SIST ISO 7507-1:2006

Petroleum and liquid petroleum products -- Calibration of vertical cylindrical tanks -- Part 1: Strapping method

This part of ISO 7507 specifies a method for the calibration of substantially vertical cylindrical tanks by measuring the tank using a strapping tape. This method is known as the strapping method and is suitable for use as a working method, a reference method or a referee method. The operation of strapping, the corrections to be made and the calculations leading to the compilation of the tank capacity table are described. This method does not apply to abnormally deformed, e.g. dented or non-circular, tanks. This method is suitable for tilted tanks with a deviation of up to 3 % from the vertical, provided that a correction for the measured tilt is applied in the calculations.

Pétrole et produits pétroliers liquides -- Jaugeage des réservoirs cylindriques verticaux -- Partie 1: Méthode par ceinturage

L'ISO 7507-1:2003 spécifie une méthode permettant de jauger les réservoirs cylindriques pratiquement verticaux par mesurage avec un ruban de ceinturage.  
Cette méthode connue sous le nom de «méthode par ceinturage» convient tant comme méthode de travail que comme méthode de référence ou encore comme méthode d'arbitrage.
Les opérations de ceinturage à mettre en oeuvre ainsi que les corrections et les calculs à effectuer pour élaborer un barème de jaugeage de réservoir sont décrits.
La présente méthode ne s'applique pas aux réservoirs anormalement déformés, par exemple les réservoirs bosselés ou non circulaires.
Cette méthode convient pour les réservoirs dont l'inclinaison par rapport à la verticale n'excède pas 3 %, à condition qu'une correction soit apportée aux calculs pour tenir compte de l'inclinaison mesurée.

Nafta in tekoči naftni proizvodi – Umerjanje navpičnih valjastih rezervoarjev – 1. del: »Strapping« metoda

General Information

• Status: Published
• Publication Date: 31-Jan-2006
• ICS: 75.180.30 - Volumetric equipment and measurements
• Technical Committee: NAD - Petroleum products, lubricants and related products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Feb-2006
• Due Date: 01-Feb-2006
• Completion Date: 01-Feb-2006
• Directive: TP009 - Pravilnik o meroslovnih zahtevah za nepremične rezervoarje
• Ref Project: ISO 7507-1:2003 - Petroleum and liquid petroleum products -- Calibration of vertical cylindrical tanks

RELATIONS

• Revised: ISO 7507-1:1993 - Petroleum and liquid petroleum products -- Calibration of vertical cylindrical tanks
• Effective Date: 12-May-2008
• Revised: ISO/TR 7507-6:1997 - Petroleum and liquid petroleum products -- Calibration of vertical cylindrical tanks
• Effective Date: 12-May-2008

Standards Content (sample)

SLOVENSKI STANDARD
SIST ISO 7507-1:2006
01-februar-2006

Nafta in tekoči naftni proizvodi – Umerjanje navpičnih valjastih rezervoarjev – 1.

del: »Strapping« metoda

Petroleum and liquid petroleum products -- Calibration of vertical cylindrical tanks -- Part

1: Strapping method

Pétrole et produits pétroliers liquides -- Jaugeage des réservoirs cylindriques verticaux --

Partie 1: Méthode par ceinturage
Ta slovenski standard je istoveten z: ISO 7507-1:2003
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
SIST ISO 7507-1:2006 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 7507-1:2006
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SIST ISO 7507-1:2006
INTERNATIONAL ISO
STANDARD 7507-1
Second edition
2003-12-15
Petroleum and liquid petroleum
products — Calibration of vertical
cylindrical tanks —
Part 1:
Strapping method
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs
cylindriques verticaux —
Partie 1: Méthode par ceinturage
Reference number
ISO 7507-1:2003(E)
ISO 2003
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2003

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2003 — All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope...................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 2

4 Precautions............................................................................................................................................ 5

5 Equipment.............................................................................................................................................. 6

6 General requirements........................................................................................................................... 7

7 Circumference measurements............................................................................................................. 7

8 Other measurements on tank shell plates........................................................................................ 10

9 Deadwood............................................................................................................................................ 10

10 Tank bottoms....................................................................................................................................... 11

11 Measurement of tilt ............................................................................................................................. 11

12 Floating-roof tanks.............................................................................................................................. 11

13 Recalibration....................................................................................................................................... 12

14 Computation of tank capacity tables — General rules ................................................................... 12

15 Form of tank capacity tables ............................................................................................................. 13

16 Computation of open capacity .......................................................................................................... 13

17 Construction of final tables................................................................................................................ 17

Annex A (normative) Specification for equipment used in strapping ........................................................ 23

Annex B (informative) Recommendations for monitoring, checking and verification of tank

calibration and capacity table............................................................................................................ 26

Annex C (informative) Tank calibration data and calculation sheet............................................................ 32

Annex D (informative) Tank calibration uncertainties .................................................................................. 36

Annex E (informative) Tank shell temperature determination ..................................................................... 47

Annex F (normative) Gauge tape temperature correction ........................................................................... 48

Annex G (informative) Expansion due to liquid head ................................................................................... 50

Annex H (normative) Expansion due to temperature ................................................................................... 58

Annex I (normative) Certificate of calibration................................................................................................ 61

Bibliography ..................................................................................................................................................... 62

© ISO 2003 — All rights reserved iii
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
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 2.

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 document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

International Standard ISO 7507-1 was prepared by Technical Committee ISO/TC 28, Petroleum products and

lubricants, Subcommittee SC 3, Static petroleum measurement.

This second edition cancels and replaces the first edition (ISO 7507-1:1993). It also cancels and replaces

ISO 7507-6:1997, the subject of which is now included in this part of ISO 7507.

ISO 7507 consists of the following parts, under the general title Petroleum and liquid petroleum products —

Calibration of vertical cylindrical tanks:
 Part 1: Strapping method
 Part 2: Optical-reference-line method
 Part 3: Optical-triangulation method
 Part 4: Internal electro-optical distance-ranging method
 Part 5: External electro-optical distance-ranging method

 Part 6: Recommendations for monitoring, checking and verification of tank calibration and capacity table

iv © ISO 2003 — All rights reserved
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
Introduction

This part of ISO 7507 forms part of a series on tank calibration including the following:

ISO 7507-2:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 2: Optical-reference-line method

ISO 7507-3:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 3: Optical-triangulation method

ISO 7507-4:1995, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 4: Internal electro-optical distance-ranging method

ISO 7507-5:2000, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 5: External electro-optical distance-ranging method

ISO 7507-6:1997, Recommendations for monitoring, checking and verification of tank calibration and capacity

table

ISO 8311:1989, Refrigerated light hydrocarbon fluids — Calibration of membrane tanks and independent

prismatic tanks in ships — Physical measurement

ISO 9091-1:1991, Refrigerated light hydrocarbon fluids — Calibration of spherical tanks in ships — Part 1:

Stereo-photogrammetry

ISO 9091-2:1992, Refrigerated light hydrocarbon fluids — Calibration of spherical tanks in ships — Part 2:

Triangulation measurement

The strapping method for the calibration of vertical cylindrical tanks has been used for many years and is a

recognized method of determining the capacity of storage tanks from measurements of the circumference of a

tank at various heights. The strapping method is also often used to establish a reference circumference at a

selected height to use as a datum in other methods of tank calibration.
© ISO 2003 — All rights reserved v
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SIST ISO 7507-1:2006
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SIST ISO 7507-1:2006
INTERNATIONAL STANDARD ISO 7507-1:2003(E)
Petroleum and liquid petroleum products — Calibration of
vertical cylindrical tanks —
Part 1:
Strapping method
1 Scope

1.1 This part of ISO 7507 specifies a method for the calibration of substantially vertical cylindrical tanks by

measuring the tank using a strapping tape.

1.2 This method is known as the “strapping method” and is suitable for use as a working method, a

reference method or a referee method.

NOTE For the reference method, the number of strappings required will be specified in the standard which refers to

this part of ISO 7507.

1.3 The operation of strapping, the corrections to be made and the calculations leading to the compilation of

the tank capacity table are described.

1.4 This method does not apply to abnormally deformed, e.g. dented or non-circular, tanks.

1.5 This method is suitable for tilted tanks with a deviation of up to 3 % from the vertical, provided that a

correction for the measured tilt is applied in the 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.

ISO 91-1:1992, Petroleum measurement tables — Part 1: Tables based on reference temperatures of 15 °C

and 60 °F

ISO 3675:1998, Crude petroleum and liquid petroleum products — Laboratory determination of density —

Hydrometer method

ISO 4269:2001, Petroleum and liquid petroleum products — Tank calibration by liquid measurement —

Incremental method using volumetric meters
© ISO 2003 — All rights reserved 1
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
3 Terms and definitions

For the purposes of this document and subsequent parts of ISO 7507, the following terms and definitions

apply.
3.1
argument
independent variable of a function

NOTE A table is entered with value(s) of the independent variable(s), the value(s) extracted from the table being

known as the dependent value(s).
3.2
bottom calibration

procedure to determine the quantity of liquid contained in a tank below the calibration datum-point

3.3
calibration

process of determining the capacity of a tank, or the partial capacities corresponding to different levels

3.4
capacity
total volume of a tank
3.5
capacity table
tank table
tank capacity table

table showing the capacities of, or volumes in, a tank corresponding to various liquid levels measured from a

stable reference point
3.6
course
one circumferential ring of plates in a tank
3.7
calibration datum-point
point used as the datum in the preparation of a calibration table

NOTE Course heights and the effective levels of deadwood are measured from this point, to which the bottom

calibration is also related.
3.8
deadwood
any tank fitting that affects the capacity of the tank

NOTE Deadwood is referred to as “positive deadwood” when the capacity of the fitting increases the effective

capacity of the tank, or “negative deadwood” when the volume of the fitting displaces liquid and reduces the effective

capacity.
3.9
dip
innage
depth of a liquid in a tank above the dipping datum-point
3.10
dip-hatch
gauge-hatch

opening in the top of a tank through which dipping and sampling operations are carried out

2 © ISO 2003 — All rights reserved
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SIST ISO 7507-1:2006
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3.11
dip-point

point on the dip-plate which the dip-weight touches during gauging and from which the measurements of the

oil and water depths are taken

NOTE The dip-point usually corresponds to the datum-point, but when this is not so, the difference in level between

the datum-point and the dip-point has to be allowed for in the calibration table.

3.12
dip-plate
striking-plate positioned below the dip-hatch

NOTE The position of the dip-plate should not be affected by bottom or wall movements.

3.13
dip-tape

graduated steel tape used for measuring the depth of the oil or water in a tank, either directly by dipping or

indirectly by ullage
3.14
dip-weight

weight attached to a steel dip-tape, of sufficient mass to keep the tape taut and of such shape as to facilitate

the penetration of any sludge that might be present on the dip-point or the dip-plate

3.15
floating cover
screen

lightweight cover of either metal or plastics material designed to float on the surface of a liquid in a tank

NOTE The cover rests upon the liquid surface and is used to retard evaporation of volatile products in a tank.

3.16
floating-roof tank

tank in which the roof floats freely on the surface of the liquid contents, except at low levels when the weight of

the roof is taken through its supports by the tank bottom
3.17
function

when two variable quantities are interrelated, one quantity is said to be a function of the other

NOTE In the context of tank calibration, the volume of liquid contained in a tank is said to be a function of the dip or

of the ullage.
3.18
gauging

process of taking all the necessary measurements in a tank in order to determine the quantity of liquid that it

contains
3.19
interpolation

process of obtaining the value of a function corresponding to a value of the argument intermediate between

those given
3.20
Littlejohn grip

quick-release clamp that may be fitted around a strapping tape at any convenient position throughout its

length

NOTE A handle is attached to the Littlejohn grip so that the strapping tape can be pulled to the correct tension.

© ISO 2003 — All rights reserved 3
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
3.21
open capacity

calculated capacity of a tank or part of a tank before any allowance has been made for deadwood

3.22
reference height
vertical distance between the dip-point and the upper reference point
3.23
overall height
total external height from the top of the shell to the base of the tank (plate)
3.24
referee method

application of the strapping method of tank calibration to give a calibration of a tank for custody transfer

purposes or to provide a basis for assessing the accuracy of other methods of tank calibration

3.25
reference method

application of the strapping method of tank calibration to the measurement of a reference circumference for

use in other methods of tank calibration

NOTE An example of such a method is the optical-reference-line method (see ISO 7507-2).

3.26
reference point
a point to which measurements in either calibration or gauging are related
3.27
step-over

device used in strapping for measuring the distance apart, along the arc, of two points on a tank shell where it

is not possible to use a strapping tape directly because of an intervening obstruction, e.g. a protruding fitting

3.28
step-over constant

distance between the measuring points of a step-over as measured along the arc of the particular course of

the tank concerned
3.29
step-over correction

difference between the apparent distance between two points on a tank shell as measured by a strapping tape

passing over an obstruction and the true arc distance as measured by a step-over, i.e. the step-over constant

3.30
strapping tape

specially designed and calibrated steel measuring tape graduated in units of length and used for taking

circumferential measurements in tank calibration
3.31
strapping method

method of tank calibration in which the capacities are calculated from the measurement of the external

circumferences, due allowance being made for the thickness of the shell of the tank

3.32
tape positioner

guide sliding freely on the strapping tape, used to pull and hold it in the correct position for taking

measurements
4 © ISO 2003 — All rights reserved
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
3.33
tensioning handles

handles fastened to the strapping tape, used for pulling it into the correct position and applying tension

3.34
ullage
outage
capacity of a tank not occupied by the liquid
3.35
upper reference point

point clearly defined on the dip-hatch directly above the dip-point to indicate the position at which dipping or

ullaging shall be carried out
3.36
working method

application of the strapping method of tank calibration by a simplified procedure that may result in some loss

of accuracy and is unsuitable for assessing other methods
4 Precautions
4.1 Introduction

This clause outlines the precautions that are applicable when tanks are being calibrated. The precautions

necessary to ensure the safety of the operator are dealt with separately from those precautions which have to

be taken to ensure the necessary precision required in the calibration of tanks.
4.2 General precautions

4.2.1 The utmost care and attention to detail shall be exercised when calibrating storage tanks.

4.2.2 All measurements shall be carefully observed and recorded as read, and any corrections which are

required shall be recorded separately. If any unusual occurrences are noted during the operations, these

occurrences shall be documented and the calibration shall be repeated, if necessary.

4.2.3 If the tank is only slightly distorted, sufficient additional measurements shall be taken to allow

satisfactory calculation of its capacity table. If such additional measurements are required, the calibrator’s

notes shall include the reasons for the extra measurements.

It is also recommended that dimensioned sketches should be provided by the calibrator to show any

abnormality of the tank or the fittings that affect calibration.

NOTE Seriously distorted tanks are best calibrated using liquid calibration methods similar to the method described

in ISO 4269.

4.2.4 To ensure accuracy and repeatability of readings, lumps of paint, scale, etc., likely to interfere with

measurement, shall be removed or the position of the measuring equipment adjusted accordingly.

4.2.5 If drawings for the tank are available, all relevant measurements shall be compared with the

corresponding dimensions shown on the drawings. Any measurement which shows a significant discrepancy

as a result of this comparison shall be reported and, if necessary, repeated.

4.2.6 If the calibration of a tank is interrupted, it may be resumed at a later date provided that:

a) if there is a change of equipment or personnel, sufficient check measurements shall be made to ensure

that the results obtained prior to the change correspond within the tolerances given in this method;

b) all records of work done are complete and legible;
© ISO 2003 — All rights reserved 5
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
c) the liquid contents remain unchanged at substantially the same level;

d) the average liquid and atmospheric temperatures are within 10 °C of the average liquid and atmospheric

temperatures recorded during the earlier working period.
4.3 Safety precautions

4.3.1 The safety precautions given in 4.3.2 to 4.3.6 constitute good practice, but the list is not necessarily

comprehensive. It is recommended that the list should be read in conjunction with the appropriate sections of

any applicable safety code. The precautions shall be taken whenever they do not conflict with legislative

requirements, which shall always be followed.

4.3.2 All regulations covering entry into hazardous areas shall be rigorously observed.

4.3.3 If a tank being strapped contains a petroleum product, attention shall be paid to the normal safety

precautions which apply to such tanks.

4.3.4 Before a tank which has been in use is entered, a safe-entry certificate issued in accordance with

local or national regulations shall be obtained. All lines entering the tank shall be disconnected and blanked.

The national or local regulations regarding the entry into tanks which have contained leaded fuels shall be

meticulously observed.
4.3.5 Hand lamps shall be of a type approved for use in explosive atmospheres.

4.3.6 The safety of operating personnel shall be safeguarded by strict attention to the following.

a) Ladders shall be inspected before use, and extendable ladders used only within their safe operating

range. The footing for each ladder shall be level and firm, and all ladders shall be securely lashed in

position before being used.

b) When painters’ cradles or bo’suns’ chairs are used, blocks, falls, ropes, etc., shall be tested before

erection, and any item of questionable strength or condition shall be replaced. Every care shall be paid to

the securing of the equipment and its operational use.

c) If calibration cannot be carried out without the use of staging, properly constructed steel tube or timber

scaffolding shall be erected. Loose bricks, drums, boxes, etc., shall not be used to form staging.

d) Where appropriate, safety harnesses shall be worn by personnel working above ground level.

5 Equipment

5.1 Strapping tape, conforming to A.1. The tape shall be well greased before use.

5.2 Spring balance, conforming to A.2, for measuring the tension applied to the tape.

5.3 Step-over, conforming to A.3.

5.4 Tape positioners and cords, conforming to A.4, fitted to the strapping tape, and supplied with plaited

cords. Both upper and lower cords shall be long enough to cover the height of the tank.

5.5 Littlejohn grip, conforming to A.5, to hold the tape, without kinking, in order to facilitate application of

the necessary tension.

5.6 Apparatus for thickness measurement, either a steel rule of convenient length graduated throughout

its length in millimetres, with at least the first 10 mm subdivided into half-millimetres, and/or another device,

such as an electronic thickness gauge.
6 © ISO 2003 — All rights reserved
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)

5.7 Dip-tape conforming to A.6, long enough to reach from the dipping reference point at the tank roof to

the dip-point on the tank bottom.
5.8 Dip-weight, conforming to A.7.

5.9 End-to-end rule, 1 m in length, with graduations in centimetres and millimetres, for measuring

deadwood, etc. If a wooden rule is used, it shall be fitted with a brass ferrule at each end and shall be free

from warp.
5.10 Ladders and staging: see 4.3.6 for safety precautions.
5.11 Density- and temperature-measuring apparatus, conforming to ISO 3675.
6 General requirements

NOTE If possible, measurements should be compared with the corresponding dimensions on the tank construction

drawings and the roundness of the tank should be ascertained.

6.1 Fill the tank to its normal working capacity at least once and allow to stand for at least 24 h prior to

calibration.

If the tank is calibrated with liquid in it, record the depth, temperature and density of the liquid at the time of

calibration. However, if the temperature of the wall surface can differ by more than 10 °C between the empty

part and the full part of the tank, the tank shall be either completely full or empty. Do not make transfers of

liquid during the calibration.
The ambient temperature before and after calibration should be recorded.

Obtain the required number of external circumference measurements, together with the subsidiary

measurements, where necessary, to correct for deviation of the strap due to obstructions, as described in 7.2.

NOTE Additional measurements required to enable a table of capacities to be prepared and the procedures to be

used in obtaining them are described in Clauses 8 to 12.

6.2 It is necessary to refer all tank dips to the dip-point, which may be in a different position from the

calibration datum-point, e.g. a point on the bottom angle, used for the purpose of tank calibration. Check that

the dip-plate has been securely mounted in a stable position so that it is not affected by movement of the tank

bottom or walls. Determine any difference in level between the dip-point and calibration datum-point, either by

normal surveying methods or by other suitable means, and record it.

6.3 Measure the height of the upper reference point above the dip-point using the dip-tape and dip-weight.

Record this reference height, to the nearest subdivision on the dip-tape, in the empty and the full conditions,

as appropriate.
7 Circumference measurements
7.1 Levels strapped

7.1.1 If the calibration is for referee purposes, measure the circumference by three or more strappings per

course, at approximately the following levels:
a) for riveted tanks:

1) 100 mm to 150 mm above the level of the top of the bottom angle of the tank, and 100 mm to

150 mm above the upper edge of each horizontal overlap between courses;
© ISO 2003 — All rights reserved 7
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
2) at the middle position of each course;

3) 100 mm to 150 mm below the lower edge of each horizontal overlap between courses and 100 mm

to 150 mm below the level of the lowest part of the top angle.
b) for welded tanks:

three or more levels as indicated in a), but the upper and lower levels shall be 270 mm to 330 mm from the

bottom angle, top angle or horizontal seams.

7.1.2 If the calibration is for the working method, the circumference may be measured, if preferred, by only

two strappings per course, taking one at each of the following levels:

 at about 1/5 to 1/4 of the course height or the ring height above the lower horizontal seam;

 at about 1/5 to 1/4 of the course height or the ring height below the upper horizontal seam.

7.1.3 If for any reason it is impracticable to take a strapping at the normal level, take a strapping as close to

this level as practicable, but not nearer the bottom or top angle or any seam than is specified in 7.1.1 a) or b).

Record in the strapper’s notes the level at which this circumference has been measured, with the reason for

abandoning the normal level.

If the tape is not in close contact with the surface of the tank throughout its whole path, apply a step-over as

in 7.5, so that a correction may be calculated to adjust the gross circumference for this effect.

7.2 Strapping procedure
7.2.1 Strap the tank by either of the methods described in 7.2.2 and 7.2.3
...

INTERNATIONAL ISO
STANDARD 7507-1
Second edition
2003-12-15
Petroleum and liquid petroleum
products — Calibration of vertical
cylindrical tanks —
Part 1:
Strapping method
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs
cylindriques verticaux —
Partie 1: Méthode par ceinturage
Reference number
ISO 7507-1:2003(E)
ISO 2003
---------------------- Page: 1 ----------------------
ISO 7507-1:2003(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2003

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2003 — All rights reserved
---------------------- Page: 2 ----------------------
ISO 7507-1:2003(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope...................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 2

4 Precautions............................................................................................................................................ 5

5 Equipment.............................................................................................................................................. 6

6 General requirements........................................................................................................................... 7

7 Circumference measurements............................................................................................................. 7

8 Other measurements on tank shell plates........................................................................................ 10

9 Deadwood............................................................................................................................................ 10

10 Tank bottoms....................................................................................................................................... 11

11 Measurement of tilt ............................................................................................................................. 11

12 Floating-roof tanks.............................................................................................................................. 11

13 Recalibration....................................................................................................................................... 12

14 Computation of tank capacity tables — General rules ................................................................... 12

15 Form of tank capacity tables ............................................................................................................. 13

16 Computation of open capacity .......................................................................................................... 13

17 Construction of final tables................................................................................................................ 17

Annex A (normative) Specification for equipment used in strapping ........................................................ 23

Annex B (informative) Recommendations for monitoring, checking and verification of tank

calibration and capacity table............................................................................................................ 26

Annex C (informative) Tank calibration data and calculation sheet............................................................ 32

Annex D (informative) Tank calibration uncertainties .................................................................................. 36

Annex E (informative) Tank shell temperature determination ..................................................................... 47

Annex F (normative) Gauge tape temperature correction ........................................................................... 48

Annex G (informative) Expansion due to liquid head ................................................................................... 50

Annex H (normative) Expansion due to temperature ................................................................................... 58

Annex I (normative) Certificate of calibration................................................................................................ 61

Bibliography ..................................................................................................................................................... 62

© ISO 2003 — All rights reserved iii
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ISO 7507-1:2003(E)
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 2.

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 document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

International Standard ISO 7507-1 was prepared by Technical Committee ISO/TC 28, Petroleum products and

lubricants, Subcommittee SC 3, Static petroleum measurement.

This second edition cancels and replaces the first edition (ISO 7507-1:1993). It also cancels and replaces

ISO 7507-6:1997, the subject of which is now included in this part of ISO 7507.

ISO 7507 consists of the following parts, under the general title Petroleum and liquid petroleum products —

Calibration of vertical cylindrical tanks:
 Part 1: Strapping method
 Part 2: Optical-reference-line method
 Part 3: Optical-triangulation method
 Part 4: Internal electro-optical distance-ranging method
 Part 5: External electro-optical distance-ranging method

 Part 6: Recommendations for monitoring, checking and verification of tank calibration and capacity table

iv © ISO 2003 — All rights reserved
---------------------- Page: 4 ----------------------
ISO 7507-1:2003(E)
Introduction

This part of ISO 7507 forms part of a series on tank calibration including the following:

ISO 7507-2:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 2: Optical-reference-line method

ISO 7507-3:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 3: Optical-triangulation method

ISO 7507-4:1995, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 4: Internal electro-optical distance-ranging method

ISO 7507-5:2000, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 5: External electro-optical distance-ranging method

ISO 7507-6:1997, Recommendations for monitoring, checking and verification of tank calibration and capacity

table

ISO 8311:1989, Refrigerated light hydrocarbon fluids — Calibration of membrane tanks and independent

prismatic tanks in ships — Physical measurement

ISO 9091-1:1991, Refrigerated light hydrocarbon fluids — Calibration of spherical tanks in ships — Part 1:

Stereo-photogrammetry

ISO 9091-2:1992, Refrigerated light hydrocarbon fluids — Calibration of spherical tanks in ships — Part 2:

Triangulation measurement

The strapping method for the calibration of vertical cylindrical tanks has been used for many years and is a

recognized method of determining the capacity of storage tanks from measurements of the circumference of a

tank at various heights. The strapping method is also often used to establish a reference circumference at a

selected height to use as a datum in other methods of tank calibration.
© ISO 2003 — All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 7507-1:2003(E)
Petroleum and liquid petroleum products — Calibration of
vertical cylindrical tanks —
Part 1:
Strapping method
1 Scope

1.1 This part of ISO 7507 specifies a method for the calibration of substantially vertical cylindrical tanks by

measuring the tank using a strapping tape.

1.2 This method is known as the “strapping method” and is suitable for use as a working method, a

reference method or a referee method.

NOTE For the reference method, the number of strappings required will be specified in the standard which refers to

this part of ISO 7507.

1.3 The operation of strapping, the corrections to be made and the calculations leading to the compilation of

the tank capacity table are described.

1.4 This method does not apply to abnormally deformed, e.g. dented or non-circular, tanks.

1.5 This method is suitable for tilted tanks with a deviation of up to 3 % from the vertical, provided that a

correction for the measured tilt is applied in the 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.

ISO 91-1:1992, Petroleum measurement tables — Part 1: Tables based on reference temperatures of 15 °C

and 60 °F

ISO 3675:1998, Crude petroleum and liquid petroleum products — Laboratory determination of density —

Hydrometer method

ISO 4269:2001, Petroleum and liquid petroleum products — Tank calibration by liquid measurement —

Incremental method using volumetric meters
© ISO 2003 — All rights reserved 1
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ISO 7507-1:2003(E)
3 Terms and definitions

For the purposes of this document and subsequent parts of ISO 7507, the following terms and definitions

apply.
3.1
argument
independent variable of a function

NOTE A table is entered with value(s) of the independent variable(s), the value(s) extracted from the table being

known as the dependent value(s).
3.2
bottom calibration

procedure to determine the quantity of liquid contained in a tank below the calibration datum-point

3.3
calibration

process of determining the capacity of a tank, or the partial capacities corresponding to different levels

3.4
capacity
total volume of a tank
3.5
capacity table
tank table
tank capacity table

table showing the capacities of, or volumes in, a tank corresponding to various liquid levels measured from a

stable reference point
3.6
course
one circumferential ring of plates in a tank
3.7
calibration datum-point
point used as the datum in the preparation of a calibration table

NOTE Course heights and the effective levels of deadwood are measured from this point, to which the bottom

calibration is also related.
3.8
deadwood
any tank fitting that affects the capacity of the tank

NOTE Deadwood is referred to as “positive deadwood” when the capacity of the fitting increases the effective

capacity of the tank, or “negative deadwood” when the volume of the fitting displaces liquid and reduces the effective

capacity.
3.9
dip
innage
depth of a liquid in a tank above the dipping datum-point
3.10
dip-hatch
gauge-hatch

opening in the top of a tank through which dipping and sampling operations are carried out

2 © ISO 2003 — All rights reserved
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ISO 7507-1:2003(E)
3.11
dip-point

point on the dip-plate which the dip-weight touches during gauging and from which the measurements of the

oil and water depths are taken

NOTE The dip-point usually corresponds to the datum-point, but when this is not so, the difference in level between

the datum-point and the dip-point has to be allowed for in the calibration table.

3.12
dip-plate
striking-plate positioned below the dip-hatch

NOTE The position of the dip-plate should not be affected by bottom or wall movements.

3.13
dip-tape

graduated steel tape used for measuring the depth of the oil or water in a tank, either directly by dipping or

indirectly by ullage
3.14
dip-weight

weight attached to a steel dip-tape, of sufficient mass to keep the tape taut and of such shape as to facilitate

the penetration of any sludge that might be present on the dip-point or the dip-plate

3.15
floating cover
screen

lightweight cover of either metal or plastics material designed to float on the surface of a liquid in a tank

NOTE The cover rests upon the liquid surface and is used to retard evaporation of volatile products in a tank.

3.16
floating-roof tank

tank in which the roof floats freely on the surface of the liquid contents, except at low levels when the weight of

the roof is taken through its supports by the tank bottom
3.17
function

when two variable quantities are interrelated, one quantity is said to be a function of the other

NOTE In the context of tank calibration, the volume of liquid contained in a tank is said to be a function of the dip or

of the ullage.
3.18
gauging

process of taking all the necessary measurements in a tank in order to determine the quantity of liquid that it

contains
3.19
interpolation

process of obtaining the value of a function corresponding to a value of the argument intermediate between

those given
3.20
Littlejohn grip

quick-release clamp that may be fitted around a strapping tape at any convenient position throughout its

length

NOTE A handle is attached to the Littlejohn grip so that the strapping tape can be pulled to the correct tension.

© ISO 2003 — All rights reserved 3
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ISO 7507-1:2003(E)
3.21
open capacity

calculated capacity of a tank or part of a tank before any allowance has been made for deadwood

3.22
reference height
vertical distance between the dip-point and the upper reference point
3.23
overall height
total external height from the top of the shell to the base of the tank (plate)
3.24
referee method

application of the strapping method of tank calibration to give a calibration of a tank for custody transfer

purposes or to provide a basis for assessing the accuracy of other methods of tank calibration

3.25
reference method

application of the strapping method of tank calibration to the measurement of a reference circumference for

use in other methods of tank calibration

NOTE An example of such a method is the optical-reference-line method (see ISO 7507-2).

3.26
reference point
a point to which measurements in either calibration or gauging are related
3.27
step-over

device used in strapping for measuring the distance apart, along the arc, of two points on a tank shell where it

is not possible to use a strapping tape directly because of an intervening obstruction, e.g. a protruding fitting

3.28
step-over constant

distance between the measuring points of a step-over as measured along the arc of the particular course of

the tank concerned
3.29
step-over correction

difference between the apparent distance between two points on a tank shell as measured by a strapping tape

passing over an obstruction and the true arc distance as measured by a step-over, i.e. the step-over constant

3.30
strapping tape

specially designed and calibrated steel measuring tape graduated in units of length and used for taking

circumferential measurements in tank calibration
3.31
strapping method

method of tank calibration in which the capacities are calculated from the measurement of the external

circumferences, due allowance being made for the thickness of the shell of the tank

3.32
tape positioner

guide sliding freely on the strapping tape, used to pull and hold it in the correct position for taking

measurements
4 © ISO 2003 — All rights reserved
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ISO 7507-1:2003(E)
3.33
tensioning handles

handles fastened to the strapping tape, used for pulling it into the correct position and applying tension

3.34
ullage
outage
capacity of a tank not occupied by the liquid
3.35
upper reference point

point clearly defined on the dip-hatch directly above the dip-point to indicate the position at which dipping or

ullaging shall be carried out
3.36
working method

application of the strapping method of tank calibration by a simplified procedure that may result in some loss

of accuracy and is unsuitable for assessing other methods
4 Precautions
4.1 Introduction

This clause outlines the precautions that are applicable when tanks are being calibrated. The precautions

necessary to ensure the safety of the operator are dealt with separately from those precautions which have to

be taken to ensure the necessary precision required in the calibration of tanks.
4.2 General precautions

4.2.1 The utmost care and attention to detail shall be exercised when calibrating storage tanks.

4.2.2 All measurements shall be carefully observed and recorded as read, and any corrections which are

required shall be recorded separately. If any unusual occurrences are noted during the operations, these

occurrences shall be documented and the calibration shall be repeated, if necessary.

4.2.3 If the tank is only slightly distorted, sufficient additional measurements shall be taken to allow

satisfactory calculation of its capacity table. If such additional measurements are required, the calibrator’s

notes shall include the reasons for the extra measurements.

It is also recommended that dimensioned sketches should be provided by the calibrator to show any

abnormality of the tank or the fittings that affect calibration.

NOTE Seriously distorted tanks are best calibrated using liquid calibration methods similar to the method described

in ISO 4269.

4.2.4 To ensure accuracy and repeatability of readings, lumps of paint, scale, etc., likely to interfere with

measurement, shall be removed or the position of the measuring equipment adjusted accordingly.

4.2.5 If drawings for the tank are available, all relevant measurements shall be compared with the

corresponding dimensions shown on the drawings. Any measurement which shows a significant discrepancy

as a result of this comparison shall be reported and, if necessary, repeated.

4.2.6 If the calibration of a tank is interrupted, it may be resumed at a later date provided that:

a) if there is a change of equipment or personnel, sufficient check measurements shall be made to ensure

that the results obtained prior to the change correspond within the tolerances given in this method;

b) all records of work done are complete and legible;
© ISO 2003 — All rights reserved 5
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ISO 7507-1:2003(E)
c) the liquid contents remain unchanged at substantially the same level;

d) the average liquid and atmospheric temperatures are within 10 °C of the average liquid and atmospheric

temperatures recorded during the earlier working period.
4.3 Safety precautions

4.3.1 The safety precautions given in 4.3.2 to 4.3.6 constitute good practice, but the list is not necessarily

comprehensive. It is recommended that the list should be read in conjunction with the appropriate sections of

any applicable safety code. The precautions shall be taken whenever they do not conflict with legislative

requirements, which shall always be followed.

4.3.2 All regulations covering entry into hazardous areas shall be rigorously observed.

4.3.3 If a tank being strapped contains a petroleum product, attention shall be paid to the normal safety

precautions which apply to such tanks.

4.3.4 Before a tank which has been in use is entered, a safe-entry certificate issued in accordance with

local or national regulations shall be obtained. All lines entering the tank shall be disconnected and blanked.

The national or local regulations regarding the entry into tanks which have contained leaded fuels shall be

meticulously observed.
4.3.5 Hand lamps shall be of a type approved for use in explosive atmospheres.

4.3.6 The safety of operating personnel shall be safeguarded by strict attention to the following.

a) Ladders shall be inspected before use, and extendable ladders used only within their safe operating

range. The footing for each ladder shall be level and firm, and all ladders shall be securely lashed in

position before being used.

b) When painters’ cradles or bo’suns’ chairs are used, blocks, falls, ropes, etc., shall be tested before

erection, and any item of questionable strength or condition shall be replaced. Every care shall be paid to

the securing of the equipment and its operational use.

c) If calibration cannot be carried out without the use of staging, properly constructed steel tube or timber

scaffolding shall be erected. Loose bricks, drums, boxes, etc., shall not be used to form staging.

d) Where appropriate, safety harnesses shall be worn by personnel working above ground level.

5 Equipment

5.1 Strapping tape, conforming to A.1. The tape shall be well greased before use.

5.2 Spring balance, conforming to A.2, for measuring the tension applied to the tape.

5.3 Step-over, conforming to A.3.

5.4 Tape positioners and cords, conforming to A.4, fitted to the strapping tape, and supplied with plaited

cords. Both upper and lower cords shall be long enough to cover the height of the tank.

5.5 Littlejohn grip, conforming to A.5, to hold the tape, without kinking, in order to facilitate application of

the necessary tension.

5.6 Apparatus for thickness measurement, either a steel rule of convenient length graduated throughout

its length in millimetres, with at least the first 10 mm subdivided into half-millimetres, and/or another device,

such as an electronic thickness gauge.
6 © ISO 2003 — All rights reserved
---------------------- Page: 11 ----------------------
ISO 7507-1:2003(E)

5.7 Dip-tape conforming to A.6, long enough to reach from the dipping reference point at the tank roof to

the dip-point on the tank bottom.
5.8 Dip-weight, conforming to A.7.

5.9 End-to-end rule, 1 m in length, with graduations in centimetres and millimetres, for measuring

deadwood, etc. If a wooden rule is used, it shall be fitted with a brass ferrule at each end and shall be free

from warp.
5.10 Ladders and staging: see 4.3.6 for safety precautions.
5.11 Density- and temperature-measuring apparatus, conforming to ISO 3675.
6 General requirements

NOTE If possible, measurements should be compared with the corresponding dimensions on the tank construction

drawings and the roundness of the tank should be ascertained.

6.1 Fill the tank to its normal working capacity at least once and allow to stand for at least 24 h prior to

calibration.

If the tank is calibrated with liquid in it, record the depth, temperature and density of the liquid at the time of

calibration. However, if the temperature of the wall surface can differ by more than 10 °C between the empty

part and the full part of the tank, the tank shall be either completely full or empty. Do not make transfers of

liquid during the calibration.
The ambient temperature before and after calibration should be recorded.

Obtain the required number of external circumference measurements, together with the subsidiary

measurements, where necessary, to correct for deviation of the strap due to obstructions, as described in 7.2.

NOTE Additional measurements required to enable a table of capacities to be prepared and the procedures to be

used in obtaining them are described in Clauses 8 to 12.

6.2 It is necessary to refer all tank dips to the dip-point, which may be in a different position from the

calibration datum-point, e.g. a point on the bottom angle, used for the purpose of tank calibration. Check that

the dip-plate has been securely mounted in a stable position so that it is not affected by movement of the tank

bottom or walls. Determine any difference in level between the dip-point and calibration datum-point, either by

normal surveying methods or by other suitable means, and record it.

6.3 Measure the height of the upper reference point above the dip-point using the dip-tape and dip-weight.

Record this reference height, to the nearest subdivision on the dip-tape, in the empty and the full conditions,

as appropriate.
7 Circumference measurements
7.1 Levels strapped

7.1.1 If the calibration is for referee purposes, measure the circumference by three or more strappings per

course, at approximately the following levels:
a) for riveted tanks:

1) 100 mm to 150 mm above the level of the top of the bottom angle of the tank, and 100 mm to

150 mm above the upper edge of each horizontal overlap between courses;
© ISO 2003 — All rights reserved 7
---------------------- Page: 12 ----------------------
ISO 7507-1:2003(E)
2) at the middle position of each course;

3) 100 mm to 150 mm below the lower edge of each horizontal overlap between courses and 100 mm

to 150 mm below the level of the lowest part of the top angle.
b) for welded tanks:

three or more levels as indicated in a), but the upper and lower levels shall be 270 mm to 330 mm from the

bottom angle, top angle or horizontal seams.

7.1.2 If the calibration is for the working method, the circumference may be measured, if preferred, by only

two strappings per course, taking one at each of the following levels:

 at about 1/5 to 1/4 of the course height or the ring height above the lower horizontal seam;

 at about 1/5 to 1/4 of the course height or the ring height below the upper horizontal seam.

7.1.3 If for any reason it is impracticable to take a strapping at the normal level, take a strapping as close to

this level as practicable, but not nearer the bottom or top angle or any seam than is specified in 7.1.1 a) or b).

Record in the strapper’s notes the level at which this circumference has been measured, with the reason for

abandoning the normal level.

If the tape is not in close contact with the surface of the tank throughout its whole path, apply a step-over as

in 7.5, so that a correction may be calculated to adjust the gross circumference for this effect.

7.2 Strapping procedure

7.2.1 Strap the tank by either of the methods described in 7.2.2 and 7.2.3. The calibration tension specified

on the strapping tape shall be applied to the tape using the tensioning handles and spring balance, and

transmitted throughout the length of the tape.

NOTE A slight sawing motion imparted to the strapping tape will achieve this, or the strapping tape can be eased

round the tank by pulling it away from the shell by the cords attached to the tape positioners, sliding these along the

strapping tape as required.

Place the strapping tape on its correct path which shall be parallel to the horizontal seams of the tank.

7.2.2 If the strapping tape used is not long enough to encircle the tank completely, choose the level of the

strapping tape path and then measure the circumference in sections. Draw scribed lines not nearer than about

one-third of a plate length from a vertical seam at such distances apart as will enable measurements to be

made conveniently. When the tension on the spring balance at the end of the strapping tape is as specified in

7.2.1 for each separate section, record the individual readings. The external circumference of the tank shall

then be the sum of the separate measurements.
7.2.3 If the strapping tape
...

SLOVENSKI STANDARD
SIST ISO 7507-1:2006
01-februar-2006

1DIWDLQWHNRþLQDIWQLSURL]YRGL±8PHUMDQMHQDYSLþQLKYDOMDVWLKUH]HUYRDUMHY±

GHOª6WUDSSLQJ©PHWRGD

Petroleum and liquid petroleum products -- Calibration of vertical cylindrical tanks -- Part

1: Strapping method

Pétrole et produits pétroliers liquides -- Jaugeage des réservoirs cylindriques verticaux --

Partie 1: Méthode par ceinturage
Ta slovenski standard je istoveten z: ISO 7507-1:2003
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
SIST ISO 7507-1:2006 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 7507-1:2006
---------------------- Page: 2 ----------------------
SIST ISO 7507-1:2006
INTERNATIONAL ISO
STANDARD 7507-1
Second edition
2003-12-15
Petroleum and liquid petroleum
products — Calibration of vertical
cylindrical tanks —
Part 1:
Strapping method
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs
cylindriques verticaux —
Partie 1: Méthode par ceinturage
Reference number
ISO 7507-1:2003(E)
ISO 2003
---------------------- Page: 3 ----------------------
SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
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ii © ISO 2003 — All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope...................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 2

4 Precautions............................................................................................................................................ 5

5 Equipment.............................................................................................................................................. 6

6 General requirements........................................................................................................................... 7

7 Circumference measurements............................................................................................................. 7

8 Other measurements on tank shell plates........................................................................................ 10

9 Deadwood............................................................................................................................................ 10

10 Tank bottoms....................................................................................................................................... 11

11 Measurement of tilt ............................................................................................................................. 11

12 Floating-roof tanks.............................................................................................................................. 11

13 Recalibration....................................................................................................................................... 12

14 Computation of tank capacity tables — General rules ................................................................... 12

15 Form of tank capacity tables ............................................................................................................. 13

16 Computation of open capacity .......................................................................................................... 13

17 Construction of final tables................................................................................................................ 17

Annex A (normative) Specification for equipment used in strapping ........................................................ 23

Annex B (informative) Recommendations for monitoring, checking and verification of tank

calibration and capacity table............................................................................................................ 26

Annex C (informative) Tank calibration data and calculation sheet............................................................ 32

Annex D (informative) Tank calibration uncertainties .................................................................................. 36

Annex E (informative) Tank shell temperature determination ..................................................................... 47

Annex F (normative) Gauge tape temperature correction ........................................................................... 48

Annex G (informative) Expansion due to liquid head ................................................................................... 50

Annex H (normative) Expansion due to temperature ................................................................................... 58

Annex I (normative) Certificate of calibration................................................................................................ 61

Bibliography ..................................................................................................................................................... 62

© ISO 2003 — All rights reserved iii
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SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
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 2.

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 document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

International Standard ISO 7507-1 was prepared by Technical Committee ISO/TC 28, Petroleum products and

lubricants, Subcommittee SC 3, Static petroleum measurement.

This second edition cancels and replaces the first edition (ISO 7507-1:1993). It also cancels and replaces

ISO 7507-6:1997, the subject of which is now included in this part of ISO 7507.

ISO 7507 consists of the following parts, under the general title Petroleum and liquid petroleum products —

Calibration of vertical cylindrical tanks:
 Part 1: Strapping method
 Part 2: Optical-reference-line method
 Part 3: Optical-triangulation method
 Part 4: Internal electro-optical distance-ranging method
 Part 5: External electro-optical distance-ranging method

 Part 6: Recommendations for monitoring, checking and verification of tank calibration and capacity table

iv © ISO 2003 — All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 7507-1:2006
ISO 7507-1:2003(E)
Introduction

This part of ISO 7507 forms part of a series on tank calibration including the following:

ISO 7507-2:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 2: Optical-reference-line method

ISO 7507-3:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 3: Optical-triangulation method

ISO 7507-4:1995, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 4: Internal electro-optical distance-ranging method

ISO 7507-5:2000, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —

Part 5: External electro-optical distance-ranging method

ISO 7507-6:1997, Recommendations for monitoring, checking and verification of tank calibration and capacity

table

ISO 8311:1989, Refrigerated light hydrocarbon fluids — Calibration of membrane tanks and independent

prismatic tanks in ships — Physical measurement

ISO 9091-1:1991, Refrigerated light hydrocarbon fluids — Calibration of spherical tanks in ships — Part 1:

Stereo-photogrammetry

ISO 9091-2:1992, Refrigerated light hydrocarbon fluids — Calibration of spherical tanks in ships — Part 2:

Triangulation measurement

The strapping method for the calibration of vertical cylindrical tanks has been used for many years and is a

recognized method of determining the capacity of storage tanks from measurements of the circumference of a

tank at various heights. The strapping method is also often used to establish a reference circumference at a

selected height to use as a datum in other methods of tank calibration.
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INTERNATIONAL STANDARD ISO 7507-1:2003(E)
Petroleum and liquid petroleum products — Calibration of
vertical cylindrical tanks —
Part 1:
Strapping method
1 Scope

1.1 This part of ISO 7507 specifies a method for the calibration of substantially vertical cylindrical tanks by

measuring the tank using a strapping tape.

1.2 This method is known as the “strapping method” and is suitable for use as a working method, a

reference method or a referee method.

NOTE For the reference method, the number of strappings required will be specified in the standard which refers to

this part of ISO 7507.

1.3 The operation of strapping, the corrections to be made and the calculations leading to the compilation of

the tank capacity table are described.

1.4 This method does not apply to abnormally deformed, e.g. dented or non-circular, tanks.

1.5 This method is suitable for tilted tanks with a deviation of up to 3 % from the vertical, provided that a

correction for the measured tilt is applied in the 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.

ISO 91-1:1992, Petroleum measurement tables — Part 1: Tables based on reference temperatures of 15 °C

and 60 °F

ISO 3675:1998, Crude petroleum and liquid petroleum products — Laboratory determination of density —

Hydrometer method

ISO 4269:2001, Petroleum and liquid petroleum products — Tank calibration by liquid measurement —

Incremental method using volumetric meters
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3 Terms and definitions

For the purposes of this document and subsequent parts of ISO 7507, the following terms and definitions

apply.
3.1
argument
independent variable of a function

NOTE A table is entered with value(s) of the independent variable(s), the value(s) extracted from the table being

known as the dependent value(s).
3.2
bottom calibration

procedure to determine the quantity of liquid contained in a tank below the calibration datum-point

3.3
calibration

process of determining the capacity of a tank, or the partial capacities corresponding to different levels

3.4
capacity
total volume of a tank
3.5
capacity table
tank table
tank capacity table

table showing the capacities of, or volumes in, a tank corresponding to various liquid levels measured from a

stable reference point
3.6
course
one circumferential ring of plates in a tank
3.7
calibration datum-point
point used as the datum in the preparation of a calibration table

NOTE Course heights and the effective levels of deadwood are measured from this point, to which the bottom

calibration is also related.
3.8
deadwood
any tank fitting that affects the capacity of the tank

NOTE Deadwood is referred to as “positive deadwood” when the capacity of the fitting increases the effective

capacity of the tank, or “negative deadwood” when the volume of the fitting displaces liquid and reduces the effective

capacity.
3.9
dip
innage
depth of a liquid in a tank above the dipping datum-point
3.10
dip-hatch
gauge-hatch

opening in the top of a tank through which dipping and sampling operations are carried out

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3.11
dip-point

point on the dip-plate which the dip-weight touches during gauging and from which the measurements of the

oil and water depths are taken

NOTE The dip-point usually corresponds to the datum-point, but when this is not so, the difference in level between

the datum-point and the dip-point has to be allowed for in the calibration table.

3.12
dip-plate
striking-plate positioned below the dip-hatch

NOTE The position of the dip-plate should not be affected by bottom or wall movements.

3.13
dip-tape

graduated steel tape used for measuring the depth of the oil or water in a tank, either directly by dipping or

indirectly by ullage
3.14
dip-weight

weight attached to a steel dip-tape, of sufficient mass to keep the tape taut and of such shape as to facilitate

the penetration of any sludge that might be present on the dip-point or the dip-plate

3.15
floating cover
screen

lightweight cover of either metal or plastics material designed to float on the surface of a liquid in a tank

NOTE The cover rests upon the liquid surface and is used to retard evaporation of volatile products in a tank.

3.16
floating-roof tank

tank in which the roof floats freely on the surface of the liquid contents, except at low levels when the weight of

the roof is taken through its supports by the tank bottom
3.17
function

when two variable quantities are interrelated, one quantity is said to be a function of the other

NOTE In the context of tank calibration, the volume of liquid contained in a tank is said to be a function of the dip or

of the ullage.
3.18
gauging

process of taking all the necessary measurements in a tank in order to determine the quantity of liquid that it

contains
3.19
interpolation

process of obtaining the value of a function corresponding to a value of the argument intermediate between

those given
3.20
Littlejohn grip

quick-release clamp that may be fitted around a strapping tape at any convenient position throughout its

length

NOTE A handle is attached to the Littlejohn grip so that the strapping tape can be pulled to the correct tension.

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3.21
open capacity

calculated capacity of a tank or part of a tank before any allowance has been made for deadwood

3.22
reference height
vertical distance between the dip-point and the upper reference point
3.23
overall height
total external height from the top of the shell to the base of the tank (plate)
3.24
referee method

application of the strapping method of tank calibration to give a calibration of a tank for custody transfer

purposes or to provide a basis for assessing the accuracy of other methods of tank calibration

3.25
reference method

application of the strapping method of tank calibration to the measurement of a reference circumference for

use in other methods of tank calibration

NOTE An example of such a method is the optical-reference-line method (see ISO 7507-2).

3.26
reference point
a point to which measurements in either calibration or gauging are related
3.27
step-over

device used in strapping for measuring the distance apart, along the arc, of two points on a tank shell where it

is not possible to use a strapping tape directly because of an intervening obstruction, e.g. a protruding fitting

3.28
step-over constant

distance between the measuring points of a step-over as measured along the arc of the particular course of

the tank concerned
3.29
step-over correction

difference between the apparent distance between two points on a tank shell as measured by a strapping tape

passing over an obstruction and the true arc distance as measured by a step-over, i.e. the step-over constant

3.30
strapping tape

specially designed and calibrated steel measuring tape graduated in units of length and used for taking

circumferential measurements in tank calibration
3.31
strapping method

method of tank calibration in which the capacities are calculated from the measurement of the external

circumferences, due allowance being made for the thickness of the shell of the tank

3.32
tape positioner

guide sliding freely on the strapping tape, used to pull and hold it in the correct position for taking

measurements
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3.33
tensioning handles

handles fastened to the strapping tape, used for pulling it into the correct position and applying tension

3.34
ullage
outage
capacity of a tank not occupied by the liquid
3.35
upper reference point

point clearly defined on the dip-hatch directly above the dip-point to indicate the position at which dipping or

ullaging shall be carried out
3.36
working method

application of the strapping method of tank calibration by a simplified procedure that may result in some loss

of accuracy and is unsuitable for assessing other methods
4 Precautions
4.1 Introduction

This clause outlines the precautions that are applicable when tanks are being calibrated. The precautions

necessary to ensure the safety of the operator are dealt with separately from those precautions which have to

be taken to ensure the necessary precision required in the calibration of tanks.
4.2 General precautions

4.2.1 The utmost care and attention to detail shall be exercised when calibrating storage tanks.

4.2.2 All measurements shall be carefully observed and recorded as read, and any corrections which are

required shall be recorded separately. If any unusual occurrences are noted during the operations, these

occurrences shall be documented and the calibration shall be repeated, if necessary.

4.2.3 If the tank is only slightly distorted, sufficient additional measurements shall be taken to allow

satisfactory calculation of its capacity table. If such additional measurements are required, the calibrator’s

notes shall include the reasons for the extra measurements.

It is also recommended that dimensioned sketches should be provided by the calibrator to show any

abnormality of the tank or the fittings that affect calibration.

NOTE Seriously distorted tanks are best calibrated using liquid calibration methods similar to the method described

in ISO 4269.

4.2.4 To ensure accuracy and repeatability of readings, lumps of paint, scale, etc., likely to interfere with

measurement, shall be removed or the position of the measuring equipment adjusted accordingly.

4.2.5 If drawings for the tank are available, all relevant measurements shall be compared with the

corresponding dimensions shown on the drawings. Any measurement which shows a significant discrepancy

as a result of this comparison shall be reported and, if necessary, repeated.

4.2.6 If the calibration of a tank is interrupted, it may be resumed at a later date provided that:

a) if there is a change of equipment or personnel, sufficient check measurements shall be made to ensure

that the results obtained prior to the change correspond within the tolerances given in this method;

b) all records of work done are complete and legible;
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c) the liquid contents remain unchanged at substantially the same level;

d) the average liquid and atmospheric temperatures are within 10 °C of the average liquid and atmospheric

temperatures recorded during the earlier working period.
4.3 Safety precautions

4.3.1 The safety precautions given in 4.3.2 to 4.3.6 constitute good practice, but the list is not necessarily

comprehensive. It is recommended that the list should be read in conjunction with the appropriate sections of

any applicable safety code. The precautions shall be taken whenever they do not conflict with legislative

requirements, which shall always be followed.

4.3.2 All regulations covering entry into hazardous areas shall be rigorously observed.

4.3.3 If a tank being strapped contains a petroleum product, attention shall be paid to the normal safety

precautions which apply to such tanks.

4.3.4 Before a tank which has been in use is entered, a safe-entry certificate issued in accordance with

local or national regulations shall be obtained. All lines entering the tank shall be disconnected and blanked.

The national or local regulations regarding the entry into tanks which have contained leaded fuels shall be

meticulously observed.
4.3.5 Hand lamps shall be of a type approved for use in explosive atmospheres.

4.3.6 The safety of operating personnel shall be safeguarded by strict attention to the following.

a) Ladders shall be inspected before use, and extendable ladders used only within their safe operating

range. The footing for each ladder shall be level and firm, and all ladders shall be securely lashed in

position before being used.

b) When painters’ cradles or bo’suns’ chairs are used, blocks, falls, ropes, etc., shall be tested before

erection, and any item of questionable strength or condition shall be replaced. Every care shall be paid to

the securing of the equipment and its operational use.

c) If calibration cannot be carried out without the use of staging, properly constructed steel tube or timber

scaffolding shall be erected. Loose bricks, drums, boxes, etc., shall not be used to form staging.

d) Where appropriate, safety harnesses shall be worn by personnel working above ground level.

5 Equipment

5.1 Strapping tape, conforming to A.1. The tape shall be well greased before use.

5.2 Spring balance, conforming to A.2, for measuring the tension applied to the tape.

5.3 Step-over, conforming to A.3.

5.4 Tape positioners and cords, conforming to A.4, fitted to the strapping tape, and supplied with plaited

cords. Both upper and lower cords shall be long enough to cover the height of the tank.

5.5 Littlejohn grip, conforming to A.5, to hold the tape, without kinking, in order to facilitate application of

the necessary tension.

5.6 Apparatus for thickness measurement, either a steel rule of convenient length graduated throughout

its length in millimetres, with at least the first 10 mm subdivided into half-millimetres, and/or another device,

such as an electronic thickness gauge.
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5.7 Dip-tape conforming to A.6, long enough to reach from the dipping reference point at the tank roof to

the dip-point on the tank bottom.
5.8 Dip-weight, conforming to A.7.

5.9 End-to-end rule, 1 m in length, with graduations in centimetres and millimetres, for measuring

deadwood, etc. If a wooden rule is used, it shall be fitted with a brass ferrule at each end and shall be free

from warp.
5.10 Ladders and staging: see 4.3.6 for safety precautions.
5.11 Density- and temperature-measuring apparatus, conforming to ISO 3675.
6 General requirements

NOTE If possible, measurements should be compared with the corresponding dimensions on the tank construction

drawings and the roundness of the tank should be ascertained.

6.1 Fill the tank to its normal working capacity at least once and allow to stand for at least 24 h prior to

calibration.

If the tank is calibrated with liquid in it, record the depth, temperature and density of the liquid at the time of

calibration. However, if the temperature of the wall surface can differ by more than 10 °C between the empty

part and the full part of the tank, the tank shall be either completely full or empty. Do not make transfers of

liquid during the calibration.
The ambient temperature before and after calibration should be recorded.

Obtain the required number of external circumference measurements, together with the subsidiary

measurements, where necessary, to correct for deviation of the strap due to obstructions, as described in 7.2.

NOTE Additional measurements required to enable a table of capacities to be prepared and the procedures to be

used in obtaining them are described in Clauses 8 to 12.

6.2 It is necessary to refer all tank dips to the dip-point, which may be in a different position from the

calibration datum-point, e.g. a point on the bottom angle, used for the purpose of tank calibration. Check that

the dip-plate has been securely mounted in a stable position so that it is not affected by movement of the tank

bottom or walls. Determine any difference in level between the dip-point and calibration datum-point, either by

normal surveying methods or by other suitable means, and record it.

6.3 Measure the height of the upper reference point above the dip-point using the dip-tape and dip-weight.

Record this reference height, to the nearest subdivision on the dip-tape, in the empty and the full conditions,

as appropriate.
7 Circumference measurements
7.1 Levels strapped

7.1.1 If the calibration is for referee purposes, measure the circumference by three or more strappings per

course, at approximately the following levels:
a) for riveted tanks:

1) 100 mm to 150 mm above the level of the top of the bottom angle of the tank, and 100 mm to

150 mm above the upper edge of each horizontal overlap between courses;
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2) at the middle position of each course;

3) 100 mm to 150 mm below the lower edge of each horizontal overlap between courses and 100 mm

to 150 mm below the level of the lowest part of the top angle.
b) for welded tanks:

three or more levels as indicated in a), but the upper and lower levels shall be 270 mm to 330 mm from the

bottom angle, top angle or horizontal seams.

7.1.2 If the calibration is for the working method, the circumference may be measured, if preferred, by only

two strappings per course, taking one at each of the following levels:

 at about 1/5 to 1/4 of the course height or the ring height above the lower horizontal seam;

 at about 1/5 to 1/4 of the course height or the ring height below the upper horizontal seam.

7.1.3 If for any reason it is impracticable to take a strapping at the normal level, take a strapping as close to

this level as practicable, but not nearer the bottom or top angle or any seam than is specified in 7.1.1 a) or b).

Record in the strapper’s notes the level at which this circumference has been measured, with the reason for

abandoning the normal level.

If the tape is not in close contact with the surface of the tank throughout its whole path, apply a step-over as

in 7.5, so that a correction may be calculated to adjust the gross circumference for this effect.

7.2 Strapping procedure
7.2.1 Strap the tank by either of the methods
...

NORME ISO
INTERNATIONALE 7507-1
Deuxième édition
2003-12-15
Pétrole et produits pétroliers liquides —
Jaugeage des réservoirs cylindriques
verticaux —
Partie 1:
Méthode par ceinturage
Petroleum and liquid petroleum products — Calibration of vertical
cylindrical tanks —
Part 1: Strapping method
Numéro de référence
ISO 7507-1:2003(F)
ISO 2003
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ISO 7507-1:2003(F)
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ii © ISO 2003 — Tous droits réservés
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ISO 7507-1:2003(F)
Sommaire Page

Avant-propos..................................................................................................................................................... iv

Introduction ........................................................................................................................................................ v

1 Domaine d'application.......................................................................................................................... 1

2 Références normatives......................................................................................................................... 1

3 Termes et définitions ............................................................................................................................ 2

4 Précautions............................................................................................................................................ 5

5 Équipement............................................................................................................................................ 7

6 Exigences générales............................................................................................................................. 7

7 Mesurages de la circonférence ........................................................................................................... 8

8 Autres mesurages effectués sur les tôles de robe du réservoir.................................................... 11

9 Corps intérieurs et extérieurs............................................................................................................ 11

10 Fonds des réservoirs.......................................................................................................................... 11

11 Mesurage de l'inclinaison .................................................................................................................. 12

12 Réservoirs à toit flottant..................................................................................................................... 12

13 Rejaugeage.......................................................................................................................................... 13

14 Calcul des barèmes de jaugeage de réservoirs — Règles générales ........................................... 13

15 Forme des barèmes de jaugeage de réservoir................................................................................. 14

16 Calcul du volume brut ........................................................................................................................ 14

17 Élaboration des barèmes définitifs ................................................................................................... 18

Annexe A (normative) Spécifications pour le matériel de ceinturage ........................................................ 24

Annexe B (informative) Recommandations relatives au suivi, au contrôle et à la vérification du

jaugeage et des barèmes de jaugeage .............................................................................................27

Annexe C (informative) Feuille de données de jaugeage et de calcul ........................................................ 33

Annexe D (informative) Incertitudes de jaugeage des réservoirs ............................................................... 37

Annexe E (informative) Détermination de la température de la robe d'un réservoir ................................. 48

Annexe F (normative) Correction de la température pour le ruban de pige .............................................. 49

Annexe G (informative) Dilatation due à la charge hydrostatique du liquide ............................................ 52

Annexe H (normative) Dilatation due à la température ................................................................................ 60

Annexe I (normative) Certificat de jaugeage ................................................................................................. 63

Bibliographie .................................................................................................................................................... 64

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ISO 7507-1:2003(F)
Avant-propos

L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de

normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée

aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du

comité technique créé à cet effet. Les organisations internationales, gouvernementales et non

gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec

la Commission électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.

Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,

Partie 2.

La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes

internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur

publication comme Normes internationales requiert l'approbation de 75 % au moins des comités membres

votants.

L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de

droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable de ne

pas avoir identifié de tels droits de propriété et averti de leur existence.

L'ISO 7507-1 a été élaborée par le comité technique ISO/TC 28, Produits pétroliers et lubrifiants, sous-comité

SC 3, Mesurage statique du pétrole.

Cette deuxième édition annule et remplace la première édition (ISO 7507-1:1993). Elle annule et remplace

également l’ISO 7507-6:1997, qui est maintenant incluse dans la présente partie de l’ISO 7507.

L'ISO 7507 comprend les parties suivantes, présentées sous le titre général Pétrole et produits pétroliers

liquides — Jaugeage des réservoirs cylindriques verticaux:
 Partie 1: Méthode par ceinturage
 Partie 2: Méthode par ligne de référence optique
 Partie 3: Méthode par triangulation optique
 Partie 4: Méthode par mesurage électro-optique interne de la distance
 Partie 5: Méthode par mesurage électro-optique externe de la distance

 Partie 6: Recommandations relatives à la surveillance, au contrôle et à la vérification du jaugeage des

réservoirs et des tables de jaugeage
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ISO 7507-1:2003(F)
Introduction

La présente partie de l’ISO 7507 fait partie d’une série de normes sur l’étalonnage des réservoirs incluant les

normes suivantes:

ISO 7507-2:1993, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —

Partie 2: Méthode par ligne de référence optique

ISO 7507-3:1993, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —

Partie 3: Méthode par triangulation optique

ISO 7507-4:1995, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —

Partie 4: Méthode par mesurage électro-optique interne de la distance

ISO 7507-5:2000, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —

Partie 5: Méthode par mesurage électro-optique externe de la distance

ISO 7507-6:1997, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —

Recommandations relatives à la surveillance, au contrôle et à la vérification du jaugeage des réservoirs et des

tables de jaugeage

ISO 8311:1989, Hydrocarbures légers réfrigérés — Étalonnage des réservoirs à membrane et réservoirs

pyramidaux — Mesurage Physique

ISO 9091-1:1991, Hydrocarbures légers réfrigérés — Jaugeage des réservoirs sphériques à bord des

navires — Partie 1: Stéréo-photogrammétrie

ISO 9091-2:1992, Hydrocarbures légers réfrigérés — Jaugeage des réservoirs sphériques à bord des

navires — Partie 2: Méthode par triangulation

La méthode par ceinturage pour le jaugeage des réservoirs verticaux est utilisée depuis de nombreuses

années et est reconnue pour déterminer la capacité des réservoirs de stockage à partir des mesures de la

circonférence d’un réservoir à différentes hauteurs. La méthode par ceinturage est également souvent utilisée

pour établir une circonférence de référence à une hauteur définie qui est ensuite utilisée comme donnée dans

les autres méthodes de jaugeage.
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NORME INTERNATIONALE ISO 7507-1:2003(F)
Pétrole et produits pétroliers liquides — Jaugeage des
réservoirs cylindriques verticaux —
Partie 1:
Méthode par ceinturage
1 Domaine d'application

1.1 La présente partie de l'ISO 7507 spécifie une méthode permettant de jauger les réservoirs cylindriques

pratiquement verticaux par mesurage avec un ruban de ceinturage.

1.2 Cette méthode connue sous le nom de «méthode par ceinturage» convient tant comme méthode de

travail que comme méthode de référence ou encore comme méthode d'arbitrage.

NOTE Pour la méthode de référence, le nombre de ceinturages requis sera spécifié dans la norme faisant appel à la

présente partie de l'ISO 7507.

1.3 Les opérations de ceinturage à mettre en œuvre ainsi que les corrections et les calculs à effectuer pour

élaborer un barème de jaugeage de réservoir sont décrits.

1.4 La présente méthode ne s'applique pas aux réservoirs anormalement déformés, par exemple les

réservoirs bosselés ou non circulaires.

1.5 Cette méthode convient pour les réservoirs dont l'inclinaison par rapport à la verticale n'excède pas 3 %,

à condition qu'une correction soit apportée aux calculs pour tenir compte de l'inclinaison mesurée.

2 Références normatives

Les documents de référence suivants sont indispensables pour l'application du présent document. Pour les

références datées, seule l'édition citée s'applique. Pour les références non datées, la dernière édition du

document de référence s'applique (y compris les éventuels amendements).

ISO 91-1:1992, Tables de mesure du pétrole — Partie 1: Tables basées sur les températures de référence de

15 °C et 60 °F

ISO 3675:1998, Pétrole brut et produits pétroliers liquides — Détermination en laboratoire de la masse

volumique — Méthode à l'aréomètre

ISO 4269:2001, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs par épalement — Méthode

par empotement utilisant des compteurs volumétriques
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ISO 7507-1:2003(F)
3 Termes et définitions

Dans le cadre de la présente partie l'ISO 7507 et de ses parties suivantes, les termes et définitions suivants

s'appliquent.
3.1
argument
variable indépendante d'une fonction

NOTE On entre dans une table numérique avec la (les) valeur(s) de la (des) variable(s) indépendante(s), la (les)

valeur(s) extraite(s) de la table étant connue(s) comme valeur(s) dépendante(s).
3.2
jaugeage du fond

procédé permettant de déterminer la quantité de liquide contenue dans un réservoir sous le point de référence

inférieur
3.3
jaugeage

processus permettant de déterminer la capacité d'un réservoir ou les capacités partielles correspondant à

différents niveaux
3.4
capacité
volume total d'un réservoir
3.5
barème de jaugeage
table de jaugeage
table des volumes

table indiquant la capacité d'un réservoir et les volumes qu'il contient à divers niveaux de liquide repérés à

partir d'un point de référence stable
3.6
virole
anneau de tôles sur la circonférence d'un réservoir
3.7
point de repère
point utilisé comme repère dans l'élaboration d'un barème de jaugeage

NOTE Les hauteurs des viroles et les niveaux réels des corps intérieurs et extérieurs sont repérés à partir de ce

point qui sert également de référence pour le jaugeage du fond.
3.8
corps intérieurs et extérieurs
tout accessoire qui influe sur la capacité d'un réservoir

NOTE Les accessoires extérieurs dont la capacité s'ajoute à celle du réservoir sont désignés «corps positifs» et les

accessoires intérieurs dont le volume déplace du liquide et réduit la capacité réelle du réservoir sont désignés «corps

négatifs».
3.9
hauteur de plein
hauteur de liquide dans un réservoir au-dessus du point de référence inférieur
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3.10
orifice de pige
orifice de repérage des niveaux

ouverture pratiquée à la partie supérieure d'un réservoir par laquelle s'effectuent les opérations de repérage

des niveaux et d'échantillonnage
3.11
point de référence inférieur

point placé sur la plaque de touche qu'atteint le lest gradué au cours d'un repérage de niveau et à partir

duquel sont effectués les mesurages des hauteurs de plein de produit et d'eau

NOTE Le point de référence inférieur correspond généralement au point de repère, mais si tel n'est pas le cas, il

convient de tenir compte de la différence de niveau entre le point de repère et le point de référence inférieur dans le

barème de jaugeage.
3.12
plaque de touche
plaque d'arrêt placée à la verticale de l'orifice de pige

NOTE Il est recommandé que la position de la plaque de touche ne subisse pas les effets dus aux mouvements du

fond ou des parois.
3.13
ruban de pige

ruban en acier gradué utilisé pour le mesurage de la hauteur d'hydrocarbures ou d'eau contenue dans un

réservoir, ce mesurage pouvant être effectué soit directement par la hauteur de plein, soit indirectement par la

hauteur de creux
3.14
lest

lest fixé au ruban de pige en acier, d'une masse suffisante pour que le ruban soit bien tendu et d'une forme

telle qu'il puisse traverser facilement des boues éventuelles au niveau du point de référence inférieur ou de la

plaque de touche
3.15
écran flottant

écran léger en métal ou en plastique conçu pour flotter à la surface d'un liquide contenu dans un réservoir

NOTE L'écran repose sur la surface du liquide et sert à retarder l'évaporation des produits volatils présents dans un

réservoir.
3.16
réservoir à toit flottant

réservoir dont le toit flotte librement sur la surface du liquide, sauf lorsque le niveau est bas, la masse du toit

étant alors supportée par le fond du réservoir par l'intermédiaire de supports
3.17
fonction

lorsque deux quantités variables sont en relation mutuelle, une quantité est dite fonction de l'autre

NOTE Dans le cadre du jaugeage des réservoirs, on dit que le volume de liquide contenu dans un réservoir est une

fonction de la hauteur de plein ou de la hauteur de creux.
3.18
jaugeage

processus consistant à effectuer tous les mesurages nécessaires dans un réservoir afin de déterminer la

quantité de liquide qu'il contient
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3.19
interpolation

processus permettant d'obtenir la valeur d'une fonction correspondant à une valeur de l'argument

intermédiaire entre les valeurs données
3.20
Étau Littlejohn

étau à desserrage rapide pouvant être fixé sur un ruban de ceinturage en tout point voulu de sa longueur

NOTE Une poignée est fixée sur l'étau Littlejohn de façon à pouvoir tendre le ruban jusqu'à la tension correcte.

3.21
capacité brute

capacité d'un réservoir, ou d'une partie d'un réservoir, calculée avant de tenir compte des corps intérieurs et

extérieurs
3.22
hauteur totale témoin

distance verticale entre le point de référence inférieur et le point de référence supérieur

3.23
hauteur totale
hauteur de robe

hauteur extérieure totale mesurée de la base du réservoir (tôle du fond) au sommet de la robe

3.24
méthode d'arbitrage

application de la méthode par ceinturage pour le jaugeage d'un réservoir à des fins de transaction

commerciale ou afin de servir de base pour apprécier l'exactitude d'autres méthodes de jaugeage de

réservoirs
3.25
méthode de référence

application de la méthode de jaugeage des réservoirs par ceinturage au mesurage d'une circonférence de

référence qui sera utilisée dans d'autres méthodes de jaugeage de réservoirs

NOTE La méthode par lignes de référence optique (voir l'ISO 7507-2) est un exemple d'une telle méthode.

3.26
point de référence

point auquel se rapportent tous les mesurages de jaugeage et de repérage de niveau d'un réservoir

3.27
cadre pour mesurage des recouvrements

dispositif utilisé dans le ceinturage pour mesurer la distance séparant, sur un arc, deux points de la robe du

réservoir entre lesquels il n'est pas possible d'utiliser un ruban de ceinturage en raison d'un obstacle, par

exemple un accessoire saillant
3.28
constante de recouvrement

distance comprise entre les pointes d'un cadre pour mesurage des recouvrements, mesurée le long de l'arc

d'une virole donnée du réservoir concerné
3.29
correction de recouvrement

différence entre la distance apparente entre deux points sur la robe d'un réservoir, mesurée à l'aide d'un

ruban de ceinturage passant au-dessus d'un obstacle et la longueur réelle de l'arc mesurée avec un cadre

pour mesure des recouvrements, c'est-à-dire la constante de recouvrement
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3.30
ruban de ceinturage

ruban de mesure en acier spécialement conçu et étalonné, gradué en unités de longueur et utilisé pour

effectuer des mesurages de circonférence lors d'un jaugeage de réservoir
3.31
méthode de jaugeage par ceinturage

méthode de jaugeage de réservoirs dans laquelle on calcule les capacités à partir de mesurages de

circonférences extérieures, en tenant compte de l'épaisseur de la robe du réservoir

3.32
positionneur de ruban

guide coulissant librement sur le ruban de ceinturage, utilisé pour tirer le ruban et le maintenir dans la position

convenable pour les mesurages
3.33
poignées de serrage

poignées fixées au ruban de ceinturage, utilisées pour le tendre en position correcte et pour appliquer une

tension
3.34
creux d'un réservoir
volume d'un réservoir non occupé par le liquide
3.35
point de référence supérieur

point clairement défini sur l'orifice de pige, situé directement au-dessus et à la verticale du point de référence

inférieur, pour indiquer l'emplacement auquel doit être pratiqué le mesurage par le creux ou par le plein

3.36
méthode de travail

application de la méthode de jaugeage de réservoirs par ceinturage selon un procédé simplifié qui peut

entraîner une certaine perte d'exactitude et ne convient donc pas pour évaluer d'autres méthodes

4 Précautions
4.1 Introduction

Le présent article trace les grandes lignes des précautions à suivre lors du jaugeage des réservoirs. Les

précautions requises pour assurer la sécurité de l'opérateur sont traitées séparément des précautions à

observer pour obtenir la précision nécessaire au jaugeage des réservoirs.
4.2 Précautions générales

4.2.1 Il faut faire preuve d'un soin extrême et porter une grande attention aux détails lors du jaugeage d'un

réservoir de stockage.

4.2.2 Tous les résultats des mesurages doivent être soigneusement lus et consignés sitôt relevés, et toutes

les corrections nécessaires doivent être notées séparément. Si des événements inhabituels sont observés au

cours des opérations, ils doivent être consignés et le jaugeage doit être recommencé si nécessaire.

4.2.3 Si le réservoir est seulement légèrement déformé, un nombre suffisant de mesurages

supplémentaires doit être effectué afin de permettre un calcul satisfaisant de son barème de jaugeage. Si de

tels mesurages supplémentaires sont nécessaires, les notes de l'opérateur doivent faire mention des raisons

pour lesquelles ils ont été effectués.

Il est également recommandé que l'opérateur produise des schémas cotés montrant toute anomalie du

réservoir et les accessoires influant sur le jaugeage.
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NOTE Pour les réservoirs fortement déformés, il est préférable d'utiliser une méthode de jaugeage par transfert de

liquide, telle que celle décrite dans l'ISO 4269.

4.2.4 Pour assurer l'exactitude et la répétabilité des lectures, les coulures de peinture, la calamine, etc.

susceptibles de gêner le mesurage doivent être retirées ou le dispositif de mesurage doit être placé en

conséquence.

4.2.5 S'il existe des plans du réservoir, tous les résultats des mesurages utiles doivent être comparés aux

dimensions correspondantes figurant sur ces plans. Tout résultat présentant une différence significative à la

suite de cette comparaison doit être signalé et, si nécessaire, le jaugeage doit être réitéré.

4.2.6 Si l'opération de jaugeage d'un réservoir est interrompue, elle peut être poursuivie ultérieurement à

condition que

a) s'il y a eu changement d'équipement ou de personnel, des mesurages de vérification seront effectués en

nombre suffisant pour s'assurer que les résultats obtenus avant le changement concordent dans les

limites des tolérances fixées dans la présente méthode;
b) toutes les notes portant sur le travail effectué sont complètes et lisibles;
c) le contenu liquide reste inchangé, sensiblement au même niveau;

d) les températures moyennes du liquide et de l'atmosphère ne différent pas de plus de 10 °C des

températures moyennes du liquide et de l'atmosphère observées au cours de la période de travail

précédente.
4.3 Précautions de sécurité

4.3.1 Les mesures de sécurité indiquées en 4.3.2 à 4.3.6 constituent une pratique courante, mais la liste

n'est pas nécessairement exhaustive. Il est recommandé d'utiliser cette liste conjointement avec les

paragraphes appropriés de tout code de sécurité applicable. Ces précautions doivent être observées chaque

fois qu'elles n'interfèrent pas avec les exigences légales, qui doivent être suivies dans tous les cas.

4.3.2 Toutes les réglementations relatives à l'accès dans des zones dangereuses doivent être strictement

observées.

4.3.3 Si le réservoir ceinturé contient un produit pétrolier, il faut observer les précautions normales de

sécurité qui s'appliquent à de tels réservoirs.

4.3.4 Avant de pénétrer à l'intérieur d'un réservoir préalablement utilisé, il faut obtenir une autorisation

d'entrée, conformément aux règlements locaux ou nationaux. Toutes les canalisations pénétrant dans le

réservoir doivent être déconnectées et obturées. Les règlements locaux ou nationaux relatifs à l'accès à

l'intérieur des réservoirs ayant contenu des carburants plombés doivent être scrupuleusement respectés.

4.3.5 Les lampes portatives doivent être d'un type agréé pour l'emploi dans des atmosphères explosives.

4.3.6 La sécurité du personnel opérationnel doit être garantie en observant strictement les points suivants.

a) Les échelles doivent être inspectées avant utilisation et les échelles à coulisse doivent être utilisées

uniquement sur leur longueur utile de sécurité. Toutes les échelles doivent être solidement attachées en

place avant utilisation et leurs pieds doivent être de niveau et stables.

b) Lorsqu'on utilise des échafaudages volants de peintre ou des «chaises suspendues» de gabier, les

chapes de palans, les câbles de mécanisme élévateur, les cordes, etc. doivent être testés avant le levage

et tout élément dont la résistance ou l'état s'avère douteux doit être remplacé. Il faut veiller tout

particulièrement à la fixation du matériel et à sa bonne utilisation.
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c) Si le jaugeage ne peut pas être effectué sans un échafaudage, un échafaudage correctement construit

en tubes d'acier ou en bois doit être monté. On ne doit pas utiliser de briques, de fûts, de caisses, etc.

pour former l'échafaudage.

d) Là où cela est nécessaire, le personnel travaillant au-dessus du niveau du sol doit porter un harnais de

sécurité.
5 Équipement

5.1 Ruban de ceinturage, conforme aux prescriptions données en A.1. Le ruban doit être bien graissé

avant emploi.

5.2 Dynamomètre, conforme aux prescriptions données en A.2, pour mesurer la tension appliquée au

ruban.

5.3 Cadre pour mesurage des recouvrements, conforme à la description donnée en A.3.

5.4 Câbles et positionneurs de ruban, conformes aux prescriptions données en A.4. Les positionneurs

doivent être montés sur le ruban de ceinturage et dotés de câbles tressés. Les câbles supérieur et inférieur

doivent être suffisamment longs pour couvrir la hauteur du réservoir.

5.5 Étau Littlejohn, conforme à la description donnée en A.5, pour maintenir le ruban sans qu'il ne vrille, et

faciliter l'application de la tension nécessaire.

5.6 Dispositif de mesurage d'épaisseur de tôle, soit une règle d'acier graduée en millimètres sur toute sa

longueur, dont au moins les premiers dix millimètres sont subdivisés en demi-millimètres, soit un autre

dispositif tel qu'une jauge d'épaisseur électronique.

5.7 Ruban de pige, conforme aux prescriptions données en A.6, suffisamment long pour atteindre, du

point de référence supérieur situé sur le toit du réservoir, le point de référence inférieur au fond du réservoir.

5.8 Lest, conforme aux prescriptions données en A.7.

5.9 Règle à bouts, d'un mètre de long, avec des graduations en centimètres et en millimètres pour

mesurer les corps extérieurs et intérieurs, etc. Si on utilise une règle en bois, elle doit être munie d'un

manchon en laiton à chaque extrémité et ne pas présenter de gauchissement.
5.10 Échelles et échafaudages: voir 4.3.6 pour les précautions de sécurité.

5.11 Appareils de mesure de la masse volumique et de la température, conformes aux prescriptions de

l'ISO 3675.
6 Exigences générales

NOTE Il convient de comparer, si possible, les mesures obtenues aux dimensions correspondantes figurant sur les

plans de construction du réservoir et de s'assurer de la rotondité de celui-ci.

6.1 Remplir au moins une fois le réservoir à sa capacité de service normale et laisser reposer au moins

24 h avant le jaugeage.

Si l'on jauge le réservoir alors qu'il contient du liquide, noter la hauteur de plein, la température et la masse

volumique du liquide lors du jaugeage. Toutefois, si la température de surface de sa paroi diffère de plus de

10 °C entre la partie vide et la partie pleine du réservoir, il devra être soit complètement rempli, soit vidé. Ne

pas transvaser de liquide pendant le jaugeage.
Il convient d'enregistrer la température ambiante avant et après le jaugeage.
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Effectuer le nombre requis de mesurages de circonférence extérieure, et le cas échéant les mesurages

supplémentaires permettant de corriger la déviation du ruban provoquée par des obstacles comme décrit

en 7.2.

NOTE Les mesurages supplémentaires nécessaires à la préparation d'un barème de jaugeage et les méthodes à

suivre pour les effectuer sont décrits dans les Articles 8 à 12.

6.2 Il est nécessaire de rapporter toutes les mesures de niveau au point de référence inférieur qui peut être

situé à une position différente du point de repère, par exemple, un point de l'angle du fond utilisé dans le but

de jauger le réservoir. Vérifier que la plaque de touche est sol
...