ISO 22804:2023

Marine technology — General technical requirement of marine conductivity-temperature-depth (CTD) measuring instrument

This document specifies the technical requirements to ensure consistent reporting on the test method, inspection rules, marks, packaging, transportation and storage of conductivity-temperature-depth (CTD) profilers. This document is applicable to marine fixed-point and mobile observation, monitoring platform and the various types of shipborne CTD measuring instruments. NOTE A CTD directly measures conductivity, temperature, pressure of seawater. Depth is the conversion of pressure according to the Formula (C.1).

Technologie maritime — Exigence technique générale de l'instrument de mesure de la conductivité, de la température et de la profondeur (CTP) en milieu marin

General Information

• Status: Published
• Publication Date: 06-Aug-2023
• ICS: 19.040 - Environmental testing
• ICS: 47.020.99 - Other standards related to shipbuilding and marine structures
• Technical Committee: ISO/TC 8/SC 13 - Marine technology
• Drafting Committee: ISO/TC 8/SC 13/WG 2 - Ocean hydrometeorological observation
• Current Stage: 6060 - International Standard published
• Start Date: 07-Aug-2023
• Due Date: 17-Apr-2023
• Completion Date: 07-Aug-2023

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22804
First edition
2023-08
Marine technology — General
technical requirement of marine
conductivity-temperature-depth
(CTD) measuring instrument
Technologie maritime — Exigence technique générale de l'instrument
de mesure de la conductivité, de la température et de la profondeur
(CTP) en milieu marin
Reference number
ISO 22804:2023(E)
© ISO 2023

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ISO 22804:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 22804:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Technical specifications.3
4.1 General . 3
4.2 Instrument appearance . 3
4.2.1 Cosmetic requirements . 3
4.2.2 Product identification . 3
4.2.3 Instrument fastener . 3
4.3 Measuring performance of instrument and product . 3
4.4 Instrument and product environmental adaptability . 4
4.5 Instrument and product interface and data format . 4
5 Test methods . 4
5.1 Test instrument and equipment . 4
5.2 Appearance inspection . 5
5.3 Instrument and product interface and data format checking . 5
5.4 Measurement performance test . 5
5.4.1 Test requirements . 5
5.4.2 Selected test points . 5
5.4.3 Test preparation . 6
5.4.4 Accuracy measurement of temperature and conductivity . 6
5.4.5 Temperature and conductivity accuracy test . 6
5.4.6 Pressure accuracy test . 7
5.4.7 Resolution test . 8
5.4.8 Stability test. 8
5.5 Environmental adaptability test . 8
6 Test requirements . 9
6.1 Number of instruments to be tested . 9
6.2 Test process . 9
6.3 Qualification requirements . 9
6.4 Delivery requirements . 9
6.5 Supporting documents . 9
7 Marking, packaging, transportation, storage .10
7.1 Marking . 10
7.1.1 Nameplate mark . 10
7.1.2 Packing mark . 10
7.2 Packaging . 10
7.2.1 Packaging requirements . 10
7.2.2 Supporting items . 10
7.3 Transportation . 10
7.3.1 Means of transport . 10
7.3.2 Transport requirement . 11
7.4 Storage . 11
7.4.1 Storage environment . 11
7.4.2 Storage requirements . 11
8 User software .11
8.1 General . 11
8.2 Measurement management . 11
8.3 Parameter calculation . 11
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ISO 22804:2023(E)
8.4 Data processing.12
Annex A (informative) Examples of record tables for CTD measuring instrument accuracy
test data .13
Annex B (informative) Calculation of practical salinity .16
Annex C (informative) Pressure to depth conversion .19
Bibliography .20
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ISO 22804:2023(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 document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 13, Marine technology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 22804:2023(E)
Introduction
Oceans are closely related to climate change and disasters, which directly affect human survival. In order
to master the law of ocean change, it is necessary to obtain hydrologic information of ocean profile. The
accuracy of this information depends on the temperature conductivity manometer used, often called
a conductivity-temperature-depth (CTD) measuring instrument. CTD measuring instruments directly
measure the temperature, conductivity and pressure of seawater. The information data of salinity,
density and depth are derived and calculated according to the international equation of seawater state.
This document is specifically for CTD measuring instruments. Using the method of classification for
CTD measuring instruments, this document defines the measurement technical indicators of CTD
measuring instruments of different grades and the CTD measuring instrument's environmental
adaptability requirements. It also defines the testing methods of CTD measuring technical indicators
and of environmental adaptability. This document can be used to guide manufacturers in the
development and testing of CTD measuring instruments, and to help CTD users select suitable CTD
measuring instruments. At the time of publication, there are a variety of technical index grade CTD
measuring instruments on the market. This document is divided into three levels according to the
temperature, conductivity and pressure measurement performance of CTD measuring instruments,
which is convenient for the selection of CTD measuring instruments and the promotion and application
of this document.
In June 2009, a new Thermodynamic Equation of Seawater, referred to as TEOS-10, was adopted by
the Intergovernmental Oceanographic Commission (IOC), and used to replace International Equation of
State of Sea Water (EOS-80). At the time of publication, the calculation of derived values such as salinity
is required to use EOS-80 or TEOS-10, which have no direct influence on the CTD measuring instrument.
Compared with the practical salinity, S , of EOS-80, the absolute salinity, S , is proposed in TEOS-10
p A
(see Reference [6] for the corresponding TEOS-10 calculation software code). The IOC recommends that
the practical salinity, S , remain in the database to avoid possible confusion between different types
p
of salinity. Therefore, this document recommends that CTD manufacturers support both EOS-80 and
TEOS-10 algorithms in their accompanying user software.
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INTERNATIONAL STANDARD ISO 22804:2023(E)
Marine technology — General technical requirement of
marine conductivity-temperature-depth (CTD) measuring
instrument
1 Scope
This document specifies the technical requirements to ensure consistent reporting on the test method,
inspection rules, marks, packaging, transportation and storage of conductivity-temperature-depth
(CTD) profilers.
This document is applicable to marine fixed-point and mobile observation, monitoring platform and the
various types of shipborne CTD measuring instruments.
NOTE A CTD directly measures conductivity, temperature, pressure of seawater. Depth is the conversion of
pressure according to the Formula (C.1).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
IEC 60068-2-1, Environmental testing — Part 2: Tests-Test A: Cold
IEC 60068-2-2, Environmental testing — Part 2-2: Tests-Test B: Dry heat
IEC 60068-2-6, Environmental testing — Part 2-6: Tests-Test Fc: Vibration (sinusoidal)
IEC 60068-2-27, Environmental testing — Part 2-27: Test-Test Ea and Guidance: Shock
IEC 60068-2-30, Environmental testing — Part 2-30: Tests-Test Db: Damp heat, cyclic (12 h+12 h cycle)
IEC 60092-504, Electrical installations in ships — Part 504: Automation, control and instrumentation
ISO 21173, Submersibles — Hydrostatic pressure test — Pressure hull and buoyancy materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
conductivity-temperature-depth measuring instrument
CTD measuring instrument
electronic devices applied to automatically measure the conductivity, temperature and pressure of
seawater
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ISO 22804:2023(E)
3.2
user software
software used to complete the special programs of measuring management, parameter calculation and
data processing of conductivity-temperature-depth measuring instruments (3.1) by users
3.3
measurement unit
unit
real scalar quantity, defined and adopted by convention, with which any other quantity of the same
kind can be compared to express the ratio of the two quantities as a number
[SOURCE: ISO 22013:2021, 3.6, modified — Notes to entry and the examples have been removed.]
3.4
accuracy
closeness of agreement between a measured quantity value (or test result) and a true quantity value of
a measurand (or accepted reference value) in the stable experimental condition
EXAMPLE Pressure accuracy = [measurement error (3.9) of pressure] / (the value of the difference between
the upper and lower limits of pressure measurement) *100 %
3.5
resolution
capability of conductivity-temperature-depth measuring instrument (3.1) to sense minimum temperature,
conductivity and pressure changes
3.6
stability
duration which describes the property of a conductivity-temperature-depth measuring instrument (3.1),
whereby its metrological properties remain constant in time
3.7
environmental adaptability
ability of a conductivity-temperature-depth measuring instrument (3.1) to maintain its performance and
function without being damaged under the action of different environmental factors during its life cycle
3.8
full scale
FS
algebraic absolute value of the difference between the measured upper output value and the measured
lower output value of the pressure sensor in a conductivity-temperature-depth measuring instrument
(3.1)
3.9
measurement error
error between a conductivity-temperature-depth measuring instrument (3.1) and standard value
(reference standard)
EXAMPLE Temperature error, conductivity error and pressure error.
3.10
fiducial error
measuring instrument within the full range of the maximum absolute measurement error (3.9) and the
ratio of the full scale value of the percentage
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ISO 22804:2023(E)
4 Technical specifications
4.1 General
This clause lists specifications and requirements for sensors during the development and production
process.
4.2 Instrument appearance
4.2.1 Cosmetic requirements
The surface of a conductivity-temperature-depth (CTD) measuring instrument shall be free of wear
and rust. At the same time, this instrument shall not have any apparent damage which can affect its
testing performance.
Marine plankton and algae attached to the CTD during use shall be removed, as well as damaged
sacrificial anodes to avoid affecting the water quality of the tank. At the same time, CTD shall not have
leakage problem.
4.2.2 Product identification
The CTD measuring instrument shall have the following identification: name and model of instrument,
manufacturer’s name, production date and factory number. The spare parts and documents shall be
complete. The CTD measuring instrument shall have the manufacturer’s product certificate.
4.2.3 Instrument fastener
The fastener of the CTD measuring instrument shall not be loosened, and all parts of instrument shall
be well sealed.
4.3 Measuring performance of instrument and product
The accuracy, resolution and stability of CTD measuring instrument shall meet the requirements of
Table 1.
Table 1 — Measuring requirement of CTD measuring instrument
Measuring performance grade First-level Second-level Third-level
Accuracy ±0,003 ±0,02 ±0,1
Temperature
Stability 0,003/year 0,02/year 0,1 /year
(°C)
Resolution 0,001 0,006 0,03
Accuracy ±0,005 ±0,02 ±0,1
Conductivity
Stability 0,005/month 0,02/month 0,1/month
(mS/cm)
Resolution 0,001 0,006 0,03
Accuracy ±0,05 % ±0,1 % FS ±0,5 % FS
a
pressure
Stability 0,05 % FS/year 0,1 % FS/year 0,5 % FS/year
(MPa)
Resolution 0,02 % FS 0,03 % FS 0,2 % FS
Key
FS  full scale
a
Pressure measurement performance of the CTD measuring instrument is described using fiducial error.
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ISO 22804:2023(E)
4.4 Instrument and product environmental adaptability
According to the environmental conditions of the CTD measuring instrument, the specific environmental
test items are determined. The CTD measuring instrument shall pass the corresponding environmental
test.
4.5 Instrument and product interface and data format
The interface and data format of the CTD measuring instrument shall conform to the requirements of
Table 2.
The general hardware communication software shall include the following functions:
a) Query working status command
b) Display instrument status command
c) Set the date command
d) Set the time command
e) Set the measuring station position command
f) Acquisition mode command
g) Measurement start command
h) Measurement end command
The data format is separated by comma-separated values (CSV). This format is used for the technical
specifications of CTD measurement instruments to determine the measurement data byte length.
Table 2 — CTD measuring instrument interface and data format requirements
Test parameter Length Usage and meaning unit
Temperature 8 -/+xx,xxx x °C
Conductivity 8 -/+xx,xxx x mS/cm
a
Pressure 9 -/+xx xxx,xx dbar
Data interface RS232/RS485/USB
a 4 2
1 dbar = 0,01 MPa = 10 Pa; 1 MPa = 1 N/mm .
The plus or minus symbol shall be reserved. The plus sign is not displayed by default, and the minus
sign shall be displayed.
EXAMPLE When the temperature is +24,245 6 °C, it shows the format ”24,245 6”. When the temperature is
−0,214 5 °C, it shows the format ”−0,214 5”.
5 Test methods
5.1 Test instrument and equipment
The standard instrument, standard material and special equipment shall be applied in the test. The
resolution of the standard instrument shall be superior to the data from Table 1. The accuracy shall
be three times higher than that specified in Table 1. The standard instruments and special equipment
recommended by this document are shown in Table 3.
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ISO 22804:2023(E)
Table 3 — Recommended standard instruments and special equipment
Test param-
Standard instrument Accuracy Special equipment Test environment
eter
Laboratory salinity meter ±0,002
Large isothermal salt
Salt
a
tank
IAPSO Standard seawater K15 ≥ 0,999
Environmental
temperature:
Platinum resistance ther-
±0,001 °C
mometer
Large isothermal salt (20 ± 5) °C
Temperature
tank
Bridge temperature meas-
Relative humidity:
±0,001 °C
ure system
(20–80) %
Standard piston precision Constant temperature
Pressure ±0,005 % FS
manometer laboratory
Key
FS  full scale
a
K15 = (Conductivity of standard seawater at 15 °C and 101 325 Pa)/ [Conductivity of KCl solution (32,4356 g/
kg) at 15°C and 101 325 Pa].
5.2 Appearance inspection
CTD measuring instrument shall be checked by visual or manual method. The appearance of CTD
measuring instrument shall conform to the requirement in 4.2.1.
5.3 Instrument and product interface and data format checking
The test process consists of connecting CTD measuring instrument to the computer and performing
interface and data format checking. The test content is specified in 4.5.
5.4 Measurement performance test
5.4.1 Test requirements
The measurements of temperature and conductivity shall be carried out in a large isothermal seawater
tank. The pressure test shall be conducted in a thermostatic laboratory. The tested CTD measuring
instrument is fully immersed in a constant temperature seawater tank. The temperature and
conductivity probes of the CTD measuring instrument shall be submerged more than 300 mm below
the water surface. The standard platinum resistance thermometer and seawater sampling tube is
inserted as close as possible to the detected sensor. The heat preservation cover of the thermostatic
seawater tank is closed.
Follow the operation rule of this tank to control the temperature, i.e.:
— Ambient temperature: (20 ± 5) °C, the detection environment temperature for the pressure of first-
level CTD measuring instrument is (20 ± 1) °C;
— Relative humidity: (20~80) %.
5.4.2 Selected test points
The selected test points of temperature, conductivity and pressure are shown in Table 4. The general
temperature points are 0 °C, 5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C and 35 °C.
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ISO 22804:2023(E)
Table 4 — Test points
Parameter Test points Remarks
In the temperature measurement range, determine 6
Temperature Cooling test
or 8 test point with a roughly evenly distributed form
In the temperature measurement range, determine 6 According to the reference of sa-
Conductivity
or 8 test point with a roughly evenly distributed form linity 35, take the cooling test
In the pressure measurement range, determine 6 or 8 Take the process of rising pres-
Pressure
test point with a roughly evenly distributed form sure and lowering pressure
5.4.3 Test preparation
Temperature drop test is usually adopted in the test process (from 35 °C to 0 °C). The accuracy of
conductivity test shall be carried out in the order of cooling. When the temperature and conductivity
are measured, the seawater with salinity of about 35 is injected into a large isothermal seawater tank.
The amount of seawater injected shall ensure that the probe of CTD measuring instrument is fully
immersed. For the CTD measuring instrument without water pump, it shall wash the conductivity probe
three or five times with seawater. Before the test, the temperature of seawater in the large isothermal
tank shall be increased to about 35 °C, and this temperature shall remain constant.
5.4.4 Accuracy measurement of temperature and conductivity
5.4.4.1 Conditions of testing
Before testing, it shall be ensured that the temperature of the seawater thermostatic bath reaches the
equilibrium state. The first temperature point with 35 °C is carried out. When the temperature of large
isothermal seawater tank reaches the test temperature point, it is required to take the temperature
control. When the temperature fluctuation is less or equal to 0,000 5 °C (1/6 for the temperature
accuracy requirement), the temperature equilibrium state has arrived.
5.4.4.2 Conditions for recording test data
Recording and sampli
...