VESSELS/HEAT EXCHANGERS CODES

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