Useful Standards for Piping
Most useful standards in mechanical industry are the ANSI-(American National Standard Institute) standards.Each country has its own Codes and Standards. On global basis, American National Standards are the most widely used and compliance with those requirements are accepted world over.In general, other than American Standards such as British ,German,Japanese,Europian and various other standards depending upon the requirement and availability are also used for design and selection of Piping Systems.
Not all American Standards are issued directly by American National Standards Institute. However in process/power industry ,the Material Standards are covered under ASTM (American Society for Testing and Materials) and Dimension Standards under ANSI (American National Standards Institute). Most of these Standards are adapted by ASME (American Society for Mechanical Engineers).
Some of the commonly used Standards referred by Piping are :
The American Iron and Steel Institute (AISI) :
These standards specify the material by its Chemical and Physical properties. When specific model of manufacture of the element is not to be specified, then the material can be identified by ANSI Standards. The most commonly used AISI specifications are :
American Society for Testing Materials (ASTM) : These consist of 16 sections on definitions and
classifications of materials of construction and Test methods. Most of the ASTM Standards are adapted by ASME
and are specified in ASME Section II. The Section II has four parts.
1.Part A - Ferrous Materials
2.Part B - Non-Ferrous Materials
3.Part C - Welding Materials
4.Part D - Properties of Materials
In Section II, the materials are listed in the index based on the available forms such as plates, castings, tubes etc., and also on the numerical index.
The selection of ASTM Specification depends on the manufacturer, form of material, its mechanical strength and corrosion properties.
The specification number is given an Alphabetical prefix "A" for ferrous and "B" for non-ferrous materials.
ASTM also specifies standard practice for numbering metal and alloys as Unified Numbering System.
Unified Numbering System (UNS) establishes 18 series numbers of metals and alloys. Each UNS number consists of a single letter prefix followed by 5 digits. In most cases the alphabet is suggestive of the family of the metal identified.
American Welding Society (AWS) : These standards provide information on the welding fundamentals, weld design,
welder's training qualifications, testing and inspection of the welds and guidance on the application and use
of welds. Individual electrode manufacturers have given their own brand names for the various electrodes and
the same are sold under these names.
American Water Works Association (AWWA) : These standards refer to the piping elements required for low
pressure water services. These are less stringent than other standards. Valves, Flanges etc., required for
large diameter water pipelines are covered under this standard and are refereed rarely by piping engineers.
The manufacturers Standardization Society of Valves and Fitting Industry - Standard Practices (MSS-SP) :In
addition to the above standards and material codes, there are standard practices followed by manufacturers.
These are published as advisory standards and are widely followed. The most common MSS-SP standards referred
for piping are :
BRITISH STANDARDS : In many instances, it is possible to find a British Standard which may be substitutes for
American Standards. For example, BS 2080 (British Standard for Face to Face or End to End dimensions of valves)
is identical to ANSI/ASME B16.10. Similarly BS 3799 and ANSI/ASME B 16.11 also compare.
The most commonly referred British Standards in the Piping Industry are :
INDIAN STANDARDS : Bureau of Indian Standards (BIS) have so far not developed an Indian Standard for the
design of Piping Systems. Hence, ANSI Standards ASME 31.1 and 31.3 are widely used for the design. These
standards also accept materials covered in other standards. Unlike American Standards, Indian Standards cover
dimensions and material specifications under the same standard number. There are no groupings based on branch
of engineering. Some of the most commonly referred Indian Standards by Piping Engineers are :
Periodic review of the standards by the committee are done and these are revised to incorporate the modified features based on the research and feedback from industry. It is, hence, necessary that the latest editions of the codes and standards are referred for the design.