Petroleum Storage Tank Overfill Prevention - My Committees

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					    API 2350: Tank Overfill Protection –
               An Overview
                     Monday, April 23 2012
                        Dallas, Texas
By PEMY Consulting
Philip E. Myers
• View and opinions are strictly those of the presenter and
  do not represent those of the American Petroleum
  Institute (API) or those of the API 2350 Overfill Revision
• At the time of this presentation the editorial process for
  API 2350 may still be in progress. While every effort is
  made to present the final outcome, no guarantee that the
  editorial process may result in changes to what is
  presented here can be made.
• All diagrams and drawings are conceptual in nature and
  cannot be directly used for design and construction of
  actual facilities. Such facilities must be individually
  engineered and designed for each tank and site by qualified
         Side Note about API/ANSI Process
•   Standards Development Processes set by American Nations Standards
    Institute (ANSI). Not all codes use this process (e.g. International Building
•   Consensus
•   Openness
•   Due Process
•   Committee balance (manufacturers, contractors, consultants,
    owner/operators, etc)
•   public review
•   All comments must be considered
•   standards are updated or reaffirmed by the same process at intervals not
    exceeding 5 years. The 2nd edition was already late and we issued the 3rd
    edition with a change that expanded the scope to include Class II liquids
•   regularly audited to ensure compliance with the Rules for Standards
    Committees and that are consistent with the American National Standards
    Institute (ANSI)
Why API 2350 Is Needed
    Overfill Prevention in Nutshell
• The Overfill Prevention Process (OPP) is simple in concept.
  When receiving product into a tank the flow is terminated
  prior to the tank level reaching the critical high (CH) level.
  Use of the word “terminate” in this standard means any of
  the following:
   – Terminating the source of pressure (e.g. shutting down a pump),
   – Diverting the incoming flow, or
   – Shutting down the flow (closing a receipt valve), or
   – Using an alternative way appropriate way of bringing the
     receipt process to a safe state without overfilling the tank
• While this desired end-result termination seems simple,
  experience suggests the need for a systematic Overfill
  Prevention Process (OPP) to ensure success over time
           Drivers for Current Changes

• API Revision Cycle past due
• Update API 2350 with current applicable
  standards such as S84 and IEC 61511 for
  automated safety instrumented systems
• Make it more enforceable and prescriptive
• Buncefield incident occurred at Sunday
  December 11th 2005 at the Buncefield Oil
  Storage Depot, Hemel Hempstead,
  Hertfordshire in the UK
    Questions You May Be Asking
• Is the new edition really that different than
  previous editions?
• Do I need to upgrade to the latest edition of
  API 2350?
• What are the benefits of upgrading?
• What is the rest of industry going to do about
           Historical Background
• 2350 first issued in March 1987. Scope restricted to
  “Terminals receiving transfer of Class I materials (e.g.
  gasoline) from mainline pipelines or marine vessels.”
• The second edition in January 1996 maintained that narrow
  scope and clarified that it covered ONLY gasoline, mainline
  pipelines and marine, and not other internal or external
  transfers. Minor non substantive revisions
• The third edition in January 2005 built on the second
  edition with the Scope significantly expanded to include
  both Class I and Class II hydrocarbon liquids as well as
  tankage in broader usage. Receipts of petroleum products
  from wheeled vehicles are specifically excluded from the
  Scope of API 2350, referring to PEI 600 for guidance.
• The scope of this Standard is specifically limited to storage tanks
  associated with marketing, refining, pipeline, terminals and similar
  facilities containing Class I or Class II petroleum liquids. (Note: API
  2350 is recommended for Class III liquids)
• This standard does not apply to:
    –   Underground storage tanks
    –   Aboveground tanks of 1320 US gallons (5000 liters) or less
    –   Aboveground tanks which comply with PEI 600
    –   Tanks (process tanks or similar flow through tanks) that are integral to
        a process.
    –   Tanks containing non-petroleum liquids
    –   Tanks storing LPG and LNG
    –   Tanks at Service Stations
    –   Loading or delivery from wheeled vehicles (such as tank trucks or
        railroad tank cars)
      New -Key Components of API 2350

• Management System
• Risk Assessment System
• Defining Operational Parameters and
• Procedures
• Equipment Systems (addition of AOPS)
                     Management System
• Management System
   –   Formal written operating procedures (including emergency response)
   –   Trained and qualified personnel
   –   Equipment systems testing and maintenance
   –   Normal and abnormal operating conditions addressed
   –   Moc (management of change)
   –   Investigation process for near misses and incidents
   –   Lessons learned
   –   Communications protocols esp between transporter and
• API 2350 does NOT specify how to develop/deploy a management
  system (we will do this in the workshop)
• Important Note: On request PEMY will send you a 25 page detailed
  write up on how to develop and deploy not only a safety
  management system but an overfill management system as well.
     Risk Assessment System
example of verbal risk assessment
  “I am willing to take the risk”
    API 2350 and Risk Assessment
• Risk Assessment system shall be used to categorize
  risks associated with potential overfilling operations as
  acceptable or unacceptable
• Risks are site and owner specific
• API 2350 does NOT specify how risk assessments
  should be conducted
• IEC 31010 “Risk management – Risk assessment
  techniques” lists many such methods. LOPA has been
  used extensively in the UK for tanks where risks
  considered significant.
• API 2350 Annex E Conceptual Tank Overfill Risk

• From the Italian word “risicare:”
  – “to dare”
• Risk defines the difference between
  – a choice and a fate
• Risk assessment:
  – The foundation for rational decision making.

                Insights.    Actions.
Why do risk assessment?


 Event /   Pathway



               Values and Consequences
                                     Values for a Pipeline Company
                                              “Be the preferred provider of
                                             liquid pipeline transportation”

                               Health                                      Employee                     Financial
 Customer      Environmental                    Regulatory    Strategic                   Public/
                                 &                                        Commitment/                  Performan
Satisfaction      Impacts                        Relations   Alignment                  Community
                               Safety                                       Alignment                      ce

                                 Public                                                   Community


                               Customers /
       Why do risk assessment?
           Because the consequences
            matter to us; values are
              adversely affected

 Event /            Pathway



             Risk assessment
• Risk assessment is a means to an end
• It aids us in protecting something of value
  from potential adverse consequences
• It is the foundation for decision making
    Assessment            Management
                Change the response      Eliminate the
                       curve             consequences


   Event /         Pathway

Eliminate the                 Impact the
 root cause                     target
                  Sever the
Risk model
   Qualitative                                Quantitative

Verbal                                 Simulation            Full economic
              Matrix                          Regression     model with
    SWOT                 Index                Decision-      uncertainty
                         models               analytic
                                    Optimization        attribute
                                                        decision analysis

Nominal    Categorical   Ordinal   Cardinal          Interval

Name         By            Rank        Differences        “Zero”
only         category      order       have               has
                                       meaning            meaning
                Tank Overfill Protection –
                  Basic Concept of Risk

                       Incident                              üAlarms
                                                             üAuto shutdown

                                                    Product receipt plan was not
No automatic
shutdown                                               Product
                                                       Receipt not
                                                  Tank flow was P
      Alarms did not          Tank rise was not
      work                    monitored
    Methods of Risk Assessment
• Many methods ranging from qualitative to
  semi-quantitative to quantitative:
  – Checklists
  – Risk matrices
  – HAZOP approach
  – Risk Graph
  – Quantitative Methods
  – Layers of Protection Analysis (LOPA)
                Consider These Likelihood
• Frequency, rate and duration of filling
• Systems used to properly measure and size receipts to tanks
• Accurate tank calibration (both strapping and verified Critical High)
• Systems used to monitor receipts
• Extent of monitoring / supervision of manual and automatic tank
• Impact of complexity and operating environment on the ability of
  Operating Personnel to execute overfill prevention tasks
    – Filling multiple tanks simultaneously
    – Switching tanks during receipt
    – Large elevation changes between tanks and backflow
             Consider these Consequence
• Hazard characteristics of material (product) in tank
• Volatility, flammability, dispersion, VCE potential
• Number of people onsite who might be affected by a tank
• Number of people offsite who might be affected by a tank
• Possibility of a tank overflowing resulting in (escalation) of
  hazardous events onsite or offsite
• Possibility of impact to nearby sensitive environmental receptors
• Physical and chemical properties of product released during
• Maximum potential overfill flow rates and duration
• Secondary containment
Initializing Operating Parameters
    Initializing Operating Parameters -

–   Level: Critical High (CH)
      • Overfill or Damage occurs
      • Activate Emergency Response

–   Level: High-High (HH)
      • Alarm or AOPS

–   Level: High (Optional)
      • Alerts NOT Alarm

–   Normal Fill Level (NFL)
      • Highest working level
             Review/revise LOCs when
•   New tank
•   Change in floating roof tank seals
•   Installation of geodesic domes or other kinds of fixed roofs (e.g. when external floating roof
    tanks receive retrofit covers).
•   New internal or external floating roof
•   Side vent changes
•   Shell extensions
•   New tank bottom
•   Addition of ancillary equipment such as foam chambers
•   Recalibration or re-strapping of the tank
•   Change of tank gauging equipment
•   Addition of a gauge tube with datum or change in datum/strike plate
•   Change in product
•   Change in incoming or outgoing lines
•   Change in flow rates,
•   Change in service if it impacts structural integrity [corrosion, temporary repairs, etc]
•   Change in operations, such as: parallel tank, floating or high suction, continuous mixer
•   Change in response time resulting from staffing, operation or equipment changes
      Initializing Operating Operating
           Parameters - Categories
• Operators shall categorize each tank
• A way to classify tank overfill systems
• Category I: manual system
• Category II: ATG with transmittable data to
  control center
• Category III: ATG and independent level alarm
  transmittable to control center
• AOPS: independent addition to Categories I, II, or
• Given all things equal, the higher the category
  of overfill protection system, the more robust
  and reliable it is.
• When a manual system (MOPS) does not have
  sufficiently low probability of failure on
  demand, then AOPS should be considered as a
  means of increasing the OPS reliability
                  Category I
– Configuration        n Does not have transmitted alarms

                       n Tank Level is determined by HAND
                         gauging or local Automatic Tank
                         Gauging (ATG) system.

                       n Requires Local “manual” shutdown or
                         diversion or transporter shutdown
                         after receiving “manual”
                         communications from facility

                       n Use only at fully-attended facilities

                       n Monitor continuously first and last
                         and every in-between hour of receipt

                       n Do not use for high frequency or
                         complex receipt operations              30
                  Category 2
– Configuration        n Tank level (ATG required) and alarm is
                         transmitted to remote location (control

                       n ATG Alarm set at LOC: HH

                       n Alarm are not independent of ATG
                         system (same sensor for ATG and alarm)

                       n May use Cat 2 at fully or semi attended
                         facility if receipts monitored at the
                         control room

                       n On site monitoring required 30 minutes
                         at start, at end of receipt; for semi
                         attended transporter must participate
                         in monitoring

                       n Alerts recommended at LOC: H
                  Category 3
– Configuration        n Tank level and alarm is transmitted
                         to remote location (control room).

                       n Alarm is independent of ATG
                         system and set at High-High LOC.

                       n Requires Local “manual” shutdown
                         or diversion

                       n For unattended operation, alarm
                         shall automatically notify
                         transporter or automatically
                         terminate receipt (AOPS) and
                         receipt termination shall commence
                         in event of power outage

Automatic Overfill Protection
     System (AOPS)
– Configuration   n Basic Process Control system can be
                    Category I, 2 or 3

                  n AOPS in independent of operation

                  n AOPS added as another layer of
                    protection on top of Category I, 2 or
                    3 if risk assessment shows
                    acceptable risk cannot be attained

                  n Two Options:

                      n 1 Existing Facilities Annex A

                      n 2 New Facilities ISA S84.01 or
                        IEC 61511
                   Response Times
• Save time: Do the calculation

        Table 1: Minimum High-High Tank (HH) Response Time
                         (if not calculated)

        Category                          Time in Minutes

           1                                    45

           2                                    30

           3                                    15
    Beware The Response Time
Recommenation: never less than 5 minutes no matter
                the calculation
  Putting It Together (partial list)
                                                     Mission vision

                                  People and
   Management                                                      assessment
     System                        resources

                                  Operational                Training,
                                  Parameters               competancy

Tank data base, tank standards, field verification, upgrading policy, prioritization for
              upgrading, policy/consultants for AOPS, etc. etc. etc.
• Is the new edition really that different than
  previous editions?
• Do I need to upgrade to the latest edition of
  API 2350?
• What are the benefits of upgrading?
• What is the rest of industry going to do about
                          Conclusions and
•   The New API 2350 will represent a significant change from past practices
    but it is consistent with today’s best practices in areas of safety and
    environmental protection as well as state-of-the-art technology
•   Authorities will consider it minimum requirements
•   OMS must be a corporate way of life – created by a vision, a mission and a
•   A high level of top level commitment and resources is required - But the
    alternatives can be costly too
•   Must be embedded into the corporate value system so that it is a long
    term process and can outlast the managers and executives who often get
    promoted out of their positions and who never really truly understood
    what a safety management system is
•   Do your part to educate top management that this is really the best way
    to go if you are going to be in the petroleum business. Do it thru
    knowledge, education and expertise and hopefully not because of a
    serious incident

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