Manual of Petroleum Standards Chapter 12—Calculation of Petroleum Quantities

Section 1—Calculation of Static Petroleum Quantities

Part 2—Calculation Procedures for Tank Cars

SECOND EDITION, FEBRUARY 2018

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Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, Acronyms, and Abbreviations 1

   1. General 1

   2. Acronyms and Abbreviations 6

4. Required Data Acquisition 7

   1. General 7

   2. Tank Car Data 7

   3. Product Data 8

5. Actual Loaded Quantity Calculations 11

   1. General 11

   2. General Purpose Cars 11

   3. Pressure Cars 11

   4. Vapor Space Heel 12

   5. Overload check 12

6. Rounding 12

   1. Data Level 12

   2. Rounding of Numbers 13

Annex A (normative) Loading Target Quantity Calculations 14

Annex B (informative) Calculation of Tank Car Shell Expansion/Contraction with Temperature 19

Annex C (informative) Calculation of Tank Car Shell Expansion with Pressure 21

Annex D (informative) Calculation of Magnetic Gauge Offsets 22

Annex E (informative) Tank Car Reconciliation 28

Annex F (informative) Calculation Examples 30

Bibliography 53

Figures

1. Magnetic Float Gauge 22

2. Derivation of a Spherical Volume Segment or Bowl 26

1. Butene Static Scale—BOL Difference 28

2. Actual Tare Minus Stenciled Weight 29

Tables

1 Significant Digits 13

B.1 Shell Temperature (°F) Tank Car Volume Correction Factors 20

C.1 Pressure (psig) Expansion Table for a Typical (D = 120 in., t = 11/16-in. mild steel) Pressure Car . . . 21

1. Temperature Offset for a Reference Relative Density of 0.50000 26

2. Temperature Offset for a Reference Relative Density of 1.0000 26

1. Outage Liquid Capacity Table—Loading Target Calculation—Volume Limitation 30

2. Outage Liquid Capacity Table—Actual Loaded Calculation 31

3. Outage Liquid Capacity Table—Loading Target Calculation—Weight Limitation 33

4. Outage Liquid Capacity Table with Nozzle Height Included—Loading Target Calculation

   —Volume Limitation 34

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   Contents

5. Example 5: Outage Liquid Capacity Table with Nozzle Height Included—Actual Loaded

   Page

   Calculation 36

6. Outage Vapor Capacity Table—Loading Target Calculation—Volume Limitation 37

7. Outage Vapor Capacity Table—Loading Target Calculation—Understated Loading Temperature . . 38

8. Outage Vapor Capacity Table—Actual Loaded Calculation 39

9. Outage Vapor Capacity Table—Actual Loaded Calculation—Overstated Target Loading Temperature Results in Overloading by Volume 41

10. Outage Vapor Capacity Table—Pressure Car Target Loading Calculation—Summer Loading 42

11. Outage Vapor Capacity Table—Pressure Car Target Loading Calculation—Winter Loading 43

12. Outage Vapor Capacity Table—Pressure Car Target Loading Calculation—Summer Loading 45

13. Innage Liquid Capacity Table—Loading Target Calculation—Volume Limitation 46

14. Tank Car Capacity Table 48

15. Tank Car Capacity Table 49

16. Tank Car Capacity Table 50

17. Tank Car Capacity Table 51

18. Tank Car Capacity Table 52

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Introduction

This chapter of the Manual of Petroleum Measurement Standards describes the standardized method for calculating target loading quantities and actual loaded quantities of liquids in tank cars. Also addressed within this chapter is an explanation of the factors required for the calculations.

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Chapter 12—Calculation of Petroleum Quantities Section 1—Calculation of Static Petroleum Quantities Part 2—Calculation Procedures for Tank Cars

1. Scope

   This chapter is applicable to all crude oils, petroleum products, and petrochemicals (including LPGs and other liquefied gases) transported by rail tank car. It does not cover any products loaded or measured as solids. It defines the terms required to understand the calculations and provides instructions for their use. The cars are assumed to be on level ground.

   
   

2. Normative References

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

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 1, Vocabulary

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 3.2, Tank Car Measurement

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 10, Sediment and Water

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 11.2.4, Temperature Correction for the Volume of NGL and LPG, Tables 23E, 24E, 53E, 54E, 59E, and 60E

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 11.2.5, A Simplified Vapor Pressure Correlation for Commercial NGLs

   
   

   API Manual of Petroleum Measurement Standards (MPMS) Chapter 12.2, Calculation of Petroleum Quantities Using Dynamic Measurement Methods and Volumetric Correction Factors

   
   

   ASTM D1555, Standard Test Method for Calculation of Volume and Weight of Industrial Aromatic Hydrocarbons and Cyclohexane

   
   

3. Terms, Definitions, Acronyms, and Abbreviations

For the purposes of this document, the following terms and definitions apply. Terms of more general use (i.e. API Gravity, Density, etc.) may be found in API MPMS Chapter 1.

3.1 General

3.1.1

capacity table adjustment factor

CTAF

Correction applied to capacity table volumes.

3.1.2

closed loading or closed unloading

The manway remains closed or covered during loading or unloading.

1