Chemical Engineering August 2023 - 35

Feature Report
Materials of Construction for the CPI
The proper selection of materials of construction is crucial. The example presented
here shows how to use standards to help narrow down the options
S
ince the late 1800s, a steady body
of pressure technology codes and
standards have been under development
(see box on p. 36) providing
engineers with standardized methods to
safely design and fabricate pressure vessels
and other pressurized process equipment
used in the chemical process industries
(CPI). This article gives an overview of the
relevant standards, and presents an example
of how they can be used to narrow
down the selection of suitable materials of
construction (MoC).
ASTM standards
Operating for 125 years, ASTM International
(ASTM; West Conshohocken, Pa.; www.
astm.org) has come a long way since standardizing
on the material and testing of railroad
track steel. It currently publishes and
maintains 12,500 standards globally in over
140 participating countries with the help of
more than 30,000 volunteer and staff members.
This is an organization that we depend
on for determining and evaluating a material's
chemistry, its strength, its testing, and
manufacturing requirements. ASTM is also
involved in developing testing methodologies
and procedures.
In all, ASTM publishes, among other
things, six different types of standards that
include the following:
Test Method Standards: A set of procedures
that provide instruction, guidelines, and
parameters necessary to acquire and analyze
sample evidence of fluids and materials.
Practice Method Standards: Are instructions
on the recommended approach to
achieving a deliverable in a standardized
fashion. Such examples include F748 Standard
Practice for Selecting Generic Biological
Test Methods for Materials and Devices
and E1816 Standard Practice for Measuring
thickness by Pulse-Echo Electromagnetic
Acoustic Transducer (EMAT) Methods.
Specification Standards: Are standards
that specify what the intended use is for
a specific material, the material's chemical
composition parameters, mechanical properties,
the manufacturing process, testing
requirements, and all other use and manufacturing
requirements pertaining to a specific
material and its various product forms
Classification Standards: Provide guidance
and requirements for the process of
assigning the various materials, services, or
systems into their proper category. These
requirements may relate to the origin, the
physical properties, or the chemical properties
of the product itself.
Guide Standards: Are collections of information
or series of options that do not recommend
specific courses of action. They
generally inform people of the knowledge
and approaches being taken in given subject
areas.
Terminology Standards: Provide definitions
of terms and explanations of symbols,
abbreviations, and acronyms used throughout
ASTM.
What we can pull from the above list, relative
to this discussion, is item three, Specification
Standards, which covers the following
seven categories:
* Class A - Ferrous iron and steel metals
and products (prefix A)
* Class B - Nonferrous metals and products
(prefix B)
* Class C - Ceramic, concrete and
masonry materials
* Class D - Miscellaneous materials
* Class E - Miscellaneous subjects
* Class F - Materials for specific
applications
* Class G - Corrosion, deterioration,
weathering, and degradation of materials
and products
We will further narrow our focus down to
the above Class A - Ferrous iron and steel
metals and products. This is where most of
the piping and equipment material for the
CPI are found. Nonferrous materials are frequently
used as well, but that would be too
much to cover here. ASTM includes plastics
under the above Class D - Miscellaneous
materials. So, for nonmetallic (NM) material,
refer to the relatively new ASME NM standards
first published in 2018 by the American
Society of Mechanical Engineers (ASME;
New York, N.Y.; www.asme.org). They include
the following:
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
AUGUST 2023
35
William M. Huitt
W. M. Huitt Co.
IN BRIEF
ASTM STANDARDS
ASTM AND ASME
DEVELOPING A MATERIAL
SPECIFICATION
FLUID SERVICE
COMPATIBILITY
PROJECT DESIGN BASIS
MATERIAL COSTS
http://www.astm.org http://www.astm.org http://www.asme.org http://WWW.CHEMENGONLINE.COM
Chemical Engineering August 2023

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