1. Differences Between API-2000 5 th and 6 th Editions Brad Otis April 26, 2010 2010 API Spring Refining and Equipment Standards Meeting

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3. Agenda  Recent History  Significant Differences o Normal Tank Venting o Internal Deflagration o Flame Propagation Through PVVs o Refrigerated Tank Venting o Testing of Venting Devices  Path Forward

4. Recent History  API-2000 5 th Edition o Published April 1998 o Work started on 6 th edition  ISO - 28300 o New work item submitted in June 2006 o Convert and update API-2000 into ISO Standard o FDIS 28300 submitted Jan 2008 o Memo highlighting differences issued o FDIS approved with no negative ballots  API adopted-back in Dec 09 with no negative ballots  Now working 2 nd edition of ISO-28300 (API-2000 7 th edition)

5. Significant Differences Normal Tank Venting  EN 14015 Tank Venting o EN 14015 Tank design standard used in Europe o Venting model based on theory and validated via test o Applicable to any tank service, any temperature, and any size o Therefore placed in main body of ISO standard  API-2000 5 th Edition Tank Venting o Venting model based on theory with simplified assumptions o Applicable to hexane or similar services, temperature < 120 F, and tanks < 180,0000 bbls o Therefore placed in Annex A of ISO standard

6. EN-14015 Validation Test Tests and model calculations at Hoechst in 1980 and 1981 Tank: V = 617 m 3 ; D = 8,5 m; H = 10,6 m 17 °C ≤ Δ T ≤ 26 °C Water (rain) flow density: about 60 kg/m 2 h TRbF-model calculation

7. Significant Differences Normal Tank Venting - continued  Discussion o Both methods are acceptable when applied correctly o Both were included To fill gap where Annex A method does not apply To allow continued use of the Annex A method To ensure global support for the FDIS o EN-14015 vent loads can be higher than Annex A Calculations and comparison courtesy of Protego (USA) Inc.

8. Calculation – Examples Tank 1 Tank: - Height: 5m - Diameter: 7m - Tank volume: 192.4 m3 - Pump in rate: 96 m3/h - Pump out rate: 96 m3/h - Vertical tank - No insulation - MAWP: 7.5 mbar - MAWV: 2.5 mbar

9. Inbreathing Requirements (Total) for Tank 1

10. Outbreathing Requirements (Total) for Tank 1 226 116 117 123 130 118122 109

11. Overview Inbreathing Venting Requirements (thermal) Small tanks (<3,180 m3)

12. Overview Inbreathing Venting Requirements (thermal) Large tanks (>3,180 m3) Outside scope of API 2000

13. Overview Outbreathing Venting Requirements (thermal) Small tanks (<3,180 m3)

14. Overview Outbreathing Venting Requirements (thermal) Large tanks (>3,180 m3) Outside scope of API 2000

15. Significant Differences Normal Tank Venting - continued  Discussion o “Operational experience with petroleum or petrochemical fluid storage tanks indicates that tank failures/damage due to vacuum have not been caused by inadequate venting when that relief system is designed using the method in this Annex” o Tanks that meet the criteria in Annex A can have tank vents designed using the method shown in Annex A. o Tanks that don’t meet the Annex A criteria, then the general method in 4.3.2.1 should be used.  Questions?

16. Significant Differences Internal Deflagration  New section on tank internal deflagration  Provides examples on how this may be mitigated  Previously no “home” for this issue  Detailed presentation on this on 4/28/10 at API-2000 meeting  Questions?

17. Significant Differences Flame Propagation Through PVV  The 5th edition states “A flame arrester is not considered necessary for use in conjunction with a PV valve venting to atmosphere because flame speeds are less than vapor velocities across the seats of PV.”  Recent controlled experiments have shown that flash back through a PVV is possible during very low unstable outflow conditions or if there is an external flammable vapor cloud that ignites with sufficient overpressure to lift the vacuum pallet.

18. Significant Differences Flame Propagation Through PVV - continued  API-2010 and NFPA-30 have language similar to what was stated in the 5th edition of API-2000  Until those standards are updated, there will appear to be an inconsistency on this issue.  Questions?

19. Significant Differences Refrigerated Tank Venting  Completely re-written  Previously was based on hexane  Borrowed heavily from EN14620 and EN1473  Questions?

20. Significant Differences Testing of Venting Devices  New section to provide consistency in capacity testing  Combination of API 2000 5th edition section 4.6 and EN 14015 Annex L.6.  Questions?

21. Path Forward  2 nd Edition of ISO-28300 is being worked now  Fall 2010 is deadline for submitting new items