Petroleum and natural gas industries - Characteristics of LNG, influencing the design, and material selection (ISO 16903:2015)

This European Standard gives guidance on the characteristics of liquefied natural gas (LNG) and the cryogenic materials used in the LNG industry. It also gives guidance on health and safety matters. It is intended to act as a reference document for the implementation of other standards of CEN/TC 282 "Installations and equipment for liquefied natural gas". It is intended as a reference for use by persons who design or operate LNG facilities. (to be modified with the scope of ISO 16903)

Erdöl- und Erdgasindustrie - Eigenschaften von Flüssigerdgas mit Einfluss auf die Auslegung und die Materialauswahl (ISO 16903:2015)

Diese Internationale Norm informiert über die Eigenschaften von Flüssigerdgas (LNG) und in der LNG-Industrie verwendeten tieftemperaturfesten Werkstoffe. Außerdem enthält sie Leitlinien zu Fragen von Gesundheit und Sicherheit. Sie soll für weitere Normen auf dem Gebiet Flüssigerdgas als Bezugsnorm dienen. Sie dient als Referenz für Personen, die LNG-Anlagen auslegen oder betreiben.

Pétrole et industries du gaz naturel - Caractéristiques du GNL influant sur la conception et le choix des matériaux (ISO 16903:2015)

L'ISO 16903:2015 donne des indications sur les caractéristiques du gaz naturel liquéfié (GNL) et sur les matériaux cryogéniques utilisés dans l'industrie du GNL. Elle donne également des indications sur la santé et la sécurité. Elle est destinée à servir de document de référence pour la mise en ?uvre des autres normes dans le domaine du gaz naturel liquéfié. Elle est destinée à servir de document de référence pour les personnes qui conçoivent ou exploitent des installations de GNL.

Industrija nafte in zemeljskega plina - Vpliv lastnosti utekočinjenega zemeljskega plina na načrtovanje in izbor materialov (ISO 16903:2015)

Ta evropski standard vsebuje smernice glede značilnosti utekočinjenega zemeljskega plina (LNG) in kriogenih materialov, ki se uporabljajo v industriji LNG. Podaja tudi smernice glede zdravstvenih in varnostnih zadev. Namenjen je uporabi kot referenčni dokument pri izvajanju drugih standardov CEN/TC 282 "Napeljave in oprema za utekočinjeni zemeljski plin". Namenjen je uporabi kot referenčni dokument za osebe, ki projektirajo ali upravljajo opremo LNG. (spremenjen bo v skladu s področjem uporabe standarda ISO 16903).

General Information

Status
Published
Public Enquiry End Date
30-Jun-2013
Publication Date
10-Aug-2015
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
09-Jul-2015
Due Date
13-Sep-2015
Completion Date
11-Aug-2015

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SLOVENSKI STANDARD
SIST EN ISO 16903:2015
01-september-2015
1DGRPHãþD
SIST EN 1160:1998

,QGXVWULMDQDIWHLQ]HPHOMVNHJDSOLQD9SOLYODVWQRVWLXWHNRþLQMHQHJD]HPHOMVNHJD

SOLQDQDQDþUWRYDQMHLQL]ERUPDWHULDORY ,62

Petroleum and natural gas industries - Characteristics of LNG, influencing the design,

and material selection (ISO 16903:2015)

Erdöl- und Erdgasindustrie - Eigenschaften von Flüssigerdgas mit Einfluss auf die

Auslegung und die Materialauswahl (ISO 16903:2015)

Pétrole et industries du gaz naturel - Caractéristiques du GNL influant sur la conception

et le choix des matériaux (ISO 16903:2015)
Ta slovenski standard je istoveten z: EN ISO 16903:2015
ICS:
75.060 Zemeljski plin Natural gas
75.180.01 Oprema za industrijo nafte in Equipment for petroleum and
zemeljskega plina na splošno natural gas industries in
general
SIST EN ISO 16903:2015 en,fr,de

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

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SIST EN ISO 16903:2015
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SIST EN ISO 16903:2015
EUROPEAN STANDARD
EN ISO 16903
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2015
ICS 75.180.01 Supersedes EN 1160:1996
English Version
Petroleum and natural gas industries - Characteristics of LNG,
influencing the design, and material selection (ISO 16903:2015)

Pétrole et industries du gaz naturel - Caractéristiques du Erdöl- und Erdgasindustrie - Eigenschaften von

GNL influant sur la conception et le choix des matériaux Flüssigerdgas mit Einfluss auf die Auslegung und die

(ISO 16903:2015) Materialauswahl (ISO 16903:2015)
This European Standard was approved by CEN on 23 April 2015.

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

© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16903:2015 E

worldwide for CEN national Members.
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SIST EN ISO 16903:2015
EN ISO 16903:2015 (E)
Contents
Page

European foreword .............................................................................................................................................3

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SIST EN ISO 16903:2015
EN ISO 16903:2015 (E)
European foreword

This document (EN ISO 16903:2015) has been prepared by Technical Committee ISO/TC 67 "Materials,

equipment and offshore structures for petroleum, petrochemical and natural gas industries" in collaboration

with Technical Committee CEN/TC 282 “Installation and equipment for LNG” the secretariat of which is held

by AFNOR.

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 December 2015, and conflicting national standards shall be withdrawn

at the latest by December 2015.

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 1160:1996.

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 16903:2015 has been approved by CEN as EN ISO 16903:2015 without any modification.

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SIST EN ISO 16903:2015
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SIST EN ISO 16903:2015
INTERNATIONAL ISO
STANDARD 16903
First edition
2015-06-15
Petroleum and natural gas industries —
Characteristics of LNG, influencing the
design, and material selection
Pétrole et industries du gaz naturel — Caractéristiques du GNL
influant sur la conception et le choix des matériaux
Reference number
ISO 16903:2015(E)
ISO 2015
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SIST EN ISO 16903:2015
ISO 16903:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland

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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved
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SIST EN ISO 16903:2015
ISO 16903:2015(E)
Contents Page

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

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Abbreviated terms .............................................................................................................................................................................................. 2

5 General characteristics of LNG ............................................................................................................................................................... 2

5.1 General ........................................................................................................................................................................................................... 2

5.2 Properties of LNG ................................................................................................................................................................................. 2

5.2.1 Composition ......................................................................................................................................................................... 2

5.2.2 Density ...................................................................................................................................................................................... 2

5.2.3 Temperature ........................................................................................................................................................................ 3

5.2.4 Viscosity .................................................................................................................................................................................. 3

5.2.5 Examples of LNG .............................................................................................................................................................. 3

5.3 Physical properties .............................................................................................................................................................................. 3

5.3.1 Physical properties of boil-off gas ..................................................................................................................... 3

5.3.2 Flash ............................................................................................................................................................................................ 4

5.3.3 Spillage of LNG ................................................................................................................................................................... 4

5.3.4 Expansion and dispersion of gas clouds ...................................................................................................... 4

5.3.5 Ignition ..................................................................................................................................................................................... 5

5.3.6 Pool fires ................................................................................................................................................................................. 5

5.3.7 Development and consequences of pressure waves ......................................................................... 5

5.3.8 Containment ........................................................................................................................................................................ 5

5.3.9 Rollover .................................................................................................................................................................................... 5

5.3.10 RPT ........................................................................................................................................... .................................................... 6

5.3.11 BLEVE ........................................................................................................................................................................................ 6

6 Health and safety .................................................................................................................................................................................................. 6

6.1 General ........................................................................................................................................................................................................... 6

6.2 Exposure to cold .................................................................................................................................................................................... 7

6.2.1 Warning notice .................................................................................................................................................................. 7

6.2.2 Handling, cold contact burns................................................................................................................................. 7

6.2.3 Frostbite .................................................................................................................................................................................. 7

6.2.4 Effect of cold on the lungs ........................................................................................................................................ 7

6.2.5 Hypothermia ....................................................................................................................................................................... 7

6.2.6 Recommended protective clothing .................................................................................................................. 7

6.3 Exposure to gas ....................................................................................................................................................................................... 7

6.3.1 Toxicity ..................................................................................................................................................................................... 7

6.3.2 Asphyxia .................................................................................................................................................................................. 7

6.4 Fire precautions and protection .............................................................................................................................................. 8

6.5 Colour .............................................................................................................................................................................................................. 8

6.6 Odour ............................................................................................................................................................................................................... 8

7 Materials of construction ............................................................................................................................................................................ 8

7.1 Materials used in the LNG industry....................................................................................................................................... 8

7.1.1 General...................................................................................................................................................................................... 8

7.1.2 Materials in direct contact ....................................................................................................................................... 8

7.1.3 Materials not in direct contact under normal operation............................................................... 9

7.1.4 Other information ........................................................................................................................................................... 9

7.2 Thermal stresses ................................................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................11

© ISO 2015 – All rights reserved iii
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SIST EN ISO 16903:2015
ISO 16903:2015(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 (see 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 (see 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 67, Materials, equipment and offshore structures

for petroleum, petrochemical and natural gas industries.
iv © ISO 2015 – All rights reserved
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SIST EN ISO 16903:2015
INTERNATIONAL STANDARD ISO 16903:2015(E)
Petroleum and natural gas industries — Characteristics of
LNG, influencing the design, and material selection
1 Scope

This International Standard gives guidance on the characteristics of liquefied natural gas (LNG) and

the cryogenic materials used in the LNG industry. It also gives guidance on health and safety matters.

It is intended to act as a reference document for the implementation of other standards in the liquefied

natural gas field. It is intended as a reference for use by persons who design or operate LNG facilities.

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

EN 1473, Installation and equipment for liquefied natural gas — Design of onshore installations

NFPA 59A, Standard for the production, storage, and handling of liquefied natural gas (LNG)

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
boil-off gas
gas generated during the storage or handling of volatile liquefied gases
3.2
condensate

hydrocarbon liquid that forms by condensation from natural gas, consisting primarily of pentanes

(C H ) and heavier components
5 12

Note 1 to entry: There will be some propane and butane dissolved within the mixture.

3.3
liquefied natural gas
LNG

colourless and odourless cryogenic fluid in the liquid state at normal pressure composed predominantly

of methane which can contain minor quantities of ethane, propane, butane, nitrogen, or other components

normally found in natural gas
3.4
liquefied petroleum gas
LPG

gaseous hydrocarbons at normal temperatures and pressures, but that readily turns into liquids under

moderate pressure at normal temperatures, e.g. propane and butane
3.5
natural gas liquids
NGL

liquid hydrocarbons, such as ethane, propane, butane, pentane, and natural gasoline, extracted from

field natural gas
© ISO 2015 – All rights reserved 1
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SIST EN ISO 16903:2015
ISO 16903:2015(E)
4 Abbreviated terms

For the purposes of this International Standard, the following abbreviations apply.

BLEVE boiling liquid expanding vapour explosion
LPG liquid petroleum gas
QRA quantitative risk analysis
RPT rapid phase transition
SEP surface emissive power
5 General characteristics of LNG
5.1 General

It is recommended that all personnel concerned with the handling of LNG should be familiar with both

the characteristics of the liquid and the gas produced.

The potential hazard in handling LNG stems mainly from three important properties.

a) It is extremely cold. At atmospheric pressure, depending upon composition, LNG boils at about

–160 °C. At this temperature, the vapour is denser than ambient air.

b) Very small quantities of liquid are converted into large volumes of gas. One volume of LNG produces

approximately 600 volumes of gas.

c) Natural gas, similar to other gaseous hydrocarbons, is flammable. At ambient conditions, the

flammable mixture range with air is from approximately 5 % to 15 % gas by volume. If vapour

accumulates in a confined space, ignition can result in detonation and shock wave overpressure.

This International Standard focuses on LNG, its properties, and resultant hazards. When evaluating the

hazards at an LNG site, designers need to consider all systems present. Often, the LNG itself does not

present the greatest hazard; other systems such as LPG-based refrigeration at the liquefaction plant or

high pressure gas send out at a regasification plant can dominate the overall site risk profile.

5.2 Properties of LNG
5.2.1 Composition

LNG is a mixture of hydrocarbons composed predominantly of methane and which can contain minor

quantities of ethane, propane, butane, nitrogen, or other components, normally found in natural gas.

The physical and thermodynamic properties of methane and other components of natural gas can be

found in reference books (see Annex A) and thermodynamic calculation codes. Although the major

constituent of LNG is methane, it should not be assumed that LNG is pure methane for the purpose of

estimating its behaviour. When analysing the composition of LNG, special care should be taken to obtain

representative samples not causing false analysis results due to distillation effects. The most common

method is to analyse a small stream of continuously evaporated product using a specific LNG sampling

device that is designed to provide a representative gas sample of liquid without fractionation. Another

method is to take a sample from the outlet of the main product vaporizers. This sample can then be

analysed by normal gas chromatographic methods, such as those described in ISO 6568 or ISO 6974.

5.2.2 Density
3 3

The density of LNG depends on the composition and usually ranges from 420 kg/m to 470 kg/m , but in

some cases can be as high as 520 kg/m . Density is also a function of the liquid temperature with a gradient

2 © ISO 2015 – All rights reserved
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SIST EN ISO 16903:2015
ISO 16903:2015(E)

of about 1,4 kg/m /K. Density can be measured directly but is generally calculated from composition

determined by gas chromatographic analysis. The method as defined in ISO 6578 is recommended.

NOTE This method is generally known as revised Klosek-McKinley method.
5.2.3 Temperature

LNG has a boiling temperature depending on composition and usually ranging from –166 °C to –157 °C

at atmospheric pressure. The variation of the boiling temperature with the vapour pressure is about

1,25 × 10 °C/Pa. The temperature of LNG is commonly measured by using copper/copper nickel

thermocouples or using platinum resistance thermometers such as those defined in ISO 8310.

5.2.4 Viscosity
−4 −4

The viscosity of LNG depends on the composition and is usually from 1,0 × 10 to 2,0 × 10 Pat –160 °C,

which is nearly 1/10 to 1/5 of the water. Viscosity is also a function of the liquid temperature.

5.2.5 Examples of LNG

Three typical examples of LNG are shown in Table 1 below which demonstrates the property variations

with different compositions .
Table 1 — Examples of LNG
Properties at boiling temperature at
LNG Example 1 LNG Example 2 LNG Example 3
normal pressure
Molar content (%)
N 0,13 1,79 0,36
CH 99,8 93,9 87,20
C H 0,07 3,26 8,61
2 6
C H — 0,69 2,74
3 8
i C H — 0,12 0,42
4 10
n C H — 0,15 0,65
4 10
C H — 0,09 0,02
5 12
Molecular weight (kg/kmol) 16,07 17,07 18,52
Boiling temperature (°C) –161,9 –166,5 –161,3
Density (kg/m ) 422 448,8 468,7
Volume of gas measured at 0 °C and 101 588 590 568
3 3
325 Pa/volume of liquid (m /m )
Volume of gas measured at 0 °C and 101 1 392 1 314 1 211
3 3
325 Pa/mass of liquid (m /10 kg)
Mass heat of vaporization (kJ/kg) 525,6 679,5 675,5
Gross heating value (MJ/m ) 37,75 38,76 42,59
5.3 Physical properties
5.3.1 Physical properties of boil-off gas

LNG is stored in bulk as a boiling liquid in large, thermally insulated tanks. Any heat leak into the tank

causes some of the liquid to evaporate as a gas. This gas is known as boil-off gas. The composition of the

boil-off gas depends on the composition of the liquid. As an example, the boil-off gas could contain 20 %

1) Values are given from simulations.
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ISO 16903:2015(E)

nitrogen, 80 % methane, and traces of ethane; the nitrogen content of the boil-off gas could be about

20 times that in the LNG.

As LNG evaporates, the nitrogen and methane are preferentially lost leaving the liquid with a larger

fraction of the higher hydrocarbons. Boil-off gases below about –113 °C for pure methane and –85 °C

for methane with 20 % nitrogen are heavier than ambient air. At normal conditions, the density of these

boil-off gases is approximately 0,6 of air.
5.3.2 Flash

As any fluid, if pressurized LNG is lowered in pressure below its boiling pressure, for example by passing

through a valve, then some of the liquid evaporates and the liquid temperature drops to its new boiling

point at that pressure. This is known as flash. Since LNG is a multi-component mixture, the composition

of the flash gas and the remaining liquid differ for similar reasons from those discussed in 5.3.1.

3 3

As a guide, a 10 Pa flash of 1 m liquid at its boiling point corresponding to a pressure ranging from

5 5

1 × 10 Pa to 2 × 10 Pa produces approximately 0,4 kg of gas. More accurate calculation of both the

quantity and composition of the liquid and gas products of flashing multi-component fluids such as LNG

are complex. Validated thermodynamic or plant simulation packages for use on computers incorporating

an appropriate database should be used for such flash calculations.
5.3.3 Spillage of LNG

When LNG is poured on the ground (as an accidental spillage), there is an initial period of intense boiling,

after which the rate of evaporation decays rapidly to a constant value that is determined by the thermal

characteristics of the ground and heat gained from surrounding air. This rate can be significantly reduced

by the use of thermally insulated surfaces where spillages are likely to occur as shown in Table 2. These

figures are given for examples, but should be checked when used for QRA or detail engineering.

Table 2 — Rate of evaporation
Rate per unit area
Material after 60 s
kg / (m h)
Aggregate 480
Wet sand 240
Dry sand 195
Water 600
Standard concrete 130
Light colloidal concrete 65

Small quantities of liquid can be converted into large volumes of gas when spillage occurs. One volume

of liquid produces approximately 600 volumes of gas at ambient conditions (see Table 1). When spillage

occurs on water, the convection in the water is so intense that the rate of evaporation related to the area

remains constant. The size of the LNG spillage extends until the evaporating amount of gas equals the

amount of liquid gas produced by the leak.
5.3.4 Expansion and dispersion of gas clouds

Initially, the gas produced by evaporation is at nearly the same temperature as the LNG and is denser

than ambient air. Such gas is, at first, subjected to gravity spreading by flowing in a layer along the

ground until it warms sufficiently by absorbing heat from the soil and mixing with the ambient air.

The dilution with warm air increases temperature and decreases the molecular weight of the mixture.

As a result, the cloud is in general denser than ambient air until diluted well below the flammable

limit. Only in case of high water content of the atmosphere (high humidity and temperature) can the

condensation of water during the mixing with the cold LNG vapours heat-up the mixture as such that it

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ISO 16903:2015(E)

becomes lighter than air and results in a buoyant cloud. Spillage, expansion, and dispersion of vapour

clouds are complex subjects and are usually predicted by computer models. Such predictions should

only be undertaken by a body competent in the subject. Following a spillage, ‘fog’ clouds are formed by

condensation of water vapour in the ambient air. When the fog can be seen (by day and without natural

fog) and if the relative humidity of the ambient air is sufficiently high, the visible fog is a useful indicator

of the travel of the vaporized gas and the cloud gives a first indication of the extent of flammability

of the mixture of gas and air as the visibility of the cloud is a function of the humidity and ambient

temperature, not a function of the natural gas release.
In the case of a leak in pressure v
...

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