A standard as something that is established for
use as basis of comparison. There are standards for practically
everything that can be measured or evaluated ... from time to
materials to processes. Congress created the National Institute
of Standards and Technology in 1901 at the start of the industrial
revolution to provide the measurements and standards needed to
resolve and prevent disputes over trade and to encourage standardization.
NIST develops technologies, measurement methods and standards
that help US companies compete in the global marketplace. NDT
personnel are sometimes required to use calibration standards
that are traceable back to a standard held by NIST. This might
be a conductivity standard, which can be shown to have the same
electrical conductivity as a NIST standard; or it could be a setup
standard that was measured with a micrometer that was calibrated
using a NIST standard.
notable development of the twentieth century is the preparation
and use of standard specifications to improve the consistency
of manufacturing materials and processes, and the resulting products.
A specification is a detailed description as to how to produce
something or how to perform a particular task. Anytime
a product is marked as meeting a specification or a contract requires
use of a specification, the product or service must meet the requirements
of document. A standard specification is the result of
agreement among the involved parties and usually involves acceptance
for use by some organization. Standard specifications do not,
however, necessarily imply a degree of permanence (like dimensional
or volumetric standards), because technical advances in a given
field usually calls for periodic revisions to the requirements.
Properly prepared, standards can be of great value
to industry. Some of the advantages are:
- They usually represent the combined knowledge of large group
of individuals including producers, consumers and other interested
parties, and, thus, reduce the possibility of misinterpretation.
- They give the manufacturer a standard of production and, therefore,
tend to result in a more uniform process or product.
- They lower unit cost by making standard processes and mass production
- They permit the consumer to use a specification that has been
tried and is enforceable.
- They set standards of testing and measurement and hence permit
the comparison of results.
The disadvantage of standard specifications is they tend to "freeze"
practices sometimes based on little data or knowledge, and slow
the development of better practices.
Standards always represent an effort by some organized group of
people. Any such organization, be it public or private, becomes
the standardizing agency. Various levels of these agencies exist,
ranging from a single business to local government to national groups
to international organizations. The professional and industrial
organizations in the United States that lead the development of
standards relative to the field of NDT include: the ASTM International,
the Society of Automotive Engineers (SAE), the American Iron and
Steel Institution (AISI), the American Welding Society (AWS) and
the ASME International. Many specifications have also been developed
by US government agencies such as the Department of Defense (DOD).
However, the US government is downscaling its specification efforts
and many military specifications are being converted to specification
controlled by industry groups. For example, MIL-I-25135 has historically
been the controlling document for both military and civilian penetrant
material uses. The recent change in military specification management
has lead to the requirement of the Mil specification be incorporated
into SAE's AMS 2644 and industry is transition towards the use of
Generally, the desired tendency is for a given standard to become
more uniformly used and accepted. One method of increasing standardization
is for a large agency to adopt a standard developed by a smaller
one. In the US, thousands of standard specifications are recognized
by the American National Standards Institute (ANSI), which is a
national, yet private, coordinating agency. At the international
level, the International Organization for Standardization (ISO)
performs this function. The ISO was formed in 1947 as a non-governmental
federation of standardization bodies from over 60 countries. The
Unites States is represented within the ISO by the ANSI.
Additional information and links to the standards and specification
organizations previously mentioned are provided below.
Partial list of ASTM standards
relative to NDT
Link to the
ASTM web site
Founded in 1898, ASTM International is a not-for-profit
organization that provides a global forum for the development
and publication of voluntary consensus standards for materials,
products, systems, and services. Formerly known as the American
Society for Testing and Materials, ASTM International provides
standards that are accepted and used in research and development,
product testing, quality systems, and commercial transactions
around the globe. Over 30,000 individuals from 100 nations
are the members of ASTM International, who are producers,
users, consumers, and representatives of government and academia.
In over 130 varied industry areas, ASTM standards serve as
the basis for manufacturing, procurement, and regulatory activities.
Each year, ASTM publishes the Annual Book of
ASTM Standards, which consists of approximately 70 volumes.
Most of the NDT related documents can be found in Volume 03.03,
Nondestructive Testing. E-03.03 is under the jurisdiction
of ASTM Committee E-7. Each standard practice or guide is
the direct responsibility of a subcommittee. For example,
document E-94 is the responsibility of subcommittee E07.01
on Radiology (x and gamma) Methods. This committee, comprised
of technical experts from many different industries, must
review the document every five years and if not revised, it
must be reapproved or withdrawn.
The Society of Automotive
Partial list of SAE standards
relative to NDT
SAE web site
|The Society of Automotive
Engineers is a professional society that serves as resource
for technical information and expertise used in designing, building,
maintaining, and operating self-propelled vehicles for use on
land or sea, in air or space. Over 83,000 engineers, business
executives, educators, and students from more than 97 countries
form the membership who share information and exchange ideas
for advancing the engineering of mobility systems. SAE is responsible
for developing several different documents for the aerospace
community. These documents include: Aerospace Standards (AS),
Aerospace Material Specifications (AMS), Aerospace Recommended
Practices (ARP), Aerospace Information Reports (AIR) and Ground
Vehicle Standards (J-Standards). The documents are developed
by SAE Committee K members, which are technical experts from
the aerospace community.
More information on the Boiler &
Pressure Vessel Code
ASME web site.
|ASME International was founded
in 1880 as the American Society of Mechanical Engineers. It
is a nonprofit educational and technical organization serving
a worldwide membership of 125,000. ASME maintains and distributes
600 codes and standards used around the world for the design,
manufacturing and installation of mechanical devices. One
of these codes is called the Boiler and Pressure Vessel Code.
This code controls the design, inspection, and repair of pressure
vessels. Inspection plays a big part in keeping the components
operating safely. More information about the B&PV Code
can be found at the links to the left.
The American Welding Society
Partial list of AWS Standards
and Documents relative to NDT
Link to the
AWS web site
|The American Welding Society (AWS)
was founded in 1919 as a multifaceted, nonprofit organization
with a goal to advance the science, technology and application
of welding and related joining disciplines. AWS serves 50,000
members worldwide. Membership consists of engineers, scientists,
educators, researchers, welders, inspectors, welding foremen,
company executives and officers, and sales associates.
The International Organization
for Standardization (ISO)
The Air Transport Association
ATA web site.
Founded by a group of 14 airlines in 1936,
the ATA was the first, and today remains, the only trade
organization for the principal US airlines. The purpose
of the ATA is to support and assist its members by promoting
the air transport industry and the safety, cost effectiveness,
and technological advancement of its operations; advocating
common industry positions before state and local governments;
conducting designated industry-wide programs; and assuring
governmental and public understanding of all aspects of
air transport. There are two ATA documents that serve
as guidelines for the training of inspection personnel.
ATA Specification 105, Guidelines for
Training and Qualifying Personnel in Non-Destructive
Methods. This document serves as a guideline for the
development of a training program for personnel who
accomplish nondestructive testing tasks. While partially
derived from more universal training standards such
as ASNT SNT-TC-1A and NAS 410, this document is dedicated
to preparing a curriculum for an airline's maintenance
training program and qualifying individuals to conduct
ATA Specification 107, Visual Inspection
Personnel Training and Qualification Guide for FAR Part
Air Carriers. This document addresses training and qualification
needs of the aircraft inspection technician and recommends
a minimum list of required inspection items.
The Aerospace Industries
AIA's web site.
The Aerospace Industries Association represents
the nation's major manufacturers of commercial, military
and business aircraft, helicopters, aircraft engines,
missiles, spacecraft, materials, and related components
and equipment. The AIA has been a aerospace industry
trade association since 1919. It was originally known
as the Aeronautical Chamber of Commerce (ACCA). The
AIA is responsible for two NDT related documents, which
NAS 410, Certification & Qualification
Of Nondestructive Test Personnel. This document is
a widely used document in the aerospace industry as
it replaces MIL-STD-410E: Military Standard, Nondestructive
Testing Personnel Qualification and Certification..
NAS 999, Nondestructive Inspection
of Advanced Composite Structure.
The American National
Standards Institute (ANSI)
ANSI web site.
|ANSI is a private, nonprofit organization
that administers and coordinates the US voluntary standardization
and conformity assessment system. The Institute's mission
is to enhance both the global competitiveness of US business
and the US quality of life by promoting and facilitating
voluntary consensus standards and conformity assessment
systems, and safeguarding their integrity.
US Department of Defense Specifications - A list
of DOD specifications (Mil Specs, NAV, Etc.) was not prepared
since the trend is to move away from their use and more documents
are being canceled or made inactive everyday. Information on
DOD specifications can be found at the following web site.
of Defense Single Stock Point for Military Specifications, Standards
and Related Publications