1. API 2350: Tank Overfill Protection – An Overview Monday, April 23 2012 Dallas, Texas
By PEMY Consulting
Philip E. Myers

2. Disclaimer
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 Taskgroup
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 personnel

3. 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 Code)
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)

4. Why API 2350 Is Needed

5. 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), or
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

6. Drivers for Current Changes
API Revision Cycle past due
Update API 2350 with current applicable standards such as S84 and IEC 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

7. 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 it?

8. Historical Background
2350 first issued in March 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.

9. Scope
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)

10. New -Key Components of API 2350
Management System
Risk Assessment System
Defining Operational Parameters and Categorization
Procedures
Equipment Systems (addition of AOPS)

11. 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 owner/operator
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.

12. Risk Assessment System example of verbal risk assessment “I am willing to take the risk”

13. 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 “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 Evaluation

14. 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.

15. Why do risk assessment? Impact Event / Pathway Scenario Consequences
Dose
Response

16. Values and Consequences
Values for a Pipeline Company
“Be the preferred provider of
liquid pipeline transportation”
Customer
Satisfaction
Environmental
Impacts
Health
&
Safety
Public
Workers
Customers / Consumers
Regulatory
Relations
Strategic
Alignment
Employee
Commitment/
Alignment
Corporate
Public/
Community
Reputation
Community relations
Corp reputation
Financial Performance 3

17. Because the consequences matter to us; values are adversely affected
Why do risk assessment?
Because the consequences matter to us; values are adversely affected
Consequences
Impact
Event /
Scenario
Pathway
Dose
Response

18. 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

19. Assessment Management
Eliminate the
consequences
Change the response curve
Consequences
Impact
Protect the
target
Eliminate the
root cause
Event /
Scenario
Sever the
pathway
Dose
Response
Pathway

20. Risk model Qualitative Quantitative Data Verbal SWOT Risk Matrix Index
models
Optimization
Simulation
Regression
Decision-
analytic
Multi-
attribute
decision analysis
Full economic
model with
uncertainty
Data
Nominal Categorical Ordinal Cardinal Interval
Name
only By
category
Rank
order
Differences
have
meaning
“Zero”
has
meaning

21. Tank Overfill Protection – Basic Concept of Risk
Behaviors
Procedures/Training
Equipment:
Gauges
Alarms
Auto shutdown
Incident
Product receipt plan was not completed
No automatic shutdown
Instructor Notes:
These were actual root causes of a recent tank overfill incident
Point out the individual layers of protection and remind class that no one layer is perfect (i.e. not a complete circle of protection)
The first layer in this example is a product receipt plan which was not followed, resulting in a gap.
If the second layer (verification of tank flow) was performed, then the incident would not occur; however, this was not done and it resulted in another gap.
If all safeguard gaps line-up then an incident occurs; if only a few gaps line-up, this results in a near loss.
(Instructor: press enter to illustrate point #5)
Instructor explain to class that the number of layers required will be based on a risk analysis as determined by Engineering’s Tank Gauging & Alarm Equipment Standard. So in some cases you may have three layers of protection, some five layers and others may be less. Point is, there must be some level of redundancy in protection.
Product Receipt P
Tank flow was not verified
Alarms did not work
Tank rise was not monitored

22. 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)

23. Consider These Likelihood Factors:
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 gauging
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

24. Consider these Consequence Factors
Hazard characteristics of material (product) in tank
Volatility, flammability, dispersion, VCE potential
Number of people onsite who might be affected by a tank overflowing
Number of people offsite who might be affected by a tank overflowing
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 overflowing
Maximum potential overfill flow rates and duration
Secondary containment

25. Initializing Operating Parameters

26. Initializing Operating Parameters - LOCs
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

27. 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 operation
Change in response time resulting from staffing, operation or equipment changes

28. 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 III

29. 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 (availability)

30. Category I Configuration Does not have transmitted alarms
Tank Level is determined by HAND gauging or local Automatic Tank Gauging (ATG) system.
Requires Local “manual” shutdown or diversion or transporter shutdown after receiving “manual” communications from facility
Use only at fully-attended facilities
Monitor continuously first and last and every in-between hour of receipt
Do not use for high frequency or complex receipt operations
Instructor Notes:
Now that we have covered the first bullet on slide 7 – understanding LOCs, we will talk about Tank Gauging & Alarm system categories.
There are 4 categories and as you go up in category, the systems provide increasing levels of protection.
Category 1 can be a completely manual operation, with or without an ATG.
If a tank does not consist of an automatic tank gauge, operations would have to use an manual tape gauge to gauge the tank for product level.
Hand gauging requires personnel to access the top of the tank, open the tank to atmosphere, and lower a manual tape to verify the tank level.
Product paste is required to verify the cut between product and water.

31. Category 2 Configuration
Tank level (ATG required) and alarm is transmitted to remote location (control room)
ATG Alarm set at LOC: HH
Alarm are not independent of ATG system (same sensor for ATG and alarm)
May use Cat 2 at fully or semi attended facility if receipts monitored at the control room
On site monitoring required 30 minutes at start, at end of receipt; for semi attended transporter must participate in monitoring
Alerts recommended at LOC: H
Instructor Notes
The next category requires an ATG on the tank that has the capability to transmit tank level and alarm information to a remote location.
A float and tape device is not acceptable for this category because of the level of reliability a newer automatic tank gauge provides
The required alarm is set at the High LOC.
Some gauges comes with 2 contacts so that multiple alarms can be set. In such cases, an optional alarm may be set at the High-High LOC.
For new installations, the remote monitoring system shall have the capability of monitoring gauge status and level alarms.

32. Category 3 Configuration
Tank level and alarm is transmitted to remote location (control room).
Alarm is independent of ATG system and set at High-High LOC.
Requires Local “manual” shutdown or diversion
For unattended operation, alarm shall automatically notify transporter or automatically terminate receipt (AOPS) and receipt termination shall commence in event of power outage
Instructor Notes:
Category 3 is requiring an addition level of protection – an independent alarm. As the figure illustrates, the alarm set at the High-high level is triggered by a sensor separate from the ATG.
In this case, you will have a High level alarm triggered by the ATG, and a second independent alarm set at the High-High level.

33. Automatic Overfill Protection System (AOPS)
Configuration
Basic Process Control system can be Category I, 2 or 3
AOPS in independent of operation
AOPS added as another layer of protection on top of Category I, 2 or 3 if risk assessment shows acceptable risk cannot be attained otherwise
Two Options:
1 Existing Facilities Annex A
2 New Facilities ISA S84.01 or IEC 61511
Instructor Notes:
Category 4 is the highest level specified in the standard. In this case, a shut/down diversion system is required when liquid reaches the High-High level.
As mentioned previously, there is a separate equipment standard that covers the details of the requirement of this automatic shutdown/diversion system. That standard is to be published later this year. When you find that a category 4 system is required, make sure you consult this standard so that the system can be properly designed.
Just like a category 3 system, a category 4 system uses the same gauging and alarm equipment as a category 2 system. The added layer of protection involves installing equipment to handle shutting down or diverting the receipt.
Explain importance of communication plan between the terminal and the shipper, regarding shutdown procedures if communication is disrupted beyond an agreed upon time.

34. Table 1: Minimum High-High Tank (HH) Response Time
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

35. Beware The Response Time
Recommenation: never less than 5 minutes no matter the calculation

36. Putting It Together (partial list)
Top management support
Mission vision values
Risk assessment system
Management System
People and resources
Define Operational Parameters
procedures
Training, competancy
Tank data base, tank standards, field verification, upgrading policy, prioritization for upgrading, policy/consultants for AOPS, etc. etc. etc.

37. Questions
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 it?

38. Conclusions and Recommendations
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 philosophy
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