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 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.

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 Boilers 2. Section II: Material Specification: i. Ferrous Material Specifications – Part A ii. Non-ferrous Material Specifications – Part B iii. Specifications for Welding Rods, Electrodes, and Filler Metals – Part C iv. Properties – Part D 3. Section III Subsection NCA: General Requirements for Division 1 and Division 2 i. Section III Division 1: a. Subsection NA: General Requirements b. Subsection NB: Class 1 Components

Subsection NC: Class 2 Components d. Subsection ND: Class 3 Components e. Subsection NE: Class MC Components f. Subsection NF: Component Supports g. Subsection NG: Core Support Structures h. 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 of Heating Boilers Section VII: Recommended Guidelines for Care of Power Boilers Section VIII i. Division 1: Pressure Vessels – Rules for Construction ii. 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 vessels ItemIS-2825ASME Code Section VIII BS-5500AD- 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 vessels ItemIS-2825ASME Code Section VIII BS-5500AD- Merkblatter Design pressure Maximum working pressure including static head + 5% maximum working pressure. 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 vessels National codeU.T.SYield strengthSr(rupture stress) Creep stress ASME: VIII Div: ASME: VIII Div BS Part II BS ANCC IS

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: 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