Petroleum and Liquid Petroleum Products—Calibration of Horizontal Cylindrical Tanks

Part 2: Internal Electro-optical Distance-ranging Method

API MPMS CHAPTER 2.2F FIRST EDITION, APRIL 2004

REAFFIRMED, SEPTEMBER 2014

ISO 12917-2, Petroleum and liquid petroleum products— Calibration of horizontal cylindrical tanks—Part 2: Internal electro-optical distance-ranging method

Special Notes

API publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed.

API is 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 under local, state, or federal laws.

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 material safety data sheet.

Nothing contained in any API 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.

Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. Sometimes a one-time extension of up to two years will be added to this review cycle. This publication will no longer be in effect five years after its publication date as an operative API standard or, where an extension has been granted, upon republication. Status of the publication can be ascertained from the API Standards department telephone (202) 682-8000. A catalog of API publications, programs and services is published annually and updated biannually by API, and available through Global Engineering Documents, 15 Inverness Way East, M/S C303B, Englewood, CO 80112-5776.

This document was produced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content of this standard or comments and questions concerning the procedures under which this standard was developed should be directed in writing to the Director of the Standards department, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. Requests for permission to reproduce or translate all or any part of the material published herein should be addressed to the Director, Business Services.

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

Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard.

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. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.

Copyright © 2004 American Petroleum Institute

API Foreword

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict.

Suggested revisions are invited and should be submitted to API, Standards department, 1220 L Street, NW, Washington, DC 20005, standards@api.org.

Contents

Page

API Foreword ii

Foreword iv

1. Scope 1

2. Normative references 1

3. Terms and definitions 2

4. Precautions 2

5. Equipment 2

   1. Electro-optical distance-ranging instrument 2

   2. Instrument mounting 2

   3. Laser-beam emitter 2

   4. Stadia 3

   5. Auxiliary equipment 3

6. General considerations 3

7. EODR instrument set up within the tank 3

8. Selection of target points 4

   1. Introduction 4

   2. Location of target points — General principle 5

   3. Cylindrical courses 5

   4. Heads 5

9. Procedure for calibration 5

10. Tolerances of reference target points 5

    1. Distance verification 5

    2. Verification of horizontal and vertical angles 6

11. Additional measurements 6

    1. Reference-height determination and reference-point position 6

    2. Data 7

    3. Drawings 7

12. Calculation and development of capacity tables 7

Annex A (normative) Determination of the limiting angle of incidence 8

Annex B (informative) Numerical example 9

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this part of ISO 12917 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 12917-2 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants, Subcommittee SC 3, Static petroleum measurement.

ISO 12917 consists of the following parts, under the general title Petroleum and liquid petroleum products — Calibration of horizontal cylindrical tanks:

• Part 1: Manual methods

  
  

• Part 2: Internal electro-optical distance-ranging method

Annex A forms a normative part of this part of ISO 12917. Annex B is for information only.

Petroleum and liquid petroleum products — Calibration of horizontal cylindrical tanks —

Part 2:

Internal electro-optical distance-ranging method

1. Scope

   
   

   This part of ISO 12917 specifies a method for the calibration of horizontal cylindrical tanks having diameters greater than 2 m by means of internal measurements using an electro-optical distance-ranging instrument, and for the subsequent compilation of tank-capacity tables.

   
   

   This method is known as the internal electro-optical distance-ranging (EODR) method.

   
   

   This part of ISO 12917 is applicable to tanks inclined by up to 10 % from the horizontal, provided a correction is applied for the measured tilt.

   
   

2. Normative references

   
   

   The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 12917. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 12917 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.

   
   

   ISO 1998 (all parts), Petroleum industry — Terminology

   
   

   ISO 7507-1:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 1: Strapping method

   
   

   ISO 7507-4:1995, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 4: Internal electro-optical distance-ranging method

   
   

   ISO 12917-1:2002, Petroleum and liquid petroleum products — Calibration of horizontal cylindrical tanks — Part 1: Manual methods

   
   

   IEC 60079-10:1995, Electrical apparatus for explosive gas atmospheres — Part 10: Classification of hazardous areas

   
   

   IEC 60825-1:1994, Safety of laser products — Part 1: Equipment classification, requirements and user’s guide

3. Terms and definitions

   
   

   For the purposes of this part of ISO 12917, the terms and definitions given in ISO 1998, ISO 7507-1 and the following apply.

   
   

   3.1

   reference target point

   fixed point clearly marked on the inside surface of the tank shell or a prism mounted on a tripod or stadia

   
   

   3.2

   slope distance

   distance measured from the electro-optical distance-ranging instrument to a target point on any given course of the tank shell

   
   

   3.3

   target point

   one of a series of points on the inside surface of the tank shell to which the slope distance, vertical angles and horizontal angles are measured by use of the electro-optical ranging instrument

   
   

4. Precautions

   
   

   The general and safety precautions given in ISO 7507-1 shall apply to this part of ISO 12917. In addition, the laser beam fitted to the EODR instrument shall be operated in conformity with IEC 60825-1. The hazards, if any, in the area in which the calibration is to be carried out shall be assessed in accordance with IEC 60079-10. The equipment to be used in the calibration shall be certified as being safe for use in the area of operation.

   
   

5. Equipment

   
   

   1. Electro-optical distance-ranging instrument

      
      

      1. The angle-measuring part of the instrument shall have an angular graduation and resolution equal to or better than 0,002 gon.

         
         

         This part of the instrument shall have a repeatability equal to or better than  0,005 gon.

         
         

      2. The distance-measuring part of the instrument, used for direct determination of distances, shall have a graduation and resolution equal to or better than  1 mm.

This part of the instrument shall have a repeatability equal to or better than  2 mm.

1. Instrument mounting

   
   

   A tripod which is firm and stable. The legs of the tripod may be held firm, and steadied, by suitable devices such as magnetic bearers.

   
   

2. Laser-beam emitter

A low-power laser beam complying with IEC 60825-1, which is either an integral part of the EODR instrument or a separate device. If the laser beam emitter is a separate device, it may be fitted with a fibre-optic light transmitter system and a theodolite telescope eyepiece connection, by which the laser beam may be transmitted through a theodolite, or such that it may be fitted to a theodolite with its axis co-incident to the axis of the theodolite.

NOTE The laser-beam emitter is used to position target points on the tank shell.