Manual of Petroleum Measurement Standards Chapter 12.1.1

Calculation of Static Petroleum Quantities— Upright Cylindrical Tanks and Marine Vessels

El Hydrocarbon Management HM 1 Part 1

FOURTH EDITION, FEBRUARY 2019

API MPMS Chapter 12.1.1/EI HM 1 Part 1

Calculation of Static Petroleum Quantities—Upright Cylindrical Tanks and Marine Vessels

Fourth Edition February 2019

Published jointly by

API

and

ENERGY INSTITUTE LONDON

The Energy Institute is a professional membership body incorporated by Royal Charter 2003 Registered charity number 1097899

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Foreword

This two-part publication presents standard calculation procedures for static petroleum liquids. The two parts consist of the following:

• Part 1—Upright Cylindrical Tanks and Marine Vessels

  
  

• Part 2—Calculation Procedure for Tank Cars

This publication was prepared jointly by the American Petroleum Institute Committee on Petroleum Measurement and the Energy Institute Hydrocarbon Management Committee.

The American Petroleum Institute Committee on Petroleum Measurement (COPM) and the Energy Institute's Hydrocarbon Management Committee (HMC) are responsible for the production and maintenance of standards and guides covering various aspects of static and dynamic measurement of petroleum. API COPM and EI HMC, their sub- committees and work groups consist of technical specialists representing oil companies, equipment manufacturers, service companies, terminal and ship owners and operators. API COPM and EI HMC encourage international participation and when producing publications their aim is to represent the best consensus of international technical expertise and good practice. This is the main reason behind the production of joint publications involving cooperation with experts from both the API and EI.

API/EI standards are published as an aid to procurement of standardized equipment and materials and/or as good practice procedures. These standards are not intended to inhibit purchasers or producers from purchasing or producing products made to specifications other than those of API or EI.

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Contents

Page

1. Scope 1

2. Normative References 1

   1. API Documents 1

   2. EI Documents 1

   3. Other Documents 2

3. Definitions 2

   1. General 2

   2. Abbreviations and Definitions 2

4. Interrelationship between Chapter 12 and Chapter 11.1 5

5. Hierarchy of Accuracies 5

6. Rounding and Discrimination 5

   1. Data Level 5

   2. Rounding of Numbers 6

   3. Discrimination 6

7. Observed Data (Input, Direct, or Primary) 6

8. Calculated Data (Indirect or Secondary) 7

9. Calculation of Gross Observed Volume (GOV) 8

   1. General 8

   2. Shore Tanks 8

   3. Marine Vessel Tanks 10

10. Calculation of Gross Standard Volume (GSV) and Total Calculated Volume (TCV)

    Shore Tanks and Marine Vessel Tanks 12

    1. Gross Standard Volume (GSV) 12

    2. Correction for the Effect of Temperature and Pressure on a Liquid (CTPL)

       or Volume Correction Factor (VCF) 13

    3. Total Calculated Volume (TCV) 13

11. Calculation of Net Standard Volume (NSV) 14

    1. Net Standard Volume (NSV) 14

    2. Calculation of the Correction for Sediment and Water (CSW) 14

    3. Calculation of the Volume of Sediment and Water (S&Wvol) 14

12. Calculation of Mass (Weight in Vacuum) and Weight (Weight in Air) 14

    1. Introduction 14

    2. Calculation Methods 14

    3. Converting Between Mass and Weight 15

13. Direct Mass Measurement 16

14. Calculation Sequence 16

    1. General 16

    2. Volume at Standard Temperature to Mass/weight Calculation Procedure 16

    3. Volume at Observed Temperature to Mass/Weight Calculation Procedure 17

15. Calculation of Transferred Volumes for Custody Transfer 18

    1. General 18

    2. Small Lease Tanks 18

       Contents

       Page

    3. Volumetric Shrinkage 19

16. Miscellaneous 19

    1. Precautions When Using an Automatic Sampler 19

    2. Interrelation of Units 19

Annex A (informative) Examples of Shore Tank and Marine Vessel Tank Calculations 21

Annex B (informative) Example of Shell Temperature Correction Factors for Expansion

and Contraction of Upright Cylindrical Steel Tanks Due to Temperature 28

Annex C (informative) Examples of Both Floating Roof Adjustments and Corrections 33

Annex D (informative) Linear Thermal Expansion Coefficients of Steel 37

Annex E (Excerpt from EI HM 43—Temperature Corrections in Tank Calibration and Gauging;

Petroleum Measurement Paper No. 11, September 1999

(Annex C—Effect of Temperature on Tank Capacity) 39

Bibliography 42

Figures

1 Method to Calculate Vessel’s List Using Amidships Draft Readings 12

Examples

1. Custody Transfer Flow Chart—Shore Tanks with a Representative Sample 21

2. Custody Transfer Flow Chart—Shore Tank(s) with Individual Tank Samples 22

3. Shore Tank Calculation Using Volume at Standard Temperature

   to Mass or Weight Calculation Procedure 23

4. Marine Vessel Tank Calculation Using Volume at Standard Temperature

   to Mass or Weight Calculation Procedure 24

5. Shore Tank Calculation of Volume at 15 °C and Weight of p-Xylene using ASTM D1555M 25

6. Shore Tank Calculation of Volume at 15 °C, Mass and Weight of MTBE using

   API MPMS Chapter 11.1/Adjunct to ASTM D1250/Adjunct to IP 200, Table 54C 26

7. Shore Tank Calculation of the Weight of Benzene Using Coefficient

of Thermal Expansion per Degree (Cs) 27

Tables

1. Significant Digits 6

2. Observed Data 7

3. Calculated Data 7

4. CTPL Factors 13

5. Mass-to-Weight Density Corrections 15

6. Discrimination Levels for Conversion Factors 20

1. Correction Factors for Effect of Temperature on the Tank Shell 31

2. Correction Factors for Effect of Temperature on the Tank Shell 32

C.1 Table 6 from API MPMS Chapter 11.1-1980/Adjunct to ASTM D1250-80/Adjunct

to IP 200/80, Table 5A Generalized Crude Oils API Correction to 60 °F 35

D.1 Linear Thermal Expansion Coefficients of Steel 37

Introduction

These procedures are intended to encourage a uniform approach to volumetric and mass calculation of crude oil, petroleum products, and petrochemicals when contained in tanks. This publication will also address calculation sequences, rounding, and significant digits, with the aim that different operators can produce identical results from the same observed data.

Calculation of Static Petroleum Quantities—Upright Cylindrical Tanks and Marine Vessels

1. Scope

   
   

   This standard is intended to guide the user through the steps necessary to calculate static liquid quantities, at atmospheric conditions, in upright, cylindrical tanks and marine tank vessels. The standard defines terms employed in the calculation of static petroleum quantities.

   
   

   The standard also specifies equations that allow the values of some correction factors to be computed. Fundamental to this process is the understanding that in order for different parties to be able to reconcile volumes, they have to start with the same basic information (tank capacity table, levels, temperatures, and so forth), regardless of whether the information is gathered automatically or manually.

   
   

   This standard does not address the calculation of clingage, non-liquid material, small quantities (such as onboard quantities, quantities remaining on board, and wedge formula, where material is not touching all bulkheads on marine vessels), and vapor space calculations.

   
   

2. Normative References

   
   

   The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

   
   

   1. API Documents

      
      

      MPMS, Chapter 2.8A, Calibration of Tanks on Ships and Oceangoing Barges MPMS, Chapter 11.5.1, Conversions of API Gravity at 60 °F

      MPMS, Chapter 11.5.2, Conversions for Relative Density (60/60 °F) MPMS, Chapter 11.5.3, Conversions for Absolute Density at 15 °C

      MPMS Chapter 12.3, Calculation of Volumetric Shrinkage From Blending Light Hydrocarbons with Crude Oil

      
      

      MPMS Chapter 16.2, Mass Measurement of Liquid Hydrocarbons in Vertical Cylindrical Storage Tanks by Hydrostatic Tank Gauging

      
      

      MPMS Chapter 17.4, Method for Quantification of Small Volumes on Marine Vessels (OBQ/ROB) MPMS Chapter 17.12, Procedures for Bulk Liquid Chemical Cargo Inspections

   2. EI Documents

HM 51, Procedures for bulk liquid chemical cargo inspections

Adjunct to IP 200 1, Temperature and Pressure Volume Correction Factors for Generalized Crude Oils, Refined Products, and Lubricating Oils

1 Energy Institute, formerly the Institute of Petroleum, 61 New Cavendish Street, London W1G 7AR, UK, www.energyinst.org.