MATERIALS lec ( 3 )

1. INTRODUCTION
This chapter covers the most commonly used materials of construction
for piping systems within a process plant.
The two principal international codes used for the design and
construction of a process plant are ASME B31.3, Process Piping, and
the ASME Boiler and Pressure Vessel Code Sections.
Generally, only materials recognized by the American Society of
Mechanical Engineers (ASME) can be used as the ‘‘materials of
construction’’ for piping systems within process plants, because they
meet the requirements set out by a recognized materials testing body, like
the American Society of Testing and Materials (ASTM).
There are exceptions, however; the client or end user must be satisfied
that the non-ASTM materials offered are equal or superior to the ASTM
material specified for the project.
The Unified Numbering System (UNS) for identifying various alloys is
also quoted. This is not a specification, but in most cases, it can be crossreferenced
to a specific ASTM specification.
1.1. American Society of Testing and Materials
The American Society of Testing and Materials specifications
cover materials for many industries, and they are not restricted to the
process sector and associated industries. Therefore, many ASTM
specifications are not relevant to this book and will never be referred to
by the piping engineer.
We include passages from a number of the most commonly used
ASTM specifications. This gives the piping engineer an overview of the
specifications and scope in one book, rather than several ASTM books,
which carry specifications a piping engineer will never use.
It is essential that at the start of a project, the latest copies of all the
relevant codes and standards are available to the piping engineer.
All ASTM specification identifiers carry a prefix followed by a
sequential number and the year of issue; for example, A105/A105M-02,
Standard Specification for Carbon Steel Forgings for Piping Applications,
breaks down as follows:
A ¼ prefix.
105 ¼ sequential number.
M means that this specification carries metric units.
02 ¼ 2002, the year of the latest version.
Official title ¼ Standard Specification for Carbon Steel Forgings for Piping
Applications.
The complete range of ASTM prefixes are A, B, C, D, E, F, G, PS, WK;
however, the piping requirements referenced in ASME B31.3, which is
considered our design ‘‘bible,’’ call for only A, B, C, D, and E.
The requirements of an ASTM specification cover the following:
. Chemical requirements (the significant chemicals used in the production
and the volumes).
. Mechanical requirements (yield, tensile strength, elongation, hardness).
. Method of manufacture.
. Heat treatment.
. Weld repairs.
. Tolerances.
. Certification.
. Markings.
. Supplementary notes.
If a material satisfies an ASTM standard, then the various characteristics
of the material are known and the piping engineer can confidently use the
material in a design, because the allowable stresses and the strength of
the material can be predicted and its resistance against the corrosion
of the process is known.
1.2. Unified Numbering System
Alloy numbering systems vary greatly from one alloy group to the
next. To avoid confusion, the UNS for metals and alloys was developed.
The UNS number is not a specification, because it does not refer to the
method of manufacturing in which the material is supplied (e.g., pipe
bar, forging, casting, plate). The UNS indicates the chemical composition
of the material.
An outline of the organization of UNS designations follows:

In this chapter, the ASTM specification is the most common reference in
the design of process plants. Extracts from a number of the most
commonly used ASTM specifications are listed in the book, along
with the general scope of the specification and the mechanical
requirements.
For detailed information, the complete specification must be referred
to and the engineering company responsible for the design of the plant
must have copies of all codes and standards used as part of their
contractual obligation.
1.3. Manufacturer’s Standards
Several companies are responsible for inventing, developing, and
manufacturing special alloys, which have advanced characteristics that
allow them to be used at elevated temperatures, low temperatures, and in
highly corrosive process services. In many cases, these materials were
developed for the aerospace industry, and after successful application,
they are now used in other sectors.
Three examples of such companies are listed below:
. Haynes International, Inc.—high-performance nickel- and cobalt-based
alloys.
. Carpenter Technology Corporation—stainless steel and titanium.
. Sandvik—special alloys.
1.4. Metallic Material Equivalents
Some ASTM materials are compatible with specifications from other
countries, such as BS (Britain), AFNOR (France), DIN (Germany), and
JIS (Japan). If a specification from one of these other countries either
meets or is superior to the ASTM specification, then it is considered a
suitable alternative, if the project certifications are met.
1.5. Nonmetallic Materials
In many cases, nonmetallic materials have been developed by a major
manufacturer, such as Dow Chemical, ICI, or DuPont, which holds the
patent on the material. This material can officially be supplied only by
the patent owner or a licensed representative.
The patent owners are responsible for material specification, which
defines the chemical composition and associated mechanical characteristics.
Four examples of patented materials that are commonly used in
the process industry are as follows:
. Nylon, a polyamide, DuPont.
. Teflon, polytetrafluoroethylene, DuPont.
. PEEK, polyetheretherketone, ICI.
. Saran, polyvinylidene chloride, Dow.
Certain types of generic nonmetallic material covering may have several
patent owners; for example, patents for PVC (polyvinyl chloride) are
owned by Carina (Shell), Corvic (ICI), Vinoflex (BASF), and many
others. Each of these examples has unique characteristics that fall into
the range covered by the generic term PVC. To be sure of these
characteristics, it is important that a material data sheet (MDS) is
obtained from the manufacturer and this specification forms part of the
project documentation.
2. MATERIALS SPECIFICATIONS
Listed below are extracts from the most commonly used material
specifications referenced in ASME B31.3.
ASTM, A53/A53M-02 (Volume 01.01), Standard
Specification for Pipe, Steel, Black and Hot-
Dipped, Zinc-Coated, Welded and Seamless
Scope.
1.1 This specification covers seamless and welded black and hot-dipped
galvanized steel pipe in NPS 1⁄8 to NPS 26 (DN 6 to DN 650) for the
following types and grades:
1.2.1 Type F—furnace-butt welded, continuous welded Grade A.
1.2.2 Type E—electric-resistance welded, Grades A and B.
1.2.3 Type S—seamless, Grades A and B.
Referenced Documents
ASTM
A90/A90M, Test Method for Weight [Mass] of Coating on Iron and Steel
Articles with Zinc or Zinc-Alloy Coatings.
A370, Test Methods and Definitions for Mechanical Testing of Steel
Products.
A530/A530M, Specification for General Requirements for Specialized
Carbon and Alloy Steel Pipe.
A700, Practices for Packaging, Marking, and Loading Methods for Steel
Products for Domestic Shipment.
A751, Test Methods, Practices, and Terminology for Chemical Analysis of
Steel Products.
A865, Specification for Threaded Couplings, Steel, Black or Zinc-Coated
(Galvanized) Welded or Seamless, for Use in Steel Pipe Joints.
B6, Specification for Zinc.
E29, Practice for Using Significant Digits in Test Data to Determine
Conformance with Specifications.
E213, Practice for Ultrasonic Examination of Metal Pipe and Tubing.
E309, Practice for Eddy-Current Examination of Steel Tubular Products
Using Magnetic Saturation.
E570, Practice for Flux Leakage Examination of Ferromagnetic Steel
Tubular Products.
E1806, Practice for Sampling Steel and Iron for Determination of Chemical
Composition.
ASC Acredited Standards Committee X12.
ASME
B1.20.1, Pipe Threads, General Purpose.
B36.10, Welded and Seamless Wrought Steel Pipe.
Military Standard (MIL)
STD-129, Marking for Shipment and Storage.
STD-163, Steel Mill Products Preparation for Shipment and Storage.
Fed. Std. No. 123, Marking for Shipment (Civil Agencies).
Fed. Std. No. 183, Continuous Identification Marking of Iron and Steel
Products.
American Petroleum Institute (API)
5L, Specification for Line Pipe.
Methods of Manufacture. Open hearth (OH), electrofurnace (EF), basic
oxygen (BO).
Chemical Requirements. Refer to ASTM A53/A53M.
Mechanical Requirements. These are extracted from ASTM A53/A53M:

ASTM, A106-02a (Volume 1.01), Standard
Specification for Seamless Carbon Steel Pipe
for High-Temperature Service
Scope. This specification covers seamless carbon steel pipe for hightemperature
service (Note: It is suggested that consideration be given to
possible graphitization) in NPS 1⁄8 –NPS 48 inclusive, with nominal
(average) wall thickness as given in ANSI B 36.10. It is permissible to
furnish pipe having other dimensions provided such pipe complies with all
other requirements of this specification. Pipe ordered under this
specification is suitable for bending, flanging, and similar forming
operations and for welding.Whenthe steel is to be welded, it is presupposed
that a welding procedure suitable to the grade of steel and intended use or
service is utilized (Note: The purpose for which the pipe is to be used should
be stated in the order. Grade A rather than Grade B or Grade C is the
preferred grade for close coiling or cold bending. This note is not intended
to prohibit the cold bending of Grade B seamless pipe).
Referenced Documents
ASTM
A530/A530M, Specification for General Requirements for Specialized
Carbon and Alloy Steel Pipe.
E213, Practice for Ultrasonic Examination of Metal Pipe and Tubing.
E309, Practice for Eddy-Current Examination of Steel Tubular Products
Using Magnetic Saturation.
E381, Method of Macroetch Testing, Inspection, and Rating Steel Products,
Comprising Bars, Billets, Blooms, and Forgings.
A520, Specification for Supplementary Requirements for Seamless and
Electric-Resistance-Welded Carbon Steel Tubular Products for High-
Temperature Service Conforming to ISO Recommendations for Boiler
Construction.
E570, Practice for Flux Leakage Examination of Ferromagnetic Steel
Tubular Products.
ASME
B36.10, Welded and Seamless Wrought Steel.
Methods of Manufacture. Open hearth (OH), electrofurnace (EF), basic
oxygen (BO).
Chemical Requirements. Refer to from ASTM A106/A106M.
Mechanical Requirements. These are extracted from ASTM A106/
A106M:

ASTM, A126-95 (2001) (Volume 01.02), Standard
Specification for Gray Iron Castings for Valves,
Flanges, and Pipe Fittings
Scope. This specification covers three classes of gray iron for castings
intended for use as valve pressure retaining parts, pipe fittings, and flanges.
Referenced Documents
ASTM
A438, Test Method for Transverse Testing of Gray Cast Iron.
A644, Terminology Relating to Iron Castings.
E8, Test Methods for Tension Testing of Metallic Materials.
A48, Specification for Gray Iron Castings.
Sizes. Varies.
Heat Treatment. Refer to ASTM A126/A126M.
Welding Repair. For repair procedures and welder qualifications, see
ASTM A488/A488M.
Chemical Requirements. Refer to ASTM A126/A126M.
MechanicalRequirements. Theseare extractedfromASTMA126/A126M:

WHAT IS A PIPING MATERIAL ENGINEER lec ( 1 )

This chapter explains briefly the role of the piping engineer, who is
responsible for the quality of piping material, fabrication, testing, and
inspection in a project and the major activities such engineers are
expected to perform. This individual can be employed by either the EPC
(engineering, procurement, and construction) contractor or the operator/
end user.
1.1. Job Title
The piping engineer, the individual responsible for creating the project
piping classes and the numerous piping specifications necessary to
fabricate, test, insulate, and paint the piping systems, is titled either the
piping material engineer or the piping spec(ification) writer.
1.2. Job Scope
Whatever the title, the piping material engineer (PME) is a very
important person within the Piping Design Group and should be

dedicated to a project from the bid stage until the design phase has been
completed. He or she should also be available during construction and
through to mechanical completion.
The lead piping material engineer, the individual responsible for all
piping engineering functions, usually reports directly to the project lead
piping engineer, and depending on the size of the project, the lead piping
material engineer may be assisted by a number of suitably qualified
piping material engineers especially during the peak period of the
project. This peak period is early in the job, while the piping classes are
being developed and the first bulk inquiry requisitions are sent out to
vendors.
1.3. The Piping Material Engineer’s
Responsibilities
The piping material engineer’s responsibilities vary from company to
company. Here is a list of typical functions that he or she is expected to
perform:
. Develop the project piping classes for all process and utility services.
. Write specifications for fabrication, shop and field testing, insulation, and
painting.
. Create and maintain all data sheets for process and utility valves.
. Create a list of piping specials, such as hoses and hose couplings, steam
traps, interlocks.
. Create and maintain data sheets for these piping special (SP) items.
. Assemble a piping material requisition with all additional documents.
. Review offers from vendors and create a technical bid evaluation.
. Make a technical recommendation.
. After placement of a purchase order, review and approve documentation
from vendors related to piping components.
. When required, visit the vendor’s premises to attend kickoff meetings, the
testing of piping components, or clarification meetings.
. Liaise with the following departments: Piping Design and Stress, Process,
Instrumentation, Vessels, Mechanical, Structural, Procurement, Material
Control.
1.4. Qualities of an Engineer
Not only is it essential that a piping material engineer be experienced
in several piping sectors, such as design, construction, and stress, he or
she must also be a good communicator, to guarantee that everyone in the
piping group is aware of the materials of construction that can be used
for piping systems.
The PME must also have a basic understanding of other disciplines
having interface with the piping, such as mechanical, process,
instrumentation, and structural engineering. He or she should also be
aware of the corrosion characteristics of piping material and welding
processes necessary for the fabrication of piping systems. Both corrosion
and welding engineering are specialist subjects, and if the PME has any
doubts, he or she must turn to a specialist engineer for advice.
1.5. Experience
There is no substitute for experience, and the piping material engineer
should have strengths in several sectors and be confident with a number
of others disciplines, to enable the individual to arrive at a suitable
conclusion when selecting material for piping systems.
Strong areas should include piping design layout and process
requirements. Familiar areas should include the following:
. Corrosion.
. Welding.
. Piping stress.
. Static equipment.
. Rotating equipment.
. Instruments.

PIPING MATERIAL ENGINEER’S
ACTIVITIES

Outlined here are the principal activities of a piping material engineer.
These are listed in chronological order as they would arise as a project
develops from preliminary to detailed design.

2.1. Development of the Project Piping Classes
All process plants have of two types of principal piping systems:
process (primary and secondary) piping systems and utility piping
systems.
Process piping systems are the arteries of a process plant. They receive
the feedstock, carry the product through the various items of process
equipment for treatment, and finally deliver the refined fluid to the
battery limits for transportation to the next facility for further
refinement. Process piping systems can be further divided into primary
process, which is the main process flow, and secondary process, which
applies to the various recycling systems.
Utility piping systems are no less important. They are there to support
the primary process, falling into three groups:
. Support—instrument air, cooling water, steam.
. Maintenance—plant air, nitrogen.
. Protection—foam and firewater.
There are other utility services such as drinking water.
Piping Classes. Each piping system is allocated a piping class, which lists
all the components required to construct the piping. A piping class
includes the following:
. Process design conditions.
. Corrosion allowance.
. List of piping components.
. Branch table.
. Special assemblies.
. Support notes.
Both process and utility piping systems operate at various temperatures
and pressures, and the following must be analyzed:
. Fluid type—corrosivity, toxicity, viscosity.
. Temperature range.
. Pressure range.
. Size range.
. Method of joining.
. Corrosion allowance.
After analyzing these characteristics, process and utility piping systems
can be grouped into autonomous piping classes. This allows piping
systems that share fundamental characteristics (pipe size range, pressure
and temperature limits, and method of joining) to be classified
together.
This standardization or optimization has benefits in the procurement,
inspection, and construction phases of the project. Too little optimization
increases the number of piping classes, making the paperwork at all
stages of the project difficult to handle and leading to confusion,
resulting in mistakes. Too much optimization reduces the number of
piping classes, however, as the piping class must satisfy the characteristics
of the most severe service and use the most expensive material. This
means that less-severe services are constructed using more-expensive
material, because the piping class is ‘‘overspecified.’’ It is the
responsibility of the piping material engineer to fine-tune this
optimization to the benefit the project.
A typical oil and gas separation process plant may have 10 process
piping classes and a similar number of utility piping classes. Morecomplex
petrochemical facilities require a greater number of piping
classes to cover the various process streams and their numerous
temperature and pressure ranges. It is not uncommon for process plants
such as these to have in excess of 50 process and piping classes.

2.2. Writing Specifications for Fabrication, Shop
and Field Testing, Insulation, and Painting

It is pointless to specify the correct materials of construction if the
pipes are fabricated and erected by poorly qualified labor, using bad
construction methods and inadequate testing inspection, insulation, and
painting.
The piping material engineer is responsible for writing project-specific
narratives covering these various activities to guarantee that they meet
industry standards and satisfy the client’s requirements. No two projects
are the same; however, many projects are very similar and most EPC
companies have corporate specifications that cover these subjects.
2.3. Creating All Data Sheets for Process
and Utility Valves
All valves used within a process plant must have a dedicated valve
data sheet (VDS). This document is, effectively, the passport for the
component, and it must detail the size range, pressure rating, design
temperature, materials of construction, testing and inspection procedures
and quote all the necessary design codes relating to the valve.
This VDS is essential for the efficient procurement and the possible
future maintenance of the valve.
2.4. Creating a List of Piping Specials and Data
Sheets
A piping system generally comprises common components such as
pipe, fittings, and valves; however, less common piping items may be
required, such as strainers, hoses and hose couplings, steam traps, or
interlocks. This second group, called piping specials, must carry an SP
number as an identifying tag.
The piping material engineer must create and maintain a list of SP
numbers that makes the ‘‘special’’ unique, based on type, material, size,
and rating. This means that there could be several 2 in. ASME 150,
ASTM A105 body strainers with the same mesh.
As with valves, each piping special must have its own data sheet, to
guarantee speedy procurement and future maintenance.
2.5. Assembling Piping Material Requisition
with All Additional Documents
When all the piping specifications have been defined and initial
quantities identified by the Material Take-off Group, the piping material
engineer is responsible for assembling the requisition packages.
The Procurement Department will break the piping requirements into
several requisitions, so that inquiry requisitions can be sent out to
manufacturers or dealers that specialize in that particular group of
piping components.
. Pipe (seamless and welded)—carbon and stainless steel.
. Pipe (exotic)—Inconel, Monel, titanium.
. Pipe fittings (seamless and welded)—carbon and stainless steel.
. Valves gate/globe/check (small bore, 11⁄2 in. and below)—carbon and
stainless steel.
. Valves gate/globe/check (2 in. and above)—carbon and stainless steel.
. Ball valves (all sizes)—carbon and stainless steel.
. Special valves (all sizes)—non-slam-check valves, butterfly valves.
. Stud bolting—all materials.
. Gaskets—flat, spiral wound, ring type.
. Special piping items (SPs)—strainers, hoses, hose couplings, sight glasses,
interlocks, and the like.
To get competitive bids, inquiries will go out to several manufacturers
for each group of piping components, and they will be invited to offer
their best price to satisfy the scope of supply for the requisition. This
includes not only supplying the item but also testing, certification,
marking, packing, and if required, shipment to the site.
2.6. Reviewing Offers from Vendors and Create
a Technical Bid Evaluation
Many clients have an ‘‘approved bidders list,’’ which is a selection of
vendors considered suitable to supply material to the company. This
bidders list is based on a track record on the client’s previous projects
and reliable recommendations.
Prospective vendors are given a date by which they must submit a
price that covers the scope of supplies laid out in the requisition. The
number of vendors invited to tender a bid varies, based on the size and
complexity of the specific requisition.
To create a competitive environment, a short list of between three and
six suitable vendors should be considered, and it is essential that these
vendors think that, at all times, they are bidding against other
competitors. Even if, sometimes, vendors drop out and it becomes a
‘‘one-horse race’’ for commercial and technical reasons, all vendors must
think that they are not bidding alone.
All vendors that deliver feasible bids should be evaluated, and it is the
responsibility of the piping material engineer to bring all vendors to the
same starting line and ensure that they are all offering material that
meets the specifications and they are ‘‘technically acceptable,’’ sometimes
called ‘‘fit for purpose.’’

Some vendors will find it difficult, for commercial or technical reasons,
to meet the requirements of the requisition. These vendors are deemed
technically unacceptable and not considered further in the evaluation.
The piping material engineer, during this evaluation, creates a bid
tabulation spreadsheet to illustrate and technically evaluate all vendors
invited to submit a bid for the requisition.
The tabulation lists the complete technical requirements for each item
on the requisition and evaluates each vendor to determine if it is technically
acceptable.
Technical requirements include not only the materials of construction
and design codes but also testing, certification, and painting. Nontechnical
areas also are covered by the piping material engineer, such as
marking and packing. The delivery, required on site (ROS) date, is
supplied by the Material Control Group as part of the final commercial
negotiations.
The Procurement Department is responsible for all commercial and
logistical aspects of the requisition, and the Project Services Group
determines the ROS date and the delivery location. It is pointless to
award an order to a manufacturer that is technically acceptable and
commercially the cheapest if its delivery dates do not meet the
construction schedule.
When this technical bid evaluation (TBE) or technical bid analysis
(TBA) is complete, with all technically acceptable vendors identified,
then it is turned over to the Procurement Department, which enters into
negotiations with those vendors that can satisfy the project’s technical
and logistical requirements.
After negotiations, a vendor is selected that is both technically acceptable
and comes up with the most competitive commercial/logistical offer. The
successful vendor is not necessarily the cheapest but the one that
Procurement feels most confident with in all areas. What initially looks to
be the cheapest might, at the end of the day, prove more expensive.
2.7. After Placement of a Purchase Order,
Reviewing and Approving Documentation
Related to All Piping Components

The importance of vendor documentation after placement of an order
must not be underestimated. It is the vendor’s responsibility to supply
support documentation and drawings to back up the material it is
supplying. This documentation includes an inspection and testing plan,
general arrangement drawings, material certification, test certificates,
and production schedules.
All this documentation must be reviewed by the piping material
engineer, approved and signed off, before final payment can be released
to the vendor for the supply of the material.
2.8. Vendor Visits
The piping material engineer may be required to visit the vendor’s
premises to witness the testing of piping components or attend clarification
meetings.
Certain piping items are more complex than others, either because of
their chemical composition and supplementary requirements or their
design, size, or pressure rating. In these cases, the relevant purchase
order requires a greater deal of attention from the piping material
engineer to ensure that no complications result in incorrect materials
being supplied or an unnecessary production delay.
To avoid this, the following additional activities should be seriously
considered:
. A bid clarification meeting to guarantee that the prospective vendor fully
understands the requisition and associated specification.
. After the order has been placed, a preinspection meeting to discuss
production, inspection, and quality control.
. Placing the requisition engineer in the vendor’s facilities during critical
manufacturing phases of the job to ensure that the specifications are
understood.
. Placing an inspector in the vendor’s facilities, who is responsible for the
inspection and testing of the order and coordinates with the piping
material engineer in the home office to guarantee that the specifications
are understood and being applied.
The first two are low-cost activities and should be a formality for most
purchase orders, the last two are more-expensive activities and should be
considered based on the complexity of the order or the need for long lead
items.
No two requisitions are the same, and a relatively simple order with a
new and untried vendor may require more consideration than a complex
order with a vendor that is a known quantity. The decision to make
vendor visits also relates to the size of the inspection budget, which might
not be significant enough to support ‘‘on-premises’’ personnel during the
manufacturing phase.
Remember that if the wrong material arrives on site, then the replacement
cost and the construction delay will be many times the cost of
on-premises supervision.
If the items concerned are custom-made for the project or they have
long lead times (three months or more), then on-premises supervision
should be seriously considered.
2.9. Bids for New Projects
All the preceding are project-related activities; however, the piping
material engineer may also be required to work on bids that the company
has been invited to tender by clients. This is preliminary engineering, but
the work produced should be accurate, based on the information provided
in a brief form the client. The usual activities are preliminary piping
classes, basic valve data sheets and a set of specifications for construction,
inspection, and painting.
A piping material engineer will either be part of a project task force
dedicated to one job or part of a corporate group working on several
projects, all in different stages of completion. Of these two options, the
most preferable is the former, because it allows the PME to become more
familiar with the project as it develops.
The role of a piping material engineer is diverse and rewarding, and
there is always something new to learn. A project may have the same
client, the same process, and be in the same geographical location, but
because of different personnel, a different budget, purchasing in a
different market, or a string of other factors, different jobs have their
own idiosyncrasies. Each one is different.
The knowledge you learn, whether technical or logistical, can be used
again, so it is important that you maintain your own files, either digital
or hard copies, preferably both.
Whether you work for one company for 30 years or 30 companies for
1 year, you will find that the role of PME is respected within the
discipline and throughout the project.
As a function, it is no more important than the piping layout or piping
stress engineer; however, its importance must not be underestimated.
The pipe can be laid out in several different routings, but if the material
of construction is wrong, then all the pipe routes are wrong, because the
material is ‘‘out of spec.’’