Solo para diseñadores de tuberias - Códigos y Estándares

CODES and STANDARDS

For Piping Systems proper selection of of Material of Construction alongwith Specifications, Adherence to Codes and Standards is essential. Standardization reduces cost, confusion and inconvenience. Standards are published by Professional Societies, Committees and Trade Organizations. It is also accepted by Governments.  The main objective is to have Standardization and Safety.

CODE : A group of general rules or systematic procedures for Design, Fabrication, Installation and Inspection methods prepared in such a manner that it can be adopted by legal jurisdiction and made into a law.

STANDARDS : Documents prepared by a Professional group or Committee which are believed to be good and proper Engineering Practices and which contain mandatory requirement.

RECOMMENDED PRACTICES : Documents prepared by professional group or committee indicating Good Engineering Practices but which are optional.

Companies also develop Guides in order to have consistency in the documentation. These cover various engineering methods which are considered good practices, without specific recommendations or requirements. 

Codes and Standards, besides being regulations, might also be considered as Design Aids since they provide guidance from experts. 

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 India, other than American Standards, British and Indian Standards are also used for design and selection of Piping Systems.

1.      AMERICAN STANDARDS : 
Not all American Standards are issued directly by American National Standards Institute. 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).
The American Standards referred by Piping Engineers are mainly the standards by :

The American Petroleum Institute (API) : The Standards referred by Piping Engineers are :

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API 5L - Specification for Line Pipe 
```

API 6D - Pipe Line Valves, End Closures, Connectors and Swivels

API 6F - Recommended Practice for Fire Test for valves

API 593 - Ductile Iron Plug Valves - Flanged Ends

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API 598 - Valve Inspection and Test 
```
```
API 600 - Steel Gate Valves 
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API 601 - Metallic Gaskets for Refinery Piping

API 602 - Compact Design Carbon Steel Gate Valves

API 604 - Ductile Iron Gate Valves - Flanged Ends

API 605 - Large Diameter Carbon Steel Flanges

API 607 - Fire Test for Soft Seated Ball Valves

```
API 609 - Butterfly Valves 
```

API 1104 - Standard for Welding Pipeline and Facilities

o        The American Iron and Steel Institute (AISI) : These 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 :

```
AISI 410 - 13% Chromium Alloy Steel 
```

AISI 304 - 18/8 Austenitic Stainless Steel

AISI 316 - 18/8/3 Austenitic Stainless Steel

o        American National Standard Institute (ANSI) and The American Society for Mechanical Engineers (ASME) : The American National Standards Institute's standards used in the design of the Piping Systems are :

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ANSI B 31.1 - Power Piping 
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```
ANSI B 31.2 - Fuel Gas Piping 
```
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ANSI B 31.3 - Process Piping 
```

ANSI B 31.4 - Pipeline Transportation System for Liquid Hydrocarbon and other Liquids.

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ANSI B 31.5 - Refrigeration Piping 
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ANSI B 31.8 - Gas Transmission and Distribution Piping System

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ANSI B 31.9 - Building Services Piping 
```

ANSI B 31.11 - Slurry Transportation Piping System

ANSI B 31.G - Manual for determining the remaining strength of corroded piping - A supplement to ANSI B31

Of the above, the most commonly used code is ASME B 31.3. Refineries and Chemical Plants are designed based on the same. All Power Plants are designed as per ASME B31.1. Other major ANSI / ASME Standards refereed for the piping elements are :

ANSI B 1.1 - Unified Inch Screw Threads

ANSI / ASME B 1.20.1 - Pipe threads for general porposes

ANSI / ASME B 16.1 - Cast Iron Pipe Flanges and Flanged Fittings

ANSI / ASME B 16.3 - Malleable Iron Threaded Fittings

ANSI / ASME B 16.4 - Cast Iron Threaded Fittings

ANSI / ASME B 16.5 - Steel Pipe Flanges and Flanged Fittings

ANSI / ASME B 16.9 - Steel Butt Welding Fittings

ANSI / ASME B 16.10 - Face to Face and End to End dimensions of Valves

ANSI / ASME B 16.11 - Forged Steel Socket Welding and Threaded fittings

ANSI B 16.20 - Metallic Gaskets for Pipe Flanges - ring joint, spiral wound

ANSI / ASME B 16.21 - Non Metallic Gaskets for Pipe Flanges

ANSI / ASME B 16.25 - Butt Welding Ends

ANSI / ASME B 16.28 - Short Radius Elbows and Returns

ANSI / ASME B 16.34 - Steel Valves, Flanged and butt welding ends

ANSI / ASME B 16.42 - Ductile Iron Pipe Flanges and Flanged Fittings - Class 150# and 300#

ANSI / ASME B 16.47 - Large Diameter Steel Flanges - NPS - 26" to 60"

ANSI / ASME B 18.2 1 and 2 - Square and Hexagonal head Bolts and Nuts (Inch and mm)

ANSI / ASME B 36.10 - Welded and Seamless Wrought Steel Pipes

ANSI / ASME B 36.19 - Welded and Seamless Austinitic Stainless Steel Pipe

o        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.

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Part A - Ferrous Materials 
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Part B - Non-Ferrous Materials 
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Part C - Welding Materials 
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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.

A00001 - A99999 - Aluminum and Aluminum alloys

C00001 - C99999 - Copper and Copper Alloys

E00001 - E99999 - Rare earth and rare earth like metals and alloys

L00001 - L99999 - Low Melting metals and alloys

M00001 - M99999 - Miscellaneous non-ferrous metals and alloys

N00001 - N99999 - Nickel and Nickel Alloys

P00001 - P99999 - Precious Metals and Alloys

R00001 - R99999 - Reactive and Refractory metals and alloys

```
Z00001 - Z99999 - Zinc and zinc alloys 
```

D00001 - D99999 - Specified mechanical properties of Steel

F00001 - F99999 - Cast Iron and Cast Steel

G00001 - G99999 - AISI and ASE Carbon and alloy steels

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H00001 - H99999 - AISI H Steels 
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J00001 - J99999 - Cast Steel 
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K00001 - K99999 - Miscellaneous Steels and Ferrous alloys

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S00001 - S99999 - Stainless Steel 
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T00001 - T99999 - Tool Steel 
```

W00001 - W99999 - Welding Filler Metals and Electrodes

o        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.

o        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.

C-500 : Gate Valves for Water and sewage system

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C-510 : Cast Iron Sluice Gate Valves 
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C-504 : Rubber Seated Butterfly Valves 
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C-507 : Ball Valves 6" to 48" 
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C-508 : Swing Check Valves 2" to 24" 
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C-509 : Resilient Seated Gate Valves for water and sewage

o        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 :

MSS-SP-6 : Standard Finishes for contact surface for flanges

MSS-SP-25 : Standard marking system for valves, fittings, flanges

MSS-SP-42 : Class 150 corrosion resistant gate, globe and check valves

MSS-SP-43 : Wrought stainless steel buttweld fittings

MSS-SP-56 : Pipe hanger supports - Material, design and manufacture

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MSS-SP-61 : Pressure testing of valves 
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MSS-SP-67 : Butterfly Valves 
```

MSS-SP-68 : High Pressure off seat butterfly valves

MSS-SP-69 : Pipe hanger supports - selection and applications

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MSS-SP-70 : Cast iron gate valves 
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MSS-SP-71 : Cast iron check valves 
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MSS-SP-72 : Ball Valves 
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MSS-SP-78 : Cast iron plug valves 
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MSS-SP-80 : Bronze gate, globe and check valves

MSS-SP-81 : Stainless steel bonnetless knife gate valves

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MSS-SP-83 : Pipe unions 
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MSS-SP-85 : Cast iron globe valves 
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MSS-SP-88 : Diaphragm valves 
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MSS-SP-89 : Pipe hangers and supports - fabrication and installation practices

MSS-SP-90 : Pipe hangers and supports - guidelines on terminology

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MSS-SP-92 : MSS valves user guide 
```

MSS-SP-108 : Resilient seated eccentric CI plug valves

2.      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.
There are certain British Standards referred by Indian Manufacturers for Piping and Valves. The most commonly referred British Standards in the Piping Industry are :

o       BS 10 : Flanges

o       BS 806 : Pipes and Fittings for Boilers

o       BS 916 : Black Bolts, Nuts and Screws

o       BS 970 : Steel for Forging, Bars, Rods, valve steel, etc.

o       BS 1212 : Specification for Float Operated Valves

o       BS 1306 : Copper and Copper alooy pressure piping system

o       BS 1414 : Gate Valves for Petroleum Industry

o       BS 1560 : Steel Pipe Flanges

o       BS 1600 : Dimensions of Steel Pipes

o       BS 1640 : Butt Welding Fittings

o       BS 1740 : Wrought Steel screwed pipe fittings

o       BS 1868 : Steel Check Valves for Petroleum Industry

o       BS 1873 : Steel Globe and Check Valves for Petroleum Industry

o       BS 1965 : Butt welding pipe fittings

o       BS 2080 : Face to Face / End to End dimensions of Valves

o       BS 2598 : Glass Pipelines and Fittings

o       BS 3059 : Boiler and Superheater Tubes

o       BS 3063 : Dimensions of Gaskets for Pipe Flanges

o       BS 3381 : Metallic Spiral Wound Gaskets

o       BS 3600 : Dimensions of Welded and Seamless Pipes and Tubes

o       BS 3601 : C.S. Pipes and Tubes for pressure purposes at room temperature

o       BS 3602 : C.S. Pipes and Tubes for pressure purposes at high temperature

o       BS 3603 : C.S. and Alloy Steel Pipes and Tubes for pressure purposes at low temperature

o       BS 3604 : Alloy Steel Pipes and Tubes for high temperature

o       BS 3605 : SS Pipes and Tubes for pressure purposes

o       BS 3799 : Socket Weld / Screwed Fittings

o       BS 3974 : Pipe hangers, Slides and Roller type supports

o       BS 4346 : PVC pressure pipe - joints and fittings

o       BS 4504 : Steel, Cast Iron and Copper alloy fittings

o       BS 5150 : Cast Iron Wedge and Double Disc Gate Valves for general purposes

o       BS 5151 : Cast Iron Gate (parallel slide) Valves for general purposes

o       BS 5152 : Cast Iron Globe and Check Valves for general purposes

o       BS 5153 : Cast Iron Check Valves for general purposes

o       BS 5154 : Copper alloy Globe, Gate and Check Valves

o       BS 5155 : Cast Iron and Cast Steel Butterfly Valves for general purposes

o       BS 5156 : Diaphragm Valves for general purposes

o       BS 5157 : Steel Gate (parallel slide) Valves for general purposes

o       BS 5158 : Cast Iron and Cast Steel Plug Valves for general purposes

o       BS 5159 : Cast Iron and Cast Steel Ball Valves for general purposes

o       BS 5160 :  Flanged Steel Globe and Check Valves for general purposes

o       BS 5163 : Flanged Cast Iron Wedge Gate Valves for general purposes

o       BS 5351 : Steel Ball Valves for Petroleum Industry

o       BS 5352 : Steel Gate, Globe and Check Valves, smaller than 2" NB

o       BS 5353 : Specifications for Plug Valves

o       BS 5391 : Specifications for ABS pressure pipes

o       BS 5392 : Specifications for ABS fittings

o       BS 5433 : Specifications for underground stop valves for water services

o       BS 5480 : Specifications for GRP pipes and fittings

o       BS 6364 : Specifications for Valves for Cryogenic services

o       BS 6755 : Testing of Valves

o       BS 6759 : Safety Valves

3.      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 :

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IS 210 : Grey Iron Castings 
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IS 226 : Structural Steel (superseded by IS 2062)

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IS 554 : Dimensions of Pipe Threads 
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IS 778 : Specification for Copper Alloy Gate, Globe and Check Valves

IS 780 : Specification for Sluice Valves - 50 NB to 300 NB

IS 1239 (Part I and II) : Specification for Mild Steel tubes and fittings

IS 1363 : Hexagonal Bolts, Screws and nuts - Grade C

IS 1364 : Hexagonal Bolts, Screws and nuts - Grade A and B

IS 1367 : Technical supply conditions for threaded steel fastners

IS 1536 : Centrifugally Cast Iron Pipes

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IS 1537 : Vertically Cast Iron Pipes 
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IS 1538 : Cast Iron Fittings 
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IS 1870 : Comparison of Indian and Overseas Standards

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IS 1879 : Malleable Iron Pipe Fittings 
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IS 1978 : Line Pipe 
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IS 1979 : High Test Line Pipe 
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IS 2002 : Steel Plates 
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IS 2016 : Plain Washers 
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IS 2041 : Steel Plates for Pressure Vessels used at moderate and low temperature

IS 2062 : Steel for general structural purposes

IS 2379 : Colour Code for Identification of Pipelines

IS 2712 : Compressed Asbestos Fibre Jointing

IS 2825 : Code for Unfired Pressure Vessels

IS 2906 : Specification for Sluice Valves - 350 NB to 1200 NB

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IS 3076 : Specification for LDPE Pipes 
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IS 3114 : Code of Practice for laying pipes

IS 3516 : Cast Iron flanges and flanged fittings for Petroleum Industry

IS 3589 : Seamless or ERW Pipes (150 NB to 2000 NB)

IS 4038 : Specifications for Foot Valves

IS 4179 : Sizes for pressure vessels and leading dimensions

IS 4853 : Radiographic Examination of Butt Weld Joints in pipes

IS 4864 to IS 4870 : Shell Flanges for vessels and equipments

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IS 4984 : Specification for HDPE Pipes 
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IS 4985 : Specification for PVC Pipes 
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IS 5312 : Specification for Check Valves

IS 5572 : Classification of Hazardous area for Electrical Installation

IS 5822 : Code of practice for laying welded steel pipes

IS 6157 : Inspection and Testing of Valve

IS 6286 : Seamless and Welded pipes for Subzero temperatures

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IS 6392 : Steel Pipe Flanges 
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IS 6630 : Seamless alloy steel pipes for high temperature service

IS 6913 : Stainless Steel tubes for food and beverage industry

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IS 7181 : Horizontally cast iron pipes 
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IS 7240 : Code of Proctice for Cold Insulation

IS 7413 : Code of Proctice for Hot Insulation

IS 7719 : Metallic spiral wound gaskets

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IS 7806 : Stainless Steel Castings 
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IS 7899 : Alloy Steel castings for pressure services

IS 8008 : Specification for moulded HDPE Fittings

IS 8360 : Specification for fabricated HDPE Fittings

IS 9890 : Ball Valves for general purposes

IS 10221 : Code of Proctice for coating and wrapping of underground MS pipelines

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IS 10592 : Eye wash and safety showers 
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IS 10605 : Steel Globe Valves for Petroleum Industries

IS 10611 : Steel Gate Valves for Petroleum Industries

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IS 10711 : Size of Drawing Sheets 
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IS 10805 : Foot Valves 
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IS 10989 : Cast / Forged Steel Check Valves for Petroleum Industry

IS 10990 : Technical drawings - Simplified representation of pipelines

IS 11790 : Code of Proctice for preparation of Butt welding ends for valves, flanges and fittings

IS 11791 : Diaphragm Valves for general purposes

IS 11792 : Steel Ball Valves for Petroleum Industry

IS 12709 : Specifications for GRP pipes

IS 13049 : Specifications for Diaphragm type float operated valves

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IS 13095 : Butterfly Valves 
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IS 13257 : Ring type joint gasket and grooves for flanges

There are certain other international standards, which are also referred in Piping Industry. These are DIN standards of Germany and JIS standards of Japan. DIN standards are more popular and equivalent.
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.