SIST EN ISO 8311:2014

SLOVENSKI STANDARD
SIST EN ISO 8311:2014
01-februar-2014
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SIST EN ISO 8311:1998
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Refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels - Calibration
of membrane tanks and independent prismatic tanks in ships - Manual and internal
electro-optical distance-ranging methods (ISO 8311:2013)
Gekühlte Kohlenwasserstoffe und verflüssigte, nicht auf Erdöl basierende gasförmige
Brennstoffe - Kalibrierung von Membrantanks und unabhängigen Prismentanks in
Schiffen - Manuelle Messung und Innenmessung nach dem elektrooptischen
Distanzmessverfahren (ISO 8311:2013)
Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à base non pétrolière -
Étalonnage des réservoirs à membrane et réservoirs pyramidaux - Méthodes manuelles
et par mesurage électro-optique interne de la distance (ISO 8311:2013)
Ta slovenski standard je istoveten z: EN ISO 8311:2013
ICS:
47.020.85 Prostori za tovor Cargo spaces
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
SIST EN ISO 8311:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 8311:2014

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SIST EN ISO 8311:2014

EUROPEAN STANDARD
EN ISO 8311

NORME EUROPÉENNE

EUROPÄISCHE NORM
December 2013
ICS 75.180.30 Supersedes EN ISO 8311:1995
English Version
Refrigerated hydrocarbon and non-petroleum based liquefied
gaseous fuels - Calibration of membrane tanks and independent
prismatic tanks in ships - Manual and internal electro-optical
distance-ranging methods (ISO 8311:2013)
Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à Gekühlte Kohlenwasserstoffe und verflüssigte, nicht auf
base non pétrolière - Étalonnage des réservoirs à Erdöl basierende gasförmige Brennstoffe - Kalibrierung von
membrane et réservoirs pyramidaux - Méthodes manuelles Membrantanks und unabhängigen Prismentanks in Schiffen
et par mesurage électro-optique interne de la distance (ISO - Manuelle Messung und Innenmessung nach dem
8311:2013) elektrooptischen Distanzmessverfahren (ISO 8311:2013)
This European Standard was approved by CEN on 9 November 2013.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8311:2013 E
worldwide for CEN national Members.

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SIST EN ISO 8311:2014
EN ISO 8311:2013 (E)
Contents Page
Foreword .3
2

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SIST EN ISO 8311:2014
EN ISO 8311:2013 (E)
Foreword
This document (EN ISO 8311:2013) has been prepared by Technical Committee ISO/TC 28 “Petroleum
products and lubricants” in collaboration with Technical Committee CEN/TC 19 “Gaseous and liquid fuels,
lubricants and related products of petroleum, synthetic and biological origin” the secretariat of which is held by
NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2014, and conflicting national standards shall be withdrawn at
the latest by June 2014.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8311:1995.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 8311:2013 has been approved by CEN as EN ISO 8311:2013 without any modification.


3

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SIST EN ISO 8311:2014

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SIST EN ISO 8311:2014
INTERNATIONAL ISO
STANDARD 8311
Second edition
2013-12-01
Refrigerated hydrocarbon and non-
petroleum based liquefied gaseous
fuels — Calibration of membrane tanks
and independent prismatic tanks in
ships — Manual and internal electro-
optical distance-ranging methods
Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à base non
pétrolière — Étalonnage des réservoirs à membrane et réservoirs
pyramidaux — Méthodes manuelles et par mesurage électro-optique
interne de la distance
Reference number
ISO 8311:2013(E)
©
ISO 2013

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SIST EN ISO 8311:2014
ISO 8311:2013(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested 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 copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

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SIST EN ISO 8311:2014
ISO 8311:2013(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Precautions . 3
4.1 General . 3
4.2 Ship’s condition during calibration . 3
4.3 Tank distortion . 3
4.4 Comparison with drawings . 4
4.5 Measurements by measuring tape . 4
4.6 Measurements by electro-optical distance-ranging (EODR) instrument . 4
4.7 Condition of membrane. 5
4.8 Safety precautions for work in membrane tanks . 5
5 Equipment . 5
6 Determination of measuring points . 6
7 Calibration by manual method . 6
7.1 General . 6
7.2 Tank length measurement . 7
7.3 Tank width measurement . 9
7.4 Tank height measurement .12
7.5 Measurement of bottom undulation and gauge reference height .14
7.6 Correction for temperature .15
8 Calibration by electro-optical distance-ranging (EODR) method .16
8.1 General .16
8.2 Setting up of EODR instrument . .16
8.3 Calibration procedure .17
9 Additional measurements .19
9.1 Location of level gauge .19
9.2 Deadwood . .19
10 Calculation .19
10.1 General .19
10.2 Calculation of tank volume .20
10.3 Effect of bottom undulation .20
10.4 Area of chamfer portion .20
10.5 Trim corrections .21
10.6 List corrections .21
10.7 Combined trim and list corrections .21
10.8 Correction for tank shell expansion or contraction .21
11 Report and tables .22
12 Recalibration .23
Annex A (informative) Uncertainty associated with tank calibration .24
Annex B (informative) Example of tank capacity table (Tank No.3) .36
Annex C (informative) Example of trim correction table (Tank No. 1) .38
Annex D (informative) Example of list correction table (Tank No. 1) .40
Bibliography .42
© ISO 2013 – All rights reserved iii

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SIST EN ISO 8311:2014
ISO 8311:2013(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 28, Petroleum products and lubricants, Subcommittee
SC 5, Measurement of refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels.
This second edition cancels and replaces the first edition (ISO 8311:1989), which has been technically revised.
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SIST EN ISO 8311:2014
ISO 8311:2013(E)

Introduction
Large quantities of light hydrocarbons consisting of compounds having one to four carbon atoms are
stored and transported by sea as refrigerated liquids at pressures close to atmospheric. These liquids
can be divided into two main groups, liquefied natural gas (LNG) and liquefied petroleum gas (LPG).
Bulk transportation of these liquids requires special technology in ship design and construction to
enable ship-borne transportation to be safe and economical.
Quantification of these cargoes in ships’ tanks for custody transfer purposes has to be of a high order of
accuracy. This International Standard (together with others in the group) specifies methods of internal
measurement of ships’ tanks, from which tank capacity tables can be derived.
This International Standard covers calibration techniques applicable to membrane type tanks, i.e. self-
supporting independent tanks in which the containment system comprises a relatively thin membrane
of either stainless steel or high-nickel steel alloy. This International Standard, with some modification,
can also be applicable to the calibration of independent prismatic tanks.
Annex A gives uncertainty associated with the measurement of membrane tanks.
Annex B gives an example of a tank capacity table relating partial filling volume as a function of liquid
level and Annexes C and D give examples of trim correction and list correction tables, respectively.
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SIST EN ISO 8311:2014

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SIST EN ISO 8311:2014
INTERNATIONAL STANDARD ISO 8311:2013(E)
Refrigerated hydrocarbon and non-petroleum based
liquefied gaseous fuels — Calibration of membrane tanks
and independent prismatic tanks in ships — Manual and
internal electro-optical distance-ranging methods
1 Scope
This International Standard specifies a method for the internal measurement of membrane tanks used
in ships for the transport of refrigerated light hydrocarbon fluids. In addition to the actual process of
measurement, it sets out the calculation procedures for compiling the tank capacity table and correction
tables to be used for the computation of cargo quantities. This International Standard, with some
modification, can also be applicable to the calibration of independent prismatic tanks.
For the manual measurement of membrane tanks, the procedures of this International Standard utilize
the scaffolding used for the installation of the membranes to support the measuring equipment but, for
the internal electro-optical distance-ranging (EODR) method, other safe means of access to the required
measuring positions are intended to be used.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 7507-1:2003, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —
Part 1: Strapping method
ISO 7507-4:2010, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks —
Part 4: Internal electro-optical distance-ranging method
IEC 60079-10-1, Explosive atmospheres — Part 10-1: Classification of areas — Explosive gas atmospheres
IEC 60079-10-2, Explosive atmospheres — Part 10-2: Classification of areas — Combustible dust atmospheres
IEC 60825-1, Safety of laser products — Part 1: Equipment classification and requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
automatic tank gauge
ATG
automatic level gauge
ALG
instrument that continuously measures liquid height (dip or ullage) in storage tanks
3.2
chamfer
slanting surface connecting the walls of a tank with its top or bottom surface
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SIST EN ISO 8311:2014
ISO 8311:2013(E)

3.3
deadwood
any tank fitting that affects the capacity of a tank
3.4
gauge reference point
point from which the liquid depth are measured
3.5
horizontal plane
any plane established parallel to the tank bottom
3.6
horizontal reference line
any horizontal line established by a string
Note 1 to entry: A calibration method using this line is adopted as an alternative to direct measurements, where
it is considered impractical to take direct measurements.
3.7
list
transverse inclination of a ship
Note 1 to entry: It is expressed in degrees.
3.8
longitudinal line
line formed by a longitudinal plane crossing a horizontal plane
3.9
longitudinal plane
vertical plane running parallel to the centreline of the tank
3.10
measuring point
one of a series of points on the inside surface of the tank shell from/to which the distance is measured by a
tape or a hand-held laser distance meter in case of manual method, or to which the slope distance, vertical
angles and horizontal angles are measured by use of the electro-optical distance-ranging instrument
3.11
port
left-hand side of a ship facing forward
3.12
reference target point
fixed point clearly marked on the inside surface to the tank shell or a prism mounted on a tripod
3.13
section line
line formed by a section plane crossing a horizontal plane
3.14
section plane
plane parallel with the fore and aft end walls of a ship’s tank
3.15
slope distance
distance measured from the electro-optical distance-ranging instrument to any measuring point or a
reference target point
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SIST EN ISO 8311:2014
ISO 8311:2013(E)

3.16
starboard
right-hand side of a ship facing forward
3.17
tank-calibration reference temperature
temperature at which the calibration of a tank has been calculated
3.18
tank capacity table
tank table
calibration table
capacity table
table showing the capacities of, or volumes in, a tank corresponding to various liquid levels measured
from a reference point
3.19
trim
difference between the fore and aft draught of the vessel
Note 1 to entry: When the aft draught is greater than the forward draught, the vessel is said to be trimmed by the
stern. When the aft draught is less than the forward draught, the vessel is said to be trimmed by the head.
3.20
uncertainty
U()
estimate characterizing the range of values within which the true value of a measurand lies
Note 1 to entry: Various types of uncertainty are defined in ISO/IEC Guide 98-3.
3.21
vertical line
line formed by a section plane on the side walls and formed by a longitudinal plane on the fore and
aft end walls
4 Precautions
4.1 General
This clause outlines the precautions to be taken during measurement. Utmost care and attention shall
be exercised in taking measurements, and any unusual occurrence during the measuring work, which
might affect the results, shall be recorded.
4.2 Ship’s condition during calibration
The calibration methods described in this International Standard may be applied to ships whether afloat
or in a dry dock. However, its use for ships in a dry dock is preferred, because trim or list, if any, will
remain the same throughout the calibration procedure. Adjustments, manually or automatically shall be
made to any measurement by optical level and EODR if the ship’s attitude has changed.
4.3 Tank distortion
If unusual distortion is found in the tank, additional measurement shall be taken by the calibrator as
considered necessary and sufficient. Notes by the calibrator detailing the extra measurements and the
reasons for them shall be included in the calibration report.
The calibrator shall provide detailed sketches of any abnormality of the tank or its fittings where such
sketches can materially assist the interpretation of the recorded data.
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SIST EN ISO 8311:2014
ISO 8311:2013(E)

4.4 Comparison with drawings
If drawings for the tank are available, all measurements taken shall be compared with the corresponding
dimensions shown on the drawings. Any measurement showing a significant discrepancy in this
comparison shall be rechecked; however, the tank capacity table shall be based on the actual
measurements.
4.5 Measurements by measuring tape
When measurements are made with a measuring tape:
a) the tension specified in the tape calibration certificate shall be applied;
b) the measuring tape shall be supported so as to prevent it from sagging. If tape sag is unavoidable,
the calibrator shall note this and a catenary correction shall be applied during calculation;
c) take multiple measurements. If the first three consecutive measurements agree within the
tolerances specified in d) below, take their mean as the measurement and their standard deviation
as the standard uncertainty. If they do not agree within the tolerances specified in d) below, repeat
the measurements until two standard deviations of the mean of all measurements is less than the
half of the tolerance specified in d) below. Use the mean as the measurement and the standard
deviation as the standard uncertainty. Use standard procedures to eliminate obvious outliers;
d) the following table shows the tolerances against the measurement distance:
Measurement Tolerance within
Up to 25 m 2 mm
over 25 m 3 mm
for offset 0,5 mm

e) if the measurements have been interrupted, the last measurements shall be repeated. If the new
measurements do not agree, within the required tolerance, with the earlier measurements, then the
earlier set shall be rejected.
4.6 Measurements by electro-optical distance-ranging (EODR) instrument
When measurements are carried out with an EODR instrument:
a) the electro-optical distance-ranging instrument shall be verified prior to calibration. The accuracy
of the distance-ranging unit as well as the angular measuring unit shall be verified using the
procedures given by ISO 7507-4:2010, Annex A;
b) the tank shall be free from vibration and air-borne dust particles. The floor of the tank should be as
free as possible from debris, dust and scales;
c) lighting, when required, shall be placed within the tank so as not to interfere with the operation the
EODR instrument;
d) the laser beam fitted to the EODR instrument shall be operated in conformity with IEC 60825-1.
The hazards, if any, in the area in which the calibration is to be carried out shall be assessed in
accordance with IEC 60079-10. The instrument to be used shall be declared (certified) as being safe
for use in the area of operation.
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SIST EN ISO 8311:2014
ISO 8311:2013(E)

4.7 Condition of membrane
Care shall be taken to ensure that the membrane is in contact with the supporting material. In some
cases, it may be possible to ensure this contact by applying a vacuum to the space behind the membrane.
4.8 Safety precautions for work in membrane tanks
a) All regulations covering entry into hazardous areas shall be rigorously observed.
b) 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 line
...