C105-05

7/24/2019 C105-05

1/32

The Authoritative Resource on Safe WaterSM

ANSI/AWWA C105/A21.5-05

(Revision of ANSI/AWWA C105/A21.5-99)

AWWA Standard

Effective date: Dec. 1, 2005.

First edition approved by AWWA Board of Directors in 1972.

This edition approved June 12, 2005.

Approved by American National Standards Institute Sept. 14, 2005.

Polyethylene Encasementfor Ductile-Iron PipeSystems

Advocacy

Communications

Conferences

Education and Training

Science and Technology

Sections

6666 West Quincy Avenue

Denver, CO 80235-3098

T 800.926.7337

www.awwa.org

Copyright 2006American Water Works Association, All Rights Reserved.
http://../GOODIES/new.pdfhttp://../awwastds.pdf

7/24/2019 C105-05

2/32

ii

AWWA Standard

This document is an American Water Works Association (AWWA) standard. It is not a specification. AWWA standards

describe minimum requirements and do not contain all of the engineering and administrative information normally

contained in specifications. The AWWA standards usually contain options that must be evaluated by the user of the

standard. Until each optional feature is specified by the user, the product or service is not fully defined. AWWA

publication of a standard does not constitute endorsement of any product or product type, nor does AWWA test, certify,or approve any product. The use of AWWA standards is entirely voluntary. AWWA standards are intended to represent a

consensus of the water supply industry that the product described will provide satisfactory service. When AWWA revises

or withdraws this standard, an official notice of action will be placed on the first page of the classified advertising

section of Journal AWWA. The action becomes effective on the first day of the month following the month of Journal

AWWA publication of the official notice.

American National Standard

An American National Standard implies a consensus of those substantially concerned with its scope and provisions. An

American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The

existence of an American National Standard does not in any respect preclude anyone, whether that person has

approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures

not conforming to the standard. American National Standards are subject to periodic review, and users are cautionedto obtain the latest editions. Producers of goods made in conformity with an American National Standard are

encouraged to state on their own responsibility in advertising and promotional materials or on tags or labels that the

goods are produced in conformity with particular American National Standards.

CAUTIONNOTICE: The American National Standards Institute (ANSI) approval date on the front cover of this standard

indicates completion of the ANSI approval process. This American National Standard may be revised or withdrawn at

any time. ANSI procedures require that action be taken to reaffirm, revise, or withdraw this standard no later than five

years from the date of publication. Purchasers of American National Standards may receive current information on all

standards by calling or writing the American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York,

NY 10036; (212) 642-4900.

Science and Technology

AWWA unites the entire water community by developing and distributing authoritative scientific and technological

knowledge. Through its members, AWWA develops industry standards for products and processes that advance public

health and safety. AWWA also provides quality improvement programs for water and wastewater utilities.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic

or mechanical, including photocopy, recording, or any information or retrieval system, except in the form of brief

excerpts or quotations for review purposes, without the written permission of the publisher.

Copyright 2005 by American Water Works Association

Printed in USA

7/24/2019 C105-05

3/32

iii

Committee Personnel

A21 Subcommittee 4, Coatings and Linings, which reviewed this standard, had the follow-ing personnel at the time:

Troy F. Stroud, Chair

Kenneth W. Henderson, Vice-Chair

General Interest Members

K.W. Henderson, Malcolm Pirnie Inc., White Plains, N.Y. (AWWA)

D.H. Kroon, Corrpro Companies Inc., Houston, Texas (AWWA)

D.A. Lincoln, Aurora Pipe Line Company, Commerce City, Colo. (AWWA)

P.I. McGrath Jr., Birmingham, Ala. (AWWA)

J.R. Plattsmier, MWH Americas Inc., Denver, Colo. (AWWA)

W.H. Smith, Flora, Ill. (AWWA)

K.E. Wilson, Post Buckley Schuh & Jernigan, Tampa, Fla. (AWWA)

Producer Members

D.R. Charko, McWane, Inc., Birmingham, Ala. (AWWA)

Chris Comins, Custom Fab Inc., Orlando, Fla. (AWWA)

A.M. Horton, U.S. Pipe & Foundry Company, Birmingham, Ala. (DIPRA)

Harold Kennedy Jr., Harold Kennedy & Associates, Cary, N.C. (AWWA)

Michael Lundstrom, Eastland, Texas (AWWA)

C.W. McCauley Jr., Griffin Pipe Products Company, Lynchburg, Va. (DIPRA)

P.L. Robertson, Specification Rubber Products Inc., Alabaster, Ala. (AWWA)

P.A. Selig, American Cast Iron Pipe Company, Birmingham, Ala. (AWWA)

E.J. Shields Jr., Waterworks Supply Corporation, Malden, Mass. (AWWA)

T.F. Stroud, Ductile Iron Pipe Research Association, Birmingham, Ala. (DIPRA)

User Members

K.A. Alms, MissouriAmerican Water Company, St. Louis, Mo. (AWWA)

D.T. Bradley, Oak Lodge Water District, Milwaukie, Ore. (AWWA)

R.R. Goold, Kansas City Water Services Department, Kansas City, Mo. (AWWA)

T.C. Moreno, Bexar Metro Water District, San Antonio, Texas (AWWA)

7/24/2019 C105-05

4/32

iv

D.W. Russom, Central Arkansas Water, Little Rock, Ark. (AWWA)

C.R. Schwenker, Fairfax Water, Fairfax, Va. (AWWA)

R.L. Worden, GuadalupeBlanco River Authority, Seguin, Texas (AWWA)

AWWA Standards Committee A21, Ductile-Iron Pipe and Fittings, which reviewed andapproved this standard, had the following personnel at the time of approval:

John R. Plattsmier, Chair

Charles W. McCauley Jr., Vice-Chair

General Interest Members

K.W. Henderson, Malcolm Pirnie Inc., White Plains, N.Y. (AWWA)

H.E. Holcomb, Jordan Jones & Goulding Inc., Norcross, Ga. (AWWA)

M.B. Horsley, Black & Veatch, Kansas City, Mo. (AWWA)

D.H. Kroon, Corrpro Companies Inc., Houston, Texas (AWWA)

G.E. Laverick, Underwriters Laboratories Inc., Northbrook, Ill. (UL)

T.J. McCandless,*Standards Engineer Liaison, AWWA, Denver, Colo. (AWWA)

P.I. McGrath Jr., Birmingham, Ala. (AWWA)

J.R. Plattsmier, MWH Americas Inc., Denver, Colo. (AWWA)

W.H. Smith, Flora, Ill. (AWWA)

L.C. Yates, McGoodwin Williams & Yates, Fayetteville, Ark. (AWWA)

Ken Zastrow,Underwriters Laboratories Inc., Northbrook, Ill. (UL)

Producer Members

John Critchlow, Pacific States Cast Iron Pipe Company, Provo, Utah (AWWA)

L.R. Dunn, U.S. Pipe & Foundry Company, Birmingham, Ala. (DIPRA)

Harold Kennedy Jr., Harold Kennedy & Associates, Cary, N.C. (AWWA)

Michael Lundstrom, Eastland, Texas (AWWA)

C.W. McCauley Jr., Griffin Pipe Products Company, Lynchburg, Va. (DIPRA)

T.J. Muntz, Fab Pipe Inc., Rogers, Minn. (AWWA)

Gene Oliver,American Cast Iron Pipe Company, Birmingham, Ala. (AWWA)

*Liaison, nonvoting

Alternate

7/24/2019 C105-05

5/32

v

P.A. Selig, American Cast Iron Pipe Company, Birmingham, Ala. (DIPRA)

J.E. Shea,*McWane Cast Iron Pipe Company, Birmingham, Ala. (AWWA)

E.J. Shields Jr., Waterworks Supply Corporation, Malden, Mass. (AWWA)

T.F. Stroud, Ductile Iron Pipe Research Association, Birmingham, Ala. (AWWA)

T.B. Wright,*National Association of Pipe Fabricators, Edmond, Okla. (AWWA)

User Members

D.T. Bradley, Oak Lodge Water District, Milwaukie, Ore. (AWWA)

T.E. Coughran, City of Santa Ana, Santa Ana, Calif. (AWWA)

A.J. DeBoy, American WaterCentral Region, St. Louis, Mo. (AWWA)

R.R. Goold, Kansas City Water Services Department, Kansas City, Mo. (AWWA)

G.L. Meyer, City of Sioux Falls, Sioux Falls, S.D. (AWWA)

D.D. Montgomery, Independence Water Department, Independence, Mo. (AWWA)

T.C. Moreno, Bexar Metro Water District, San Antonio, Texas (AWWA)

C.J. Patla, Connecticut Water Company, Clinton, Conn. (AWWA)

C.R. Schwenker, Fairfax Water, Fairfax, Va. (AWWA)

R.L. Worden, GuadalupeBlanco River Authority, Seguin, Texas (AWWA)

R.D. Zwygart, Tampa Water Department, Tampa, Fla. (AWWA)

*Alternate

7/24/2019 C105-05

6/32

This page intentionally blank.

7/24/2019 C105-05

7/32

vii

Contents

All AWWA standards follow the general format indicated subsequently. Some variations from this formatmay be found in a particular standard.

SEC. PAGE SEC. PAGE

Foreword

I Introduction...................................... ix

I.A Background....................................... ix

I.B Research............................................. x

I.C History............................................... x

II Special Issues..................................... xi

II.A Useful Life of Polyethylene............... xi

II.B Type of Material .............................. xii

II.C Exposure to Sunlight ....................... xii

II.D Copper Service Connections............ xii

III Use of This Standard ...................... xiii

III.A Purchaser Options and

Alternatives .................................. xiii

III.B Modification to Standard................ xiii

IV Major Revisions .............................. xiii

V Comments ...................................... xiii

Standard

1 General

1.1 Scope ................................................. 1

1.2 Purpose .............................................. 1

1.3 Application ........................................ 1

2 References.......................................... 2

3 Definitions ........................................ 2

4 Requirements

4.1 Materials ............................................ 3

4.2 Tube Size or Sheet Width ................. 4

4.3 Marking ............................................. 5

4.4 Installation......................................... 5

5 Verification

5.1 Inspection and Affidavit of

Compliance................................... 10

6 Delivery ........................................... 10

AppendixA Notes on Procedures for Soil

Survey Tests and Observations

and Their Interpretation to

Determine Whether

Polyethylene Encasement

Should Be Used............................ 11

Figures

1 Installation Method A........................ 6

2 Slack-Reduction Procedure for

Installation Methods A and B......... 7

3 Installation Method B........................ 7

4 Installation Method C ....................... 8

5 Preferred Method for Making Direct

Service Taps on Polyethylene-

Encased Iron Pipe........................... 9

Tables

1 Polyethylene Tube and Sheet

Sizes for Push-on Joint Pipe ........... 4

A.1 Soil-Test Evaluation......................... 14

7/24/2019 C105-05

8/32


7/24/2019 C105-05

9/32

ix

Foreword

This Foreword is for information only and is not a part of ANSI/AWWA C105/A21.5.

I. Introduction.

I.A. Background. In 1926, the American Standards Association (ASA) (now

American National Standards Institute [ANSI]) Committee A21, Cast-Iron Pipe and

Fittings, was organized under the sponsorship of the American Gas Association

(AGA), the American Society for Testing and Materials (ASTM), American Water

Works Association (AWWA), and the New England Water Works Association

(NEWWA). The current sponsor is AWWA, and the present scope of Committee

A21 is to develop standards and manuals for ductile-iron pressure pipe for water

supply service and ductile-iron and gray-iron fittings for use with this pipe. These

standards and manuals include design, dimensions, materials, coatings, linings,joints, accessories, and methods of inspection and testing.

In 1958, Committee A21 was reorganized. Standards were divided into groups

focusing on the topics listed above, and subcommittees were established to study each

group in accordance with the review and revision policy of ASA. In 1984, the

committee became AWWA Standards Committee A21 on Ductile-Iron Pipe and

Fittings.

The present scope of A21 Subcommittee 4, Coatings and Linings, is to review

interior and exterior corrosion of ductile-iron pipe and fittings and to draft standards

for the interior and exterior protection of ductile-iron pipe and fittings. Accordingly,

Subcommittee 4 is responsible for the development of

1. Standards on polyethylene encasement materials and their installation to

provide corrosion protection, when required, for ductile-iron pipe and fittings.

2. Procedures for the investigation of soil to determine when polyethylene pro-

tection is indicated.

I.A.1. History of polyethylene encasement. Loose polyethylene encasement

was first used experimentally in the United States in 1951 for protection of gray-iron

pipe in corrosive environments. The first field installation of polyethylene wrap ongray-iron pipe in an operating water system was in 1958. The installation consisted

of approximately 600 ft (180 m) of 12-in. (305-mm) pipe installed in a waste-dump

fill area. Since 1958, polyethylene encasement has been used extensively in

installations in severely corrosive soils throughout the United States on pipe ranging

7/24/2019 C105-05

10/32

x

in size from 3 in. to 64 in. (76 mm to 1,600 mm) in diameter. Polyethylene

encasement has been used as a soil-corrosion preventive in a number of other

countries as well. An International Standard for Polyethylene Sleeving (ISO-8180)*

has been adopted since the procedure was developed in the United States.

I.B. Research. The Cast Iron Pipe Research Association (CIPRA)

(nowknown as the Ductile Iron Pipe Research Association [DIPRA]) has researched

several severely corrosive test sites. The tests indicate that polyethylene encasement

provides a high degree of protection resulting in minimal and generally insignificant

exterior surface corrosion of ductile-iron and gray-iron pipe protected in this manner.

Investigations of many field installations in which loose polyethylene encasement

has been used as protection for ductile-iron and gray-iron pipe against soil corrosion

confirm DIPRAs findings. These field installations also indicate that the dielectric

capability of polyethylene provides shielding for ductile-iron and gray-iron pipe from

stray direct current at most levels encountered in the field.

I.C. History. The first edition of this standard was published in 1972 as

American National Standard for Polyethylene Encasement for Gray and Ductile

Cast-Iron Piping for Water and Other Liquids.

In 1976, Subcommittee 4 reviewed the 1972 edition and submitted a

recommendation to Committee A21 that the standard be reaffirmed without change,

except for updating the Foreword.

In the 1982 revision, ANSI/AWWA C105/A21.5-82, references to gray cast-iron

pipe were deleted from the title and throughout the standard because gray cast-ironpipe was no longer produced in the United States. Also, metric conversions of all

dimensions were added to the standard.

The 1986 edition of the standard defined the thickness requirement for

polyethylene film; provided new figures showing installation methods; and extended

the length of connecting piping to be wrapped from 2 ft (0.6 m) to 3 ft (0.9 m).

Additionally, a requirement for wrapping service lines of dissimilar metals for a

distance of 3 ft (0.9 m) from the ductile-iron pipe was also incorporated.

In the 1993 revision of the standard, Sec. 4.1, Materials, was expanded to include

4-mil high-density cross-laminated (HDCL) polyethylene, and Class B (colors)

*International Organization for Standardization (ISO), ISO Central Secretariat, 1 rue de Varemb,Case postale 56, CH-1211, Geneva 20, Switzerland.

CIPRA became the Ductile Iron Pipe Research Association (DIPRA) in 1979.

7/24/2019 C105-05

11/32

xi

material was added to allow the purchase of colored polyethylene. Additionally, Table 1

was modified to reflect reduced tube widths comparable with push-on joint pipe and

fittings, and the size range was expanded to include 60- and 64-in. (1,500- and

1,600-mm) pipe. A recommendation that circumferential wraps of tape be placed at

2-ft (0.6-m) intervals along the barrel of the pipe for installation below the watertable or in areas subject to tidal actions was added to Sec. 4.3.1, and Sec. 4.3.6 was

revised to indicate the preferred method of making direct service taps on

polyethylene-encased pipe. An illustration of this procedure was added.

In 1999, the format was changed to AWWA standard style; Sec. II.D, Copper

Service Connections, was added to the Foreword of the standard; and, definitions of

parties and types of polyethylene film were added to Sec. 3, Definitions, of the

standard. Additionally, changes to Sec. 4.1, Materials, included: (1) deletion of low-

density polyethylene film; (2) the addition of linear low-density polyethylene film

and appropriate material requirements and physical properties; (3) increasing the

tensile strength requirements for the high-density cross-laminated polyethylene film;

(4) the addition of impact- and tear-resistance requirements for both polyethylene

materials; (5) deletion of the minus tolerance on film thickness for both materials;

and, (6) the addition of an ultraviolet inhibitor to any natural or colored film except

black film containing 2 percent or more of carbon black. Other changes to the

standard included the addition of Sec. 4.3, Marking, to facilitate traceability and to

help ensure compliance with the standard; the addition of an alternate method of

using a 3-ft sheet of polyethylene rather than a 3-ft length of polyethylene tube forjoint makeup to Sec. 4.4.2.2, Method; and, the addition of Sec. 5.1, Inspection and

Certification by Manufacturer, to help ensure compliance with the standard. Also,

in Appendix A, a new paragraph on stray current corrosion and a new section on

uniquely severe environments were added. Additionally, the resistivity ranges in

Table A.1, Soil-Test Evaluation, were increased to make the procedure more

conservative.

This edition of ANSI/AWWA C105/A21.5 was approved by the AWWA Board

of Directors on June 12, 2005.

II. Special Issues.

II.A. Useful life of polyethylene. Tests of polyethylene used to protect ductile-

iron and gray-iron pipe have shown that after 40 years of exposure to severely

corrosive soils, strength loss and elongation reduction are insignificant. US Bureau of

7/24/2019 C105-05

12/32

xii

Reclamation (BUREC) studies*of polyethylene film used underground illustrate that

tensile strength was nearly constant and that elongation was only slightly affected

during a seven-year test period. BURECs accelerated soil-burial testing (acceleration

estimated to be 5 to 10 times that of field conditions) shows polyethylene to be

highly resistant to bacteriological deterioration.II.B. Type of material. The materials described in this standard are a linear

low-density polyethylene film and a high-density cross-laminated film. A low-density

film was used in the initial research and testing of polyethylene encasement to protect

ductile-iron and gray-iron pipe from corrosion. The current materials provide the

same degree of protection as the low-density film and are stronger and more damage

resistant. Other types of polymeric material are also available that may provide

equally suitable protection.

II.C. Exposure to sunlight. Prolonged exposure to sunlight will eventually

deteriorate polyethylene film. Although the film is required to contain not less than

2 percent carbon black or 2 percent of a hindered-amine ultraviolet inhibitor,

exposure of wrapped pipe should be kept to a minimum.

II.D. Copper service connections. The direct connection of copper services to

ductile- and gray-iron pipelines has historically been a common practice in the

waterworks industry. To minimize the possibility of bimetallic corrosion, service lines

of dissimilar metals and the attendant corporation stop should be wrapped with

polyethylene or a suitable dielectric tape for a minimum clear distance of 3 ft (0.9 m)

from the main (Sec. 4.4.7).In addition, the grounding of household electrical services to the copper water

service line may also result in stray current corrosion of the copper service or the

ductile-iron or gray-iron main. AWWA policy opposes the grounding of electrical

systems to pipe systems conveying drinking water to a customers premises. AWWA

further states that interior piping systems may be connected to an electrical service

neutral and to a separate grounding electrode, provided these systems are electrically

insulated from the water utilitys pipe system. To minimize the possibility of stray-

current corrosion on the ductile-iron or gray-iron main, electrical insulating

couplings should be installed at the water main.

*Laboratory and Field Investigations of Plastic Films. US Department of the Interior, Bureau ofReclamation, Rept. No. ChE-82 (September 1968).

7/24/2019 C105-05

13/32

xiii

III. Use of This Standard. It is the responsibility of the user of an AWWA

standard to determine that the products described in that standard are suitable for use

in the particular application being considered.

III.A. Purchaser options and alternatives. The following items should be pro-

vided by the purchaser:1. Type of polyethylene material (Sec. 4.1.1 and Sec. 4.1.2).

2. Color of polyethylene material (Sec. 4.1.3).

3. Installation methodA, B, or C (Sec. 4.3)if there is a preference.

4. Requirement for delivery of an Affidavit of Compliance (Sec. 5.1.2).

III.B. Modification to standard. Any modification to the provisions, defini-

tions, or terminology in this standard must be provided by the purchaser.

IV. Major Revisions. There were no major revisions to this edition of the

standard.

V. Comments. If you have any comments or questions about this standard,

please call the AWWA Volunteer & Technical Support Group, 303.794.7711,

FAX 303.795.7603, or write to the group at 6666 West Quincy Avenue, Denver, CO

80235-3098, or e-mail at [email protected].

7/24/2019 C105-05

14/32


7/24/2019 C105-05

15/32

1

AWWA Standard

ANSI/AWWA C105/A21.5-05

(Revision of ANSI/AWWA C105/A21.5-99)

Polyethylene Encasement

for Ductile-Iron Pipe Systems

SECTION 1: GENERAL

Sec. 1.1 Scope

This standard describes materials and installation procedures for polyethylene

encasement to be applied to underground installations of ductile-iron pipe. This

standard also may be used for polyethylene encasement of fittings, valves, and other

appurtenances to ductile-iron pipe systems.

Sec. 1.2 Purpose

The purpose of this standard is to provide the minimum requirements for

polyethylene sheet and tubes to be used for external corrosion protection of buried

ductile-iron pipe, fittings, and appurtenances.

Sec. 1.3 Application

This standard or sections of this standard can be referenced in documents for

the purchasing and installation of polyethylene sheet or tubes for corrosion

protection of buried ductile-iron pipe, fittings, and appurtenances.

7/24/2019 C105-05

16/32

2 AWWA C105/A21.5-05

SECTION 2: REFERENCES

This standard references the following documents. In their latest editions, they

form a part of this standard to the extent specified within the standard. In any case

of conflict, the requirements of this standard shall prevail.ANSI*/AWWA C600Installation of Ductile-Iron Water Mains and Their

Appurtenances.

ASTM D149Standard Test Method for Dielectric Breakdown Voltage and

Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power

Frequencies.

ASTM D882Standard Test Method for Tensile Properties of Thin Plastic

Sheeting.

ASTM D1709Standard Test Methods for Impact Resistance of Plastic Film

by the Free-Falling Dart Method.

ASTM D1922Standard Test Method for Propagation Tear Resistance of

Plastic Film and Thin Sheeting by Pendulum Method.

ASTM D4976Standard Specification for Polyethylene Plastics Molding and

Extrusion Materials.

SECTION 3: DEFINITIONS

The following definitions shall apply in this standard:

1. High-density cross-laminated polyethylene film: Film extruded from virgin

high-density polyethylene raw material, which is molecularly oriented by stretching.

Two single-ply layers of the film are laminated together with their orientations at 90

to one another to form the final product.

2. Linear low-density polyethylene film: Film extruded from virgin linear

low-density polyethylene raw material.

3. Manufacturer: The party that manufactures, fabricates, or produces

materials or products.4. Polyethylene encasement: The encasement of piping with polyethylene

film in tube or sheet form.

*American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036.

ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

7/24/2019 C105-05

17/32

POLYETHYLENE ENCASEMENT FOR DUCTILE-IRON PIPE SYSTEMS 3

5. Purchaser: The person, company, or organization that purchases any

materials or work to be performed.

SECTION 4: REQUIREMENTS

Sec. 4.1 Materials

4.1.1 Linear low-density polyethylene film. Linear low-density polyethylene

film shall be manufactured from virgin polyethylene material conforming to the

following:

4.1.1.1 Raw material requirements, per ASTM D4976

Group: 2 (Linear)

Density: 0.910 to 0.935 g/cm3

Dielectric strength: Volume resistivity, 1015ohm-cm, minimum

4.1.1.2 Physical properties of finished film.

Tensile strength: 3,600 psi (24.8 MPa), minimum in machine and transverse

direction (ASTM D882)

Elongation: 800 percent, minimum in machine and transverse direction

(ASTM D882)

Dielectric strength: 800 V/mil (31.8 V/m) thickness, minimum (ASTM

D149)

Impact resistance: 600 g, minimum (ASTM D1709 Method B)Propagation tear resistance: 2,550 gf (grams force), minimum in machine and

transverse direction (ASTM D1922)

4.1.1.3 Thickness. Linear low-density polyethylene film shall have a mini-

mum thickness of 0.008 in. (8 mil or 200 m).

4.1.2 High-density, cross-laminated polyethylene film. High-density cross-lami-

nated polyethylene film shall be manufactured of virgin polyethylene material

conforming to the following:

4.1.2.1 Raw material requirements per ASTM D4976

Group: 2 (Linear)

High-density: 0.940 to 0.960 g/cm3

Dielectric strength: Volume resistivity, 1015ohm-cm, minimum

4.1.2.2 Physical properties of finished film.

Tensile strength: 6,300 psi (43.4 MPa), minimum in machine and transverse


7/24/2019 C105-05

18/32

4 AWWA C105/A21.5-05

Elongation: 100 percent, minimum in machine and transverse direction

(ASTM D882)

Dielectric strength: 800 V/mil (31.8 V/m) thickness, minimum (ASTM

D149)

Impact resistance: 800 g, minimum (ASTM D1709 Method B)Propagation tear resistance: 250 gf, minimum in machine and transverse


4.1.2.3 Thickness. High-density cross-laminated polyethylene film shall

have a minimum thickness of 0.004 in. (4 mil or 100 m).

4.1.3 Color. Polyethylene film may be supplied with its natural color, colors

including white and black, or black (weather-resistant) containing not less than

2 percent carbon black with an average particle diameter of 50 nm or less. A

minimum of 2 percent of a hindered-amine ultraviolet inhibitor is required in any

natural or colored film except black film containing 2 percent or more carbon black.

Sec. 4.2 Tube Size or Sheet Width

Tube size or sheet width for each pipe diameter shall be as listed in Table 1.

Sec. 4.3 Marking

4.3.1 Marking requirements. The polyethylene film supplied shall be clearly

marked, at a minimum of every 2 ft along its length, containing the following

information:a. Manufacturers name or trademark.

b. Year of manufacture.

c. ANSI/AWWA C105/A21.5.

d. Minimum film thickness and material type (LLDPE or HDCLPE).

e. Applicable range of nominal pipe diameter size(s).

f. WarningCorrosion ProtectionRepair Any Damage.

4.3.2 Marking height. Letters and numerals used for marking items a

through ein Sec. 4.3.1 shall not be less than 1 in. in height. Item fin Sec. 4.3.1 shall

be not less than 1 in. in height.

Sec. 4.4 Installation

4.4.1 General. The polyethylene encasement shall prevent contact between

the pipe and the surrounding backfill and bedding material, but it is not intended to

be a completely airtight or watertight enclosure. Lumps of clay, mud, cinders, etc., on

the pipe surface shall be removed prior to installation of the polyethylene

7/24/2019 C105-05

19/32


encasement. During installation, soil or embedment material shall not be trapped

between the pipe and the polyethylene.

The polyethylene film shall be fitted to the contour of the pipe creating a snug,

but not tight, encasement with minimum space between the polyethylene and the

pipe. Sufficient slack shall be provided in contouring to prevent stretching the

polyethylene where it bridges irregular surfaces, such as bell-spigot interfaces, bolted

joints, or fittings, and to prevent damage to the polyethylene caused by backfilling

operations. Overlaps and ends shall be secured with adhesive tape or plastic tie straps.

For installations below the water table or in areas subject to tidal actions, tube-

form polyethylene should be used with both ends thoroughly sealed with adhesive

tape or plastic tie straps at the joint overlap. Also, circumferential wraps of tape

Table 1 Polyethylene tube and sheet sizes for push-on joint pipe*

Nominal Pipe Diameter Minimum Polyethylene Widthin.(cm)

in. (mm) Flat Tube Sheet

3 (76) 14 (36) 28 (71)

4 (102) 14 (36) 28 (71)6 (152) 16 (41) 32 (81)

8 (203) 20 (51) 40 (102)

10 (254) 24 (61) 48 (122)

12 (305) 27 (69) 54 (137)

14 (356) 30 (76) 60 (152)

16 (406) 34 (86) 68 (173)

18 (457) 37 (94) 74 (188)

20 (508) 41 (104) 82 (208)

24 (610) 54 (137) 108 (274)

30 (762) 67 (170) 134 (340)36 (914) 81 (206) 162 (411)

42 (1,067) 81 (206) 162 (411)

48 (1,219) 95 (241) 190 (483)

54 (1,400) 108 (274) 216 (549)

60 (1,500) 108 (274) 216 (549)

64 (1,600) 121 (307) 242 (615)

* These wrap sizes should work with most push-on joint pipe and fitting bell sizes. Where bell circumferences are largerthan the sheet sizes shown, the bell areas should be carefully wrapped with cut film sections, effectively lapping andsecuring cut edges as necessary; or, alternatively, sufficiently large tube or sheet film to effectively cover these joints

should be ordered.

7/24/2019 C105-05

20/32

6 AWWA C105/A21.5-05

should be placed at 2-ft (0.6-m) intervals along the barrel of the pipe to minimize the

space between the polyethylene and the pipe.

4.4.2 Pipe. This standard includes three methods of installation of polyeth-

ylene encasement on pipe. Methods A and B are for use with polyethylene tubes, and

method C is for use with polyethylene sheets.

4.4.2.1 Method A (Refer to Figure 1.). Cut polyethylene tube to a length

approximately 2 ft (0.6 m) longer than the pipe section. Slip the tube around the

pipe, centering it to provide a 12-in. (305-mm) overlap on each adjacent pipe section

and bunching it accordion-fashion lengthwise until it clears the pipe ends.

Lower the pipe into the trench and make up the pipe joint with the preceding

section of pipe. A shallow bell hole must be made at the joints to facilitate installation

of the polyethylene tube.After assembling the pipe joint, make the overlap of the polyethylene tube. Pull

the bunched polyethylene from the preceding length of pipe, slip it over the end of

the new length of pipe, and secure it in place. Slip the end of the polyethylene from

the new pipe section over the end of the first wrap until it overlaps the joint at the

end of the preceding length of pipe. Secure the overlap in place. Take up the slack

width at the top of the pipe as shown in Figure 2 to make a snug but not tight fit

along the barrel of the pipe, securing the fold at quarter points.

Cuts, tears, punctures, or other damage to the polyethylene shall be repaired as

described in Sec. 4.4.5. Proceed with the installation of the next section of pipe in the

same manner.

4.4.2.2 Method B (Refer to Figure 3.). Cut polyethylene tube to a length

approximately 12 in. (305 mm) shorter than that of the pipe section. Slip the tube

around the pipe, centering it to provide 6 in. (150 mm) of bare pipe at each end.

Figure 1 Installation method A

12-in. (305-mm) Minimum

One length of polyethylene tube for each length of pipe, overlapped at joint.

7/24/2019 C105-05

21/32


Take up the slack width at the top of the pipe as shown in Figure 2 to make a snug

but not tight fit along the barrel of the pipe, securing the fold at quarter points.

Secure the ends as described in Sec. 4.4.1.

Before making up a joint, slip a 3-ft (0.9-m) length of polyethylene tube over

the end of the preceding pipe section, bunching it accordion-fashion lengthwise.

Alternatively, place a 3-ft (0.9-m) length of polyethylene sheet in the trench under

the joint to be made. After completing the joint, pull the 3-ft (0.9-m) length of

polyethylene over or around the joint, overlapping the polyethylene previously

installed on each adjacent section of pipe by at least 12 in. (305 mm). Make each end

snug and secure as described in Sec. 4.4.1. A shallow bell hole is necessary and shall

be made at joints to facilitate the installation of the polyethylene tube or sheet.

Figure 2 Slack-reduction procedure for installation methods A and B

Figure 3 Installation method B

Take up the slack in the tube to make a snug but not tight fit. Fold the excess back over the top of thepipe, securing the fold at the quarter points along the length of the pipe.


Separate pieces of polyethylene tube for barrel of pipe and polyethylene tube or sheet for joints. Thepolyethylene over joints overlaps tube encasing barrel. (Method B is not recommended for bolted-type

joints unless an additional layer of polyethylene is provided over the joint area as in methods A and C.)

7/24/2019 C105-05

22/32

8 AWWA C105/A21.5-05


described in Sec. 4.4.5. Proceed with installation of the next section of pipe in the

same manner.

4.4.2.3 Method C (Refer to Figure 4.). Cut polyethylene sheet to a length

approximately 2 ft (0.6 m) longer than that of the pipe section. Center the cut length

to provide a 12-in. (305-mm) overlap on each adjacent pipe section, bunching it

until it clears the pipe ends. Wrap the polyethylene around the pipe so that it

circumferentially overlaps the top quadrant of the pipe. Secure the cut edge of

polyethylene sheet at intervals of approximately 3 ft (0.9 m).

Lower the wrapped pipe into the trench and make up the pipe joint with thepreceding section of pipe. A shallow bell hole is necessary and shall be made at the

joints to facilitate installation of the polyethylene. After completing the joint, make

the overlap and secure the ends as described in Sec. 4.4.1.


described in Sec. 4.4.5. Proceed with installation of the next section of pipe in the

same manner.

4.4.3 Pipe-shaped appurtenances. Bends, reducers, offsets, and other pipe-

shaped appurtenances shall be covered with polyethylene in the same manner as the

pipe.

4.4.4 Odd-shaped appurtenances. When it is not practical to wrap valves,

tees, crosses, and other odd-shaped pieces in a tube, wrap with a flat sheet or split

length of polyethylene tube by passing the sheet under the appurtenance and

bringing the sheet around the body. Make seams by bringing the edges of the

Figure 4 Installation method C


Pipe completely wrapped with flat polyethylene sheet.

7/24/2019 C105-05

23/32


polyethylene sheet together, folding them over twice, and taping them. Handle width

and overlaps at joints as described in Sec. 4.4.2.1. Tape the polyethylene securely in

place at the valve stem and other penetrations.

4.4.5 Repairs. Repair cuts, tears, punctures, or damage to polyethylene with

adhesive tape or with a short length of polyethylene sheet, or with a tube cut open,wrapped around the pipe to cover the damaged area, and secured in place.

4.4.6 Openings in encasement. Provide openings for branches, service taps,

blowoffs, air valves, and similar appurtenances by cutting an X in the polyethylene

and temporarily folding back the film. After the appurtenance is installed, tape the

slack securely to the appurtenance, and repair the cut and any other damaged areas

in the polyethylene with tape. Direct service taps may also be made through the

polyethylene, with any resulting damaged areas being repaired as described

previously. To make direct service taps, apply two or three wraps of adhesive tape

completely around the polyethylene-encased pipe to cover the area where the tapping

machine and chain will be mounted. This method minimizes possible damage to the

polyethylene during the direct-tapping procedure. After the tapping machine is

mounted, the corporation stop is installed directly through the tape and polyethylene

as shown in Figure 5. This method is very effective in eliminating damage to the

polyethylene encasement caused by the tapping machine and chain during the

Figure 5 Preferred method for making direct service taps on polyethylene-encased iron pipe

7/24/2019 C105-05

24/32

10 AWWA C105/A21.5-05

tapping operation. After the direct tap is completed, the entire circumferential area

shall be closely inspected for damage and repaired if needed.

4.4.7 Junctions between wrapped and unwrapped pipe. Where polyethylene-

wrapped pipe joins an adjacent pipe that is not wrapped, extend the polyethylene

wrap to cover the adjacent pipe for a distance of at least 3 ft (0.9 m). Secure the endwith circumferential turns of adhesive tape.

Service lines of dissimilar metals shall be wrapped with polyethylene or a

suitable dielectric tape for a minimum clear distance of 3 ft (0.9 m) away from the

ductile-iron pipe.

4.4.8 Backfill for polyethylene-wrapped pipe. Use the same backfill material as

that specified for pipe without polyethylene wrap, exercising care to prevent damage

to the polyethylene wrapping when placing backfill. Backfill material shall be free

from cinders, refuse, boulders, rocks, stones, or other material that could damage the

polyethylene. In general, backfilling practice should be in accordance with ANSI/

AWWA C600.

SECTION 5: VERIFICATION

Sec. 5.1 Inspection and Affidavit of Compliance

5.1.1 Quality control and inspection. The manufacturer shall establish the

necessary quality control and inspection practice to ensure compliance with thisstandard.

5.1.2 Affidavit of compliance. The manufacturer shall, if requested by the

purchaser, provide a sworn statement that the polyethylene encasement provided

complies with the requirements of this standard.

5.1.3 Freedom from defects. All polyethylene film shall be clean, sound, and

without defects that could impair service.

SECTION 6: DELIVERY

This standard has no applicable information for this section.

7/24/2019 C105-05

25/32

11

APPENDIX A

Notes on Procedures for Soil Survey Tests and Observations and TheirInterpretation to Determine Whether Polyethylene Encasement Should Be Used

This appendix is for information only and is not a part of ANSI/AWWA C105/A21.5.

In the appraisal of soil and other conditions that affect the corrosion rate of

ductile-iron pipe,*many factors must always be considered. They are outlined here.

A method of evaluating and interpreting each factor and a method of weighing each

factor to determine whether polyethylene encasement should be used are subse-

quently described.

These methods should be employed only by qualified personnel who are

experienced in soil analysis and evaluation of conditions potentially corrosive to

ductile-iron pipe. Factors such as moisture content, soil temperature, location of soilsample with respect to pipe, time between removal of soil sample and testing, and

other factors can significantly affect the soil-test evaluation. For example, certain soil

environments are considered to be potentially corrosive to ductile-iron pipe and,

therefore, do not require evaluation to determine the need for corrosion protection.

These environments include, but are not limited to, coal, cinders, muck, peat, mine

wastes, and landfill areas high in foreign materials. Existing installations and the

potential for stray direct-current corrosion should also be a part of the evaluation.

Sec. A.1 Soil Survey Tests and Observations

Factors to consider when determining the need for polyethylene encasement of

pipe are outlined below. A discussion of each point follows the outline.

1. Earth resistivity.

a. Four-pin

b. Single-probe

c. Saturated-sample (soil-box)

2. pH.

3. Oxidation-reduction (redox) potential.

4. Sulfides.

a. Azide (qualitative)

*NOTE: The information contained in Appendix A is also applicable to gray-iron pipe. Although gray-iron pipe is no longer produced in the United States, many miles of this product remain in service.

7/24/2019 C105-05

26/32

12 AWWA C105/A21.5-05

5. Moisture content (relative).

a. Prevalence

6. Soil description.

a. Particle size

b. Uniformityc. Type

d. Color

7. Potential stray direct current.

a. Nearby cathodic-protection-utilizing rectifiers

b. Railroads (electric)

c. Industrial equipment, including welding equipment

d. Mine transportation equipment

8. Experience with existing installations in the area.

1. Earth resistivity. There are three methods for determining earth resistiv-

ity: four-pin, single-probe, and soil-box. In the field, a four-pin determination should

be made with pins spaced at approximate pipe depth. This method yields an average

of resistivity from the surface to a depth equal to pin spacing. However, results are

sometimes difficult to interpret where dry topsoil is underlain with wetter soils and

where soil types vary with depth. The Wenner configuration is used with a

soil-resistance meter, which is available with varying ranges of resistance. For

all-around use, a meter with a capacity of up to 104ohms is suggested, because it

permits both field and laboratory testing of most soils.

Because of this difficulty in interpretation, the same meter may be used with a

single probe that yields resistivity at the point of the probe. A boring is made into the

subsoil allowing the probe to be pushed into the soil at the desired depth.

Because the soil may not be typically wet, a sample should be removed for

saturated resistivity determination. This may be accomplished with a laboratory unit

that permits the introduction of water to saturation, therefore simulating saturated

field conditions. The unit is used in conjunction with a soil-resistance meter.

The interpretation of the results of resistivity measurements is extremelyimportant. A determination based on a four-pin reading with dry topsoil averaged with

wetter subsoil would probably be inaccurate. Only by determining the resistivity in soil

at pipe depth can an accurate interpretation be made. Also, the local situation should

be determined concerning groundwater table, the presence of shallow groundwater, and

the approximate percentage of time the soil is likely to be water saturated.

7/24/2019 C105-05

27/32


With ductile-iron pipe, corrosion protection provided by products of corrosion

is enhanced if there are dry periods during each year. Dry periods seem to permit

hardening, or toughening, of the corrosion scale or products, which become

impervious and serve as better insulators.

In making field determinations of resistivity, temperature is important. Theresistivity increases as the temperature decreases. As the water in the soil approaches

freezing, resistivity increases greatly and, therefore, is not reliable. Field determina-

tions under frozen soil conditions should be avoided. Reliable results under these

conditions can be obtained only by the collection of suitable subsoil samples for

analysis in laboratory conditions at a proper temperature.

Interpretation of resistivity data. Because of the wide variance in results

obtained using the methods described, it is difficult to interpret any single reading

without knowing which method was used to obtain the reading. The interpretation

should be based on the lowest reading obtained, with consideration to other

conditions, such as typical moisture content of the soil. Because of the lack of exact

correlation between experiences and resistivity, it is necessary to assign ranges of

resistivity rather than specific numbers. Table A.1 shows the points assigned to

various ranges of resistivity. These points, when considered along with points

assigned to other soil characteristics (also shown in Table A.1), are significant.

2. pH. In the pH range of 0.0 to 4.0, soil serves well as an electrolyte. In the

pH range of 6.5 to 7.5, soil conditions are optimum for sulfate reduction. In the pH

range of 8.5 to 14.0, soils are generally high in dissolved salts, yielding a low soilresistivity.

In testing pH, a combination pH electrode is pushed into the soil sample, and

a direct reading is made, following suitable temperature setting on the instrument.

Normal procedures are followed for standardization.

3. Oxidation-reduction (redox) potential. The redox potential of a soil is

significant, because the most common sulfate-reducing bacteria can live only in

anaerobic conditions. A redox potential greater than +100 mV demonstrates that the

soil is sufficiently aerated, preventing sulfate reducers from forming. Potentials of 0 to

+100 mV may or may not indicate anaerobic conditions; however, a negative redox

potential definitely indicates the anaerobic conditions in which sulfate reducers thrive.

The redox test is performed using a pH/mV meter with a combination ORP electrode

inserted into the soil sample. It should be noted that soil samples removed from a

boring or excavation can undergo a change in redox potential when exposed to air.

7/24/2019 C105-05

28/32

14 AWWA C105/A21.5-05

These samples should be tested immediately after the excavation. Heavy clays, muck,and organic soils are often anaerobic. For this reason, these soils should be regarded as

potentially corrosive.

4. Sulfides. The sulfide determination is recommended because of its field

expediency. A positive sulfide reaction reveals a potential problem caused by

sulfate-reducing bacteria. The sodium azideiodine qualitative test is used to identify

Table A.1 Soil-test evaluation

Soil Characteristics Based on Samples Taken Down to Pipe Depth Points*

Resistivityohm-cm (based on water-saturated soil box):

1,8002,100................................................................................................... 5

>2,1002,500................................................................................................... 2

>2,5003,000................................................................................................... 1

>3,000.............................................................................................................. 0

pH:

02................................................................................................................... 5

24................................................................................................................... 3

46.5................................................................................................................ 0

6.57.5............................................................................................................. 0.

7.58.5............................................................................................................. 0>8.5.................................................................................................................. 3

Redox potential:

> +100 mV ...................................................................................................... 0

+50 to +100 mV.............................................................................................. 3.5

0 to +50 mV.................................................................................................... 4

Negative ........................................................................................................... 5

Sulfides:

Positive............................................................................................................. 3.5

Trace ................................................................................................................ 2

Negative ........................................................................................................... 0Moisture:

Poor drainage, continuously wet ...................................................................... 2

Fair drainage, generally moist........................................................................... 1

Good drainage, generally dry ........................................................................... 0

*Ten points indicates that soil is corrosive to ductile-iron pipe; protection is needed.

If sulfides are present and low or negative redox-potential results are obtained, add three points for this range.

7/24/2019 C105-05

29/32


sulfides. In this determination, a solution of 3 percent sodium azide in a 0.1Niodine

solution is introduced into a test tube containing a sample of the soil. Sulfides

catalyze the reaction between sodium azide and iodine, resulting in nitrogen. If

strong bubbling or foaming results, sulfides are present, as are sulfate-reducing

bacteria. If very slight bubbling is noted, sulfides are probably present in smallconcentration, and the result is noted as a trace.

5. Moisture content. Because prevailing moisture content is extremely impor-

tant to soil corrosion, this condition must be determined. It is not necessary that the

specific moisture content of a soil sample be determined, because the content probably

varies throughout the year. However, local authorities should observe the soil moisture

conditions many times during the year. (Although mentioned in item 1, Earth

resistivity, this variability factor is reiterated to emphasize the importance of notation.)

6. Soil description. In each investigation, soil types should be completely

described. The description should include color and physical characteristics, such as

particle size, plasticity, friability, and uniformity. Observation and testing will reveal

whether the soil is high in organic content; this should be noted. In a given area,

corrosivity may often be reflected in certain types and colors of soil. This information

is valuable for future investigations or for determining suspect soils.

Soil uniformity is important because of the possible development of local

corrosion cells caused by the difference in potential, such as different soil types

contacting the pipe. The same is true for uniformity of aeration. If one segment of

soil contains more oxygen than a neighboring segment, a corrosion cell can developfrom the difference in potential. This cell is known as a differential aeration cell.

There are several basic types of soils that should be noted in the soil description:

sand, loam, silt, clay, and muck. In addition, unusual soils, such as peat or soils high

in foreign material, should be noted.

7. Potential stray direct current. Soil surveys should consider the possibility of

stray direct current that might interfere with the ductile-iron-pipe installation. The

widespread use of rectifiers and ground beds for cathodic protection of underground

structures has increased the potential of stray direct current. The proximity of these

cathodic protection systems should be noted. Among other potential sources of stray

direct current are electric railways, industrial equipment (including welding

equipment), and mine-transportation equipment.

Normally, the amount of stray current influence from cathodic protection

systems on an electrically discontinuous ductile-iron pipeline will be negligible. It is

7/24/2019 C105-05

30/32

16 AWWA C105/A21.5-05

not detrimental to the expected life of the system, unless the pipeline comes close to

an impressed-current, cathodic-protection anode bed where the current density is

high. When ductile iron pipelines are exposed to high-density stray current

environments, the pipeline should be rerouted or the anode bed relocated. If neither

of these options is feasible, the ductile iron pipe in this area should be electricallybonded together, electrically isolated from adjacent pipe, polyethylene encased, and

appropriate test leads and current drain installed.

8. Experience with existing installations. The best information on soil corro-

sivity with respect to ductile-iron pipe results from experience with this material in

the area under investigation. Every effort should be made to acquire these data by

questioning local officials and, if possible, by observing existing installations.

Sec. A.2 Soil-Test Evaluation

When the soil-test procedures described in this standard are employed, the

following tests are used in evaluating corrosivity of the soil: resistivity, pH, redox

potential, sulfides, and moisture. For each of these tests, results are categorized

according to their contribution to corrosivity. Point values are assigned, based on

experience with ductile-iron pipe (see Table A.1). When results of these five tests/

observations are available, the assigned points are totaled. If the sum is equal to 10 or

more, the soil is corrosive to ductile-iron pipe, and protection against exterior

corrosion should be provided. This system of evaluation is limited to soil corrosion

and does not include consideration of stray direct current.General. These notes address only ductile-iron pipe, the soil environment in

which the pipe will serve, and the methods of determining a need for polyethylene

encasement.

Sec. A.3 Uniquely Severe Environments

Research has shown that polyethylene encasement alone is a viable corrosion

protection system for ductile- and gray-iron pipe in most environments. However,

other options should be considered for environments where the following character-

istics co-exist: (1) soil resistivity 500 ohm-cm; (2) anaerobic conditions in which

sulfate-reducing bacteria thrive (neutral pH [6.5 to 7.5], low or negative redox

potential [negative to +100 mV], and the presence of sulfides [positive or trace]); and

(3) where the water table is intermittently or continually above the invert of the pipe.

7/24/2019 C105-05

31/32


7/24/2019 C105-05

32/32

AWWA is the authoritative resource for knowledge, information, and advocacy to improve the quality and

supply of water in North America and beyond. AWWA is the largest organization of water professionals in the

world. AWWA advances public health, safety, and welfare by uniting the efforts of the full spectrum of the

entire water community. Through our collective strength we become better stewards of water for the greatest

good of the people and the environment.

Documents

C105-05