EN ISO 8311:1995
(Main)Refrigerated light hydrocarbon fluids - Calibration of membrane tanks and independent prismatic tanks in ships - Physical measurement (ISO 8311:1989)
Refrigerated light hydrocarbon fluids - Calibration of membrane tanks and independent prismatic tanks in ships - Physical measurement (ISO 8311:1989)
Includes a method for the internal measurement of thanks used for the transport. In addition to the actual process of measurement, it sets out the calculation procedures for compiling the calibration table and correction tables to be used for the computation of cargo quantities. Definitions are given.
Verflüssigte leichte Kohlenwasserstoffe - Kalibrierung von Membrantanks und abhängigen Prismentanks in Schiffen - Physikalische Messung (ISO 8311:1989)
Hydrocarbures légers réfrigérés - Etalonnage des réservoirs à membrane et réservoirs pyramidaux - Mesurage physique (ISO 8311:1989)
1.1 La présente Norme internationale spécifie une méthode de mesure interne des réservoirs à membrane et des réservoirs pyramidaux auto-porteurs dans les navires transporteurs de gaz liquéfié. Outre le processus actuel pour effectuer les mesures, la présente Norme internationale incorpore des méthodes de calcul pour établir des tables de barémage de réservoir et des tables de correction à utiliser pour le calcul des quantités de cargaison. 1.2 La présente Norme internationale s'applique aux réservoirs à membrane, où des échafaudages sont montés pour revêtir l'intérieur avec des membranes; dans le cas de réservoirs pyramidaux auto-porteurs, d'autres moyens de sécurité d'accès aux emplacements requis de mesurage peuvent être utilisés.
Ohlajene lahke ogljikovodikove tekočine - Kalibracija membranskih rezervoarjev in samostojnih prizmatičnih rezervoarjev na ladjah - Fizikalna meritev (ISO 8311:1989)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-1998
2KODMHQHODKNHRJOMLNRYRGLNRYHWHNRþLQH.DOLEUDFLMDPHPEUDQVNLKUH]HUYRDUMHYLQ
VDPRVWRMQLKSUL]PDWLþQLKUH]HUYRDUMHYQDODGMDK)L]LNDOQDPHULWHY ,62
Refrigerated light hydrocarbon fluids - Calibration of membrane tanks and independent
prismatic tanks in ships - Physical measurement (ISO 8311:1989)
Verflüssigte leichte Kohlenwasserstoffe - Kalibrierung von Membrantanks und
abhängigen Prismentanks in Schiffen - Physikalische Messung (ISO 8311:1989)
Hydrocarbures légers réfrigérés - Etalonnage des réservoirs a membrane et réservoirs
pyramidaux - Mesurage physique (ISO 8311:1989)
Ta slovenski standard je istoveten z: EN ISO 8311:1995
ICS:
47.020.85 Prostori za tovor Cargo spaces
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 8311
First edition
1989-07-01
Refrigerated light hydrocarbon fluids -
Calibration of membrane tanks and independent
prismatic tanks in ships - Physical
measurement
H ydrocarbures Egers r6 frig&& - Etalonnage des r&ervoirs a membrane
et reservoirs p yramidaux - Mesurage ph ysigue
Reference number
ISO 8311 : 1989 (El
ISO8311 : 1989 (E)
Page
Contents
iv
..............................................................
Foreword
V
............................................................
Introduction
..............................................................
1 Scope
.................................................
2 Normative references
.......................................................... 1
3 Definitions
......................................................... 2
4 Precautions
5 Equipment .
5.1 Dynamometer .
5.2 End-to-end rule .
5.3 Lasertransmitter .
................................................. 3
5.4 Measuringtape
Opticallevel . 3
5.5
5.6 Steelrule .
................................................... 3
5.7 Thermometer
................................................. 3
5.8 Tension handle.
........................................................ 3
6 Measurement
6.1 Method .
.............................. 3
6.2 Determination of measuring positions
6.3 Marking .
........................................ 3
6.4 Tank length measurement
......................................... 4
6.5 Tank width measurement
Tank height measurement .
6.6
@ ISO 1989
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronie cr mechanical, including photocopying and microfilm, without Permission in
writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
ii
ISO8311 : 1989 (E)
6.7 Bottom calibration . 6
6.8 Location of level gauge . 6
6.9 Temperature. . 9
6.10 Deadwood . 9
7 Calculation procedure . 9
7.1 Calculation of tank volume . 9
7.2 Effect of bottom undulation . 9
7.3 Area of chamfer Portion . 9
7.4 Trim corrections. . 9
7.5 List corrections .
7.6 Combined trim and list corrections . 9
7.7 Correction for tank Shell expansion or contraction . 9
8 Calibration tables. . 10
8.1 Calibration report . 10
8.2 Main gauge table . 10
8.3 Trim correction table . 10
8.4 List correction table . 10
............... 10
8.5 Correction table for tank Shell expansion or contraction
8.6 Correction for float-type level gauge . 10
Annexes
A Safety precautions for work in membrane tanks . 11
............... 12
B Example of calculation of errors for a typical membrane tank
C Example of a main gauge table. . 14
...................................... 15
D Example of a trim correction table
E Example of a list correction table .
........ 17
F Example of a correction table for expansion/contraction of tank Shell
. . .
Ill
ISO8311 : 1989 (EI
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of
national Standards bodies (ISO member bedies). The work of preparing International
Standards is normally carried out through ISO technical committees. Esch 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, govern-
mental and non-governmental, in liaison with ISO, also take patt in the work. ISO
collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the ISO Council. They are approved in accordance with ISO procedures requiring at
least 75 % approval by the member bodies voting.
International Standard ISO 8311 was prepared by Technical Committee ISO/TC 28,
Petroleum products and lubrican ts.
Annexes A to F are for information only.
ISO8311 : 1989(E)
Introduction
Large quantities of light hydrocarbons consisting of compounds having 1 to 4 carbon
atoms are stored and transported by sea as refrigerated liquids at pressures close to
atmospheric. These liquids tan be divided into two main groups, liquefied natura) gas
(LNG) and liquefied Petroleum gas (LPG). Bulk transportation of these liquids requires
a special technology in ship design and construction to enable shipborne trans-
portation to be safe and economical.
Measurement of cargo quantities in ships’ tanks for custody transfer purposes has to
be of a high Order of accuracy. This International Standard, together with others in the
series, specifies methods of internal measurement of ships’ tanks from which tank
calibration tables tan be derived.
This International Standard covers calibration techniques applicable to membrane type
tanks, i.e. tanks in which the containment System comprises a relatively thin mem-
brane of either stainless steel or high-nickel steel alloy supported by insulation and
also, with some modifications, to tanks constructed of aluminium alloy or steel for low-
temperature Service that are independent, self-supporting and approximately prismatic
in shape.
Annex A gives recommendations on safety precautions to be observed during the
calibration.
Annex B gives an analysis sf the sources of error for a typical membrane tank.
Annex C gives an example of a calibration table relating partial filling volume as a func-
tion of liquid level and annexes D, E and F give examples of trim, list and temperature
correction tables.
V
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ISO 8311 : 1989 (EI
INTERNATIONAL STANDARD
Refrigerated light hydrocarbon fluids - Calibration
of membrane tanks and independent prismatic tanks
Physical measurement
in ships -
Measurements made to provide
1 Scope 3.1.1 bottom calibration :
calibration of the bottom part of a tank to take account of un-
dulation in the bottom plate.
1.1 This International Standard specifies a method for the
internal measurement of membrane tanks and independent
prismatic tanks used in ships for the transport of refrigerated
32 calibration table (main gauge table) : A table, often
light hydrocarbon fluids. In addition to the actual process of
referred to as a tank table or a tank capacity table, showing the
measurement, it sets out the calculation procedures for com-
capacity of, or volumes in, a tank corresponding to various li-
piling the calibration table and correction tables to be used for
quid levels measured from the gauge reference Point (sec 3.6),
the computation of cargo quantities.
with the ship on an even keel and upright.
1.2 For membrane tanks, the procedures of this International
3.3 chamfer : A slanting surface connecting the Walls of a
Standard utilize the scaffolding used for the installation sf the
tank with its top or bottom surface (see figure 5).
membranes to support the measuring equipment but, for in-
dependent prismatic tanks, other safe means of access to the
required measuring positions have to be used. 3.4 deadwood : Any tank fitting or structure, including
rounded corners or radiussed ends, which affect the capacity
of the tank. Deadwood is referred to as “positive deadwood”
when the capacity of the fitting adds to the effective capacity of
2 Normative references
the tank, or “negative deadwood” when the volume of the
fitting displaces liquid and reduces the effective capacity.
The following Standards contain provisions which, through
reference in this text, constitute provisions of this International
3.5 gauging : All the measurements taken in a tank
Standard. At the time of publication, the editions indicated
necessary to determine the quantity of liquid and vapour con-
were valid. All Standards are subject to revision, and Parties to
tained therein.
agreements based on this International Standard are encouraged
to investigate the possibility of applying the most recent editions
of the Standards listed below. Members of IEC and ISO main-
3.6 gauge reference point : The Point from which the
tain registers of currently valid International Standards
liquid depths are measured.
ISO 4512 : -l), Petroleum and liquid Petroleum products -
3.7 horizontal plane : A plane established parallel to the
Eguipment - Tank gauging and calibration - Manual
tank bottom.
methods.
ISO 7507-1 : - ‘1, Petroleum and liquid petroleum products -
3.8 liquid level : Height of the liquid surface measured from
Volumetric calibration of vertical c ylindrical tanks -- Part 7 :
the gauge reference Point. When the ship is in list or trim con-
S trapping me thod.
dition, the height is measured at a right angle to the tank
bottom.
3 Definitions
3.9 list : Transverse inclination of a ship.
For the purposes of this International Standard, the following
3.10 longitudinal fine : A line formed by a longitudinal
definitions shall apply.
plane crossing a horizontal plane.
31 . calibration : The process of determining the total
3.1’1 longitudinal plane : A vertical plane running parallel to
capacity or partial capacities of a tank corresponding to dif-
the centreline of the tank.
ferent levels.
1) To be published.
ISO8311 : 1989 (E)
3.12 : A line (Iongitudinal, transverse or ver- The calibrator shall provide detailed Sketches of any abnor-
measuring line
mality of the tank or its fittings where such Sketches will
tical) on a three-dimensional rectangular grid with a pitch not
materially assist the interpretation of the recorded data.
greater than 5 m. Measurement for calibration purposes is
taken along these measuring lines.
4.3 If drawings for the tank are available, all measurements
3.13 port : The left-hand side of a ship facing forward. taken shall be compared with the corresponding dimensions
shown on the drawings. Any measurement showing a signifi-
cant discrepancy in this comparison shall be rechecked.
3.14 reference line : A Standard line established by a string
or laser. A calibration method using this line is adopted as an
alternative to direct measurements, where it is considered im-
4.4 Measurements shall be taken twice to check whether
practical to take direct measurements.
they agree within the following tolerantes; if they do not agree,
measurements shall be continued until two consecutive
readings agree, and their average shall be taken as the result.
3.15 reference offsets : Clearances or offsets between the
tank bottom and a horizontal plane set over it, which are
measured along all the vertical lines drawn on the fore and aft Measurement Tolerante
end Walls.
up to 20 m + 2mm
+ 3 mm
over 20 m
3.16 reference plane : A plane parallel to a side Wall, end
for offset + 0,5 mm
Passes through a reference line.
wall or tank bottom which
If the measurements have been interrupted, the last measure-
ments taken shall be repeated. If the new measurements do not
3.17 section line : A line formed section plane crossing
bY a
agree, within the required tolerante, with the earlier measure-
a horizontal plane.
ments, then the earlier set shall be rejected.
3.18 section plane : A plane parallel with the fore and aft
end Walls of a tank.
4.5 When measurements are made with a measuring tape,
the tension specified in the tape calibration certificate shall be
applied.
The right-hand side of a ship facing
3.19 starboard :
forward.
4.6 The measuring tape shall be supported, if necessary, so
as to prevent it from sagging. If tape sag is unavoidable, the
3.20 trim : Longitudinal
...
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