Full Content is available to subscribers

Subscribe/Learn More  >

A Comparative Study of Concentrically and Eccentrically Pierced Flat Unstayed Heads

[+] Author Affiliations
Dipak K. Chandiramani

Independent Consultant, Chembur, India

Shyam Gopalakrishnan, Ameya Mathkar

Lloyd’s Register Asia, Andheri, India

Suresh K. Nawandar

Fluor Daniel India Pvt. Ltd., Gurugram, India

Paper No. PVP2017-65521, pp. V01BT01A064; 9 pages
  • ASME 2017 Pressure Vessels and Piping Conference
  • Volume 1B: Codes and Standards
  • Waikoloa, Hawaii, USA, July 16–20, 2017
  • Conference Sponsors: Pressure Vessels and Piping Division
  • ISBN: 978-0-7918-5791-5
  • Copyright © 2017 by ASME


Clause UG - 39 of ASME Section VIII Division 1 [1] provide rules for compensation of openings in flat stayed/ flat unstayed heads having fitted nozzles.

The rules provided in Clause UG - 39 and its sub clauses apply to all openings other than small openings covered by UG - 36 (c)(3)(a) and provide rules for compensation of openings to those geometries which confirms to the geometric limitations specified therein.

The rules provided in Clause UG - 39 of ASME Section VIII Division 1 are based on area replacement method. This method is also elaborated in WRC Bulletin 335 Aug 1988[4]. The conclusion of this bulletin is applicable to ASME Section VIII Div 1, ASME Section I, ASME B 31.1 and ASME Section III Class 2 and 3. This method requires that the metal cut out by an opening be replaced by reinforcement within a prescribed zone around the opening. This methodology is relatively simple and vast majority of the piping and pressure vessels with openings conforming to this methodology have given satisfactory service.

In Code [1], as such there appears to be no restriction on the location of the nozzle opening, i.e., a header flat head pierced concentrically or eccentrically to locate the nozzle opening as long as the required area is obtained and the stresses are within allowable limits. While both these alternatives would be acceptable in Code [1] constructions, the actual stresses at the header flat heads/nozzle junction may vary considerably.

The work reported in this paper was undertaken to make a comparative study on the effect of unstayed flat head pierced concentrically or eccentrically by using ASME Section VIII Division 1 and to study the stress pattern in both the cases using Finite Element Analysis (FEA) as a referral methodology.

Copyright © 2017 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In