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Rupture Disks for Process Engineers - Part 3

Nov 08 2010 01:30 PM | pleckner in Safety and Pressure Relief -----


  • What is the maximum allowable specified burst pressure?

- Design Pressure or MAWP if the rupture disk is the only relief device


- For special cases, 105% (or even 110%) of design pressure or MAWP if the rupture disk is a secondary device


  • What should be the expected stamped (rated) burst pressure of the rupture disk?

- As specified by the process engineer for a Manufacturing Range of ± 0%


- As specified by the process engineer but could be adjusted per the Manufacturing Range if other than ± 0%

  • At what pressure(s) can we expect the delivered rupture disk to actually burst at?

- ± 5% of stamped burst pressure for stamped pressures greater than 40 psig


- ± 2 psi for stamped pressures 40 psig and lower

  • What is the maximum allowable operating pressure in the vessel?

- Specified by the process engineer based on operating need but must be checked against the Operating Ratio of the rupture disk
- I strongly suggest you also check against the minimum expected burst pressure as well.

  • Manufacturing Range is applied to the specified burst pressure
  • Burst Tolerance is applied to the stamped burst pressure
  • Set the design pressure appropriately
  • Choose a rupture disk with a MR of ± 0%
  • Choose a rupture disk with a OR of 90%
Don't go running out and specifying a rupture disk just quite yet! We still need to consider the affects of temperature and backpressure and the relief valve-rupture disk combination.


  1. API (www.api.org) Recommended Practice 520, "Sizing, Selection, and Installation of Pressure-Relieving Device in Refineries, Part 1-Sizing and Selection", 7th Edition (January 2000)
  2. API (www.api.org) Recommended Practice 521, "Guide for Pressure-Relieving and Depressuring Systems", 4th Edition (March 1997)
  3. ASME (www.asme.org) "Boiler and Pressure Vessel Code, Section VIII, Division 1" (1998)
  4. Continental Disc Corporation, ULTRX ® Catalogue 3-2210-3


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