FprEN 13555
(Main)This document specifies the gasket parameters required by EN 1591 1 and provides the test procedures for establishing the values of these parameters.
Gaskets which are wholly based upon elastomers, or based upon elastomers with only the inclusion of particulate fillers or particulate reinforcement, as opposed to gaskets combining elastomers, fillers and fibrous reinforcement, are beyond the scope of this document.
NOTE The testing procedures given might be applicable to gaskets of other shapes and dimensions.
Flansche und ihre Verbindungen - Dichtungskennwerte und Prüfverfahren für die Anwendung der Regeln für die Auslegung von Flanschverbindungen mit runden Flanschen und Dichtungen
Dieses Dokument legt die nach EN 1591 1 geforderten Dichtungskennwerte fest und enthält die Prüfverfahren zur Ermittlung der Zahlenwerte dieser Kennwerte.
Dichtungen, die gänzlich auf Elastomeren basieren oder die auf Elastomeren mit lediglich dem Einschluss feinteiliger Füllstoffe oder feinteiliger Verstärkungen basieren, liegen im Gegensatz zu Dichtungen, in denen Elastomere, Füllstoffe und Faserverstärkungen miteinander kombiniert werden, nicht im Anwendungs¬bereich dieses Dokumentes.
ANMERKUNG Die enthaltenen Prüfverfahren können auch für andere Dichtungsformen und maße angewendet werden.
Brides et leurs assemblages - Paramètres de joints et procédures d'essai relatives aux règles de calcul des assemblages à brides circulaires avec joint
Le présent document définit les paramètres de joints requis par l’EN 1591 1 et décrit les modes opératoires d’essai permettant de déterminer les valeurs de ces paramètres.
Les joints entièrement fabriqués en matériaux élastomères ou fabriqués à partir de matériaux élastomères additionnés uniquement de charges particulaires ou de renforts sous forme de particules, par opposition aux joints combinant des matériaux élastomères, des charges et des renforts fibreux, ne relèvent pas du domaine d’application du présent document.
NOTE Les modes opératoires d'essai indiqués peuvent s'appliquer à des joints ayant d'autres formes et dimensions.
Prirobnice in prirobnični spoji - Preskusni postopki in parametri tesnil, ki so potrebni za konstruiranje prirobničnih spojev, sestavljenih iz okroglih prirobnic in tesnil
General Information
RELATIONS
Standards Content (sample)
SLOVENSKI STANDARD
oSIST prEN 13555:2019
01-november-2019
Prirobnice in prirobnični spoji - Preskusni postopki za določanje parametrov
tesnil, ki so potrebni za konstruiranje prirobničnih spojev, sestavljenih iz okroglih
prirobnic in tesnilFlanges and their joints - Gasket parameters and test procedures relevant to the design
rules for gasketed circular flange connectionsFlansche und ihre Verbindungen - Dichtungskennwerte und Prüfverfahren für die
Anwendung der Regeln für die Auslegung von Flanschverbindungen mit runden
Flanschen und Dichtungen
Brides et leurs assemblages - Paramètres de joints et procédures d'essai relatives aux
règles de calcul des assemblages à brides circulaires avec jointTa slovenski standard je istoveten z: prEN 13555
ICS:
23.040.60 Prirobnice, oglavki in spojni Flanges, couplings and joints
elementi
23.040.80 Tesnila za cevne zveze Seals for pipe and hose
assemblies
oSIST prEN 13555:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------oSIST prEN 13555:2019
---------------------- Page: 2 ----------------------
oSIST prEN 13555:2019
DRAFT
EUROPEAN STANDARD
prEN 13555
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2019
ICS 23.040.60; 23.040.80 Will supersede EN 13555:2014
English Version
Flanges and their joints - Gasket parameters and test
procedures relevant to the design rules for gasketed
circular flange connections
Brides et leurs assemblages - Paramètres de joints et Flansche und ihre Verbindungen - Dichtungskennwerte
procédures d'essai relatives aux règles de calcul des und Prüfverfahren für die Anwendung der Regeln für
assemblages à brides circulaires avec joint die Auslegung von Flanschverbindungen mit runden
Flanschen und DichtungenThis draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 74.If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 13555:2019 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
oSIST prEN 13555:2019
prEN 13555: 2019 (E)
Contents Page
Introduction .................................................................................................................................................................... 5
1 Scope .................................................................................................................................................................... 6
2 Normative references .................................................................................................................................... 6
3 Terms and definitions ................................................................................................................................... 7
4 Symbols .............................................................................................................................................................. 8
5 List of gasket parameters ............................................................................................................................. 9
6 Test equipment ................................................................................................................................................ 9
6.1 Design .................................................................................................................................................................. 9
6.2 Test platens ..................................................................................................................................................... 10
6.3 Metal Foils ....................................................................................................................................................... 10
6.4 Surface finish .................................................................................................................................................. 10
6.5 Measurement of gasket thickness ........................................................................................................... 10
6.6 Loading ............................................................................................................................................................. 10
6.7 Temperature................................................................................................................................................... 11
6.8 Leakage measurement ................................................................................................................................ 11
7 Test gaskets ..................................................................................................................................................... 11
7.1 Number of gaskets ........................................................................................................................................ 11
7.2 Procurement and identification of gaskets ......................................................................................... 11
7.3 Pre-conditioning of the gaskets ............................................................................................................... 11
7.4 Dimensions of test gaskets ........................................................................................................................ 11
7.5 Measurement of test gaskets as received ............................................................................................. 12
7.6 Influence of gasket dimensions ............................................................................................................... 12
8 Test procedures ............................................................................................................................................. 13
8.1 General.............................................................................................................................................................. 13
8.2 Testing Strategy ............................................................................................................................................. 13
8.3 Reference gasket thickness ....................................................................................................................... 13
8.4 Compression curve ....................................................................................................................................... 13
8.5 Determination of Q ............................................................................................................................ 14
smax8.5.1 Generation of Q .................................................................................................................................... 14
smax8.6 Determination of the values of E .......................................................................................................... 18
8.6.1 Generation of E from the data generated for the Q test ..................................................... 18
G smax8.7 Determination of P and Δe .............................................................................................................. 20
QR Gc8.8 Determination of Q and Q ............................................................................................. 21
min(L) smin(L)8.8.1 General.............................................................................................................................................................. 21
8.8.2 Leakage diagram ........................................................................................................................................... 24
8.9 Determination of Q at elevated temperatures ................................................................... 24
smin(L)8.10 Determination of axial coefficient of thermal expansion ............................................................... 24
8.11 Determination of the coefficient of static friction ............................................................................. 25
9 Report details ................................................................................................................................................. 25
Annex A (informative) Generalized test rig schematic ................................................................................ 26
Annex B (informative) Test rig schematic for compression and compression creep tests ............. 27
---------------------- Page: 4 ----------------------oSIST prEN 13555:2019
prEN 13555:2019 (E)
Annex C (informative) Test rig schematic for ambient temperature leakage measurement ........ 28
Annex D (informative) Schematic of leakage rig allowing use of interchangeable face plate ....... 29
Annex E (informative) Transferability of measured leakage rates to service conditions .............. 30
Annex F (informative) The measurement of the sealing parameter Q after longsmin(L)
term service simulating exposure to elevated temperature ........................................................ 31
Annex G (informative) Determination of the sealing characteristics of strip sealing
materials available in coil form ............................................................................................................... 33
Annex H (informative) Proposed method for the determination of the coefficient of static
friction, µ , of gaskets ................................................................................................................................. 34
Annex I (informative) Guideline for interpretation of test results and acceptable
modification of measured characteristics ........................................................................................... 36
Bibliography ................................................................................................................................................................. 40
---------------------- Page: 5 ----------------------oSIST prEN 13555:2019
prEN 13555:2019 (E)
European foreword
This document (prEN 13555:2019) has been prepared by Technical Committee CEN/TC 74 “Flanges
and their joints”, the secretariat of which is held by DIN.This document is currently submitted to the CEN Enquiry.
This document will supersede EN 13555:2014.
In comparison with the previous edition, the following technical modifications have been made:
a) in Clause 3 the list of definitions has been revised;b) in Clause 4 the list of symbols has been revised;
c) a new subclause 6.3 with testing requirements for metal foils has been added;
d) subclause 6.4 on surface finish has been revised;
e) subclauses 7.2 and 7.3 on test gaskets have been revised;
f) Clause 8 including Figure 1) to Figure 8 on testing procedures has been completely revised;
g) in Clause 9 the report details have been revised;h) Annex F on relationship of gasket parameters in EN 13555 with those from PVRC method has been
revised;i) a new informative Annex G on determination of the sealing characteristics of strip sealing materials
available in coil form has been added;j) a new informative Annex H on the proposed method for the determination of the coefficient of
static friction of gaskets has been added.---------------------- Page: 6 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
Introduction
This document provides the test procedures to allow the generation of the gasket parameters to enable
the design equations established in EN 1591-1 to be employed. The same test procedures may be used
for “Type Testing” of gaskets and gasket materials. These procedures are not for routine quality control
purposes.---------------------- Page: 7 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
1 Scope
This document specifies the gasket parameters required by EN 1591-1 and provides the test
procedures for establishing the values of these parameters.Gaskets which are wholly based upon elastomers, or based upon elastomers with only the inclusion of
particulate fillers or particulate reinforcement, as opposed to gaskets combining elastomers, fillers and
fibrous reinforcement, are beyond the scope of this document.NOTE The testing procedures given might be applicable to gaskets of other shapes and dimensions.
2 Normative referencesThe 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.
EN 1092 (all parts), Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories,
PN designatedEN 1514-1, Flanges and their joints — Dimensions of gaskets for PN-designated flanges — Part 1: Non-
metallic flat gaskets with or without insertsEN 1514-2, Flanges and their joints — Gaskets for PN-designated flanges — Part 2: Spiral wound gaskets
for use with steel flangesEN 1514-3, Flanges and their joints — Dimensions of gaskets for PN-designated flanges — Part 3: Non-
metallic PTFE envelope gasketsEN 1514-4, Flanges and their joints — Dimensions of gaskets for PN-designated flanges — Part 4:
Corrugated, flat or grooved metallic and filled metallic gaskets for use with steel flanges
EN 1514-6, Flanges and their joints — Dimensions of gaskets for PN-designated flanges — Part 6: Covered
serrated metal gaskets for use with steel flangesEN 1514-7, Flanges and their joints — Gaskets for PN-designated flanges — Part 7: Covered metal
jacketed gaskets for use with steel flangesEN 1591-1:2013, Flanges and their joints — Design rules for gasketed circular flange connections — Part
1: CalculationEN 1759 (all parts), Flanges and their joint — Circular flanges for pipes, valves, fittings and accessories,
Class designatedEN 1779, Non-destructive testing — Leak testing — Criteria for method and technique selection
EN 12560-1, Flanges and their joints — Gaskets for Class-designated flanges — Part 1: Non-metallic flat
gaskets with or without insertsEN 12560-2, Flanges and their joints — Dimensions of gaskets for Class-designated flanges — Part 2:
Spiral wound gaskets for use with steel flangesEN 12560-3, Flanges and their joints — Gaskets for Class-designated flanges — Part 3: Non-metallic PTFE
envelope gaskets---------------------- Page: 8 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
EN 12560-4, Flanges and their joints — Gaskets for Class-designated flantes — Part 4: Corrugated, flat or
grooved metallic and filled metallic gaskets for use with steel flangesEN 12560-5, Flanges and their joints — Gaskets for Class-designated flanes — Part 5: Metallic ring joint
gaskets for use with steel flangesEN 12560-6, Flanges and their joints — Gaskets for Class-designated flanges — Part 6: Covered serrated
metal gaskets for use with steel flangesEN 12560-7, Flanges and their joints — Gaskets for Class-designated flanges — Part 7: Covered metal
jacketed gaskets for use with steel flanges3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
smax
maximum surface pressure that may be imposed on the gasket at the indicated temperatures without
collapse or “crash”, compressive failure, unacceptable intrusion into the bore or damage of the stressed
area of the gasket such that failure is imminent3.2
min(L)
minimum gasket surface pressure on assembly required at the ambient temperature in order to seat the
gasket into the flange facing roughness and close the internal leakage channels so that the tightness
class is to the required level L for the internal test pressure3.3
smin(L)
minimum gasket surface pressure required under the service pressure conditions, (i.e.) after off-loading
and at the service temperature, so that the required tightness class L is maintained for the internal test
pressure3.4
tightness classes are defined in Table 1 in terms of specific leak rates
Note 1 to entry: Additional, better, tightness classes can be introduced as required by continuing the series.
Table 1 — Tightness classesTightness class L L L L
N 1,0 0,1 0,01
–1 –1
≤ 1,0 ≤ 0,1 ≤ 0,01
Specific leak rate [mg s m ]
---------------------- Page: 9 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
3.5
factor allowing for the effect on the imposed load of the relaxation of the gasket between the completion
of bolt up and long term experience of the service temperature3.6
unloading modulus of elasticity that is determined from the thickness recovery of the gasket between
the initial compression surface pressure and unloading to a third of this initial surface pressure
3.7coefficient of thermal expansion of the gasket under the service conditions of temperature and gasket
surface pressure in the axial direction3.8
additional change in thickness of the gasket or sealing element due to creep between the completion of
the loading and the end of the test period3.9
static friction factor between the gasket and the flange facing during service conditions and under
external loading4 Symbols
For the purposes of this document, the following notations apply.
Where units are applicable, they are shown in brackets. Where units are not applicable, no indication is
given.α the axial coefficient of thermal expansion of gasket –1
G [K ]
µ the static friction factor between the gasket and the flange facing —
e gasket or sealing element thickness [mm]
Δe change in gasket or sealing element thickness due to creep [mm]
A area of gasket subjected to surface pressure 2
G [mm ]
d internal diameter of gasket [mm]
d internal diameter of area of gasket subjected to surface pressure [mm]
D external diameter of gasket [mm]
D external diameter of area of gasket subjected to surface pressure [mm]
E unloading modulus of elasticity of the gasket [MPa]
L tightness class — subscript N indicates the maximum specific leakage rate –1 –
N [mg s m
for that tightness class
---------------------- Page: 10 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
P creep relaxation factor, the ratio of the residual and initial surface —
pressures
Q surface pressure [MPa]
Q gasket surface pressure at assembly prior to unloading [MPa]
Q the minimum level of surface pressure required for leakage rate class L on [MPa]
min(L)assembly
Q the minimum level of surface pressure required for leakage rate class L [MPa]
smin(L)
after off-loading
Q the maximum surface pressure that can be safely imposed upon the gasket [MPa]
smax
at the service temperature without damage
Concordance with EN 1591-1:
Q , the gasket surface pressure at assembly is the gasket stress at the load situation 0 and is defined by
Q in EN 1591-1.5 List of gasket parameters
The gasket parameters relevant to the calculation procedures for the design of bolted flange
connections as given in EN 1591-1 are shown in Table 2 together with the test procedures applicable
for determining the value of the parameter in each case.Table 2 — Gasket parameters and test procedures
Gasket parameter Definition Test procedure(s)
Subclause Subclause
Q 3.1 8.5
smax
Q 3.2 8.8
min(L)
Q 3.3 8.8 and 8.9
smin(L)
L 3.4 8.8 and 8.9
P 3.5 8.7
E 3.6 8.6
α 3.7 8.10
Δe 3.8 8.7
µ 3.9 8.11
6 Test equipment
6.1 Design
Schematics of test rigs for compression, creep relaxation, and tightness measurement are shown in
informative Annexes A to D, Figures A.1, B.1, C.1 and D.1. Annex A is a generalized schematic with the
other figures providing further detail for specific aspects of the tests.---------------------- Page: 11 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
6.2 Test platens
The test platens, and heater assembly where appropriate, shall be sufficiently rigid so that any load
imposed on the gasket can be withstood and so that there is no platen deformation which results in
gasket surface pressure variation. This rigidity aspect can also be important when gasket elastic
recovery is being investigated.The dimensions of the test platen raised faces shall be as given in EN 1092-1 for a DN 40/PN 40 gasket
and EN 1759-1 for an NPS 4 CLASS 300 gasket.For testing in tongue and groove geometries the test platens should be in accordance with EN 1092-1,
Form C and Form D or EN 1759-1.6.3 Metal Foils
Experience has shown that during hot compression tests, that is the P , Q and elevated
QR smaxtemperature tightness tests, some gasket materials are likely to adhere badly enough to the test platens
during the test to cause difficulty in the removal of the gasket after the completion of the test and
damage the platen surface finish.To avoid such damage, stainless steel foils or shims of thickness of 0,05 mm placed between the test
gasket and the platens during P and Q tests may be used.QR smax
Where foils or shims are used the fact of their use shall be included in the test report.
Foils or shims shall not be re-used or used in tightness tests at any temperature nor in the Coefficient of
Static Friction determination defined in 8.11 and provisionally detailed in Annex H.
NOTE A formal investigation into the effect of the use of foils during P and Q testing is planned to be
QR smaxcarried out and, as a result, the next revision of this document might not continue to allow the use of foils or shims.
6.4 Surface finishThe platen surface finish shall be within the range specified by the relevant flange standards in the
EN 1092 series and EN 1759 series. For sheet materials where the standards are EN 1092-1 and
EN 1759-1 the finish should be as specified below.The surface finish of the test platens shall conform to the following:
3,2 µm < R < 6,3 µm
Exceptions to this range are acceptable where the gasket is intended for use with a surface finish
outside of this range. In this case the surface finish used shall be recorded.Before each test, the freedom from debris from the previous test and from scratch and impact damage
to the surface finish of the platens shall be checked visually.6.5 Measurement of gasket thickness
For those procedures where the gasket thickness shall be monitored during the test there shall be
either three displacement transducers at 120° spacing around the circumference of the platens or one
displacement transducer placed on the central line.However, for a leak test, the use of an axial transducer is not recommended as it introduces a sealing
complication to the rig design.6.6 Loading
Any loading means may be used that allows the gasket to be loaded and unloaded at a required and
consistent rate. The rate of loading and unloading to be used is fixed as:---------------------- Page: 12 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
0,5 MPa/s for all types of gasket except for PTFE based gaskets when 0,1 MPa/s shall be used.
The loading shall be recorded as a function of time.6.7 Temperature
The rate of increase of temperature in all elevated temperature tests shall be 2 K/min.
6.8 Leakage measurementEN 1779 gives the limits that can be achieved by various method of leakage measurement. The
information given in that document shall be taken into account when selecting a measurement system.
For modern, high performance, sealing materials and gasket styles, the most appropriate method of
measurement is very likely to be mass spectrometry.7 Test gaskets
7.1 Number of gaskets
At least two gaskets for each type of test shall be tested.
NOTE More rigorous guidance on the number of repeat tests required for each test type will be available for
the next revision of this document.7.2 Procurement and identification of gaskets
The gaskets to be tested shall be selected at random from production gaskets or shall be cut from sheet
representative of normal production. Prior to selection for test the gaskets or sheet shall have been
stored in accordance with the recommendations of the manufacturer and the time since manufacture
should be within any time limit set by the manufacturer.Some basic checks shall be made in order to ensure that the gaskets or sheet are acceptable by the
normal quality assurance criteria before the tests to this document are carried out. The results of these
checks shall be recorded.In all cases, full traceability to production shall be maintained.
7.3 Pre-conditioning of the gaskets
For every gasket type where the sealing element is not solid metal the gasket shall be conditioned as
indicated below before any of the tests of this document are carried out.The test gasket shall be held for at least 48 hours in air with a relative humidity of (50 ± 6) % at ambient
temperature.The required relative humidity can for example be generated and maintained by the use of a saturated
solution of magnesium nitrate hexahydrate, Mg (NO ) 6H O. The test gaskets that are to be held at the
3 2 2required relative humidity should be stored above a saturated solution of the salt, containing an excess
of the solid salt, in a glass container fitted with a ground glass lid and held in an area at ambient
temperature.The test gaskets shall be removed from the conditioning atmosphere no more than 30 min before the
test is carried out.7.4 Dimensions of test gaskets
The test gasket dimensions shall be either of those specified in Table 3.
---------------------- Page: 13 ----------------------
oSIST prEN 13555:2019
prEN 13555:2019 (E)
Table 3 — Test gasket dimensions for Raised Face Flanges
Raised face dimensions
Flange description Gasket dimensions according to
according to
DN 40/PN 40 EN 1092-1 EN 1514-1 to EN 1514-7 (according to the type of gasket)
EN 12560-1 to EN 12560-7 (according to the type of
NPS 4 CLASS 300 EN 1759-1
gasket)
For convenience for sheet materials the gasket dimensions are given below:
EN 1514-1 ID 49,0 mm OD 92,0 mm
EN 12560-1 ID 115,0 mm OD 148,0 mm
Where the intended service is in tongue and groove flanges, the test gasket size is specified in
EN 1092-1 or in EN 1759-1, and the test shall be carried out with test platens which have a tongue and
groove configuration.Tolerance of the platens for tongue and groove configurations shall be as given below:
— negative tolerance for tongue width,— positive tolerance for groove width.
If this mode of testing is used it shall be clearly stated in the report.
7.5 Measurement of test gaskets as received
The internal and external diameter of the gasket or sealing face shall be measured with an appropriate
device such as micrometer, caliper or circometer (π tape) at ambient temperature.
Except where a circometer is used, the measurement shall be taken at not less than four positions
around the gasket and the mean diameter shall be reported.The mean values shall conform to the theoretical values within the tolerances given in the appropriate
document or the supplier's information.The as received thickness of the gasket or sealing element shall be measured by a micrometer or other
suitable device with contact faces wide enough to provide a measurement without penetration. The
value of the reference gasket thickness is obtained by measuring the gasket thickness under a 1 MPa
surface pressure at ambient temperature and after a one minute stabilization period. The
measurements of thickness shall be taken at not less than four positions around the gasket or ring and
the mean reported. The measured thickness shall be within the tolerances given in the appropriate
document or the supplier's information if no document exists.Where the gasket has centering or locating rings associated with the sealing elem
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.