Differences Between API th and 6 th Editions Brad Otis April 26, API Spring Refining and Equipment Standards Meeting

The companies in which Royal Dutch Shell plc directly or indirectly owns investments are separate entities. In this presentation the expressions "Shell", "Group" and "Shell Group" are sometimes used for convenience where references are made to Group companies in general. Likewise the words "we", "us" and "our" are also used to refer to Group companies in general or those who work for them. The expressions are also used where there is no purpose in identifying specific companies. Shell Global Solutions is a network of independent technology companies in the Shell Group. In this presentation the expression ‘ Shell Global Solutions ’ is sometimes used for convenience where reference is made to these companies in general, or where no useful purpose is served by identifying a particular company. The information contained in this presentation contains forward-looking statements, that are subject to risk factors which may affect the outcome of the matters covered. None of Shell International B.V., any other Shell company and their respective officers, employees and agents represents the accuracy or completeness of the information set forth in this presentation and none of the foregoing shall be liable for any loss, cost, expense or damage (whether arising from negligence or otherwise) relating to the use of such information. The information contained in this presentation is intended to be general in nature and must not be relied on as specific advice in connection with any decisions you may make. Shell Global Solutions is not liable for any action you may take as a result of you relying on such material or for any loss or damage suffered by you as a result of you taking this action. Furthermore, these materials do not in any way constitute an offer to provide specific services. Some services may not be available in certain countries or political subdivisions thereof. Copyright © 2010 Shell Global Solutions (US) Inc. All copyright and other (intellectual property) rights in all text, images and other information contained in this presentation are the property of Shell International B.V. or other Shell companies. Permission should be sought from Shell International B.V. before any part of this presentation is reproduced, stored or transmitted by any means, electronic or mechanical including by photocopy, recording or information storage and retrieval system.

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

Recent History  API th Edition o Published April 1998 o Work started on 6 th edition  ISO o New work item submitted in June 2006 o Convert and update API-2000 into ISO Standard o FDIS 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 (API th edition)

Significant Differences Normal Tank Venting  EN Tank Venting o EN 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 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

EN 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

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 vent loads can be higher than Annex A Calculations and comparison courtesy of Protego (USA) Inc.

Calculation – Examples Tank 1 Tank: - Height: 5m - Diameter: 7m - Tank volume: 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

Inbreathing Requirements (Total) for Tank 1

Outbreathing Requirements (Total) for Tank

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

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

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

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

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 should be used.  Questions?

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?

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.

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?

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

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

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