ACI 350.1M-10
(metric)
Specification for Tightness Testing of
Environmental Engineering Concrete
Containment Structures
(ACI 350.1M-10) and Commentary
Reported by ACI Committee 350
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First Printing
March 2011
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Specification for Tightness Testing of Environmental Engineering
Concrete Containment Structures (ACI 350.1M-10) and Commentary
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ACI 350.1M-10
An in.-lb version of this document (ACI 350.1-10)
is available at www.concrete.org
Specification for Tightness Testing of Environmental
Engineering Concrete Containment Structures
(ACI 350.1M-10) and Commentary
An ACI Standard
Reported by ACI Committee 350
Satish K. Sachdev
Chair
Jon B. Ardahl*
Vice Chair
John W. Baker
Secretary
Iyad M. Alsamsam
Charles S. Hanskat
Daniel J. McCarthy
*
Keith W. Jacobson
Andrew R. Minogue
Risto Protic
Robert E. Doyle
M. Reza Kianoush
Javeed Munshi
William C. Sherman
Anthony L. Felder
Carl A. Gentry
Ramon E. Lucero
Jerry Parnes
Lawrence M. Tabat
Steven R. Close
Andrew R. Philip
*
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.
CONTENTS
(mandatory portion follows)
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These test methods give procedures and criteria for tightness testing of
environmental engineering concrete structures. They are applicable to
liquid and gas containment structures constructed with concrete or a
combination of concrete and other materials. This document includes
hydrostatic, surcharged hydrostatic, and pneumatic tests.
These test methods may involve hazardous materials, operations, and
equipment. This document does not purport to address all of the safety
problems associated with its use. It is the responsibility of the user of this
document to establish appropriate safety and health practices and
determine the applicability of regulatory limitations before use.
SPECIFICATION
Section 1—General requirements, p. 3
1.1—Scope
1.1.1—Work specified
1.1.2—Work not specified
1.2—Definitions
1.3—Description
1.4—Submittals
1.4.1—General
1.4.2—Repair procedures
1.4.3—Test reports
1.5—Quality assurance
1.5.1—Duties and responsibilities of Contractor
Keywords: containment structures; hydrostatic; leakage; pneumatic;
reservoirs; tests; tightness; tightness criteria.
ACI Committee Reports, Guides, Manuals, and Commentaries
are intended for guidance in planning, designing, executing,
and inspecting construction. This document is intended for the
use of individuals who are competent to evaluate the
significance and limitations of its content and recommendations
and who will accept responsibility for the application of the
material it contains. The American Concrete Institute disclaims
any and all responsibility for the stated principles. The Institute
shall not be liable for any loss or damage arising therefrom.
Reference to this document shall not be made in contract
documents. If items found in this document are desired by the
Architect/Engineer to be a part of the contract documents, they
shall be restated in mandatory language for incorporation by
the Architect/Engineer.
ACI 350.1M-10 supersedes 350.1M-01, was adopted October 25, 2010, and published
March 2011.
Copyright © 2011, American Concrete Institute.
All rights reserved including rights of reproduction and use in any form or by any
means, including the making of copies by any photo process, or by electronic or
mechanical device, printed, written, or oral, or recording for sound or visual reproduction
or for use in any knowledge or retrieval system or device, unless permission in writing
is obtained from the copyright proprietors.
1
2
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
Section 2—Hydrostatic tightness test for open or
covered containment structures, p. 4
2.1—General
2.1.1—Scope
2.2—Products
2.2.1—Materials
2.3—Execution
2.3.1—Test preparation
2.3.2—Hydrostatic tightness test—Part 1: Qualitative
criteria
2.3.3—Hydrostatic tightness test—Part 2: Quantitative
criteria
2.3.4—Retesting
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Section 3—Surcharged hydrostatic tightness test
for closed containment structures, p. 5
3.1—General
3.1.1—Scope
3.2—Products
3.2.1—Materials
3.3—Execution
3.3.1—Test preparation
3.3.2—Surcharged hydrostatic tightness test—Part 1:
Qualitative criteria
3.3.3—Surcharged hydrostatic tightness test—Part 2:
Quantitative criteria
3.3.4—Retesting
Section 4—Pneumatic tightness test for closed
containment structures, p. 7
4.1—General
4.1.1—Scope
4.2—Products
4.2.1—Materials
4.3—Execution
4.3.1—Test preparation
4.3.2—Pneumatic tightness test—Part 1: Qualitative
criteria
4.3.3—Pneumatic tightness test—Part 2: Quantitative
criteria
4.3.4—Retesting
Section 5—Combination hydrostatic-pneumatic
tightness test for closed containment structures,
p. 8
5.1—General
5.1.1—Scope
5.1.2—Submittals
5.2—Products
5.2.1—Materials
5.3—Execution
5.3.1—Test preparation
5.3.2—Hydrostatic tightness testing—Parts 1 and 2 and
retesting
5.3.3—Pneumatic tightness testing—Parts 1 and 2 and
retesting
(nonmandatory portion follows)
Notes to Specifier, p. 9
General notes
Foreword to Checklists
Mandatory Requirements Checklist
Optional Requirements Checklist
Submittals Checklist
COMMENTARY
Section R1—General requirements, p. 11
R1.1—Scope
R1.1.2—Work not specified
R1.3—Description
Section R2—Hydrostatic tightness test for open or
covered containment structures, p. 11
R2.1—General
R2.3.1—Test preparation
R2.3.2—Hydrostatic tightness test—Part 1: Qualitative
criteria
R2.3.3—Hydrostatic tightness test—Part 2: Quantitative
criteria
R2.3.4—Retesting
Section R3—Surcharged hydrostatic tightness
test for closed containment structures, p. 13
R3.1—General
R3.3.1—Test preparation
R3.3.2—Surcharged hydrostatic tightness test—Part 1:
Qualitative criteria
R3.3.3—Surcharged hydrostatic tightness test—Part 2:
Quantitative criteria
R3.3.4—Retesting
Section R4—Pneumatic tightness test for closed
containment structures, p. 14
R4.1—General
R4.3.1—Test preparation
R4.3.2—Pneumatic tightness test—Part 1: Qualitative
criteria
R4.3.3—Pneumatic tightness test—Part 2: Quantitative
criteria
R4.3.4—Retesting
Section R5—Combination hydrostatic-pneumatic
tightness test for closed containment structures,
p. 15
R5.1—General
R5.3.1—Test preparation
R5.3.2—Hydrostatic tightness testing—Parts 1 and 2
and retesting
R5.3.3—Pneumatic tightness testing—Parts 1 and 2 and
retesting
Section R6—References, p. 15
(mandatory portion follows)
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
SPECIFICATION
SECTION 1—GENERAL REQUIREMENTS
1.1—Scope
1.1.1 Work specified—This Specification covers tightness
testing of liquid and gaseous environmental containment
structures designed to resist liquid or gaseous loads. Provisions
of this Specification shall govern except where other provisions
are specified in Contract Documents.
1.1.1.1 These test methods are for the tightness testing of
concrete environmental engineering liquid and gaseous
containment structures. The included tests are:
(a)Hydrostatic tightness test for open or covered containment structures.
(b)Surcharged hydrostatic tightness test for closed
containment structures.
(c)Pneumatic tightness test for closed containment
structures.
(d) Combination hydrostatic-pneumatic tightness test for
closed containment structures.
1.1.1.2 The tightness testing procedures and requirements
contained herein are applicable to reservoirs, basins, and
tanks constructed of concrete or a combination of concrete
and other materials. Preparatory items indicated are
required, unless otherwise specified, but the waiver of such
items shall not change the test criteria.
1.1.1.3 Each cell of multi-cell containment structures
shall be considered a single containment structure and tested
individually unless otherwise permitted.
1.1.1.4 The hydrostatic tightness testing procedures and
requirements herein are also applicable for tightness testing
of open concrete liquid transmission structures such as castin-place concrete channels and conduits.
1.1.1.5 The hydrostatic tightness testing procedures and
requirements herein, where applicable, can be used for tightness
testing of concrete paved structures, such as channels and
impoundments.
1.1.2 Work not specified—These provisions are not
intended for hazardous material primary or secondary
containment structures, cryogenic storage structures, highpressure gas tanks, or miscellaneous precast concrete structures
such as culverts, pipes, and manholes.
1.2—Definitions
accepted—determined to be satisfactory by Architect/Engineer.
Architect/Engineer—the Architect, Engineer, architectural
firm, or engineering firm, developing Contract Documents,
or administering the Work under Contract Documents, or
both.
containment structure—a basin, reservoir, channel, or
conduit to be tightness tested regardless of whether it has a
closed or open top or is constructed partially or entirely of
concrete.
containment structure, closed—a containment structure where the roof or cover is used to prevent the escape of
the contents, including gases emanating from the contents, to
the outside atmosphere.
3
containment structure, covered—a containment
structure where the contents are protected from exterior
contamination by the presence of a cover or roof over the top
of the containment structure.
containment structure, open—a containment structure
where the top surface of the containment structure’s contents
is exposed to the atmosphere.
Contract Documents—a set of documents supplied by
Owner to Contractor as the basis for construction; these
documents contain contract forms, contract conditions,
specifications, drawings, addenda, and contract changes.
Contractor—the person, firm, or entity under contract for
construction of the Work.
environmental engineering concrete structures—as
used in this Specification, concrete structures intended for
conveying, storing, or treating water, wastewater, or other
nonhazardous liquids.
fitting—an object that passes through the concrete or is
embedded in the concrete to facilitate a connection to the
containment structure.
Owner—the corporation, association, partnership,
individual, public body, or authority for whom the Work is
constructed.
permitted—accepted by or acceptable to Architect/Engineer, usually pertaining to a request by Contractor,
or when specified in Contract Documents.
Project Drawings—graphic presentation of project
requirements.
Project Specifications—the written documents that detail
requirements for the Work in accordance with service
parameters and other specific criteria.
Reference Specification—a specification that is intended
to be a reference standard for Contractor to use in the
construction of the Work.
reference standards—standards of a technical society,
organization, or association, including the codes of local or
state authorities, which are referenced in Contract Documents.
required—mandatory in this Specification or Contract
Documents.
soap suds—water impregnated with soap or synthetic
detergent used to indicate air passage through joints or
defects by the formation of soap bubbles.
submit—provide to Architect/Engineer for review or
acceptance.
submittal—document or material provided to Architect/Engineer for review or acceptance.
vacuum box—a box with a transparent top, open
bottom, and air sealing bottom edges used in conjunction
with an air pump capable of creating at least a 0.02 MPa
vacuum within the box.
Work—the entire construction or separately identifiable parts
thereof required to be furnished under Contract Documents.
1.3—Description
1.3.1 The structural adequacy of the containment structure
shall be verified for the test pressure or pressures to be
applied. One type of test shall not be substituted for another
type of test without acceptance of the Architect/Engineer.
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4
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
1.3.2 Unless specifically allowed by the Architect/Engineer, the containment structure shall not be tested before all
of the structure is complete and the concrete has attained its
specified compressive strength.
2.2—Products
2.2.1 Materials
2.2.1.1 Water—Use potable water unless otherwise
specified.
1.4—Submittals
1.4.1 General—Submittals required in this Specification
shall be submitted for review and acceptance.
1.4.2 Repair procedures—Submit for acceptance the
proposed repair methods, materials, and modifications
needed to assure that the Work will meet tightness requirements of Contract Documents.
1.4.3 Test reports—Test reports provided by the
Contractor shall include the results of tightness testing
performed during the course of the Work and shall be
submitted to the Architect/Engineer. Test reports shall
include test locations in the containment structure, dates of
testing, water level measurements, amounts of precipitation
or evaporation (when applicable), measured temperatures
and volume corrections (if any), retest results, corrective
actions taken, if any, and final results. Final reports shall be
provided within 7 days of test completion.
2.3—Execution
2.3.1 Test preparation
2.3.1.1 The exposed concrete surfaces of the containment
structure, including the floor, shall be cleaned of all foreign
material and debris. Standing water in or outside of the
containment structure that would interfere with the examination
of the exposed concrete surfaces of the containment structure
shall be removed. The concrete surfaces and concrete joints
shall be visually examined by the Contractor for potential
leakage points. Areas the Contractor believes are areas of
potential leakage shall be repaired before filling the containment
structure with water. Unless otherwise specified, coatings
shall not be applied until after the hydrostatic tightness
testing has been completed.
2.3.1.2 All openings, fittings, and pipe penetrations in
the containment structure shell shall be visually examined at
both faces, if practical.
2.3.1.3 Liners that are mechanically locked to the
surface during the placement of the concrete shall be
installed before the hydrostatic tightness testing. Interior
liners shall be visually examined for pinholes, tears, and
partially fused splices by the Contractor. Integrity testing of
interior 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 and
inlet/outlets shall be securely sealed to prevent the loss of
water from the containment structure during the test. If the
containment structure is to be filled using the containment
structure inlet/outlet pipe, positive means shall be provided
to check that water is not entering or leaving the containment
structure through this pipe once the containment structure is
filled to the test level.
2.3.1.5 Containment structure penetrations and pipe,
channel, and conduit inlets/outlets shall be monitored before
and during the test to verify the watertightness of these
appurtenances. Seepage at these locations shall be repaired
before test measurements. No allowance shall be made in
test measurements for uncorrected known points of seepage.
The flow from any underdrain system, if a system is
provided, shall be monitored during this same period, and
any increase in flow shall be recorded and considered for
information as a part of the hydrostatic tightness testing.
2.3.1.6 The ground water level shall be brought to a level
below the top of the base slab and kept at that elevation or at
a lower elevation during the test.
2.3.1.7 No backfill shall be placed against the walls or on
the wall footings of the containment structures to be tested,
unless otherwise specified.
2.3.1.8 The initial filling of a new containment structure
should not exceed a rate of 1.2 m/hour. Filling shall be
continued until the water surface is at the design maximum
liquid level, or either 25 mm below any fixed overflow level
1.5—Quality assurance
1.5.1 Duties and responsibilities of Contractor—Unless
otherwise specified in Contract Documents, the Contractor
shall prepare and fill the containment structure and provide
access and equipment and make the measurements and
observations for the required testing. The Architect/Engineer shall have access to observe measurements and witness
observations included in the test reports, for verification.
SECTION 2—HYDROSTATIC TIGHTNESS TEST
FOR OPEN OR COVERED
CONTAINMENT STRUCTURES
2.1—General
2.1.1 Scope—This section covers the hydrostatic tightness
test, which consists of two parts. Part 1 shall be a qualitative
criterion. Part 2 shall be a quantitative criterion expressed as
the maximum allowable percent volume loss per day.
2.1.1.1 The hydrostatic tightness test shall be the preliminary test for all other tightness tests as well as an individual test.
2.1.1.2 Containment structures shall be tested for hydrostatic tightness when required by Contract Documents.
When a hydrostatic tightness test is required and a particular
criterion is not specified, the quantitative criteria shall be:
Type of containment structure
Fully lined prior to hydrostatic test
Default hydrostatic test
quantitative criterion
No measurable loss
Required to have secondary containment
No measurable loss
With monolithically placed floors designed
to be shrinkage crack free
0.0125% of volume per day
Other types
Concrete-paved reservoirs and channels
0.050% of volume per day
0.100% of volume per day
2.1.1.3 “No measurable loss” of water means the drop in
the water surface shall not exceed 3 mm in 3 days when
adjusted for evaporation and precipitation.
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TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
in covered containment structure or 100 mm in open
containment structure, whichever is lower.
2.3.1.9 Unlined concrete containment structures shall be
kept full to the level specified in 2.3.1.8 for at least 3 days
before Part 2 of the hydrostatic tightness test described in
2.3.3.
2.3.2 Hydrostatic tightness test—Part 1: Qualitative
criteria
2.3.2.1 The exterior surfaces of the containment structure
shall be observed in both the early mornings and late afternoons during the 3-day period before Part 2 of the test. If any
water is observed on the containment structure exterior
surfaces, including joints, repaired honeycombed areas and
cracks, where moisture can be picked up on a dry hand, the
containment structure shall be considered to have failed Part
1 of the hydrostatic test.
2.3.2.2 Wet areas on top of the wall footing shall not be
cause to fail Part 1 of the hydrostatic tightness test, unless the
water can be observed to be flowing.
2.3.2.3 Although Part 2 of the test may begin prior to
completion of repairs for Part 1, all defects causing the
failure of Part 1 of the hydrostatic tightness test shall be
repaired before acceptance of the containment structure.
2.3.3 Hydrostatic tightness test—Part 2: Quantitative
criteria
2.3.3.1 Part 2 of the hydrostatic tightness test shall not be
scheduled for a period when the forecast is for a difference
of more than 19°C between the ambient temperature readings at
the times of the initial and final level measurements of the
water surface. The test shall also not be scheduled when the
weather forecast indicates the water surface could freeze
before the test is completed.
2.3.3.2 The vertical distance to the water surface shall be
measured to within 2 mm from a fixed point on the containment
structure above the water surface. Measurements shall be
recorded at 24-hour intervals.
2.3.3.3 The test period for the no measurable loss criterion
shall be 3 days (72 hours). For other criteria, the test period
shall be at least the theoretical time required to lower the
water surface 10 mm, assuming a loss of water at the
maximum allowable rate. The test period need not be longer
than 5 days.
2.3.3.4 The water temperature shall be recorded at a
depth of 450 mm, unless otherwise specified, below the water
surface at the start and end of the test. Volume corrections for
temperature differences shall be included in Part 2 of the test.
2.3.3.5 In uncovered containment structures, evaporation
and precipitation shall be measured. Evaporation shall also be
measured in well-ventilated covered containment structures.
2.3.3.6 The containment structure shall continue to be
observed in both the early mornings and late afternoons to
verify compliance with Part 1 of the hydrostatic tightness
testing during Part 2 of the hydrostatic test.
2.3.3.7 At the end of the test period, the water surface
shall be recorded to within 2 mm at the location of the original
measurements. The water temperature and the evaporation and
precipitation measurements shall be recorded.
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5
2.3.3.8 The change in water volume in the containment
structure shall be calculated and corrected, if necessary, for
evaporation, precipitation, and temperature. If the loss
exceeds the required criterion, the containment structure
shall be considered to have failed Part 2 of the test.
2.3.4 Retesting
2.3.4.1 A restart of the test shall be required when test
measurements become unreliable due to unusual precipitation or other external factors.
2.3.4.2 It shall be permitted to immediately retest a
containment structure failing Part 2 of the hydrostatic test
when Part 1 is passed. If the containment structure fails the
second test or if not immediately retested after the first test
failure, the interior of the containment structure shall be
observed for probable problem areas by the Contractor. The
containment structure shall only be retested after the probable problem areas are repaired.
2.3.4.3 Containment structures shall be retested until
they meet the required Part 1 and Part 2 criteria. Repairs shall
be made before each retest.
SECTION 3—SURCHARGED
HYDROSTATIC TIGHTNESS TEST
FOR CLOSED CONTAINMENT STRUCTURES
3.1—General
3.1.1 Scope—This section covers the surcharged hydrostatic
tightness test, which consists of two parts. Part 1 shall be a
qualitative criterion. Part 2 shall be a quantitative criterion and
the results shall be expressed as the maximum allowable
percent loss per day of the test water volume, as specified in
2.1.1.2.
3.1.1.1 Surcharged hydrostatic tightness testing shall be
confined to containment structures that have been designed
and constructed to be filled with liquid to the underside of the
roof and surcharged. The surcharge test pressure at the
underside of the roof high point shall be within the specified
pressure range.
3.1.1.2 Containment structures shall be tested for
surcharged hydrostatic tightness when required by Contract
Documents. When a surcharged hydrostatic tightness test is
required and a specific criterion is not stated, the quantitative
criteria shall be based on the containment structure construction type, as described in 2.1.1.2, except a surcharged
containment structure required to have no measurable loss
shall also have a monolithically placed roof (as well as the
floor) designed to be shrinkage-crack-free.
3.1.1.3 When no measurable loss of water is specified or
required for containment structures subjected to a
surcharged hydrostatic tightness test, no measurable loss of
water shall mean a drop in water surface in the standpipe
(refer to 3.3.1.8) indicating less than 0.01% loss of containment
structure water volume per day.
3.2—Products
3.2.1 Materials
3.2.1.1 Water—Use potable water unless otherwise
specified.
6
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
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3.3—Execution
3.3.1 Test preparation
3.3.1.1 The exposed concrete surfaces of the containment
structure, including the floor, shall be cleaned of all foreign
material and debris. Standing water in or outside of the
containment structure that would interfere with the inspection
of the exposed concrete surfaces of the containment structure
shall be removed. The concrete surfaces and concrete joints
shall be visually reviewed by the Contractor for potential
leakage points. Areas the Contractor believes are areas of
potential leakage shall be repaired before filling the
containment structure with water. Unless otherwise specified,
coatings shall not be applied until after tightness testing has
been completed.
3.3.1.2 All openings, fittings, and pipe penetrations in
the containment structure shall be visually examined at both
faces, if practical.
3.3.1.3 Liners that are mechanically locked to the
surface during the placement of the concrete shall be installed
before the inspections. Interior liners shall be visually
examined for pinholes, tears, and partially fused splices by
the Contractor, and integrity testing of interior liners, when
required by the Contract Documents, shall be performed and
passed prior to hydrostatic testing. Deficiencies shall be
repaired.
3.3.1.4 All containment structure penetrations and
inlet/outlets shall be securely sealed to prevent the loss of
water from the containment structure during the test. If the
containment structure is to be filled using the containment
structure inlet/outlet pipe, positive means shall be provided
to verify that water is not entering or leaving the containment
structure through this pipe once the containment structure is
filled to test level.
3.3.1.5 Containment structure penetrations and pipe,
channel, and conduit inlet/outlets shall be monitored before
and during the test to verify the watertightness of these
appurtenances. Seepage at these locations shall be repaired
before test measurements. No allowance shall be made in
test measurements for uncorrected known points of seepage.
The flow from any underdrain system, if a system is
provided, shall be monitored during this same period, and
any increase in flow shall be recorded and considered for
information as part of the tightness testing.
3.3.1.6 The ground water level shall be brought to a level
below the top of the base slab and kept at that elevation or at
a lower elevation during the test.
3.3.1.7 After the containment structure examinations have
been completed, the pressure-relief valve or valves shall be
plugged and the top of the containment structure vented to
the atmosphere. The containment structure shall be filled
with water, at a rate not exceeding 1.2 m/hour, to the
underside of the roof while allowing all air to freely escape.
The water level shall be kept near or at the top of unlined or
uncoated containment structures for a period of at least 3 days
before the test.
3.3.1.8 The containment structure vent at the roof high
point shall be replaced with an open-ended pipe to form a
standpipe. The diameter of the standpipe shall not be less
than the diameter of the vent it replaces nor more than six
times the vent diameter. The top of the standpipe shall be
located to limit the hydraulic surcharge to 1.25 times the design
surcharge at the high point of the underside of the roof. The
standpipe shall be slowly filled to the point of overflow.
3.3.2 Surcharged hydrostatic tightness test—Part 1: Qualitative criteria
3.3.2.1 The exterior containment structure examinations
shall be in accordance with the requirements of Part 1 of the
hydrostatic test as described in 2.3.2.
3.3.2.2 There is no numerical value for the allowable
loss 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 the
containment structure is filled to the test level, as described
further in 2.3.2.
3.3.3 Surcharged hydrostatic tightness test—Part 2:
Quantitative criteria
3.3.3.1 The duration of the test shall be 1 hour. The water
temperature 3 m below the bottom of the standpipe shall be
taken at the start and end of each test.
3.3.3.2 The water level in the standpipe shall be maintained
for 1 hour. If the water level starts to drop below the top-most
point of the standpipe, the standpipe shall be refilled.
Makeup water of a monitored volume shall be added during
the test to keep the water level near the top of the standpipe.
If the amount of makeup water required is higher than the
allowable, and is suspected to be due to water temperature
change, the containment structure shall be retested after the
water temperature stabilizes.
3.3.3.3 Once the amount of makeup water has remained
within the allowable range in the standpipe for the test period
of 1 hour, the water level shall be kept in the standpipe until
another close visual examination of all visible containment
structure joints and around hatches, manways, nozzles, pipe
connections, and other openings and penetrations has been
performed.
3.3.3.4 The water level shall then be lowered below the
inlets to the pressure relief valves, and the plugs shall be
removed from the relief valves. The operation of the relief
valves shall then be checked by removing the standpipe, plugging the air vent, and injecting air into the top of the containment structure until the pressure in the vapor space equals the
design pressure. If the relief valves do not start to release air at
the design pressure, they shall be adjusted or repaired.
3.3.3.5 Upon completion of the test, the pressure in the
containment structure shall be released and the containment
structure emptied. A thorough visual examination shall be
made of both the inside and outside of the containment
structure. 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 the
containment structure.
3.3.4 Retesting
3.3.4.1 A restart of the test shall be required when test
measurements become unreliable due to a sudden change in
temperature or other external factors. If the water level in the
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
standpipe falls below the level of the roof, or overflows the
standpipe during the test, the test shall be restarted.
3.3.4.2 If the water level fails to remain within the
allowable range in the standpipe, or the amount of makeup
water exceeds the allowable rate, in the initial test or up to
two retests, the containment structure shall be observed for
seepage on the exterior surface and then drained and
reviewed for defects that are suspected water loss locations
in the interior surfaces. All defects or points of suspected
seepage shall be repaired and the test repeated.
3.3.4.3 Containment structures shall be retested until
they meet the required criterion. Repairs shall be made to the
probable leakage areas before each retest.
SECTION 4—PNEUMATIC TIGHTNESS TEST FOR
CLOSED CONTAINMENT STRUCTURES
4.1—General
4.1.1 Scope—This section covers the standard pneumatic
tightness test for closed containment structures and shall be
expressed as the maximum allowable percent loss per day of
the test air volume. There shall be two parts to the pneumatic
test for closed containment structures. Part 1 shall detect air
losses from visible surfaces. Part 2 (Section 4.3.3) is
expressed as the maximum allowable percent loss per day of
the test air volume.
4.1.1.1 Pneumatic tightness testing shall be confined to
containment structures that have been designed and
constructed to be tested with pneumatic pressure. The
pneumatic testing of containment structures shall occur after
any lining or interior waterproofing membrane is in place.
Unless otherwise specified, coatings shall not be applied
until after the pneumatic tightness testing has been
completed. Pneumatic tests shall be limited to test pressures
within the specified pressure range.
4.1.1.2 Containment structures shall be tested for
pneumatic tightness when required by Contract Documents.
When a pneumatic tightness test is required and a specific
criterion is not stated, the quantitative criteria shall be no
measurable loss for containment structures that are enclosed
or partially enclosed in a building, and 2.0% per day for
containment structures that are surrounded by outside air. No
measurable loss shall mean less than 0.5% loss of test air
volume per day after correction for any changes in barometric
pressure and test air temperature.
4.2—Products
4.2.1 Materials
4.2.1.1 Air—Use oil-free air unless otherwise specified.
4.3—Execution
4.3.1 Test preparation
4.3.1.1 The test preparations shall be in accordance with
the requirements of 2.3.1.
4.3.1.2 After the containment structure has been
reviewed for potential sources of air loss, a calibrated pressure
gauge or manometer shall be connected to the containment
structure, and the pressure-relief valve or valves and vents
shall be plugged. The containment structure shall then be
slowly filled with air to a pressure of 1.25 times the design
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7
pressure or the maximum specified pressure the tank can
safely withstand, whichever is smaller for Part 1 of the
pneumatic tightness test.
4.3.2 Pneumatic tightness test—Part 1: Qualitative criteria
4.3.2.1 Soap suds shall be applied to the exterior of the
containment structure. Joints and repaired concrete cracks
shall be tested with a vacuum box.
4.3.2.2 The test pressure shall be held until an examination
of all visible joints in the containment structure and around
manways, nozzles, and other openings and penetrations has
been performed. During such examinations, soap suds shall
be applied to the surfaces, and vacuum boxes shall be used
where 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 complete
when no leaks are found.
4.3.2.4 All soap solutions shall be thoroughly flushed
and rinsed from the concrete and metal surfaces after use.
4.3.3 Pneumatic tightness test—Part 2: Quantitative criteria
4.3.3.1 Air shall be slowly injected into, or released
from, the containment structure until the internal pressure
reaches the test pressure.
4.3.3.2 After the test pressure is achieved, the inlet shall
be closed and the containment structure kept pressurized for
at least 2 hours. The barometric pressure and pressurized air
temperature at the start and end of the test period shall be
recorded. The gauge pressure drop and elapsed time between
the start and conclusion of the test shall be measured, and
variations in the barometric pressure and temperature
changes of the test air shall be corrected for the purpose of
calculating the volume change over a 24-hour period.
4.3.3.3 If the containment structure does not meet the
test criterion, the pressure shall be released slowly, and the
plugs shall be removed from the relief valves. The operation
of the relief valves shall then be verified in accordance with
the manufacturer’s specifications. If the relief valves do not
start to release air, they shall be adjusted or repaired. The
containment structure shall be retested after repair of any
known defect.
4.3.3.4 Upon completion of the test, the pressure in the
containment structure shall be released and a thorough
review made of both the inside and outside of the containment
structure. On combination metal containment structures,
particular attention shall be given to all internal metal ties,
braces, trusses, and their attachments to the walls of the
containment structure.
4.3.4 Retesting
4.3.4.1 It shall be permitted to immediately retest a
containment structure that does not meet the acceptance
criterion when no obvious sources of pressure loss are
known. If the containment structure still does not meet the
acceptance criterion on the second test or if not immediately
retested after the first test, the containment structure shall be
reviewed to determine probable areas of air loss by the
Contractor. The containment structure shall only be retested
after the probable areas of air loss are repaired or isolated.
8
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
4.3.4.2 Containment structures shall be retested until
they meet the required criterion. Repairs shall be made to the
probable areas of air loss before each retest.
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SECTION 5—COMBINATION HYDROSTATICPNEUMATIC TIGHTNESS TEST FOR CLOSED
CONTAINMENT STRUCTURES
5.1—General
5.1.1 Scope—This section covers the combination
hydrostatic-pneumatic tightness test and shall be conducted
in two combined parts. Part 1, the qualitative criteria, is based
on Part 1 of the hydrostatic tightness test criterion (Section
2.3.2) and Part 1 of the pneumatic tightness test criterion
(Section 4.3.2). Part 2, the quantitative criteria, shall be based
on Part 2 of the hydrostatic tightness test (Section 2.3.3),
expressed as the maximum allowable percent volume loss of
the test water per day, and Part 2 of the pneumatic tightness
test (Section 4.3.3), which shall be expressed as the maximum
allowable percent loss per day of the test air volume.
5.1.1.1 Combination hydrostatic-pneumatic tightness
tests shall be limited to pneumatic test pressures within the
pressure range specified.
5.1.1.2 Containment structures shall be tested for tightness
when required by Contract Documents.
5.1.1.3 When a combination hydrostatic-pneumatic
tightness test is required and the specific criteria are not
stated, the quantitative criteria shall be based on Sections 2
and 4.
5.1.2 Submittals
5.1.2.1 Submit results of the tightness testing in accordance
with 1.4.3.
5.2—Products
5.2.1 Materials
5.2.1.1 Water—Use potable water unless otherwise
specified.
5.2.1.2 Air—Use oil-free air unless otherwise specified.
5.3—Execution
5.3.1 Test preparation
5.3.1.1 Hydrostatic tightness test preparation
5.3.1.1.1 The exposed concrete surfaces of the
containment structure, including the floor, shall be cleaned
of all foreign material and debris. Standing water in or
outside of the containment structures that would interfere
with the examination of the exposed concrete surfaces of the
containment structure shall be removed. The concrete
surfaces and concrete joints shall be visually examined by
the Contractor for potential leakage points. Areas the
Contractor believes are areas of potential leakage shall be
repaired before filling the containment structure with water.
5.3.1.1.2 All openings, fittings, and pipe penetrations
in the containment structure shell shall be reviewed at both
faces, if practical.
5.3.1.1.3 Liners that are mechanically locked to the
surface during the placement of the concrete shall be
installed before the hydrostatic tightness testing. Interior
liners, 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 not
be applied until after Part 1 of the tightness testing has been
completed.
5.3.1.1.5 After all the joints have been examined and
all defective joints disclosed by such examinations have
been repaired, the containment structure shall be filled with
water to the design water level. The top of the containment
structure shall be vented to the atmosphere during the filling
of the containment structure to prevent pressurization by
trapped air. The rate at which water is introduced into a
containment structure shall not exceed 1.2 m/hour.
5.3.1.1.6 The water in unlined or uncoated containment
structures shall remain at the design water level for at least
3 days. Pressure shall not be applied above the surface of the
water before the temperature of the containment structure
and its contents are within 3°C of each other. Parts 1 and 2 of the
hydrostatic test of Section 2 may be performed during
this time.
5.3.1.2 Pneumatic tightness test preparation
5.3.1.2.1 The preparations for the pneumatic test shall
be in accordance with 4.3.1. All water used in the hydrostatic
test shall be removed from the containment structure before
the pneumatic testing.
5.3.2 Hydrostatic tightness testing—Parts 1 and 2 and
retesting
5.3.2.1 The containment structure exterior shall be
observed in accordance with the requirements of Part 1 of the
standard hydrostatic test as described in 2.3.2. All defects
allowing water seepage shall be repaired, and the containment
structure shall be rechecked for liquid tightness.
5.3.2.2 For Part 2 of the hydrostatic test, measurements
as described in 2.3.3 shall also be made before testing the
containment structure for gas tightness. The allowable loss
criteria, unless otherwise specified, shall be in accordance
with 2.1.1.2.
5.3.2.3 Containment structures shall be retested until
they meet the required Part 1 and Part 2 criteria of the standard
hydrostatic test. Repairs shall be made before each retest.
5.3.3 Pneumatic tightness testing—Parts 1 and 2 and
retesting
5.3.3.1 Part 1 of the pneumatic test shall be in accordance
with 4.3.2.
5.3.3.2 Part 2 of the pneumatic test shall be in accordance
with 4.3.3.
5.3.3.3 Pneumatic retesting
5.3.3.3.1 A restart of the pneumatic portion of the test
shall be required when test measurements become unreliable
due to a rapid change of barometric pressure or other
external factors.
5.3.3.3.2 It shall be permitted to immediately retest a
containment structure that does not meet the acceptance
criterion when no obvious sources of pressure loss are
known. If the containment structure still does not meet the
acceptance criterion on the second test or if not immediately
retested after the first test, the containment structure shall be
reviewed to determine probable areas of air loss by the
Contractor. The containment structure shall only be retested
after the probable areas of air loss are repaired or isolated.
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
NOTES TO SPECIFIER
General notes
G1. ACI Specification 350.1M is to be used by reference
or incorporation in its entirety in the Project Specification.
Do not copy individual Sections, Parts, Articles, or Paragraphs
into the Project Specification, because taking them out of
context may change their meaning.
G2. If Sections or Parts of ACI Specification 350.1M are
copied into the Project Specification or any other document,
do not refer to them as an ACI Specification, because the
specification has been altered.
G3. A statement such as the following will serve to make
ACI Specification 350.1M a part of the Project Specification:
“Work on (Project Title) shall conform to all requirements
of ACI 350.1-10 published by the American Concrete Institute, Farmington Hills, Michigan, except as modified by
these Contract Documents.”
G4. Each technical Section of ACI Specification 350.1M
is written in the three-part section format of the Construction
Specifications Institute, as adapted for ACI requirements.
The language is imperative and terse.
G5. ACI Specification 350.1M is written to the Contractor.
When a provision of this specification requires action by the
Contractor, the verb “shall” is used. If the Contractor is allowed
to exercise an option when limited alternatives are available,
the phrasing “either...or...” is used. Statements provided in
the specification as information to the Contractor use the
verbs “may” or “will.” Informational statements typically
Foreword to Checklists
F1. This foreword is included for explanatory purposes
only; it is not a part of ACI Specification 350.1M.
F2. ACI Specification 350.1M may be referenced by the
Specifier in the Project Specification for any environmental
containment structure project, together with supplementary
requirements for the specific project. Responsibilities for project
participants must be defined in the Project Specification. ACI
Specification 350.1M cannot and does not address responsibilities
for any project participant other than the Contractor.
F3. Checklists do not form a part of ACI Specification
350.1M. Checklists assist the Specifier in selecting and specifying
project requirements in the Project Specification.
F4. The Mandatory Requirements Checklist indicates
work requirements regarding specific qualities, procedures,
materials, and performance criteria that are not defined in
ACI Specification 350.1M. The Specifier must include these
requirements in the Project Specification.
F5. The Optional Requirements Checklist identifies
Specifier choices and alternatives. The checklist identifies
the Sections, Parts, and Articles of the ACI Specification
350.1M and the action required or available to the Specifier.
The Specifier should review each of the items in the Checklist
and make adjustments to the needs of a particular project by
including those selected alternatives as mandatory requirements
in the Project Specification.
F6. The Submittals Checklist identifies information or
data to be provided by the Contractor before, during, or after
construction.
MANDATORY REQUIREMENTS CHECKLIST
Notes to Specifier
General requirements
1.5.1
Specify source of, and responsibility for handling, contents used for tightness testing.
Hydrostatic tightness test for open or covered containment structures
2.1.1.2
Specify in Contract Documents which containment structures are to be tested for hydrostatic tightness.
Surcharged hydrostatic tightness test for closed containment structures
3.1.1.1
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 structures
4.1.1.1
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 structures
5.1.1.1
Specify the pressure range for the pneumatic test.
5.1.1.2
Specify in Contract Documents which containment structures are to be tightness tested.
No reproduction or networking permitted without license from IHS
identify activities or options that “will be taken” or “may be
taken” by the Owner or Architect/Engineer.
(nonmandatory portion follows)
Section/Part/Article
9
10
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
OPTIONAL REQUIREMENTS CHECKLIST
Section/Part/Article
Notes to Specifier
General requirements
1.1.1.2
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 the
structure being complete and prior to all concrete obtaining its specified compressive strength, provided that the
structure 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 structures
2.1.1.2
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 structures
3.1.1.2
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 structures
4.1.1.2
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 structures
5.2.1.1
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 CHECKLIST
Section/Part/Article
Notes to Specifier
General requirements
1.4.2
Proposed repair methods, materials, and modifications to the Work.
Hydrostatic tightness testing for open or covered containment structures
3.3.1.5
Submit information on changes in flow in any underdrain system after filling the containment structure.
5.1.2.1
Submit test results.
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TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
R1.1—Scope
The American Concrete Institute Committee 350 recognized
the need for standardized procedures of testing of environmental containment structures constructed of reinforced
concrete or reinforced concrete and other materials for liquid
tightness. A joint committee of ACI 350 and American
Water Works Association Committee 400, Waterproofing,
prepared ACI 350.1R/AWWA 400 (ACI Committee 350
1993) on recommendations for watertightness of reinforced
concrete containment structures. These test methods are an
evolution of that report.
The pneumatic tests in this document are based on
ANSI/API 620 (American Petroleum Institute 1992) for
large, welded, low-pressure storage containment structures.
Under most circumstances, only one type of test would be
used for a containment structure. The type of test selected
should best represent the design loading condition of the
containment structure. If the containment structure is
designed 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 containment
structures for the containment of liquids and low-pressure
gases may be necessary to verify that the structure can fulfill
its intended purpose. Containment structures for environmental facilities often include structures designed with a
combination of concrete and other materials. These include
concrete digesters with floating steel covers; containment
structures with aluminum dome roofs; basins with metal,
wood or plastic covers; process basins with steel walls and
concrete floors; and similar structures. The combination of
materials in the containment structure construction should
not preclude performing the tightness testing of the containment structure or the tightness testing of the joints between
the different materials.
R1.1.1.3 Multi-cell containment structures for water and
wastewater facilities are not always designed for watertightness between adjacent cells. During maintenance, it is sometimes considered acceptable for these containment structures
to have some seepage into an empty cell from an adjacent
full cell. It is not practical to establish a water loss criterion
for testing cells where seepage is acceptable. Therefore,
these multi-cell containment structures should be tested as a
unit. The design of multi-cell containment structures should
be reviewed to determine that they are multi-cell containment
structures rather than a single containment structure with
nonstructural baffle walls.
R1.1.1.4 Tightness testing of liquid transmission structures
requires the use of major, very tight, temporary bulkheads—
a feature typically designed and provided by the Contractor.
R1.1.1.5 Concrete paving is placed, finished, and jointed
in a different manner than cast-in-place concrete containment
structures. The differences in design, details, and construction affect the tightness of the structure, and some test procedures may not be applicable.
R1.1.2 Work not specified—Concrete structures for the
primary or secondary containment of hazardous materials,
cryogenic fluids, or high-pressure gases require specialized
testing methods, procedures, and criteria. Some of these
standards, however, may be partially applicable. Tightness
testing of various precast products is covered in ASTM
C1244.
R1.3—Description
R1.3.1 When using the stated procedures and criteria for
an existing containment structure, it should not be assumed
that the containment structure was designed for the test pressure
or for the specific type of test. A containment structure
designed for a triangular hydrostatic pressure may not be
able to withstand a uniform pneumatic pressure with the
same maximum intensity.
R1.3.2 Typically a structure is designed for hydrostatic
loading on the final, completed structure. Testing an incomplete
structure may cause damage and present safety concerns.
Testing an incomplete structure should occur only if
permitted by the Architect/Engineer. Also, pressure testing
of a partially completed containment structure may not be a
true test of tightness of the containment structure. Shrinkage
cracks may continue to propagate during the construction
period after the test. The fastening of walkways, exterior
stairways, roof beams, or other structural elements above or
outside of the containment structure’s liquid containment
shell, after the tightness test, may provide additional shell
restraint and result in the formation of concrete cracks.
No reproduction or networking permitted without license from IHS
COMMENTARY
11
SECTION R2—HYDROSTATIC TIGHTNESS TEST
FOR OPEN OR COVERED
CONTAINMENT STRUCTURES
R2.1—General
R2.1.1 Both Parts 1 and 2 of the hydrostatic tightness test
are equally important. Part 1 deals with the visible portion of
the containment structure, particularly the walls and wall
base joint. Part 2 primarily deals with the floor, where water
loss is not normally visible.
R2.1.1.2 Because Part 1 of the test requires that virtually
no water is lost through the walls and wall-base joints of
containment structures, the tightness criteria of containment
structures is mainly controlled by the floor details. Different
materials, methods of construction, and design concepts may
result in different containment structure tightness. A monolithically placed, prestressed concrete, containment structure
floor with the concrete always in compression may have a
different tightness than a monolithically placed nonprestressed
concrete containment structure floor with the concrete
partially in tension. A monolithically placed floor using
shrinkage-compensating concrete should be more watertight
than the same containment structure floor with construction
joints. This is due to the difficulty of placing honeycombfree concrete on the undersides of PVC waterstops. A lined
containment structure will have a different tightness than an
unlined containment structure. Based on reasonable tightness
of different types of containment structure construction, three
standard criteria were established. The selected criterion
should consider the containment structure design, construction, 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)
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designed to remain in compression and properly designed
floors that use shrinkage-compensating concrete.
R2.3.1 Test preparation
R2.3.1.1 The requirement to clean the containment
structure surfaces is to allow cracks and defects to be
observed and not obscured by mud, material spills, or stains.
Sprayed water may be necessary to wash foreign material
from the concrete surfaces. Mud, soil, or other foreign material
on the containment structure floor may not only obscure the
floor condition, but may temporarily fill defects, voids, or
cracks, thus giving test results that may not reflect the true
condition of the containment structure. It is preferred that
coatings not be applied until after testing is complete.
R2.3.1.2 Fittings and pipe penetrations have the potential
for allowing water to flow along the contact surface between
the fitting or pipe and the concrete. Metal fittings and pipes,
unlike concrete, do not change in volume during wetting or
drying. Metal pipes and fittings may resist the volume
change of the concrete, and result in the formation of
concrete cracks. It is usually impractical to observe the
bottom of pipe penetrations passing through the base slab.
R2.3.1.3 Liners are generally used to obtain a very tight
structure. Therefore, the basic structure should also be
reasonably tight to serve as a barrier to the stored material if
pinholes occur in the liner. Generally, the same review and
observation procedures are required for the concrete that is
to be covered by a liner as for concrete that will be exposed.
However, concrete surfaces to which liners are mechanically
locked during the placement of concrete cannot be visually
observed. Different liner materials require different liner
tests and different methods of repair. It is beyond the scope
of this document to go into the details of testing liner material
and, therefore, the user is advised to contact the liner
manufacturer for recommended repair procedures.
R2.3.1.4 Leaking or partially seated valves and gates are
a source of water loss from containment structures. A
containment structure inlet pipe, if connected to a water
source, may be difficult to check for leakage. One possible
method of checking for leakage is to install a sampling cock
in the pipe invert between two valves in series.
R2.3.1.5 An increase in flow from an underdrain system
may indicate water lost through the containment structure
floor. It may, however, also be due to rain or some other
external source of water. The conditions at each event should
be evaluated to estimate the most probable cause of the
increased flow.
R2.3.1.6 Ground water can cause a back pressure on the
walls and floor of containment structures and reduce the
outflow of the test water through defects. The presence of
ground water may indicate a greater watertightness of the
containment structure than is actually present.
R2.3.1.7 Backfill against the wall or on top of the wall
footing would interfere with Part 1 of the hydrostatic test.
The containment structure should have the maximum
amount of the exterior surface visible during the test. New
partially buried or buried containment structures should be
designed for loading without reliance on the backfill to resist
the interior pressures, and should not have the backfill placed
against the walls and on the wall footing before testing,
unless otherwise specified. When backfilling is unavoidable
prior to testing all or part of the structure, so indicate in the
Contract Documents. In this case, Part 1 of the testing is not
applicable for backfilled portions of the containment structure.
If a structure was not designed to be test loaded without
backfill in place, Part 1 of the test may not be possible.
R2.3.1.8 The water should be far enough below the overflow level to prevent the overflow from skimming off water
from wind-generated waves, from slight differential settlement,
or both.
R2.3.1.9 Because the rate of water absorption or evaporation from concrete is very slow, a slight drop in water level
due to swelling of the diameter may occur during Part 2 of
the hydrostatic test. The 3-day waiting period for the usual
tightness tests is normally considered sufficient allowance
for moisture absorption by the concrete and temperature
stabilization of the test water for most practical test criteria.
A longer waiting period, however, may be desired for the
more stringent test criteria. A waiting period may not be
required for lined or coated containment structures, as the
barrier should prevent water from reaching the concrete.
R2.3.2 Hydrostatic tightness test—Part 1: Qualitative
criteria
R2.3.2.1 Moisture-darkened areas on wall external
surfaces with flow insufficient to cause moisture to be able
to be picked up on a dry hand will usually not detrimentally
affect the structure, and are generally considered acceptable.
Observed flow or seepage should be repaired before
beginning Part 2 of the test. The quantified maximum water
loss included in this document is for unexplained losses; it is
not a criterion for acceptance of known sources of lost water.
R2.3.3 Hydrostatic tightness test—Part 2: Quantitative
criteria
R2.3.3.1 It is preferable to minimize temperature change
of the water during the test. This would minimize computed
temperature corrections of measurements. Temperature
stratifications can occur in the contained water and affect the
test results.
R2.3.3.2 Measurements taken at two locations, 180 degrees
apart, will usually minimize the effect of differential settlement
on the computed values for small- and medium-size containment structures. Measurements at four points, 90 degrees apart,
will give more accurate results. Measurements taken at the
same time of day will reduce the probability of temperature
difference.
R2.3.3.3 Part 2 of the hydrostatic test should be of
sufficient duration to be certain of the results. An example of
the method of calculating the duration of the test is as
follows. A flat-bottom concrete containment structure,
required to pass a tightness test, has a 6 m water depth. The
acceptance criterion is a maximum of 0.05% loss of water
volume in 24 hours. The required duration of the test would be
10 mm
--------------------------------------------------------------------------------------------------= 3.33 days
0.0005 mm/mm/day × 6 m × 1000 mm/m
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
Measurements are taken at 24-hour intervals; therefore, the
test duration should be at least 4 days.
R2.3.3.4 If the specified tightness criterion for the tank
is “no measurable loss,” the water temperature should be recorded
at 1.5 m intervals of depth for volume change corrections.
R2.3.3.5 A floating, restrained, partially filled, calibrated,
open container for evaporation and precipitation measurement
should be positioned in open containment structures, and the
water level in the container recorded. Determination of
evaporation by a shallow pan-type measuring device is
discouraged. The heating of the bottom of a shallow pan can
cause accelerated evaporation of water compared with that
taking place from a deep containment structure.
R2.3.3.6 Observed flow or seepage of water from the
exterior 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 angle
of the sun, it is recommended that the wall surfaces be
checked at different times of the day. The limits of flowing
water on the footing or wet spots on the walls, observed
during daily observations, should be marked for later repair.
R2.3.3.7 Measurements taken at the same location will
reduce the probability of measurement differences.
R2.3.3.8 When numerical limits are given for the allowable
loss of water during the tightness test, they are for the
undetected loss of water from the containment structure.
Therefore, test values should be corrected for temperature
change, evaporation, and precipitation, if present.
Temperature corrections to the water volume should be
based on the change in water density, but may also include
the effect of the thermal change to the structure dimensions.
Structure dimension changes may be slightly larger for
circular containment structures that have a sliding joint at the
base of the perimeter wall.
R2.3.4 Retesting
R2.3.4.1 Unusual precipitation would be when the
amount of precipitation would exceed the capacity of the
precipitation gauge, or would plug the precipitation gauge
with snow, or would cause water to spill over the containment
structure overflow.
R2.3.4.2 The immediate retest is allowed for confirmation
of the first test results. This should minimize the cost of
review time and wasted water due to measurement errors or
slower-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 the
suspect area, and the area is covered with a vacuum box. A
vacuum of at least 0.2 bar is created within the box. Air leakage
through or at the suspect area will result in the formation of soap
bubbles. All soap solutions should be thoroughly flushed and
rinsed from the concrete and metal surfaces after use.
SECTION R3—SURCHARGED HYDROSTATIC
TIGHTNESS TEST FOR CLOSED CONTAINMENT
STRUCTURES
R3.1—General
R3.1.1 Scope—Both Parts 1 and 2 of the surcharged
hydrostatic tightness test are equally important. Part 1 deals
13
with the visible portion of the containment structure, the
walls, and wall base joint, in particular. Part 2 primarily deals
with the floor, which is not normally visible.
R3.1.1.1 A surcharged hydrostatic tightness test should
be used only on containment structures that have been
structurally analyzed for the test surcharge loading that will
be applied. The test should only be performed on containment
structures with the intended use of storing water or other
fluids under a surcharged pressure. Composite containment
structures of concrete and steel should be periodically tested
as the loss of corrosion allowance metal may reduce the
strength and tightness of the containment structure.
R3.1.1.2 Different materials, methods of construction,
and design concepts may result in different containment
structure tightness. Based on reasonable tightness of
different types of containment structure construction, three
standard criteria have been established. The selected criterion
should consider the containment structure design, construction,
and the tightness necessary for the stored contents. Refer to
R2.1.1.2 for more discussion of this topic.
R3.3.1 Test preparation
R.3.3.1.1 through R.3.3.1.6. See R.2.3.1.1 through
R2.3.1.6.
R3.3.1.7 The requirement for the free escape of air while
filling the containment structure is to prevent the water from
being pressurized by trapped air. The foundation, venting
equipment, or other conditions may limit the water filling to
a lower rate. The containment structure contents should not
be surcharged until the test water temperature has stabilized.
It is preferred that the test water temperature be 16°C or
above. The 3-day waiting period for the test is normally
considered sufficient allowance for moisture absorption by
the concrete and temperature stabilization of the test water
for most practical test criteria. The waiting period can be
extended for unlined or uncoated containment structures, or
for the more stringent test criteria, if desired, to obtain
additional moisture absorption. A waiting period is not required
for moisture absorption of lined containment structures, as the
liner should prevent water from reaching the concrete.
R3.3.1.8 The standpipe protects the containment structure
from unanticipated pressure. If there is not a free water
surface at the standpipe, rapid pressure changes can occur
due to a water temperature change, or a vacuum can occur
due to water leakage.
R3.3.2 Surcharged hydrostatic tightness test—Part 1:
Qualitative criteria—Refer to R2.3.2.
R3.3.3 Surcharged hydrostatic tightness test—Part 2:
Quantitative criteria
R3.3.3.1 It is not expected that there will be a significant
change in water temperature during the 1-hour test period.
The temperature readings are taken primarily to verify that
the temperature has not affected the test results. The depth of
the measurement is selected to be well within the mass of the
test water, and away from the point of insertion of the
makeup 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 30 m diameter, 6 m high
containment structure with a flat floor and 2% (upward)
--```,`,``,,,,```,``,,```,````-`-`,,`,,`,`,,`---
14
TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
sloping conical roof would result in an allowable makeup
volume rate of 94.3 L per hour.
89.8 Lph = {π(15 m)2 × [6 m + 1/3(0.02 × 15 m)] × 1000 L/m3 ×
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 be
checked to see that the containment structure will be protected
when the containment structure is placed in operation.
R3.3.3.5 The final visual observation review is required to
verify that no damage has occurred to the containment
structure from the test loading.
R3.3.4 Retesting
R3.3.4.1 It is recognized that for the more stringent
criteria, the test is very temperature sensitive. Other criteria
may be set by the Architect/Engineer if needed for the stored
liquid. The test should be sufficient for most containment
structures constructed for the storage of liquids under
surcharged pressure; if, however, in the opinion of the
Architect/Engineer, additional tests are needed to investigate
the safety of a containment structure under certain other
conditions of loading as determined from the design
computations, such tests should also be made on the
containment structure in addition to this test.
SECTION R4—PNEUMATIC TIGHTNESS TEST
FOR CLOSED CONTAINMENT STRUCTURES
R4.1—General
R4.1.1 There are two parts to the pneumatic tightness test
for closed containment structures as well. Part 1 uses soap
suds and vacuum boxes to detect air losses. Part 2 measures
the overall air loss, expressed as the maximum allowable
percent loss per day of the test air volume.
R4.1.1.1 A pneumatic tightness test should only be used
to check the tightness of a containment structure when specified
by an Architect/Engineer who has structurally analyzed the
containment structure considering the pressure test loading
that will be applied. The test should be performed on
containment structures with the intended use of storing water
or gas or a combination of water and gas under pneumatic
pressure. The test is sometimes used as an alternate test for a
hydrostatic test when allowed in the specifications. Liners
that are mechanically locked to the surface during concrete
placement should be installed before Part 1 of the test.
Liners, membranes, or coatings, when included in the
design, should be installed before Part 2 of the test when no
measurable loss is specified, due to the stringent criteria of
the test.
R4.1.1.2 The 2% air loss criterion was selected due to
the calculation of air loss being very sensitive to atmospheric
pressure. The 2% is consistent with loss at unidentifiable
locations. Liners or coatings should be considered when a no
measurable loss tightness criterion is required.
Different materials, methods of construction, and design
concepts may result in different containment structure
tightness. Based on reasonable tightness of different types of
containment structure construction, two standard criteria
were established. The selected criterion should consider the
containment structure design, construction, and the tightness
necessary for the stored contents. Refer to R2.1.1.2 for more
discussion of this topic.
R4.3.1 Test preparation
R4.3.1.1 Refer to R2.3.1.
R4.3.1.2 A test pressure 25% higher than the design
pressure is used for Part 1 of the test to better identify potential
problem areas. Refer to R4.1.1.1.
R4.3.2 Pneumatic tightness test—Part 1: Qualitative
criteria
R4.3.2.1 The stringent criterion for this test requires
additional checking for potential leaks. Vacuum boxes are
used to locate leaking joints, cracks, and porous spots. Soap
suds are applied to the suspect area, and the area is covered
with a vacuum box. A vacuum of at least 0.2 bar is created
within the box. Air leakage through or at the suspect area
results 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 if
air loss occurs. Observed seepage of air should be repaired
before the start of Part 2 of the test. The quantified maximum
air 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 test—Part 2: Quantitative
criteria
R4.3.3.2 The criterion can be very stringent; therefore,
the 2-hour time period may not be sufficient to accurately
determine the tightness of the containment structure
(because any errors in measurement are multiplied by 12).
Where greater accuracy is desired, the test time may be
extended to 1 or more days. The operability of the relief
valves is checked to see that the containment structure will
be protected when placed in operation.
An example of the calculations for determining the
percent of air volume loss for a test would be:
Initial readings:
Pressure (P1)
0.01551 MPa
Barometric pressure
0.1014 MPa
Temperature of test air (T1)
22.31°C
Volume
(V1)
Final readings:
Pressure (P2)
0.01531 MPa
Barometric pressure
0.1011 MPa
Temperature of test air (T2)
21.61°C
Volume
(V2)
Test duration:
2 hours
Absolute values:
Initial
P1 (pressure) 0.01551 + 0.1014 = 0.1169 MPa
T1 (temperature) 22.31 + 273.15 = 295.46 K
Final
P2 (pressure) 0.01531 + 0.1011 = 0.1164 MPa
T2 (temperature) 21.61 + 273.15 = 294.75 K
--```,`,``,,,,```,``,,```,````-`-`,,`,,`,`,,`---
V2 = P1× V1 × T2/P2 × T1
V2 = 0.1169 × V1 × 294.75/0.1164(295.46)
V2 = 1.001916 × V1
% loss of air volume = 1.001916(100) = 0.1916% in 2 h
% loss of air volume in 1 day = 0.1916(12) = 1.6%
R4.3.3.4 The final review is required to verify that no
damage occurred to the containment structure from the test
loading.
R4.3.4 Retesting
R4.3.4.1 The immediate retest is allowed for confirmation
of the first test results. This should minimize the cost of
review time due to measurement errors or other factors.
SECTION R5—COMBINATION HYDROSTATICPNEUMATIC TIGHTNESS TEST FOR CLOSED
CONTAINMENT STRUCTURES
R5.1—General
R5.1.1 There are four parts to the combination hydrostaticpneumatic tightness test for closed containment structures. The
first two parts include Parts 1 and 2 of the hydrostatic test
(Section 2). The third and fourth parts include Parts 1 and 2
of the pneumatic test for closed containment structures
(Section 4).
R5.1.1.1 A combination hydrostatic-pneumatic tightness
test should only be used to check the tightness of a containment
structure when specified by an Architect/Engineer who has
structurally designed or analyzed the containment structure
for the combination hydrostatic-pneumatic test loading that
will be applied. The test should be performed on containment structures with the intended use of storing water or
other liquids under air or gas pressure.
R5.1.1.3 Different materials, methods of construction,
and design concepts may result in different containment
structure tightness. The selected criterion should consider the
containment structure design, construction, and the tightness
necessary for the stored contents. The quantitative criteria
discussions for the types of containment structures discussed
in Sections 2 and 4 will help the user select the appropriate
quantitative criteria when the particular criteria is not
otherwise specified.
R5.3.1 Test preparation
R5.3.1.1 Hydrostatic tightness test preparation
R5.3.1.1.1 Refer to R2.3.1.
15
R5.3.1.1.3 Liners and membranes, when included in
the design, should be installed after the hydrostatic test
whenever possible. Liners, mechanically locked to the
surface during concrete placement, may be installed before
hydrostatic testing.
R5.3.1.1.4 It is better to check for seepage on the
wall’s exterior and through any possible honeycombing or
cracks before applying any coatings.
R5.3.1.1.5 The foundation, venting equipment, or
other conditions may limit the water filling to a lower rate.
R5.3.1.1.6 The 3-day waiting period is considered
sufficient allowance for moisture absorption by the concrete.
The waiting period can be extended for unlined or uncoated
containment structures, if desired.
R5.3.2 Hydrostatic tightness testing—Parts 1 and 2 and
retesting
R5.3.2.1 The exterior qualitative test can indicate
defects in liners, membranes, and coatings.
R5.3.3 Pneumatic tightness testing—Parts 1 and 2 and
retesting
R5.3.3.1 Refer to R4.3.2.
R5.3.3.2 Refer to R4.3.3. Also, refer to R4.3.3.2 for an
example calculation of volume loss.
R5.3.3.3.1 A change in the air temperature of the
pressurized air could affect the results of the test. The
immediate retest is allowed for confirmation of the first test
results. This should minimize the cost of review time due to
measurement errors or other factors.
SECTION R6—REFERENCES
ACI Committee 350, “Testing Reinforced Concrete Structures for Watertightness (ACI 350.1R-93/AWWA 400-93),”
American Concrete Institute, Farmington Hills, MI, 1993, 5 pp.
American Petroleum Institute, 1992, “Design and
Construction of Large, Welded, Low-Pressure Storage
Tanks (ANSI/API—620),” Washington, DC, 1992.
ASTM C1244-05, “Standard Test Method for Concrete
Sewer Manholes by Negative Air Pressure (Vacuum) Test
Prior to Backfill,” ASTM International, West Conshohocken,
PA, 2005, 4 pp.
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TIGHTNESS TESTING OF ENVIRONMENTAL ENGINEERING CONCRETE CONTAINTMENT STRUCTURES (ACI 350.1-10)
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--```,`,``,,,,```,``,,```,````-`-`,,`,,`,`,,`---
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Specification for Tightness Testing of Environmental Engineering
Concrete Containment Structures (ACI 350.1M-10) and Commentary