American Bureau of Shipping – ABS Pressure Vessels
Some of the criteria required by ABS are listed below as excerpts from the rules.
CHAPTER 4 Boilers, Pressure Vessels and Fired Equipment
SECTI O N 1 Boilers and Pressure Vessels and Fired
1.1 Application (2008)
Regardless of the system in which they formed a part, boilers, fired and unfired heaters, pressure vessels and heat exchangers of the following categories are to be subjected to the provisions of this section:
i) Boilers and steam generators with design pressure over 3.5 bar (3.6 kgf/cm2, 50 psi).
ii) Fired heaters for oil with design pressure over 1 bar (1 kgf/cm2, 15 psi).
iii) Independent pressure vessel tanks for the carriage of liquefied gases, defined in Section 5C-8-4.
iv) (2008) Accumulators, regardless of their diameters, see 4-6-7/3.5.4.
v) Other pressure vessels and heat exchangers of 150 mm (6 in.) diameter and over, having design pressure, temperature and volume as defined in 4-4-1/Table 1. Pressure vessels and heat exchangers under 150 mm (6 in.) in diameter are not required to comply with the provisions of this section.
Acceptance of them will be based on manufacturer’s guarantee of physical properties and suitability for the intended service, provided the installation is carried out to the satisfaction of the Surveyor.
ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2011 275
1.3.1 Design Pressure
Design Pressure is the gauge pressure to be used in the design of the boiler or pressure vessel. It is to be at least the most severe condition of coincidental pressure and temperature to be expected in normal operation. For pressure vessels having more than one chamber, the design pressure of the inner chamber is to be the maximum difference between the inner and outer chambers. 1.3.2 Maximum Allowable Working Pressure
The Maximum Allowable Working Pressure (MAWP) of a boiler or pressure vessel is the maximum pressure permissible at the top of the boiler or pressure vessel in its normal operating condition and at the designated coincidental temperature specified for that pressure. It is the least of the values found for MAWP for any pressure-bearing parts, adjusted for the difference in static head that may exist between the part considered and the top of the boiler or pressure vessel. MAWP is not to exceed the design pressure.
1.3.3 Design Temperature
The maximum temperature used in design is not to be less than the mean metal temperature (through the thickness) expected under operating conditions. The minimum metal temperature used in design is to be the lowest expected in service, except when lower temperatures are permitted by the Rules of the recognized code or standard.
1.5 Recognized Codes or Standards
All boilers and pressure vessels required to be certified by 4-4-1/1.1 are to be designed, constructed and tested in accordance with Appendix 4-4-1A1 of this section. Alternatively, they may comply with a recognized code or standard. The following are some of the national standards that are considered recognized for the purpose of this section:
• ASME Boiler and Pressure Vessel Code Section I
• British Standard BS 1113 Design and manufacture of water tube steam generating plant (including superheaters, reheaters and steel tube economizers)
• British Standard BS 2790 Specifications for the design and manufacture of shell boilers of welded construction
Pressure vessels and heat exchangers:
• ASME Boiler and Pressure Vessel Code Section VIII Div. 1; or Section VIII Div. 2
• Standards of Tubular Exchanger Manufacturers Association
• British Standard BS 5500 Specification for unfired fusion welded pressure vessels
• Japanese Industrial Standard JIS B8270 et al for Pressure vessels
Other national standards or codes will be considered, provided that they are no less effective.
1.7 Grouping of Boilers and Pressure Vessels For purpose of specifying the degree of inspection and testing during the certification process, boilers and
pressure vessels are categorized as in 4-4-1/Table 2.
All boilers and pressure vessels within the scope of 4-4-1/1.1 are to be certified by ABS. Mass-produced pressure vessels, including seamless extruded cylinders and fluid power cylinders, may be certified by alternative means as described in 4-4-1/1.11. 4-4-1/Table 3 provides important elements of the certification process for each group of boilers and pressure vessels. Columns 1, 2 and 3 in the table are to be complied with for all boilers and pressure vessels regardless of the chosen standard or code of compliance. Fabrication and inspection details in column 4 (see Section 2-4-3) are to be complied with also, except that considerations will be given to alternative provisions in the chosen standard or code of compliance.
Part 4 Vessel Systems and Machinery
1 2 3 4
Design approvalSurvey during fabrication Material test witnessed by Surveyor.
Full radiography Post-weld heat treatment Production test plate Charpy V-notch test Welding of pressure parts and of non-pressure parts to pressure parts is to be performed by means of qualified welding procedures and by qualified welders. The qualification of welding procedures is to be
conducted in accordance with Section 2-4-3 or the applicable boiler or pressure vessel standard or code. Welding procedure specifications and their qualification records are to be submitted for review as indicated
in 4-4-1/1.13.5. The Surveyor is to have the option of witnessing the conduct of the qualification test, and may request additional qualification tests if there are reasons to doubt the soundness of the qualified procedure. Similarly, qualification of welders is to be in accordance with the applicable code and is to be to the satisfaction of the Surveyor.
7.5 Dimensional Tolerances
Parts to be welded are to be aligned within the tolerances specified in Section 2-4-2 or the applicable standard or code. The fitting of the main seams is to be examined by the Surveyor prior to welding. The
conformance of formed heads to the theoretical shape and the out-of-roundness of the finished shells are to be within specified tolerances and are to be verified to the satisfaction of the Surveyor.
7.7 Nondestructive Examination
Radiographic examinations are to be in accordance with 2-4-2/23 or the applicable standard or code. All Group I boilers and pressure vessels are to have their butt seams fully radiographed. See 4-4-1/1.9. Group
II pressure vessels are to be radiographed to the extent as required by the designed joint-efficiency. The radiography standard and acceptance criteria, along with the degree of other nondestructive examination, such as ultra-sonic, dye penetrant, or magnetic particle, are to be in accordance with the chosen standard or code. Radiographic films are to be submitted to the surveyor for review. 7.9 Preheat and Postweld Heat Treatment
Preheat and postweld heat treatment are to be in accordance with 2-4-2/11 through 2-4-2/17 or the applicable standard or code. All Group I boilers and pressure vessels are to be postweld heat treated. See 4-4-1/1.9. In addition, postweld heat treatment is to be carried out where required by, and in accordance with the applicable boiler or pressure vessel code or standard. The postweld heat treatment procedure is to be submitted to the Surveyor for review prior to the heat treatment.
7.11 Hydrostatic Tests (1 July 2003)
The Surveyor is to witness hydrostatic tests on all boilers. The test pressure on pressure vessels is not to be less than 1.5 times the maximum allowable working pressure or at such pressures as specified by the standard or code of compliance.
7.11.2 Pressure Vessels The Surveyor is to witness hydrostatic tests on all pressure vessels. The test pressure is not to be less than 1.3 times the maximum allowable working pressure or at such pressures as specified by
the standard or code of compliance. Where hydrostatic tests are impracticable, alternative methods of pressure tests, such as a pneumatic pressure test, may be considered for pressure vessels, subject to such test procedures being submitted for consideration in each case.
7.13 Manufacturer’s Documentation
The manufacturer is to submit documentation of fabrication records, including but not limited to material certificates, welding procedure qualification records, welder qualification records, heat treatment reports,
non destructive examination reports and dimensional check reports, as applicable, to the Surveyor for final review and acceptance.
Other Pressure Vessel design code info. can be found with the links below
PD5500, EN286, DNV, ASME, LLOYDS, 97/23/EC, EN13445, 87/404/EEC, 2009/105/EC, ABS, BS5169