ACI-350-1-10-guide.pdf

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ACI 350.1-10

Reported by ACI Committee 350

Specification for Tightness Testing of

Environmental Engineering Concrete

Containment Structures

(ACI 350.1-10) and Commentary

Copyright American Concrete Institute

Provided by IHS under license with ACI Licensee=Bechtel Corp Loc 1-19/9999056100

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--``````,`,`````,`,,``,,,`,``,-`-`,,`,,`,`,,`---Specification for Tightness Testing of Environmental Engineering

Concrete Containment Structures (ACI 350.1-10) and Commentary

February 2011

ISBN 978-0-87031-418-6

American Concrete Institute

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--``````,`,`````,`,,``,,,`,``,-`-`,,`,,`,`,,`---ACI 350.1-10 supersedes 350.1-01, was adopted October 25, 2010, and published January 2011.

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 reproduc-tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.

1 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.

Specification for Tightness Testing of Environmental

Engineering Concrete Containment Structures

(ACI 350.1-10) and Commentary

An ACI Standard

Reported by ACI Committee 350

ACI 350.1-10

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.

Keywords: containment structures; hydrostatic; leakage; pneumatic; reservoirs; tests; tightness; tightness criteria.

CONTENTS

(mandatory portion follows)

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

Iyad M. Alsamsam Charles S. Hanskat Daniel J. McCarthy Andrew R. Philip Steven R. Close* Keith W. Jacobson Andrew R. Minogue Risto Protic

Robert E. Doyle M. Reza Kianoush Javeed Munshi William C. Sherman Anthony L. Felder Ramon E. Lucero Jerry Parnes Lawrence M. Tabat

Carl 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. Sachdev Chair Jon B. Ardahl* Vice Chair John W. Baker Secretary is available at www.concrete.org

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--``````,`,`````,`,,``,,,`,``,-`-`,,`,,`,`,,`---American Concrete Institute Copyrighted Material—www.concrete.org

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

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

R3.3.2—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

R4.3.2—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

R5.3.2—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)

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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 contain-ment 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 cast-in-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, high-pressure gas tanks, or miscellaneous precast concrete structures such as culverts, pipes, and manholes.

1.2—Definitions

accepted—determined to be satisfactory by Archi-tect/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 struc-ture where the roof or cover is used to prevent the escape of the contents, including gases emanating from the contents, to the outside atmosphere.

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 Archi-tect/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 Archi-tect/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 3 psi 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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1.3.2 Unless specifically allowed by the Architect/Engi-neer, the containment structure shall not be tested before all of the structure is complete and the concrete has attained its specified compressive strength.

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 require-ments of Contract Docurequire-ments.

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.

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/Engi-neer 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 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 particular criterion is not specified, the quantitative criteria shall be:

2.1.1.3 “No measurable loss” of water means the drop in the water surface shall not exceed 1/8 in. in 3 days when adjusted for evaporation and precipitation.

2.2—Products 2.2.1 Materials

2.2.1.1 Water—Use potable water unless otherwise specified.

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 4 ft/h. Filling shall be continued until the water surface is at the design maximum liquid level, or either 1 in. below any fixed overflow level in covered

Type of containment structure

Default hydrostatic test quantitative criterion Fully lined prior to hydrostatic test 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 0.050% of volume per day Concrete-paved reservoirs and channels 0.100% of volume per day

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containment structure or 4 in. 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 after-noons 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 35°F 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 1/16 in. 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 3/8 in., 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 18 in., 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 1/16-in. at the location of the orig-inal measurements. The water temperature and the evaporation and precipitation measurements shall be recorded.

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 precipita-tion 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 prob-able 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 construc-tion 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.

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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 4 ft/h, 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:

Qual-itative 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 10 ft 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, plug-ging the air vent, and injecting air into the top of the contain-ment 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

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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.

4.2.1.1 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

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.

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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.

SECTION 5—COMBINATION HYDROSTATIC-PNEUMATIC 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.

5.2.1.2 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 4 ft/h.

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 5°F 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.

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--``````,`,`````,`,,``,,,`,``,-`-`,,`,,`,`,,`---American Concrete Institute Copyrighted Material—www.concrete.org (nonmandatory portion follows)

NOTES TO SPECIFIER General notes

G1. ACI Specification 350.1 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 350.1 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 350.1 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 Insti-tute, Farmington Hills, Michigan, except as modified by these Contract Documents.”

G4. Each technical Section of ACI Specification 350.1 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 350.1 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 identify activities or options that “will be taken” or “may be taken” by the Owner or Architect/Engineer. Foreword to Checklists

F1. This foreword is included for explanatory purposes only; it is not a part of ACI Specification 350.1.

F2. ACI Specification 350.1 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 350.1 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 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 350.1. 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 350.1 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 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

Section/Part/Article 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.

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OPTIONAL REQUIREMENTS CHECKLIST

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

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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COMMENTARY

SECTION R1—GENERAL REQUIREMENTS R1.1—Scope

The American Concrete Institute Committee 350 recognized the need for standardized procedures of testing of environ-mental 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 environ-mental 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 contain-ment 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 watertight-ness between adjacent cells. During maintenance, it is some-times 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 construc-tion affect the tightness of the structure, and some test proce-dures 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.

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 mono-lithically 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 honeycomb-free 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, construc-tion, and the tightness necessary for the stored contents. Floors designed to be shrinkage-crack-free include floors

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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 over-flow level to prevent the overover-flow 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 evapo-ration 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 contain-ment structures. Measurecontain-ments 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 20 ft 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

0.375 in.

0.0005 in./in./day × 20 ft × 12 in./ft

--- = 3.13 days