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CODES FOR VESSELS/HEAT EXCHANGERS
Avinash Nayak. (46)Shrikantkumar Padhy (47)Jitendra Patil (48)Manoj Patil (49)Ganeshprasad Pavaskar (51)
History of pressure vessel codes
• Boiler explosion on March 20, 1905 in Brockton, Massachusetts.
• 58 killed and 117 injured.• Need of legislative rules and regulation for
construction of boilers.• The first Boiler and Pressure Vessel Code was
published in 1915.• Necessary changes made and new sections
added as need arose.
What is a Code?• A code is a standard that has been adopted by
one or more governmental bodies and has the force of law, or when it has been incorporated into a business contract.
• Codes specify requirements of design, fabrication, inspection and testing of pressure vessels.
• Number of national codes have been developed for pressure vessels by different countries.
• In India, the code for pressure vessels is IS-2825
WHAT ARE ASME CODES?
• It is a standard that provides rules for the design, fabrication, and inspection of boilers and pressure.
• This establishes and maintains design, construction and inspection standards providing for maximum protection of life and property.
ASME Codes - Manufacturer• A manufacturer obtains permission to use one of the
stamps through the ASME conformity assessment process.
• The manufacturer’s quality control system is reviewed by an ASME team.
• If it meets ASME requirements and the manufacturer successfully demonstrates implementation of the program, the manufacturer is accredited by ASME.
• The manufacturer then may certify the product as meeting ASME standards and apply the stamp to the product.
Why follow ASME codes?
• Excessive elastic deformation including elastic instability
• Excessive plastic deformation• Brittle fracture• Stress rupture or creep deformation (inelastic)• Plastic instability and incremental collapse• High strain and low cycle fatigue• Stress corrosion• Corrosion fatigue
ASME Codes - User
• ASME Publications Catalog,• The ANSI Catalog of American National
Standards, • the US government’s OSHA General Industry
Standards, • contact a standards organization directly. • http://www.asme.org/catalog
ASME Codes – User
• Insurance
• Replacement
• Proper Compliance- Size specific- Jurisdiction
• Proper ASME stamps
The organization of the ASME Boiler and Pressure Vessel Code is as follows:1. Section I: Power Boilers2. Section II: Material Specification:
i. Ferrous Material Specifications – Part Aii. Non-ferrous Material Specifications – Part Biii. Specifications for Welding Rods, Electrodes, and Filler Metals – Part Civ. Properties – Part D
3. Section III Subsection NCA: General Requirements for Division 1 and Division 2i. Section III Division 1:
a. Subsection NA: General Requirementsb. Subsection NB: Class 1 Components
• Subsection NC: Class 2 Componentsd. Subsection ND: Class 3 Componentse. Subsection NE: Class MC Componentsf. Subsection NF: Component Supportsg. Subsection NG: Core Support Structuresh. Appendices: Code Case N-47 Class 1: Components in Elevated Temperature
Service• Section III, Division 2: Codes for Concrete Reactor
Vessel and Containment• Section IV: Rules for Construction of Heating Boilers• Section V: Nondestructive Examinations
• Section VI: Recommended Rules for the Care and Operation ofHeating Boilers
• Section VII: Recommended Guidelines for Care of Power Boilers
• Section VIIIi. Division 1: Pressure Vessels – Rules for
Constructionii. Division 2: Pressure Vessels – Alternative Rules
• Section IX: Welding and Brazing Qualifications• Section X: Fiberglass-Reinforced Plastic Pressure Vessels• Section XI: Rules for In-Service Inspection of Nuclear
Power Plant Components
Stamps
Nomenclature
Example
• A heat exchanger qualifies as a UM stamped pressure vessel if:
- Design pressure < 15psig- Internal volume < 1.5 cubic ft. for 150<P<600
psig- Internal volume < 5 cubic ft. for design P upto
250 psig
Example
• A heat exchanger qualifies as a U stamped pressure vessel if:
- Design pressure > 600 psig- Internal volume > 1.5 cubic ft. for 150<P<600
psig- Internal volume > 5 cubic ft. for design P upto
250 psig
Comparison of pressure vesselsItem IS-2825 ASME Code
Section VIIIBS-5500 AD-
Merkblatter
Scope •Unfired fusion welded pressure vessels•Pressure < 20 N/mm2•Do/Di < 1.5•Di > 150 mm•Water capacity > 50 litres
•Welded, riveted, forged and brazed vessels•Water capacity>120 gal•Operating pressure > 15 psi•Di>6”
• Unfired fusion welded pressure vessels•Medium and high pressure storage vessels•Excludes transportable vessels.
•Do/Di < 1.7•Vessels and vessel parts predominantly under static load.
materials •Carbon and low alloy steels, high alloy steel, Cu and Cu alloys, Al and alloys, bolting and casting alloys
•Same as IS-2825•Cast iron, lined material cast iron, ferritic steel
•Carbon, ferritic alloy(low and high) and austenitic steels
All metallic materials and graphite, glass.
Comparison of pressure vesselsItem IS-2825 ASME Code
Section VIIIBS-5500 AD-
MerkblatterDesign pressure
Maximum working pressure including static head + 5% maximum working pressure.
Maximum pressure at most severe conditions
Maximum pressure at most severe conditions
Based on permissible service pressure
Design tempera-ture
Highest metal temperature expected under operating conditions
Actual metal temperature expected under operating conditions
Actual metal temperature expected under operating conditions + margin for uncertainties
Highest wall temperature expected under working conditions
Comparion of pressure vesselsNational code U.T.S Yield strength Sr(rupture
stress)Creep stress
ASME: VIIIDiv: 1
4 1.6 - 1
ASME: VIIIDiv-2
3 1.5 - -
BS-1515 4 - - -
BS-1515Part II
2.5 1.5 1.5 1
BS-5500 2.35 1.5 1.3 1
ANCC - 1.5 1.5 -
IS-2825 3 1.5 1.5 1
Explosions
• In spite of some of the most rigorous, well-conceived safety rules and procedures ever put together, boiler and pressure vessel accidents continue to occur.
• In 1980, for example, the National Board of Boiler and Pressure Vessel Inspectors reported:
- 1972 boiler and pressure vessel accidents, 108 injuries and 22 deaths.
• The pressure vessel explosions are of course rare nowadays and are often caused by incorrect operation or poorly monitored corrosion.
• Safety in boiler and pressure vessels can be achieved by:
Proper design and construction
Proper maintenance and inspection
Proper operator performance and vessel operation