Facility piping systems handbook2nd edition

CONTENTS Preface to the Second Edition xxi General / 1.1 American Gas Association AGA / 1.2 American National Standards Institute ANSI / 1.2 American Petroleum Institute API / 1.2 Americ

PIPING SYSTEMS

HANDBOOK

Michael Frankel, CIPE, CPD

President, Utility Systems Consultants

Second Edition

McGRAW-HILL New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul

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Information contained in this work has been obtained by The McGraw-Hill Companies, Inc (‘‘McGraw-Hill’’) from sources be- lieved to be reliable However, neither McGraw-Hill nor its authors guarantee the accuracy or completeness of any information pub- lished herein and neither McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information This work is published with the under- standing that McGraw-Hill and its authors are supplying infor- mation but are not attempting to render engineering or other pro- fessional services If such services are required, the assistance of

an appropriate professional should be sought.

engineers, and designers who make concepts into solutions

Michael Frankel, CIPE, CPD, is president of Utility Systems Consultants, a chanical and electrical consulting engineering firm A graduate of the City Univer- sity of New York (CUNY) with more than 44 years of experience, he is an often- quoted and recognized authority in the field of plumbing and piping engineering.

me-A frequent lecturer and author, his articles have appeared primarily in Plumbing Engineer, the journal of the American Society of Plumbing Engineers (ASPE), and

he serves as a member of the editorial advisory board He has contributed to several

handbooks, including McGraw-Hill’s Piping Handbook, now in its Sixth Edition.

Mr Frankel is a faculty member of CUNY, teaching extension division courses

in plumbing design and specification writing He is a member of ASPE and former president of the New Jersey chapter He is Certified in Plumbing Engineering (CIPE) and Certified in Plumbing Design (CPD) by ASPE In addition, he is ASPE code liaison to the National Fire Protection Association (NFPA), and is a member of the Technical Committee on Piping Systems for NFPA-99 (Health Care Facilities).

SECOND EDITION

The acceptance of the first edition of the Facility Piping Systems Handbook by

engineers throughout the world has been very gratifying This second edition pands on the previous work by providing additional information to the chapters onindividual private sanitary sewage disposal systems, installation of natural gas pip-ing on a site, and fixture and equipment mounting heights More specific infor-mation regarding acids and acid drainage is also provided Codes have been updatedfor these topics

ex-Additional chapters have been written on drinking water, heat exchangers, andmeasurement equipment and methods

Where applicable, metric units have been included along with the Inch Poundnumbers to make their conversion easier A fourth appendix has been added tofacilitate the conversion of Inch Pound (IP) to Metric (SI) units

I would like to thank the National Fire Protection Association for allowing me

to use the diagrams that appear throughout this book I also thank the NFPA forthe material reproduced with their permission It is important to note that this ma-terial does not represent the official and complete position of the NFPA on theparticular subject to which the material refers The reader should consult the specificcode or standard concerning the subject to which the material refers to fully un-derstand the NFPA’s position on that subject

Michael Frankel

CONTENTS

Preface to the Second Edition xxi

General / 1.1

American Gas Association (AGA) / 1.2

American National Standards Institute (ANSI) / 1.2

American Petroleum Institute (API) / 1.2

American Society of Heating, Refrigerating, and Air Conditioning Engineers

(ASHRAE) / 1.2

American Society of Plumbing Engineers (ASPE) / 1.3

American Society of Testing and Materials (ASTM) / 1.3

American Society of Mechanical Engineers (ASME) / 1.3

American Society of Sanitary Engineers (ASSE) / 1.3

American Water Works Association (AWWA) / 1.4

American Welding Society (AWS) / 1.4

Compressed Gas Association (CGA) / 1.4

Current Good Manufacturing Practice (cGMP) / 1.4

Code of Federal Regulations (CFR) / 1.5

Environmental Protection Agency (EPA) / 1.5

Food and Drug Administration (FDA) / 1.5

ISO 9000 / 1.5

Occupational Safety and Health Administration (OSHA) / 1.6

Model Regional Building Codes / 1.6

Manufacturers Standardization of the Valve and Fittings Industry (MSS) / 1.7

National Electrical Manufacturers Association (NEMA) / 1.7

National Fire Protection Association (NFPA) / 1.7

National Institutes of Health (NIH) / 1.7

National Oceanic and Atmospheric Administration (NOAA) / 1.8

Nuclear Regulatory Commission (NRC) / 1.8

National Sanitation Foundation, International (NSF) / 1.8

Underwriters Laboratories (UL) / 1.8

Brass (BR) / 2.6

Cast Iron Soil Pipe (CI) / 2.7

Acid-Resistant Cast Iron (AR) / 2.7

Corrugated Steel Pipe / 2.12

Other Metallic Piping Materials / 2.13

Key Properties of Plastic Pipe / 2.15

Description and Classification / 2.16

Plastic Pipe Standards and Nomenclature / 2.17

Elements for Selection / 2.19

Plastic Pipe Materials / 2.24

Asbestos Cement Pipe (ACP) / 2.28

Joints for Plastic Piping / 2.47

Joints for FRP Piping / 2.49

Pressure Loss through Valves / 2.62

Valve Selection Considerations / 2.63

Deep Bed Granular (Sand) Filtration / 3.14

Activated Carbon Filters / 3.18

Cartridge Depth Filters / 3.19

Codes and Standards / 4.1

Suspended Matter (Particulates) / 4.5

Dissolved Minerals and Organic Substances / 4.6

Langelier Saturation Index (LSI) / 4.16

Ryznar Stability Index (RI) / 4.18

Aggressiveness Index (AI) / 4.18

Ion Exchange and Removal / 4.27

Membrane Filtration and Separation / 4.36

Microbial Control / 4.40

Utility Water Treatment / 4.44

Boiler Feedwater Conditioning / 4.45

Cooling Water Conditioning / 4.46

Potable Water Treatment / 4.47

Codes and Standards / 4.51

Laboratory Systems / 4.51

Pharmaceutical Water / 4.53

Purified Water Types / 4.53

Pharmaceutical Water Treatment Process / 4.55

Feedwater / 4.57

Purification System Design / 4.57

Central Purification Equipment / 4.59

References / 4.62

Chapter 5 Heat Transfer, Insulation, and Freeze Protection 5.1

Codes and Standards / 5.1

Basics / 5.2

Types of Insulation / 5.7

Jackets / 5.9

Coatings, Adhesives, and Sealants / 5.13

Insulation Material and Thickness Selection / 5.14

Calculation of Insulation Thickness / 5.19

Freezing of Water / 5.24

The Mechanics of the Freezing Process / 5.24

Pipe Damage Due to Freezing / 5.25

The Freezing of Water in Atmospheric Vessels / 5.27

Sewer and Water Supply Piping Design / 5.30

Frost Closure of Vents / 5.35

Derivation of the Basic Formula for Frost Depth / 5.36

Electric Heat Tracing / 5.50

Storm Water Inlet Selection / 6.11

System Design Criteria / 6.21

System Design Procedure / 6.29

System Design Considerations / 6.33

Roof Retention / 6.35

Site Retention Methods / 6.35

General / 6.53

Codes and Standards / 6.53

Pipe and Installation Classifications / 6.53

Loads Acting on a Pipe / 6.54

Superimposed Loads / 6.57

Bedding / 6.67

Strength of Pipe Materials / 6.69

Total Load on Buried Pipe / 6.74

Sizing the Sanitary Sewer / 6.84

Sanitary Sewer Design Considerations / 6.96

Codes and Standards / 6.100

System Components / 6.100

Component Design and Selection / 6.102

System Design Considerations / 6.104

Storm Water Disposal / 6.106

Water Supplied from a Public Utility / 6.112

Water Supplied from Wells / 6.131

Water Supplied from Surface Water Sources / 6.142

Domestic Water Service / 6.143

Fire Protection Water Service / 6.150

Codes and Standards / 6.153

Codes and Standards / 7.2

General Design Considerations / 7.2

Sizing the Large Bulk Tank / 8.4

Sizing the Vaporizer / 8.8

Pressure from Liquid Gases / 8.9

Pressure Relief Valves / 8.10

Pipe Materials and Insulation / 8.11

Pipe Sizing Methods / 8.12

System Design Considerations / 8.13

Major System Components / 9.7

Sanitary System Design / 9.11

Suds Pressure Areas / 9.14

Sump Pumps and Sewage Ejectors / 9.15

House Sewer Design / 9.20

Introduction / 9.21

Codes and Standards / 9.21

Septic System / 9.21

Collection and Treatment Alternatives / 9.33

Solvent Plumbing System / 9.34

Suds Relief Vents / 9.39

Sump and Ejector Vents / 9.39

Vent Headers / 9.40

System Description / 9.42

General System Criteria / 9.42

Roof Drainage Systems / 9.42

Water Distribution Systems / 9.60

Estimating Water Demand / 9.60

Design of the Water Supply Distribution System / 9.62

Adjusting Water Pressure / 9.64

Pipe Size Selection / 9.75

System Description / 9.76

Codes and Standards / 9.76

Water Heating Methods and Equipment / 9.76

Acceptable Hot Water Temperatures / 9.78

Water Heater Sizing / 9.79

Safety and Protective Devices / 9.88

System Design Considerations / 9.89

Hot Water Temperature Maintenance / 9.90

Circulating Water System / 9.94

Electric Heating Cable / 9.102

Codes and Standards / 10.1

System Approval Requirements / 10.2

Pipe Material and Joint Selection Considerations / 10.3

Pipe Sizing Considerations / 10.3

pH Definition / 10.4

General System Design Considerations / 10.4

General / 10.7

Selection of Laboratory Waste Piping and Joint Material / 10.10

System Design Considerations / 10.10

Acid Waste Treatment / 10.10

General / 10.12

The Nature of Radiation / 10.12

Radiation Measurement / 10.13

Units of Radiation Dose / 10.14

Allowable Radiation Levels / 10.14

Shielding / 10.15

Radioactive Materials / 10.16

System Design Criteria / 10.16

General Design Criteria / 10.17

Pipe Material Selection / 10.17

General Design Considerations / 10.18

Decontamination / 10.19

Codes and Standards / 10.21

Biological Safety Levels / 10.22

Liquid Waste Decontamination System / 10.23

System Design Considerations / 10.24

General / 10.25

Codes and Standards / 10.25

Pipe Material and Joint Selection / 10.25

System Design Considerations / 10.25

Steam System Venting / 11.8

Steam Supply Systems / 11.9

Condensate Return Systems / 11.11

General / 11.13

Component Description / 11.13

Steam System Component Sizing / 11.28

Boiler Feed Pumps / 11.31

Condensate Recovery System Description / 11.33

Component Description / 11.34

Component Selection and Sizing Criteria / 11.36

Steam Trap Selection and Sizing / 11.39

Project Design Examples / 11.44

System Design Considerations / 11.49

Acknowledgments / 11.53

References / 11.53

Definitions and Liquid Fuel Classifications / 12.1

Codes and Standards / 12.2

System Description / 12.5

System Components / 12.6

Storage Tanks / 12.7

Leak Detection and System Monitoring / 12.17

Vapor Recovery Systems / 12.23

Product Dispensing Systems / 12.25

Storage Tanks / 12.29

Atmospheric Tank Venting / 12.32

Leak Detection and System Monitoring / 12.32

System Monitoring / 12.33

Vapor Recovery / 12.33

Product Dispensing Systems / 12.33

Tank Protection / 12.34

Fire Pump Fuel Storage / 12.37

Emergency Generator Fuel Storage / 12.38

Piping Materials / 12.41

Pipe Sizing / 12.42

Submersible Pump Sizing / 12.44

General Design Considerations / 12.46

Fuel Gas Description / 13.1

Codes and Standards / 13.1

System Operating Pressures / 13.3

General / 13.5

Major Natural Gas System Components / 13.6

Site Distribution / 13.9

Site Service Sizing Procedure / 13.11

NG Site Service Pipe Sizing Methods / 13.14

Pipe and System Materials for Site Installation / 13.14

Interior Pipe Sizing Procedure / 13.18

Storage Tanks / 13.28

Maximum Content of Liquid in Tanks / 13.31

Location of Equipment on the Site / 13.31

Tank Foundations and Support / 13.31

Regulators / 13.33

Pressure Relief Devices / 13.33

Excess Flow Valve / 13.35

Service Line Valves / 13.35

Filler Valves / 13.36

Vapor Equalizing Valves / 13.36

Liquid Level Gauges / 13.36

System Design Considerations / 13.50

References / 13.51

General / 14.2

Definitions and Pressure Measurements / 14.2

Physical Properties of Air / 14.4

Water Vapor in Air / 14.5

Impurities and Contamination / 14.8

System Components / 14.12

System Design / 14.33

Project Design Example / 14.56

General / 14.62

Codes and Standards / 14.62

Air Quality Standards / 14.62

Air Pressure Requirements / 14.63

Generation of Instrument Air / 14.63

Pipe and Fittings / 14.63

General / 14.64

Codes and Standards / 14.64

Classification of Specialty Gases / 14.65

Grades of Specialty Gases / 14.65

Storage and Generation of Gases / 14.68

Distribution System Components / 14.71

Distribution Network / 14.80

General / 14.98

Codes and Standards / 14.98

Description and General Uses for the Common Gases / 14.99

Storage and Generation of Gases / 14.100

The Surgical-Medical Air Compressor Assembly / 14.106

Dental Air Compressor Assembly / 14.109

The Distribution Network / 14.110

Pipe Materials, Joints, and Installation / 14.110

Required Pressure and Flow Rate / 14.133

System Design Considerations / 14.134

General / 14.135

Acknowledgments / 14.137

References / 14.137

Definitions and Pressure Measurement / 15.2

System Components / 15.11

General / 15.19

Codes and Standards / 15.19

Medical-Surgical Vacuum Air Systems Description / 15.20

System Components / 15.20

Vacuum Source / 15.20

Distribution Network Sizing and Arrangement / 15.24

General Design Considerations / 15.43

Codes and Standards / 15.44

Vacuum Source / 15.44

Redundancy / 15.45

Distribution Network / 15.45

Sizing Criteria / 15.47

Types of Systems and Equipment / 15.49

Codes and Standards / 15.49

Codes and Standards / 16.1

Animal Drinking Water System / 16.2

Drinking Water Treatment / 16.3

Drinking Water System Components and Selection / 16.5

Animal Rack Manifold Configurations / 16.6

System Sizing Methods / 16.8

Cleaning and Drainage Practices / 16.12

Equipment Washing / 16.18

Equipment Sanitizing / 16.18

Monitoring Systems / 16.18

General Systems Design Considerations / 16.19

Swine Cooling Systems / 16.19

Codes and Standards / 17.2

Types of Drench Equipment / 17.3

Installation Requirements for Drench Equipment / 17.8

Drench Equipment Components / 17.12

Flushing Water Disposal / 17.16

Types of Personal Respirators / 17.21

Breathing Air Purity / 17.24

Codes and Standards / 19.12

Methods of Preventing Attachment of Organisms / 19.12

Codes and Standards / 20.1

System Components / 20.2

Drinking Fountain Installation / 20.3

System Design / 20.4

Pipe and Insulation Sizing and Selection / 20.5

System and Component Sizing / 20.5

References / 20.10

Acknowledgments / 20.10

Introduction / 21.1

Codes and Standards / 21.1

ASTM B-31.9, Code for Pressure Piping, ASHRAE B-90.1, Conservation of Energy

Definitions / 21.2

General Heat Exchanger Types / 21.3

Choosing Off-the-Shelf Shell and Tube Exchangers / 21.9

Plate Type Heat Exchangers / 21.10

Plate and Frame Heat Exchangers / 21.10

Immersion Heat Exchangers / 21.14

Air-Cooled Exchangers / 21.14

Heat Exchanger Selection / 21.15

Shell and Tube Heat Exchangers / 21.17

Sizing Pressure and Temperature Relief Valve / 21.19

Principles of Flowmeter Operation / 22.5

Electronic (Electromagnetic) Flowmeters / 22.18

Flowmeter Selection / 22.21

General / 22.23

Level Technologies / 22.23

Level Measurement Selection / 22.33

Liquid Expansion Thermometers / 22.35

Metering Pump Description / 22.43

Metering Pump Considerations / 22.47

Calculating the Hydraulic Radius of an Open Channel / 22.50

Calculating the Flow of an Open Channel / 22.50

Meters for Measuring Flowrate in Open Channels / 22.51

Miscellaneous Devices and Measurement Methods / 22.58

References / 22.60

Appendix A Pipe Distribution Systems A.1

Index I.1

CODES AND STANDARDS

This chapter describes the codes and standards used and referenced most often thataffect the materials, design, and installation of the service and utility systems de-scribed in this handbook

GENERAL

Codes relating to piping provide specific design criteria such as allowable materials,working stresses, seismic loads, thermal expansion, and other imposed internal orexternal loads as well as fabrication, installation, and testing for many aspects of atotal piping system Code compliance is mandated by various federal, state, andlocal agencies that have jurisdiction and enforcement authority Each code has pre-cisely defined limitations on its jurisdiction Familiarity with these limitations can

be obtained only after a thorough reading of the code

These codes often refer to standards prepared by nationally recognized

organi-zations The term nationally recognized is defined as a group or organization

com-posed of a nationwide membership representative of its members’ views To achievenationally recognized status, an association must have been in existence for a rea-sonable period of time, be active in research and other issues relating to its area ofinterest, and be generally regarded by its peers to be scientifically accurate.Standards provide specific design criteria and rules for specific components orclasses of components such as valves, joints, and fittings Dimensional standardsprovide control for components to assure that components supplied by differentmanufacturers are physically interchangeable Pressure integrity standards provideperformance criteria so that components supplied by different manufacturers willfunction and be service rated (pressure and temperature) in a similar manner Stan-dards compliance is usually required by construction or building codes or purchaserspecifications

In any piping system design, if different code requirements are discovered, themost stringent requirements must be followed

The applicability of various codes and standards must be ascertained before thestart of a project, because submission of plans is often required for approval prior

to construction and installation of the piping systems This requires a code searchand consultation with the various authorities having jurisdiction

Fire insurance carriers are another consideration in the area of standards Theyvery often have more restrictive requirements than the building and constructioncodes that are normally applicable to every project, particularly in the area of watersupply storage and distribution for fire protection purposes, which may be combinedwith the domestic water system

AMERICAN GAS ASSOCIATION (AGA)

The AGA advances the safe, economical, and dependable transport of gas to thepublic In conjunction with the NFPA, it publishes NFPA-54, the Fuel Gas Code

AMERICAN NATIONAL STANDARDS INSTITUTE

(ANSI )

ANSI serves as the national coordinating institution for voluntary standardizationand related activities in the United States Through ANSI, organizations concernedwith such activities may cooperate in establishing, improving, and approving stan-dards and certification that such activities remain dynamically responsive to nationalneeds and prevent duplication of work ANSI’s goals are to further the voluntarystandards movement as a means of advancing national economy and benefitingpublic health, safety, and welfare; to facilitate domestic and international trade; toassure that the interests of the public, including consumers, labor, industry, andgovernment, have appropriate protection, participation, and representation in stan-dardization and certification; to provide the means for determining the need for newstandards and certification programs; to assure activities by existing organizationscompetent to resolve the need; to establish, promulgate, and administer proceduresand criteria for recognition and approval of standards as American National Stan-dards and to encourage existing organizations and committees to prepare and submitsuch standards for approval by the institute; to cooperate with departments andagencies of the federal, state, and local governments in achieving optimum use ofANSI in regulation and procurement; and to serve as a clearinghouse for infor-mation on standards and standardization, certification, and related activities in theUnited States and abroad

AMERICAN PETROLEUM INSTITUTE (API )

This organization affords a means to cooperate with the government in all matters

of national concern relating to American petroleum products; to foster foreign anddomestic trade in American petroleum products; to promote in general the interests

of all branches of the petroleum industry; to promote the mutual improvement ofits members and the study of the arts and sciences connected with the petroleumindustry

AMERICAN SOCIETY OF HEATING,

REFRIGERATING, AND AIR CONDITIONING

ENGINEERS (ASHRAE )

The purpose of ASHRAE is to advance the art and science of heating, ventilation,and air conditioning and allied arts and sciences, as well as related human factorsfor the benefit of the general public To fulfill its role, the society recognizes theeffect of its technology on environmental and natural resources

AMERICAN SOCIETY OF PLUMBING ENGINEERS

(ASPE )

The purpose of this organization is to develop and disseminate technical information

in the field of engineered plumbing systems and to provide a forum for exchange

of this information with other technical and construction code organizations

AMERICAN SOCIETY OF TESTING AND

MATERIALS (ASTM )

ASTM’s objectives are to develop full consensus standards for the characteristicsand performance of various materials, products, standards, and services; to developand publish information designed to promote the understanding and advancement

of technology; and to ensure the quality and safety of products and services.ASTM has developed standards that consist of 67 volumes divided into 16 sec-tions Each volume is published annually to incorporate new standards andrevisions

AMERICAN SOCIETY OF MECHANICAL

B31.l Power Piping

B31.3 Chemical Plant and Petroleum Refinery Piping

B31.4 Liquid Transpiration Systems for Hydrocarbons, Liquid and PetroleumGas, Anhydrous Ammonia, and Alcohols

B31.5 Refrigeration Piping

B31.8 Gas Transmission and Distribution Piping

B31.9 Building Services Piping

B31.11 Slurry Transportation Piping

AMERICAN SOCIETY OF SANITARY ENGINEERS

(ASSE )

ASSE promotes the welfare, health, and safety of the public through better sanitaryengineering principles

AMERICAN WATER WORKS ASSOCIATION

(AWWA)

The purpose of the AWWA is to promote public health, safety, and welfare byimproving the quality and increasing the quantity of water delivered to the publicand to further an understanding of the problems involved by:

1 Advancing the knowledge, design, construction, operation, water treatment, and

management of water utilities

2 Developing standards for procedures, equipment, and materials used by public

water supply systems

3 Advancing the knowledge of problems involved in the development of resources,

production, and distribution of safe and adequate water supplies

4 Educating the public on the problems of water supply and promoting a spirit of

cooperation between consumers and suppliers in solving problems

5 Conducting research to determine the causes of the problems of providing a safe

and adequate water supply and proposing solutions in an effort to improve thequality and quantity of the water supply

AMERICAN WELDING SOCIETY (AWS )

The purpose of the AWS is to encourage in the broadest sense the advancement ofwelding, to encourage and conduct research in sciences related to welding, and toengage and assist in the development of sound practices for the application ofwelding and related processes

COMPRESSED GAS ASSOCIATION (CGA)

The CGA is a trade organization that writes and publishes guides, in the form ofpamphlets, that include all aspects of compressed gas storage, distribution, andpurity

CURRENT GOOD MANUFACTURING PRACTICE

(cGMP)

cGMP is a regulation established by 21 CFR 210 and 211 in the Federal Food,Drug, and Cosmetic Act It establishes minimum good practices for methods, con-trols, facilities, manufacturing, processing, and packing of items to assure they meetthe requirements covered by the act Enforcement is provided by the FDA.cGMP has no strict guidelines and is completely subject to reviewers of theFDA It is intended to detail what must be done rather than how The manufacturersmust establish the durability and safety to the public of all products, and prove theymeet the purity and efficacy characteristics that they represent to possess by appli-cation to the FDA

CODE OF FEDERAL REGULATIONS (CFR)

The Code of Federal Regulations is the collection of the general and permanentrules and regulations originally published in the Federal Register by agencies ofthe federal government There are 50 separate titles that are revised once a year.The most up-to-date information will be found in the Federal Register on a dailybasis until revision is made to the CFR

ENVIRONMENTAL PROTECTION AGENCY (EPA)

Created in 1970, the EPA is the government organization responsible for the vention of pollution to the environment The EPA creates national pollution stan-dards and criteria, creates compliance and enforcement plans, and performs researchand development for identifying pollution-related risks Criminal enforcement isalso within the jurisdiction of the EPA

pre-FOOD AND DRUG ADMINISTRATION (FDA)

The FDA is a government agency originally created by the Federal Food, Drug,and Cosmetic Act and charged with the responsibility to see that all drugs are safe,effective, and properly labeled The regulation implementing its authority is 21 CFR211

ISO 9000

ISO is the English translation of the International Organization for Standardizationbased in Geneva, Switzerland ISO consists of national standards organizations fromapproximately 100 countries throughout the world The United States is represented

by ANSI Internationally recognized and accepted standards are required to lish a minimum level of consistency and standard of quality (quality assurance) forany product to be sold internationally These are called ISO 9000 standards Con-formance with these standards is assured by audit, inspection, and review fromthird-party organizations, called registrars, which receive their accreditation throughindividual countries’ accreditation bodies, approved by the ISO

estab-ISO standards are voluntary between members and are not a legal requirement.They assure that a manufacturer has a quality assurance system in place and thatthe procedures are written, documented, and observed by all employees The ISO

9000 series consists of five quality standards:

1 ISO 9000, ANSI / ASQC Q90 defines the terms and presents principal quality

management and quality assurance practices used in the ISO 9000 series of dards and establishes guidelines for their selection and use This standard is appli-cable to all industries

stan-2 ISO 9001, ANSI / ASQC Q91 establishes models for quality assurance in the

design, development, production, manufacture, installation, and service sectors of

an organization This standard, which is the most comprehensive of the three ternal quality assurance standards, is applicable to organizations that develop andproduce their own products This also applies to construction and engineeringservices.

ex-3 ISO 9002, ANSI / ASQC Q92 establishes models for quality assurance in

pro-duction and installation This standard is applicable to service industries and ufacturers that produce designs and specifications for other organizations

man-4 ISO 9003, ANSI / ASQC Q93 establishes models for quality assurance during

final inspections and testing This standard is applicable to testing laboratories,small shops, divisions within a firm, and equipment distributors that inspect andtest supplied products

5 ISO 9004, ANSI / ASQC Q94 establishes internal organization management

guidelines for design and implementation of quality systems; it is applicable to allindustries

OCCUPATIONAL SAFETY AND HEALTH

ADMINISTRATION (OSHA)

The purpose of OSHA, a division of the Department of Labor, is to establish ulations that control and promote safety in the workplace These regulations pri-marily concern the manufacturing, construction, transportation, and agricultural in-dustries OSHA also determines permissible exposure limits for chemicals andestablishes norms for safety and monitoring procedures where workers are exposed

reg-to hazardous and reg-toxic chemicals These regulations require that all chemicals andhazardous materials be labeled and defined by material safety data sheets (MSDS)

MODEL REGIONAL BUILDING CODES

There are six regional building codes that along with their associated plumbing,mechanical, and fire protection codes have found general acceptance over variouslarge areas of the country They are:

1 Building Officials Code Authority (BOCA) Plumbing Code: BOCA National

Plumbing Code

2 International Association of Plumbing and Mechanical Officials (IAPMO).

Plumbing Code: Uniform Plumbing Code

3 National Association of Plumbing-Heating-Cooling Contractors (PHCC ).

Plumbing Code: National Standard Plumbing Code

4 Southern Building Code Congress International (SBCCI ) Plumbing Code:

Na-tional Standard Plumbing Code

5 Council of American Building Officials (CABO) One and Two Family Dwelling

Code

6 International Conference of Building Officials (ICBO) Plumbing Code: Uniform

Plumbing Code

MANUFACTURERS STANDARDIZATION OF THE

VALVE AND FITTINGS INDUSTRY (MSS )

The MSS is a technical industry association organized for the development andimprovement of industrial, national, and international codes and standards forvalves, valve actuators, pipe fittings, flanges, pipe hangers, and seals Society mem-bership is composed of companies involved in the manufacture of these products.This society is recognized as the technical counterpart of the Valve ManufacturersAssociation and the American Pipe and Fittings Association, two nationally rec-ognized trade associations

Development of standards is a major part of its activities The MSS providestechnical assistance to other standards writing bodies in need of the expertise pro-vided by its members Many standards developed by MSS have been adopted asnational standards, referenced by many codes

NATIONAL ELECTRICAL MANUFACTURERS

ASSOCIATION (NEMA)

NEMA is a nonprofit trade organization that establishes standards for motors, motordimensions, and enclosures and sets minimum performance standards for manyelectrical devices

NATIONAL FIRE PROTECTION ASSOCIATION

(NFPA)

The NFPA (also abbreviated NFiPA to avoid conflict with the National Fluid PowerAssociation) is a scientific and educational organization concerned with the causes,prevention, and control of destructive fire Its purpose is to facilitate and encourageinformation exchange and to enhance the standards development process by pro-viding the broadest possible forum for the consideration of proposed fire safetystandards

The NFPA is the principal source of consensus fire protection standards andcodes These codes and standards are written by voluntary technical committeesand have been recognized by their adaptation and reference by statutory and reg-ulatory law at all levels of government More than 250 separate standards and codes

have been published and are codified in the volumes of the National Fire Codes.

NATIONAL INSTITUTES OF HEALTH (NIH )

The NIH, a division of the Public Health Service, is a government agency sible for biomedical research and science It is one of eight agencies, comprising

respon-24 separate institutes, centers, and divisions each devoted to a separate disease ordisease group Its mission is to discover new knowledge, conduct and fund research,and train research personnel

NATIONAL OCEANIC AND ATMOSPHERIC

ADMINISTRATION (NOAA)

Established as part of the Department of Commerce, NOAA monitors and predictsthe state of the solid earth, the oceans and their living resources, the atmosphere,and the space environment of the earth and assesses the socioeconomic impact ofnatural and technological changes on the environment

NOAA publishes various types of scientific and technical information Of mary importance to facilities are technical memoranda, which report on researchand technology results, and the atlas, which presents analyzed data generally in theform of maps showing distribution of rainfall

pri-NUCLEAR REGULATORY COMMISSION (NRC )

Created in 1975, the NRC is the government agency responsible for protecting thepublic health and safety relating to the use and disposal of nuclear material TheNRC regulates all industrial, commercial, and institutional uses of nuclear materialincluding power plants Services include the establishment of standards and regu-lations for the use and disposal of nuclear material, licenses for the use of nuclearmaterial, and inspection of users to assure compliance with the applicable rules andregulations and the terms of individual license agreements The NRC also providesservices to states when a request is made and regulatory criteria and regulationsare in place

NATIONAL SANITATION FOUNDATION,

INTERNATIONAL (NSF )

The NSF is an independent, not-for-profit organization of scientists, engineers, andeducators It is a neutral agency serving government, industry, and consumers inachieving solutions to problems relating to public health and the environment Ser-vices include development of consensus standards, voluntary product testing, andcertification of products in conformance with NSF standards

In general, compliance with NSF standards is required for any material or ponent that is intended to process or prepare food, clean food-processing equipment,

com-or carry potable water

UNDERWRITERS LABORATORIES (UL)

Underwriters Laboratories is an independent, public service corporation, originallyfounded in 1968 by the life insurance industry

Its purpose is the promotion of public safety through scientific investigation,study, experiments, and tests to determine the relative safety of various materials,devices, products, equipment, constructions, methods, and systems

UL develops specifications and standards for materials, products, and equipmentaffecting the safety of the public It tests items to conform with nationally recog-nized standards, and approves such items if acceptable

3-A STANDARDS

3-A Standards have been prepared by three organizations with input from the PublicHealth Service:

1 International Association of Milk, Food, and Environmental Sanitarians

2 The Milk Industry Foundation

3 Dairy and Food Industries Supply Association

In an abbreviated form, the standard mandates the following:

1 Material of construction shall be 18-8 stainless steel with a carbon content of

not more than 12 percent, or of a material of equal corrosion resistance

2 Thickness or gauge of the material shall be sufficient for the purpose intended.

3 Surfaces in contact with product shall have a number 4 finish or smoother This

is the equivalent of an 80 to 150 grit finish, or an Ra value of 20 to 25 croinches (␮in)

mi-4 No threads shall contact product.

5 Square corners shall be avoided.

6 Piping shall be sloped to drain properly.

7 Design shall permit interchangeable parts.

Many pharmaceutical applications, particularly for pure water systems, are quired by cGMP to exceed these requirements This requires that metal surfaces bepolished to a 150 to 240 grit (32 to 18␮in) finish to eliminate bacterial growth

PIPE AND COMPONENT SELECTION

When renovating an existing facility or where circumstances require a uniquedesign, it may be necessary to request a deviation from the accepted list of materials

in order to match existing piping or obtain special design characteristics The thorities reviewing such requests require enough information to determine that theintent of the applicable code provisions is followed in terms of safety and suitability

au-of materials for the purpose intended

Applicable plumbing and model building codes are discussed in Chap 9,

‘‘Plumbing Systems.’’

Other Code Requirements

Codes required for systems other than plumbing are generally the following:

1 ANSI B31.l-9 series

2 FDA requirements, such as cGMP

3 Sanitary 3-A Standards for the food and pharmaceutical industries

PRESSURE AND TEMPERATURE RATINGS

The pressure rating for a wide range pipe and other components is provided by theANSI Pressure Classification System, which publishes qualitative performance stan-dards The design pressure is the maximum sustained (steady-state) pressure that apiping system must contain without exceeding its code-defined stress limits.The design temperature of a component must be equal to or greater than themaximum sustained temperature that will be experienced during any normal orabnormal mode of operation Normal operating temperature is the temperaturemaintained by the system while it is operating at steady-state, full-load, nontransientoperation It is the temperature at which the allowable stress is calculated

The total installed cost of the network includes the piping material cost, assembly

of the joint selected, handling due to the weight of the material, physical damageallowance, and the support system required

CORROSION RESISTANCE

Corrosion is the thinning of a pipe wall (usually) caused by a chemical reactionfrom a corroding fluid or agent and is limited almost exclusively to metal products.Corrosion resistance is the ability of a pipe to resist the internal corrosive effects

of the fluid flowing through it, as well as the external corrosive forces on the pipe,for example, soils (if underground) or surrounding atmospheric conditions (wheninstalled above ground) Corrosion can be reduced or eliminated with the applica-tion of suitable coatings, linings, and cathodic protection, depending on the nature

of the problem Since there is no universal corrosion-resistant material, the selection

of a specific grade or class of pipe material with specific alloys to resist expectedcorrosion resulting from specific fluids within a pipe is a matter of tradeoffs unique

to each project

Corrosion is separated into two basic types: general and localized General rosion describes the potential dissolution of pipe over its entire exposed surface.Localized corrosion affects only a small area of the pipe surface

cor-General Corrosion

This is a breakdown of the pipe material at a uniform rate over its entire surface

by direct chemical attack It is caused by the loss of the protective passive film thatforms on the surface of the pipe coupled with a chemical reaction occurring betweenthe pipe material and the chemical in the fluid

Galvanic Corrosion. This type of corrosion occurs in a liquid medium (called anelectrolyte) when a more active metal (anode) and a less active metal (cathode)come in contact with one another and form an electrode potential When this occurs,the more active (noble) metal will tend to dissolve in the electrolyte and go intosolution This is shown in the galvanic series of metals (Table 2.1)

Intergranular Corrosion. This type of corrosion occurs in the pipe wall whenmaterial in the grain boundary of some alloys is less resistant to the corroding agentthan the grains themselves, and the bond between the grains is destroyed

Erosion Corrosion. This is caused by a wearing away of the pipe wall, usually

as a result of excessive fluid velocity or impingement by suspended solids

Localized Corrosion

This takes place on small areas of the surface, usually at high rates, and takesvarious forms:

Stress-Corrosion Cracking. This type of corrosion is the physical deteriorationand cracking of the pipe wall caused by a combination of high operating temper-ature, tensile stress on the pipe, and chemicals in the fluid stream.

Pitting. This is characterized by deep penetration of the metal at small areas ofthe surface, concentrating in small cells, without affecting the entire surface

Crevice Attack Corrosion. This occurs at junctions between surfaces (often calledcrud traps) where a crack exists that allows an accumulation of a corroding agent.Corrosion failure occurs if any pipe material is reduced to a minimum thicknessmandated by code

Manufacturers of pipes and fittings publish corrosion-resistance tables ing chemical resistance and compatibility with fluids carried by the piping theyproduce These relate to temperature, concentration, and specific chemicals Thesetables should be used for selection of a specific pipe to transport any specificchemical

be selected

AVAILABILITY

Any pipe is considered available when it can be supplied at a competitive price tothe area where the project is under construction In addition, obtaining the me-chanics and special tools needed to assemble the piping system must also be pos-sible

METALLIC PIPE AND PIPING MATERIALS

ALUMINUM (Al )

Aluminum pipe is manufactured in various wall thicknesses similar to copper and

in sizes ranging from1⁄8to 12 in Sizes above 3 in are not readily available minum is manufactured in various alloys; the most commonly used for facilitiesconforms to ASTM B-210 Joints are made using brazing or welding with specialaluminum alloy filler metals

Alu-Aluminum tubing is light in weight and generally used for specialty services,such as cryogenics (where ductility and strength are necessary) and for carryingcompressed specialty gases (because of its corrosion resistance) It also resists manyspecialty chemicals and is resistant to atmospheric corrosion It is not suitable foracids, mercury, and strong alkalis It has a high rate of expansion

For a list of various alloys, refer to Table 2.2

BRASS (BR)

Brass is an alloy of copper and zinc The proportion varies from 85% copper to

67% copper Pipe with a high copper content is known as red brass, and that with

a lower content is known as yellow brass When used for drainage systems, it isobtained plain end Joints for this pipe can be either threaded, flanged, brazed, orsoldered Brass pipe for utility piping systems shall conform to ASTM B 43: RedBrass Tube, Seamless

Brass is generally used for local branch drainage lines, where this alloy willresist specific corrosive drainage effluent and, in larger sizes, for potable and otherwater supply lines and to match existing work for alterations Its advantages anddisadvantages are the same as for copper

Brass castings for pipe fittings and components of plumbing fixtures are notmade with the same alloy as pipe and often contain lead Pipe is lead free and brassfittings with lead are no longer permitted by code to be used for potable water

CAST IRON SOIL PIPE (CI )

Technically known as gray cast iron, this pipe is a ferrous material alloyed withcarbon in the form of free graphite flakes, silicon, and other impurities It is avail-able in three classifications: service (standard) weight, extra heavy, and hubless.The pipe is commonly lined internally with cement or coal tar enamel, and coatedexternally with a variety of materials to reduce corrosion by soils

Joints require two types of pipe ends: hub and spigot or hubless The hub andspigot ends can be joined either by caulking or by the use of an elastomeric com-pression gasket Hubless pipe is joined by an external compression coupling.Cast iron soil pipe should conform to the following standards:

1 ASTM A 74: Hub and Spigot Cast Iron Soil Pipe and Fittings

2 CISPI 301: Hubless Cast Iron Soil Pipe

3 CISPI 310: Hubless Cast Iron Fittings for Soil Pipe

Cast iron is well suited for sanitary effluent and can be used in any part of agravity drainage and vent system Advantages include an ability to withstand mod-erate external pressure (such as direct burial in soil), good fire resistance, good flowcharacteristics, and good corrosion resistance in most natural soils Piping in usefor over 100 years has been documented Disadvantages are that the pipe is brittleand subject to breakage when roughly handled, it is subject to corrosive attack byaggressive soils and highly septic effluent, it is heavy, and it has a high initialmaterial cost

Cast iron pipe is manufactured with both inside and outside coated for corrosionresistance A PE wrapping is often used to eliminate external corrosion of cast ironpipe buried underground on a site

ACID-RESISTANT CAST IRON (AR)

Commonly referred to as high silicon iron pipe, acid-resistant CI is an alloy of graycast iron containing between 14.25 and 15% silicon, and small amounts of man-ganese, sulfur, and carbon It is available only in extra heavy pattern, with the samedimensions as CI piping

Joints require two types of pipe ends: hub and spigot or hubless The hub andspigot ends can be joined by caulking Rubless pipe is joined by a compressioncoupling

Acid-resistant cast iron pipe shall conform to ASTM A 861 and ASTM A 518.This specialty piping material is used for drainage of various corrosive liquids,and since it is stronger than glass, is recommended for exposed or undergroundapplications where there is a possibility of physical damage

CARBON STEEL (ST )

Steel is a very broad category of piping because of the large number of alloys thathave been produced It is divided into two broad categories according to the method

of manufacture: mill pipe and fabricated pipe Mill pipe is produced to meet finishedpipe specifications Fabricated pipe is manufactured from steel plate with spiral orstraight welded seams.

Steel pipe is manufactured by either the seamless (extruded) or welded method,and is available either plain (black) or galvanized (zinc plated inside, outside, orboth) Wall thickness is expressed as ‘‘schedule,’’ and ranges from schedule 5 (light-est) to schedule 160 The wall thickness varies with the size of the pipe The largerthe schedule number, the thicker the pipe wall for a specific pipe size

Steel pipe, depending upon type, can be obtained with threaded ends for screwedfittings, plain ends, and flanged and beveled ends for welding

There is an extremely large number of steel pipe alloys available The selectiondepends on the intended service The steel pipe alloys most commonly used forservice and utility systems conform to ASTM A 53: Steel Pipe, Welded or Seam-less, Black or Galvanized and ASTM A-106: Steel Pipe, Welded or Seamless, Black

or Galvanized

Steel pipe is generally used for pressure piping Its advantages are long layinglengths, high internal and external strength, and the availability of varying pipethickness to meet almost any design pressure It has good flow characteristics andfire resistance and is low in initial cost The most serious disadvantage is lowcorrosion resistance This requires internal and external protection, with galvanizingthe most commonly used method

COPPER

Copper tubing is seamless, made from almost pure copper (99.9 percent), and isavailable in hard (annealed) and soft (drawn) form It is manufactured in sizesranging from1⁄8to 12 in, but sizes over 6 in are not generally available All tubing

is manufactured with plain ends only Joints are made by soldering, and brazing,and with flared and flanged fittings

The six types of copper tubing used most often are:

1 ASTM B-88 is the grade used most often for potable water, and also for

compressed gases and vacuum systems where high purity is not a factor It isseamless, available in nominal pipe sizes from3⁄8to 12 in, in hard and soft temper,and in three wall thickness grades—K (thickest wall), L, and M (thinnest wall) Ifpatented flare fittings are used, the pipe must be obtained without outside diameterembossing, which would interfere with the sealing of the pipe wall against the side

of the fitting

2 ASTM B-819 is similar to B-88, except that it is available only in grades K

and L and, in addition, the pipe is factory cleaned, capped, and specially marked.This pipe is required to be used for medical gas systems in health-care facilities

It should also be considered as the primary copper pipe for gases in laboratories

as well

3 ASTM B-75 is seamless, available as either hard or drawn, and in nominal

sizes from1⁄8to 2 in O.D The smaller sizes are often referred to as capillary tubing.This is the grade most often used for very small diameter pipe [1⁄4in O.D (6 mm)

or less] connecting instruments to the distribution piping This pipe is commonlyjoined by patented flare joints, which require temper 060 to seal correctly.

4 ASTM B-280, type ACR (air conditioning and refrigeration), is available

cleaned and capped for field refrigeration piping and could also be considered forlaboratory use It is available only in hard temper, and its size is the actual O.D

of the pipe This requires that all non-ACR fittings used in the system, which aremanufactured in nominal pipe size, be dimensionally compatible with the ACRpipe, which is manufactured in actual pipe size

5 ASTM B-306, copper drainage tube, is known as DWV (drainage, waste, and

vent) This designation applies to copper tube used for nonpressure drainage tems This tube has the thinnest wall of any copper product The preferred jointingmethod is soldering, which is adequate in strength and the least costly Primary use

sys-is in residential construction as indirect waste lines and in larger projects for localbranch lines where human waste is not discharged Advantages are its light weight,ease of assembly, and smooth interior Disadvantages include corrosive attack byordinary sewage, poor fire resistance, and the need for dielectric connections toeliminate galvanic corrosion where this material is connected to any iron piping

6 ASTM B-837 Type G is seamless tube, available in either hard (drawn) or

soft (annealed) temper, and in nominal sizes from3⁄8to 11⁄8-in O.D This tubing isidentified by the O.D rather than nominal size This grade is manufactured specif-ically for natural gas and LP fuel gas systems Fittings shall be similar to thoseused with type ACR copper The pipe is joined by either brazing or flare type joints.Brazed joints are required for system pressures above 14 in WC where installed ininaccessible locations Brazing alloys shall contain less than 0.05 percent phospho-rus

DUCTILE IRON PIPE (DI )

Ductile iron is a cast ferrous material alloyed with free nodular or spheroidal ite in lieu of the flakes that are present in cast iron This is achieved by the addition

graph-of a magnesium inoculant It is used either as a gravity sewer or pressure pipe.Sizes available range from 3 to 54 in There are eight pressure ratings—class 50(125 psi) to class 56 (350 psi), and gravity sewer pipe A cement or bituminouslining can be provided to resist internal corrosion This pipe can be assembled withmechanical, gasketed, or flanged joints Ductile iron pipe shall conform to ASTM

A 518 and ASTM A 861

The advantages of ductile iron are the same as those for CI pipe, except that it

is far stronger in terms of allowable pressure ratings and external load-bearingcapacity It is also not as brittle, allowing rougher handling It has a higher initialcost than CI

LEAD (LD)

Lead pipe is made from 99.7% pig lead with various alloys available for specialapplications Joints for this pipe are either wiped, burned, or mechanically flanged.Lead pipe shall conform to WW-P-325a: Lead Pipe, Bends and Traps

Uses of lead pipe include existing connections to floor-mounted water closets,radioactive wastes, and special laboratory corrosive wastes It has very limited use

in modern drainage systems

STAINLESS STEEL (SS )

The term stainless steel encompasses a wide variety of alloys containing 11 to 30%

chromium (Cr), 0 to 35% nickel (Ni), and 0 to 6% molybdenum (Mo) in variouscombinations as well as small amounts of other elements such as titanium, man-ganese, niobium, and nitrogen It is widely used in the chemical, pharmaceutical,and food processing industries

Pipe is available in sizes ranging from1⁄8to 48 in, and is manufactured in plainend, prepared end for welding, and flanged Joints can be welded, threaded, orflanged Wall thickness is expressed as a ‘‘schedule,’’ and ranges from schedule 5(lightest) to schedule 160 The wall thickness varies with the size of the pipe Thelarger the schedule number, the thicker the pipe wall for a specific pipe size Stain-less steel pipe is also available as tubing with wall thickness designated as a dec-imal

The composition of a stainless steel alloy determines its metallurgical structure

or grade, and therefore its properties There are five groups of stainless steel based

on metallurgical structure: ferritic, austenitic, superaustenitic, martensitic, and plex

du-1 Ferritic stainless steels contain 12 to 30% (more typically 16 to 18%) Cr, 0

to 4% Ni, and 0 to 4% Mo with a low carbon content This material is magneticand has good ductility and cold formability but is not hardenable by heat treatment.This class is generally less vulnerable to chloride-induced stress corrosion cracking.Its primary use is in transport of strong oxidizing fluids (such as nitric acid) inprocess environments, machinery, and kitchen equipment This class is exemplified

by type ASTM grade 430

2 Austenitic stainless steels contain 17 to 27% Cr, 8 to 35% Ni, and 0 to 6%

Mo This material is typically nonmagnetic and readily weldable, and has goodductility (even at cryogenic temperatures) and cold formability but is not hardenable

by heat treatment This class is more generally corrosion resistant, but is generallyvulnerable to chloride-induced stress corrosion cracking Regular carbon grades aresusceptible to corrosion around welded joints due to migration of Cr away fromthe weld site These problems are overcome by using a low carbon grade, indicated

by an L suffix, that reduces carbon to below 0.035 percent Grades within this classare the most commonly used stainless steels This class is exemplified by typeASTM grades 304 and 316 (304L and 316L) A superaustenitic grade is also avail-able with superior resistance to chloride pitting

3 Superaustenitic stainless steel alloys were created to better withstand

corro-sion in a more severe environment than conventional stainless steel They are alloys

of Ni, Cr, Mo, copper, and iron typified by UNS (Unified Numbering System) alloysN08020, N08024, and N08026

4 Martensitic stainless steels contain 11 to 18% Cr, 0 to 6% Ni, 0 to 2% Mo,

and 0.1 to 1% C This class is magnetic, oxidation resistant, and hardenable byheat treatment Little used in piping applications, its primary uses are in cutlery,turbine blades, and high-temperature parts This class is exemplified by type ASTMgrade 410

5 Duplex stainless steel is characterized by a microstructure containing both

ferritic and austenitic types with different grades, having a mixture of 40 to 60%

of each for various alloys Its advantages are good resistance to chloride-inducedstress corrosion cracking and high mechanical strength properties along with goodductility and impact strength Disadvantages include corrosion of pipe by reducingacids and weld site corrosion by oxidizing acids

Stainless steel is available in various wall thicknesses Pipe is commonly able from schedule 5 to 80, and tubing from 0.028 to 0.188

avail-Stainless Steel Finishes

For stainless steel piping used in pharmaceutical, food-processing, chemical, andelectronics applications, the interior and exterior of the piping are often required to

be finished as required by FDA, EPA, USDA, or other applicable codes Finishingthe exterior makes it easier to keep clean Finishing the interior will prevent theadherence of any solids, increase corrosion protection, and shorten pipe interiorcleaning procedures Finishing can be abrasive, electropolished, or both

Abrasive finishes are mechanically produced by polishing and wearing away ofthe surface This is often specified by a particular size or ‘‘grit’’ of the abrasiveused, such as a 220 grit This signifies the size of the abrasive passing through aspecific size mesh The larger the number, the finer the finish Electropolishing is

an electrochemical process using an electrical current to deposit metal from ananode to a cathode Electropolishing, which is the opposite of electroplating, re-moves surface metal from microscopic high points faster than from low points Themetal to be polished is the sacrificial anode Surface ions of iron are removedleaving a chromium-rich surface resulting in a smooth, corrosion-resistant pipe in-terior Another method used to specify standard sheet and pipe exterior finishes usesnumbers 1 to 8 An explanation of sheet finishes is given in Table 2.3 Table 2.4gives the grit equivalent of microinch measurement

Finishes are often indicated as Ra (arithmetic mean roughness average, or ness average) and Rq, the equivalent of RMS (root mean square) Both of these aremeasured in microinches and denote the smoothness of the surface The smallerthe number, the finer and finish The Ra reading is approximately 87.5 percent ofthe Rq (RMS) reading Other methods of expressing smoothness are centerlineaverage (CLA) and arithmetic average (AA)

CORRUGATED STEEL PIPE

Corrugated steel pipe is available from 6 in (125 mm) to 96 in (2.66 m) It isfabricated from flat steel that has been rolled into various shapes and impressedwith grooves around the circumference of the pipe, generally described as circulararcs connected by tangents Corrugations are measured by pitch (the dimensionfrom crest to crest at right angles to the corrugations) and depth

Longitudinal pipe seams are riveted, welded, bolted or have helical lock seams.Joints are generally steel bands with a gasket under the sleeve and tightened bybolts inserted in an integral angle Fittings are usually made from straight pipingand shop fabricated into the desired shape.

Corrugated steel pipe shall conform to different AASHTO standards depending

on the actual pipe material specification

OTHER METALLIC PIPING MATERIALS

The chemical compositions of various metal piping materials selected for specialcorrosion-resistant characteristics are given in Table 2.5