API Manual of Petroleum Measurement Standards Chapter 17.12

EI Hydrocarbon Management HM 51

Procedures for bulk liquid chemical cargo inspections

2nd edition, August 2015

API MPMS CHAPTER 17.12/EI HM 51

PROCEDURES FOR BULK LIQUID CHEMICAL CARGO INSPECTIONS

2nd edition August 2015

Published by

ENERGY INSTITUTE, LONDON

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

ISBN 978 0 85293 737 2

CONTENTS

Page

Special notes and disclaimers 6 Foreword 8

1 Scope 9

1. General 9

2. Measurement stages 9

3. Quality control 10

4. Summary of data to be reported 10

2 Normative references 11

1. General 11

2. API/EI documents 11

3. EI documents 11

4. API documents 11

5. API/ASTM documents 12

6. American Society for Testing and Materials (ASTM) 12

7. Other documents 12

3 Terms and definitions 13

1. Accuracy 13

2. Ballast 13

3. Capacity table, tank 13

4. Critical zone 13

5. Density 13

6. Density, relative 13

7. Dip 14

8. Displacer (tank gauging) 14

9. Floating cover 14

10. Floating roof tank 14

11. Gauging 14

12. Inert gas 14

13. Inhibitors 14

14. List 14

15. Mass 15

16. Measurement 15

17. Meter factor 15

18. On board quantity (OBQ) 15

19. Outturn 15

20. Reference gauge height 15

21. Representative sample 15

22. Restricted gauging 15

23. Sampling 16

24. Slops 16

25. Spot sample 16

26. Stripping 16

27. Tape 16

28. Trim 16

29. Trim correction 16

    Contents continued Page

30. Ullage 16

31. Ullage gauge 17

32. Vapour 17

33. Vessel experience factor (VEF, VEFL, VEFD) 17

34. Volume correction factor (VCF) 17

35. Volume, gross observed (GOV) 17

36. Volume, gross standard (GSV) 17

37. Volume, net standard (NSV) 17

38. Volume, total calculated (TCV) 17

39. Water, free 18

40. Water cut (static measurement) 18

41. Wedge formula 18

4 General principles 19

1. The purpose of a cargo inspection 19

2. General responsibilities 19

   1. Communications, capabilities and performance 19

   2. Equipment 20

   3. Letters of protest/notices of apparent discrepancy 20

   4. Reporting 21

3. Potential measurement error 21

5 Safety recommendations 22

1. General 22

2. Safety aspects of equipment 22

3. Safety at sampling points 23

4. Static electricity 23

5. Health hazards 24

6. Entry into confined spaces 24

7. Personnel transfer offshore 25

1. Operation planning (loading and discharge) 27

   1. Key meeting 27

   2. Information to be determined before an operation commences 27

2. Inspection, sampling and quality control procedures 30

   1. Load procedures 30

      1. Shore tanks 30

      2. Dynamic measurement (metering) – See Annex B 32

      3. Sampling 33

      4. Manual sampling of shore tanks 34

      5. Automatic sampling 34

      6. Pipelines 35

      7. Vessel procedures before loading 36

      8. Vessel procedures at start of loading 40

      9. Vessel procedures after loading 41

      10. Calculations 42

      11. Vessel experience factor 42

      12. Reconciliation of measured qualities 42

          Contents continued Page

   2. Discharge procedures 42

      1. Vessel measurements before discharge 42

      2. In-transit difference 43

      3. Sampling 43

      4. Tank stripping operations/ROB 43

      5. Shore tank gauging and sampling 44

      6. Reconciliation of measured quantities 44

8 Calculation of quantities 45

1. General 45

2. Calculation methods 45

3. Examples of shore tank and marine tank calculations 46

8.3.1 Weight calculations 46

9 Final report 47

9.1 Inspection data 47

Annexes

Annex A Guidelines for verifying the accuracy of manual gauging equipment 49

1. Introduction 49

2. Liquid-in-glass thermometers 49

   1. Laboratory inspection 49

   2. Field inspection 49

3. Portable electronic gauging devices (PEGDs) 49

4. Manual gauging tapes 49

5. Density determination 50

   1. Hydrometers 50

   2. Densitometers 50

Annex B Monitoring metering system performance at loading 51

1. Introduction 51

2. Description of meter loading measurement systems 51

   B.2.1 Meter factor 51

3. Monitoring procedures 53

Annex C Wedge formula calculation 55

1. Calculation of the trim factor 55

2. Calculation of the length of the wedge 55

3. Calculation of DA 56

4. Wedge formula based on the tank width 57

5. Wedge formula based on theoretical tank width 58

Annex D Offshore operations 58

1. General 60

2. Safety – Personnel transfers 60

3. Inspection 60

4. Reconciliation of figures 60

5. Reporting and final report 61

Annex E Wall wash guidelines 62

SPECIAL NOTES AND DISCLAIMERS

API and EI publications are recommended for general adoption but should be read and interpreted in conjunction with Weights and Measures, Safety, Customs and Excise and other regulations in force in the country in which they are to be applied With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed Such regulatory requirements have precedence over corresponding clauses in API/EI publications However, where requirements of API/EI publications are more rigorous, then their use is recommended Where applicable, authorities having jurisdiction should be consulted The information contained in this publication is provided as guidance only. Neither API and EI nor any of API/EI’s employees, subcontractors, consultants, committees, or other assignees make any warranty or representation, either express or implied, with respect to the accuracy, completeness, or usefulness of the information contained herein, or assume any liability or responsibility for any use, or the results of such use, of any information or process disclosed in this publication. Neither API and EI nor any of API/EI’s employees, subcontractors, consultants, or other assignees represent that use of this publication would not infringe upon privately owned rights.

Users of this publication should not rely exclusively on the information contained in this document. Sound business, scientific, engineering, and safety judgment should be used in employing the information contained herein. Work sites and equipment operations may differ. Users are solely responsible for assessing their specific situation in determining the appropriateness of applying the information.

Information concerning safety and health risks and proper precautions with respect to particular materials and conditions should be obtained from the employer, the manufacturer or supplier of that material, or the applicable safety data sheet.

Classified areas may vary depending on the location, conditions, equipment, and substances involved in any given situation. Users of this Standard should consult with the appropriate authorities having jurisdiction.

API/EI joint publications may be used by anyone desiring to do so. Every effort has been made by the Institutes to assure the accuracy and reliability of the data contained in them; however, the Institutes make no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaim any liability or responsibility for loss or damage resulting from its use or for the violation of any authorities having jurisdiction with which this publication may conflict.

API/EI joint publications are published to facilitate the broad availability of proven, sound engineering and operating practices. These publications are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utilised. The development and publication of API/EI joint publications is not intended in any way to inhibit anyone from using any other practices.

Nothing contained in any API/EI joint publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.

API/EI are not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations to comply with authorities having jurisdiction.

The above disclaimer is not intended to restrict or exclude liability for death or personal injury caused by own negligence.

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

Copyright © 2015 by API, Washington DC and Energy Institute, London: All rights reserved.

No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher.

FOREWORD

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 subcommittees 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.

Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the specification.

Should: As used in a standard, “should” denotes a recommendation or that which is advised but not required in order to conform to the specification.

This publication was produced following API/EI standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API/EI standard. Questions concerning the interpretation of the content of this publication or comments and questions concerning the procedures under which this publication was developed should be directed in writing to the Director of Standards, American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005, USA, or the Technical Department, Energy Institute, 61 New Cavendish Street, London, W1G 7AR, UK.

Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the Director of Standards (API) or the Technical Department (EI). Generally, API/EI standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A one- time extension of up to two years may be added to this review cycle. Status of the publication can be ascertained from the API Standards Department, 1220 L Street, NW, Washington, DC 20005, USA, or the EI Technical Department, Energy Institute, 61 New Cavendish Street, London, W1G 7AR, UK.

A catalogue of API publications can be found at www.api.org/publications.

A catalogue of EI publications can be found at https://publishing.energyinst.org.

Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, DC 20005, USA, standards@api.org or to the Technical Department, Energy Institute, 61 New Cavendish Street, London, W1G 7AR, UK.

1 SCOPE

1 1 GENERAL

This document provides cargo measurement procedures for use primarily by inspectors and specifies procedures directed at minimising cargo contamination and losses. In the absence of, or in conjunction with, specific instructions from principal(s), this document should be considered a summary of good practice used within the industry.

Where the term 'measurement' is used in a general sense, it should be taken to include all aspects of cargo inspection including (but not limited to) tank inspection, sampling, laboratory analysis and testing and other superintending activities, as required by the inspector’s principals.

The points at which inspectors are required to make their measurements are described and definitions of the terms used throughout this document are provided in section 3. Where possible terms approved by API, EI and ISO/TC28 have been adopted.

The document also considers the purpose of a cargo survey and summarises the responsibilities of those involved. These procedures may become contractual if reference to them is made in either a nomination or acknowledgement.

Safety matters and related responsibilities are defined and emphasis is placed on the need for inspectors to be continually conscious that safety requirements take precedence over all other considerations.

The document describes the procedures which inspectors should follow and provides references to analytical test methods and calculations. Reference is made to alternative methods since it is recognised that opinions may vary regarding the use of test methods, and that different methods may be specified by the parties involved.

1 2 MEASUREMENT STAGES

When a cargo is transported by vessel from one shore terminal to another, measurements are normally made at four locations, as shown in Figure 1 for the purpose of establishing:

1. the quantity of cargo delivered (i.e. to confirm the quantity of cargo shown on the Bill of Lading);

2. the quantity of cargo loaded by the vessel;

3. the quantity of cargo discharged by the vessel;

4. the quantity of cargo received by the receiving terminal, and

5. the difference between the quantities established under (a) to (d) above.

Note: for a particular voyage involving more than one loading port or discharge port, measurements should be made at all such additional ports in order that a reliable comparison can be made between the quantities shown on the Bill of Lading, the cumulative outturn and ship’s figures.

Note 2: For ship to ship (STS) transfer operations please refer to Annex D.

TOTAL PHYSICAL AND APPARENT DIFFERENCES (Incl. MEASUREMENT ERROR)

1

2

3

4

Product loading terminal (Bill of Lading)

Loading

In transit Discharge

Receiver’s terminal (shore outturn)

Overall analyses of outturn difference

Supplier (B/Lading) 1

Tanker after loading

2

Tanker before discharging

3

Receiver (outturn) 4

Outturn difference

– = ( 1 –

) + ( 2 –

) + ( 3 – )

Shore to shore difference, (4-1) = (2-1) + (3-2) + (4-3) Note: by convention, losses have a negative sign

Figure 1: Marine transfer measurement points

1 3 QUALITY CONTROL

It is recognised that contamination may occur during the various transfer and transportation stages of cargo movement.

Procedures and recommendations for a testing schedule are given which can help to minimise such contamination risk.

1 4 SUMMARY OF DATA TO BE REPORTED

Due to the reporting requirements of each cargo inspection company and their clients (principals), specific reporting formats are not recommended in this document. However, a listing of the typical information sufficient to define a cargo loading or discharge operation is provided in section 4. This listing represents a consensus of a number of cargo inspection companies and their principals. The detailed format of these forms should be agreed with principals when contracts are being arranged.