containment structures shall be
retested untilthey meet the required Part 1 and Part 2 criteria of
the standardhydrostatic test. Repairs shall be made before each
retest.5.3.3 Pneumatic tightness testingParts 1 and 2
andretesting5.3.3.1 Part 1 of the pneumatic test shall be in
accordancewith 4.3.2.5.3.3.2 Part 2 of the pneumatic test shall be
in accordancewith 4.3.3.5.3.3.3 Pneumatic retesting5.3.3.3.1 A
restart of the pneumatic portion of the testshall be required when
test measurements become unreliabledue to a rapid change of
barometric pressure or otherexternal factors.5.3.3.3.2 It shall be
permitted to immediately retest acontainment structure that does
not meet the acceptancecriterion when no obvious sources of
pressure loss areknown. If the containment structure still does not
meet theacceptance criterion on the second test or if not
immediatelyretested after the first test, the containment structure
shall bereviewed to determine probable areas of air loss by
theContractor. The containment structure shall only be
retestedafter the probable areas of air loss are repaired or
isolated.
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 9American Concrete Institute
Copyrighted Materialwww.concrete.org(nonmandatory portion
follows)NOTES TO SPECIFIERGeneral notesG1. ACI Specification 350.1
is to be used by reference orincorporation in its entirety in the
Project Specification. Donot copy individual Sections, Parts,
Articles, or Paragraphsinto the Project Specification, because
taking them out ofcontext may change their meaning.G2. If Sections
or Parts of ACI Specification 350.1 arecopied into the Project
Specification or any other document,do not refer to them as an ACI
Specification, because thespecification has been altered.G3. A
statement such as the following will serve to makeACI Specification
350.1 a part of the Project Specification:Work on (Project Title)
shall conform to all requirementsof ACI 350.1-10 published by the
American Concrete Insti-tute, Farmington Hills, Michigan, except as
modified bythese Contract Documents.G4. Each technical Section of
ACI Specification 350.1 iswritten in the three-part section format
of the ConstructionSpecifications Institute, as adapted for ACI
requirements.The language is imperative and terse.G5. ACI
Specification 350.1 is written to the Contractor.When a provision
of this specification requires action by theContractor, the verb
shall is used. If the Contractor isallowed to exercise an option
when limited alternatives areavailable, the phrasing either...or...
is used. Statementsprovided in the specification as information to
the Contractoruse the verbs may or will. Informational
statementstypically identify activities or options that will be
taken ormay be taken by the Owner or Architect/Engineer.Foreword to
ChecklistsF1. This foreword is included for explanatory
purposesonly; it is not a part of ACI Specification 350.1.F2. ACI
Specification 350.1 may be referenced by theSpecifier in the
Project Specification for any environmentalcontainment structure
project, together with supplementaryrequirements for the specific
project. Responsibilities forproject participants must be defined
in the Project Specification.ACI Specification 350.1 cannot and
does not address responsi-bilities for any project participant
other than the Contractor.F3. Checklists do not form a part of ACI
Specification 350.1.Checklists assist the Specifier in selecting
and specifyingproject requirements in the Project Specification.F4.
The Mandatory Requirements Checklist indicateswork requirements
regarding specific qualities, procedures,materials, and performance
criteria that are not defined inACI Specification 350.1. The
Specifier must include theserequirements in the Project
Specification.F5. The Optional Requirements Checklist
identifiesSpecifier choices and alternatives. The checklist
identifiesthe Sections, Parts, and Articles of the ACI
Specification350.1 and the action required or available to the
Specifier.The Specifier should review each of the items in the
Check-list and make adjustments to the needs of a particular
projectby including those selected alternatives as
mandatoryrequirements in the Project Specification.F6. The
Submittals Checklist identifies information ordata to be provided
by the Contractor before, during, or afterconstruction.MANDATORY
REQUIREMENTS CHECKLISTSection/Part/Article Notes to
SpecifierGeneral requirements1.5.1 Specify source of, and
responsibility for handling, contents used for tightness
testing.Hydrostatic tightness test for open or covered containment
structures2.1.1.2 Specify in Contract Documents which containment
structures are to be tested for hydrostatic tightness.Surcharged
hydrostatic tightness test for closed containment structures3.1.1.1
Specify the test pressure range for the surcharged hydrostatic
tightness test.3.1.1.2 Specify in Contract Documents which
containment structures are to be surcharged hydrostatic tightness
tested.Pneumatic tightness test for closed containment
structures4.1.1.1 Specify the test pressure range for the pneumatic
tightness test.4.1.1.2 Specify in Contract Documents which
containment structures are to be pneumatic tightness
tested.Combination hydrostatic-pneumatic tightness test for closed
containment structures5.1.1.1 Specify the pressure range for the
pneumatic test.5.1.1.2 Specify in Contract Documents which
containment structures are to be tightness tested.
10 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.orgOPTIONAL REQUIREMENTS
CHECKLISTSection/Part/Article Notes to SpecifierGeneral
requirements1.1.1.2 Specify when preparatory items may be
waived.1.1.1.3 Specify if multi-cell containment structures are to
be tested other than individually.1.3.2 Specify or indicate on
Contract Documents when a structure, or portions of a structure,
may be tested prior to thestructure being complete and prior to all
concrete obtaining its specified compressive strength, provided
that thestructure was designed for these conditions. Indicate the
maximum water surface elevation permitted for the testing.1.5.1
Specify if other measurement and observation procedures are
required.Hydrostatic tightness test for open or covered containment
structures2.1.1.2 Specify when quantitative criteria need to be
other than default requirements.2.2.1.1 Specify when water source
other than potable water will be permitted.2.3.1.1 Specify if the
coating should be or may be applied before testing is
conducted.2.3.1.3 Specify if integrity testing of interior liners
is required prior to hydrostatic testing.2.3.1.7 Specify when
backfill may be placed before tightness testing.2.3.3.4 Specify if
additional temperature measurements are required.2.3.4.2 Specify
what retesting procedures will be permitted.Surcharged hydrostatic
tightness test for closed containment structures3.1.1.2 Specify
when quantitative criteria need to be other than default
requirements.3.2.1.1 Specify when water source other than potable
water will be permitted.3.3.1.1 Specify when coatings may be
applied before testing is conducted.3.3.1.5 Submit information on
changes in flow in any underdrain system after filling the
containment structure.Pneumatic tightness test for closed
containment structures4.1.1.2 Specify when quantitative criteria
need to be other than default requirements.4.2.1.1 Specify when air
source other than the default requirement will be
permitted.Combination hydrostatic-pneumatic tightness test for
closed containment structures5.2.1.1 Specify when water source
other than potable water will be permitted.5.2.1.2 Specify when air
source other than the default requirement will be
permitted.5.3.1.1.4 Specify when coatings may be applied before
Part 1 of the testing is conducted.5.3.2.2 Specify when
qualification criteria need to be more stringent than default
requirements.SUBMITTALS CHECKLISTSection/Part/Article Notes to
SpecifierGeneral requirements1.4.2 Proposed repair methods,
materials, and modifications to the Work.Hydrostatic tightness
testing for open or covered containment structures3.3.1.5 Submit
information on changes in flow in any underdrain system after
filling the containment structure.5.1.2.1 Submit test results.
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 11American Concrete
Institute Copyrighted Materialwww.concrete.orgCOMMENTARYSECTION
R1GENERAL REQUIREMENTSR1.1ScopeThe American Concrete Institute
Committee 350 recognizedthe need for standardized procedures of
testing of environ-mental containment structures constructed of
reinforcedconcrete or reinforced concrete and other materials for
liquidtightness. A joint committee of ACI 350 and AmericanWater
Works Association Committee 400, Waterproofing,prepared ACI
350.1R/AWWA 400 (ACI Committee 3501993) on recommendations for
watertightness of reinforcedconcrete containment structures. These
test methods are anevolution of that report.The pneumatic tests in
this document are based onANSI/API 620 (American Petroleum
Institute 1992) forlarge, welded, low-pressure storage containment
structures.Under most circumstances, only one type of test would
beused for a containment structure. The type of test selectedshould
best represent the design loading condition of thecontainment
structure. If the containment structure isdesigned for several
different types of loading conditions,tests should be selected to
represent each of the types.R1.1.1.2 Tightness testing of concrete
containmentstructures for the containment of liquids and
low-pressuregases may be necessary to verify that the structure can
fulfillits intended purpose. Containment structures for
environ-mental facilities often include structures designed with
acombination of concrete and other materials. These includeconcrete
digesters with floating steel covers; containmentstructures with
aluminum dome roofs; basins with metal,wood or plastic covers;
process basins with steel walls andconcrete floors; and similar
structures. The combination ofmaterials in the containment
structure construction shouldnot preclude performing the tightness
testing of the contain-ment structure or the tightness testing of
the joints betweenthe different materials.R1.1.1.3 Multi-cell
containment structures for water andwastewater facilities are not
always designed for watertight-ness between adjacent cells. During
maintenance, it is some-times considered acceptable for these
containment structuresto have some seepage into an empty cell from
an adjacentfull cell. It is not practical to establish a water loss
criterionfor testing cells where seepage is acceptable.
Therefore,these multi-cell containment structures should be tested
as aunit. The design of multi-cell containment structures shouldbe
reviewed to determine that they are multi-cell
containmentstructures rather than a single containment structure
withnonstructural baffle walls.R1.1.1.4 Tightness testing of liquid
transmission structuresrequires the use of major, very tight,
temporary bulkheadsa feature typically designed and provided by the
Contractor.R1.1.1.5 Concrete paving is placed, finished, and
jointedin a different manner than cast-in-place concrete
containmentstructures. The differences in design, details, and
construc-tion affect the tightness of the structure, and some test
proce-dures may not be applicable.R1.1.2 Work not specifiedConcrete
structures for theprimary or secondary containment of hazardous
materials,cryogenic fluids, or high-pressure gases require
specializedtesting methods, procedures, and criteria. Some of
thesestandards, however, may be partially applicable.
Tightnesstesting of various precast products is covered in ASTM
C1244.R1.3DescriptionR1.3.1 When using the stated procedures and
criteria foran existing containment structure, it should not be
assumedthat the containment structure was designed for the test
pressureor for the specific type of test. A containment
structuredesigned for a triangular hydrostatic pressure may not
beable to withstand a uniform pneumatic pressure with thesame
maximum intensity.R1.3.2 Typically a structure is designed for
hydrostaticloading on the final, completed structure. Testing an
incompletestructure may cause damage and present safety
concerns.Testing an incomplete structure should occur only
ifpermitted by the Architect/Engineer. Also, pressure testingof a
partially completed containment structure may not be atrue test of
tightness of the containment structure. Shrinkagecracks may
continue to propagate during the constructionperiod after the test.
The fastening of walkways, exteriorstairways, roof beams, or other
structural elements above oroutside of the containment structures
liquid containmentshell, after the tightness test, may provide
additional shellrestraint and result in the formation of concrete
cracks.SECTION R2HYDROSTATIC TIGHTNESS TEST FOR OPEN OR
COVEREDCONTAINMENT STRUCTURESR2.1GeneralR2.1.1 Both Parts 1 and 2
of the hydrostatic tightness testare equally important. Part 1
deals with the visible portion ofthe containment structure,
particularly the walls and wallbase joint. Part 2 primarily deals
with the floor, where waterloss is not normally visible.R2.1.1.2
Because Part 1 of the test requires that virtuallyno water is lost
through the walls and wall-base joints ofcontainment structures,
the tightness criteria of containmentstructures is mainly
controlled by the floor details. Differentmaterials, methods of
construction, and design concepts mayresult in different
containment structure tightness. A mono-lithically placed,
prestressed concrete, containment structurefloor with the concrete
always in compression may have adifferent tightness than a
monolithically placed nonprestressedconcrete containment structure
floor with the concretepartially in tension. A monolithically
placed floor usingshrinkage-compensating concrete should be more
watertightthan the same containment structure floor with
constructionjoints. This is due to the difficulty of placing
honeycomb-free concrete on the undersides of PVC waterstops. A
linedcontainment structure will have a different tightness than
anunlined containment structure. Based on reasonable tightnessof
different types of containment structure construction,
threestandard criteria were established. The selected
criterionshould consider the containment structure design,
construc-tion, and the tightness necessary for the stored
contents.Floors designed to be shrinkage-crack-free include
floors
12 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.orgdesigned to remain in
compression and properly designedfloors that use
shrinkage-compensating concrete.R2.3.1 Test preparationR2.3.1.1 The
requirement to clean the containmentstructure surfaces is to allow
cracks and defects to beobserved and not obscured by mud, material
spills, or stains.Sprayed water may be necessary to wash foreign
materialfrom the concrete surfaces. Mud, soil, or other foreign
materialon the containment structure floor may not only obscure
thefloor condition, but may temporarily fill defects, voids,
orcracks, thus giving test results that may not reflect the
truecondition of the containment structure. It is preferred
thatcoatings not be applied until after testing is
complete.R2.3.1.2 Fittings and pipe penetrations have the
potentialfor allowing water to flow along the contact surface
betweenthe fitting or pipe and the concrete. Metal fittings and
pipes,unlike concrete, do not change in volume during wetting
ordrying. Metal pipes and fittings may resist the volumechange of
the concrete, and result in the formation ofconcrete cracks. It is
usually impractical to observe thebottom of pipe penetrations
passing through the base slab.R2.3.1.3 Liners are generally used to
obtain a very tightstructure. Therefore, the basic structure should
also bereasonably tight to serve as a barrier to the stored
material ifpinholes occur in the liner. Generally, the same review
andobservation procedures are required for the concrete that isto
be covered by a liner as for concrete that will be exposed.However,
concrete surfaces to which liners are mechanicallylocked during the
placement of concrete cannot be visuallyobserved. Different liner
materials require different linertests and different methods of
repair. It is beyond the scopeof this document to go into the
details of testing liner materialand, therefore, the user is
advised to contact the linermanufacturer for recommended repair
procedures.R2.3.1.4 Leaking or partially seated valves and gates
area source of water loss from containment structures. Acontainment
structure inlet pipe, if connected to a watersource, may be
difficult to check for leakage. One possiblemethod of checking for
leakage is to install a sampling cockin the pipe invert between two
valves in series.R2.3.1.5 An increase in flow from an underdrain
systemmay indicate water lost through the containment
structurefloor. It may, however, also be due to rain or some
otherexternal source of water. The conditions at each event
shouldbe evaluated to estimate the most probable cause of
theincreased flow.R2.3.1.6 Ground water can cause a back pressure
on thewalls and floor of containment structures and reduce
theoutflow of the test water through defects. The presence ofground
water may indicate a greater watertightness of thecontainment
structure than is actually present.R2.3.1.7 Backfill against the
wall or on top of the wallfooting would interfere with Part 1 of
the hydrostatic test.The containment structure should have the
maximumamount of the exterior surface visible during the test.
Newpartially buried or buried containment structures should
bedesigned for loading without reliance on the backfill to
resistthe interior pressures, and should not have the backfill
placedagainst the walls and on the wall footing before
testing,unless otherwise specified. When backfilling is
unavoidableprior to testing all or part of the structure, so
indicate in theContract Documents. In this case, Part 1 of the
testing is notapplicable for backfilled portions of the containment
structure.If a structure was not designed to be test loaded
withoutbackfill in place, Part 1 of the test may not be
possible.R2.3.1.8 The water should be far enough below the
over-flow level to prevent the overflow from skimming off waterfrom
wind-generated waves, from slight differential settlement,or
both.R2.3.1.9 Because the rate of water absorption or evapo-ration
from concrete is very slow, a slight drop in water leveldue to
swelling of the diameter may occur during Part 2 ofthe hydrostatic
test. The 3-day waiting period for the usualtightness tests is
normally considered sufficient allowancefor moisture absorption by
the concrete and temperaturestabilization of the test water for
most practical test criteria.A longer waiting period, however, may
be desired for themore stringent test criteria. A waiting period
may not berequired for lined or coated containment structures, as
thebarrier should prevent water from reaching the concrete.R2.3.2
Hydrostatic tightness testPart 1: QualitativecriteriaR2.3.2.1
Moisture-darkened areas on wall externalsurfaces with flow
insufficient to cause moisture to be ableto be picked up on a dry
hand will usually not detrimentallyaffect the structure, and are
generally considered acceptable.Observed flow or seepage should be
repaired beforebeginning Part 2 of the test. The quantified maximum
waterloss included in this document is for unexplained losses; it
isnot a criterion for acceptance of known sources of lost
water.R2.3.3 Hydrostatic tightness testPart 2:
QuantitativecriteriaR2.3.3.1 It is preferable to minimize
temperature changeof the water during the test. This would minimize
computedtemperature corrections of measurements.
Temperaturestratifications can occur in the contained water and
affect thetest results.R2.3.3.2 Measurements taken at two
locations, 180 degreesapart, will usually minimize the effect of
differential settlementon the computed values for small- and
medium-size contain-ment structures. Measurements at four points,
90 degrees apart,will give more accurate results. Measurements
taken at thesame time of day will reduce the probability of
temperaturedifference.R2.3.3.3 Part 2 of the hydrostatic test
should be ofsufficient duration to be certain of the results. An
example ofthe method of calculating the duration of the test is
asfollows. A flat-bottom concrete containment structure,required to
pass a tightness test, has a 20 ft water depth. Theacceptance
criterion is a maximum of 0.05% loss of watervolume in 24 hours.
The required duration of the test would be0.375 in.0.0005
in./in./day 20 ft 12
in./ft-------------------------------------------------------------------------------------
3.13 days=
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 13American Concrete
Institute Copyrighted Materialwww.concrete.orgMeasurements are
taken at 24-hour intervals; therefore, thetest duration should be
at least 4 days.R2.3.3.4 If the specified tightness criterion for
the tankis no measurable loss, the water temperature should
berecorded at 5 ft intervals of depth for volume change
corrections.R2.3.3.5 A floating, restrained, partially filled,
calibrated,open container for evaporation and precipitation
measurementshould be positioned in open containment structures, and
thewater level in the container recorded. Determination
ofevaporation by a shallow pan-type measuring device isdiscouraged.
The heating of the bottom of a shallow pan cancause accelerated
evaporation of water compared with thattaking place from a deep
containment structure.R2.3.3.6 Observed flow or seepage of water
from theexterior surface, including that from cracks and
joints,should be considered as a failure of Part 1 of the
testing.Because flow and evaporation rates can vary with the
angleof the sun, it is recommended that the wall surfaces bechecked
at different times of the day. The limits of flowingwater on the
footing or wet spots on the walls, observedduring daily
observations, should be marked for later repair.R2.3.3.7
Measurements taken at the same location willreduce the probability
of measurement differences.R2.3.3.8 When numerical limits are given
for the allowableloss of water during the tightness test, they are
for theundetected loss of water from the containment
structure.Therefore, test values should be corrected for
temperaturechange, evaporation, and precipitation, if
present.Temperature corrections to the water volume should bebased
on the change in water density, but may also includethe effect of
the thermal change to the structure dimensions.Structure dimension
changes may be slightly larger forcircular containment structures
that have a sliding joint at thebase of the perimeter wall.R2.3.4
RetestingR2.3.4.1 Unusual precipitation would be when theamount of
precipitation would exceed the capacity of theprecipitation gauge,
or would plug the precipitation gaugewith snow, or would cause
water to spill over the containmentstructure overflow.R2.3.4.2 The
immediate retest is allowed for confirmationof the first test
results. This should minimize the cost ofreview time and wasted
water due to measurement errors orslower-than-normal water
absorption by the concrete.Vacuum boxes can be used to locate
seeping joints, cracks,and porous spots in the floor. Soap suds are
applied to thesuspect area, and the area is covered with a vacuum
box. Avacuum of at least 3 psig is created within the box. Air
leakagethrough or at the suspect area will result in the formation
of soapbubbles. All soap solutions should be thoroughly flushed
andrinsed from the concrete and metal surfaces after use.SECTION
R3SURCHARGED HYDROSTATIC TIGHTNESS TEST FOR CLOSED CONTAINMENT
STRUCTURESR3.1GeneralR3.1.1 ScopeBoth Parts 1 and 2 of the
surchargedhydrostatic tightness test are equally important. Part 1
dealswith the visible portion of the containment structure,
thewalls, and wall base joint, in particular. Part 2 primarily
dealswith the floor, which is not normally visible.R3.1.1.1 A
surcharged hydrostatic tightness test shouldbe used only on
containment structures that have beenstructurally analyzed for the
test surcharge loading that willbe applied. The test should only be
performed on containmentstructures with the intended use of storing
water or otherfluids under a surcharged pressure. Composite
containmentstructures of concrete and steel should be periodically
testedas the loss of corrosion allowance metal may reduce
thestrength and tightness of the containment structure.R3.1.1.2
Different materials, methods of construction,and design concepts
may result in different containmentstructure tightness. Based on
reasonable tightness ofdifferent types of containment structure
construction, threestandard criteria have been established. The
selected criterionshould consider the containment structure design,
construction,and the tightness necessary for the stored contents.
Refer toR2.1.1.2 for more discussion of this topic.R3.3.1 Test
preparationR.3.3.1.1 through R.3.3.1.6. See R.2.3.1.1
throughR2.3.1.6.R3.3.1.7 The requirement for the free escape of air
whilefilling the containment structure is to prevent the water
frombeing pressurized by trapped air. The foundation,
ventingequipment, or other conditions may limit the water filling
toa lower rate. The containment structure contents should notbe
surcharged until the test water temperature has stabilized.It is
preferred that the test water temperature be 60F orabove. The 3-day
waiting period for the test is normallyconsidered sufficient
allowance for moisture absorption bythe concrete and temperature
stabilization of the test waterfor most practical test criteria.
The waiting period can beextended for unlined or uncoated
containment structures, orfor the more stringent test criteria, if
desired, to obtainadditional moisture absorption. A waiting period
is not requiredfor moisture absorption of lined containment
structures, as theliner should prevent water from reaching the
concrete.R3.3.1.8 The standpipe protects the containment
structurefrom unanticipated pressure. If there is not a free
watersurface at the standpipe, rapid pressure changes can occurdue
to a water temperature change, or a vacuum can occurdue to water
leakage.R3.3.2 Surcharged hydrostatic tightness testPart
1:Qualitative criteriaRefer to R2.3.2.R3.3.3 Surcharged hydrostatic
tightness testPart 2:Quantitative criteriaR3.3.3.1 It is not
expected that there will be a significantchange in water
temperature during the 1-hour test period.The temperature readings
are taken primarily to verify thatthe temperature has not affected
the test results. The depth ofthe measurement is selected to be
well within the mass of thetest water, and away from the point of
insertion of themakeup water, which may be a different
temperature.R3.3.3.2 An example of a makeup water rate for a
0.05%loss of the volume of water from a 100 ft diameter, 20 ft
highcontainment structure with a flat floor and 2% (upward)
14 TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10)American Concrete Institute
Copyrighted Materialwww.concrete.orgsloping conical roof would
result in an allowable makeupvolume rate of 24.9 gallons per
hour.24.9 gph = {(50 ft)2 [20 + 1/3(0.02 50 ft)] 7.48 g/ft3
0.0005}/24 h per day R3.3.3.3 The potential for leakage is greater
at joints,fittings, and accessories.R3.3.3.4 The operability of the
relief valves should bechecked to see that the containment
structure will be protectedwhen the containment structure is placed
in operation.R3.3.3.5 The final visual observation review is
required toverify that no damage has occurred to the
containmentstructure from the test loading.R3.3.4 RetestingR3.3.4.1
It is recognized that for the more stringentcriteria, the test is
very temperature sensitive. Other criteriamay be set by the
Architect/Engineer if needed for the storedliquid. The test should
be sufficient for most containmentstructures constructed for the
storage of liquids undersurcharged pressure; if, however, in the
opinion of theArchitect/Engineer, additional tests are needed to
investigatethe safety of a containment structure under certain
otherconditions of loading as determined from the
designcomputations, such tests should also be made on
thecontainment structure in addition to this test.SECTION
R4PNEUMATIC TIGHTNESS TEST FOR CLOSED CONTAINMENT
STRUCTURESR4.1GeneralR4.1.1 There are two parts to the pneumatic
tightness testfor closed containment structures as well. Part 1
uses soapsuds and vacuum boxes to detect air losses. Part 2
measuresthe overall air loss, expressed as the maximum
allowablepercent loss per day of the test air volume.R4.1.1.1 A
pneumatic tightness test should only be usedto check the tightness
of a containment structure when specifiedby an Architect/Engineer
who has structurally analyzed thecontainment structure considering
the pressure test loadingthat will be applied. The test should be
performed oncontainment structures with the intended use of storing
wateror gas or a combination of water and gas under
pneumaticpressure. The test is sometimes used as an alternate test
for ahydrostatic test when allowed in the specifications.
Linersthat are mechanically locked to the surface during
concreteplacement should be installed before Part 1 of the
test.Liners, membranes, or coatings, when included in thedesign,
should be installed before Part 2 of the test when nomeasurable
loss is specified, due to the stringent criteria ofthe
test.R4.1.1.2 The 2% air loss criterion was selected due tothe
calculation of air loss being very sensitive to
atmosphericpressure. The 2% is consistent with loss at
unidentifiablelocations. Liners or coatings should be considered
when a nomeasurable loss tightness criterion is required.Different
materials, methods of construction, and designconcepts may result
in different containment structuretightness. Based on reasonable
tightness of different types ofcontainment structure construction,
two standard criteriawere established. The selected criterion
should consider thecontainment structure design, construction, and
the tightnessnecessary for the stored contents. Refer to R2.1.1.2
for morediscussion of this topic.R4.3.1 Test preparationR4.3.1.1
Refer to R2.3.1.R4.3.1.2 A test pressure 25% higher than the
designpressure is used for Part 1 of the test to better identify
potentialproblem areas. Refer to R4.1.1.1.R4.3.2 Pneumatic
tightness testPart 1: QualitativecriteriaR4.3.2.1 The stringent
criterion for this test requiresadditional checking for potential
leaks. Vacuum boxes areused to locate leaking joints, cracks, and
porous spots. Soapsuds are applied to the suspect area, and the
area is coveredwith a vacuum box. A vacuum of at least 3 psig is
createdwithin the box. Air leakage through or at the suspect
arearesults in the formation of soap bubbles.R4.3.2.3 The potential
for air loss is greatest at joints,fittings, and accessories. The
use of soap suds at these locations,with the containment structure
pressurized, should indicate ifair loss occurs. Observed seepage of
air should be repairedbefore the start of Part 2 of the test. The
quantified maximumair loss included in this document is for
unexplained losses;it is not a criterion for acceptance of known
sources of lost air.R4.3.3 Pneumatic tightness testPart 2:
QuantitativecriteriaR4.3.3.2 The criterion can be very stringent;
therefore,the 2-hour time period may not be sufficient to
accuratelydetermine the tightness of the containment
structure(because any errors in measurement are multiplied by
12).Where greater accuracy is desired, the test time may beextended
to 1 or more days. The operability of the reliefvalves is checked
to see that the containment structure willbe protected when placed
in operation.An example of the calculations for determining
thepercent of air volume loss for a test would be:Initial
readings:Pressure (P1) 2.25 psigBarometric pressure 14.70
psiTemperature of test air (T1) 72.15FVolume (V1)Final
readings:Pressure (P2) 2.22 psigBarometric pressure 14.67
psiTemperature of test air (T2) 70.89FVolume (V2)Test duration: 2
hoursAbsolute values:InitialP1 (pressure) 2.25 + 14.70 = 16.95
psiT1 (temperature) 72.15 + 459.67 = 531.82 RFinalP2 (pressure)
2.22 + 14.67 = 16.89 psiT2 (temperature) 70.89 + 459.67 = 530.56
RV2 = P1 V1 T2/P2 T1
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE
CONTAINTMENT STRUCTURES (ACI 350.1-10) 15American Concrete
Institute Copyrighted Materialwww.concrete.orgV2 = 16.95 V1
530.56/16.89(531.82)V2 = 1.001175 V1% loss of air volume =
0.001175(100) = 0.1175% in 2 h % loss of air volume in 1 day =
0.1175(12) =1.4%R4.3.3.4 The final review is required to verify
that nodamage occurred to the containment structure from the
testloading.R4.3.4 RetestingR4.3.4.1 The immediate retest is
allowed for confirmationof the first test results. This should
minimize the cost ofreview time due to measurement errors or other
factors.SECTION R5COMBINATION HYDROSTATIC-PNEUMATIC TIGHTNESS TEST
FOR CLOSED CONTAINMENT STRUCTURESR5.1GeneralR5.1.1 There are four
parts to the combination hydrostatic-pneumatic tightness test for
closed containment structures. Thefirst two parts include Parts 1
and 2 of the hydrostatic test(Section 2). The third and fourth
parts include Parts 1 and 2of the pneumatic test for closed
containment structures(Section 4).R5.1.1.1 A combination
hydrostatic-pneumatic tightnesstest should only be used to check
the tightness of a containmentstructure when specified by an
Architect/Engineer who hasstructurally designed or analyzed the
containment structurefor the combination hydrostatic-pneumatic test
loading thatwill be applied. The test should be performed on
contain-ment structures with the intended use of storing water
orother liquids under air or gas pressure.R5.1.1.3 Different
materials, methods of construction,and design concepts may result
in different containmentstructure tightness. The selected criterion
should consider thecontainment structure design, construction, and
the tightnessnecessary for the stored contents. The quantitative
criteriadiscussions for the types of containment structures
discussedin Sections 2 and 4 will help the user select the
appropriatequantitative criteria when the particular criteria is
nototherwise specified.R5.3.1 Test preparationR5.3.1.1 Hydrostatic
tightness test preparationR5.3.1.1.1 Refer to R2.3.1.R5.3.1.1.3
Liners and membranes, when included inthe design, should be
installed after the hydrostatic testwhenever possible. Liners,
mechanically locked to thesurface during concrete placement, may be
installed beforehydrostatic testing.R5.3.1.1.4 It is better to
check for seepage on thewalls exterior and through any possible
honeycombing orcracks before applying any coatings.R5.3.1.1.5 The
foundation, venting equipment, orother conditions may limit the
water filling to a lower rate.R5.3.1.1.6 The 3-day waiting period
is consideredsufficient allowance for moisture absorption by the
concrete.The waiting period can be extended for unlined or
uncoatedcontainment structures, if desired.R5.3.2 Hydrostatic
tightness testingParts 1 and 2 andretestingR5.3.2.1 The exterior
qualitative test can indicatedefects in liners, membranes, and
coatings.R5.3.3 Pneumatic tightness testingParts 1 and 2
andretestingR5.3.3.1 Refer to R4.3.2.R5.3.3.2 Refer to R4.3.3.
Also, refer to R4.3.3.2 for anexample calculation of volume
loss.R5.3.3.3.1 A change in the air temperature of thepressurized
air could affect the results of the test. Theimmediate retest is
allowed for confirmation of the first testresults. This should
minimize the cost of review time due tomeasurement errors or other
factors.SECTION R6REFERENCESACI Committee 350, Testing Reinforced
Concrete Struc-tures for Watertightness (ACI 350.1R-93/AWWA
400-93),American Concrete Institute, Farmington Hills, MI, 1993, 5
pp.American Petroleum Institute, 1992, Design andConstruction of
Large, Welded, Low-Pressure StorageTanks (ANSI/API620), Washington,
DC, 1992.ASTM C1244-05, Standard Test Method for ConcreteSewer
Manholes by Negative Air Pressure (Vacuum) TestPrior to Backfill,
ASTM International, West Conshohocken,PA, 2005, 4 pp.
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The AMERICAN CONCRETE INSTITUTEwas founded in 1904 as a
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gathers anddistributes information on the improvement of design,
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Environmental Engineering Concrete Containment Structures (ACI
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