Fire safety engineering -- Survey of performance-based fire safety design practices in different countries

This document is a summary of the results of a questionnaire survey, which was conducted to gather information on the current state of performance-based fire safety design (P-B FSD) practices in various countries. The questions include what types of buildings and areas of fire safety systems are being applied, what are the legislative environments in terms of acceptance of P-B FSD, and what documents are needed/desired from ISO/TC 92/SC 4 if the countries/regions wish to adopt P-B FSD.

Ingénierie de la sécurité incendie -- Recensement des pratiques nationales sur la conception de la sécurité incendie fondée sur la performance

General Information

Status
Published
Publication Date
08-Dec-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
10-Nov-2021
Completion Date
10-Nov-2021
Ref Project

Buy Standard

Technical report
ISO/TR 20413:2021 - Fire safety engineering -- Survey of performance-based fire safety design practices in different countries
English language
29 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

TECHNICAL ISO/TR
REPORT 20413
First edition
2021-12
Fire safety engineering — Survey of
performance-based fire safety design
practices in different countries
Ingénierie de la sécurité incendie — Recensement des pratiques
nationales sur la conception de la sécurité incendie fondée sur la
performance
Reference number
ISO/TR 20413:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO/TR 20413:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 20413:2021(E)
Contents Page

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

Introduction .................................................................................................................................................................................................................................v

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

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

3 Terms, definitions and abbreviated terms .............................................................................................................................. 1

3.1 Terms and definitions ...................................................................................................................................................................... 1

3.2 Abbreviated terms .............................................................................................................................................................................. 2

4 Method of survey ................................................................................................................................................................................................. 2

5 Results of survey ..................................................................................................................................................................................................2

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

5.2 Usage of P-B FSD to actual buildings (answers to Q1) ......................................................................................... 3

5.3 Subjects of P-B FSD (answers to Q2 to Q4) .................................................................................................................... 4

5.4 Societal and regulatory systems (answers to Q5 to Q9) ................................................................................... 8

5.5 Design fires and scenarios, criteria and calculation methods (answers to Q10 to

Q15) ............................................................................................................................................................................................................... 16

5.6 Why P-B FSD is not being adopted (answers to Q16 to Q17) ...................................................................... 20

6 Conclusion ................................................................................................................................................................................................................21

Annex A (informative) Questionnaire survey for performance-based fire safety design

practices in different countries/regions .................................................................................................................................22

Bibliography .............................................................................................................................................................................................................................29

iii
© ISO 2021 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/TR 20413:2021(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 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 92, Fire safety, Subcommittee SC 4, Fire

safety engineering.

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.
© ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 20413:2021(E)
Introduction

Since the 1980s, performance-based fire safety design (P-B FSD) have been increasingly popular

in many countries. In recent years, the trend has been accelerated by factors such as the emergence

of large-scale buildings, diversification of building uses, desire for cost-effective construction and

development of new building technologies. However, building control has been traditionally carried out

based on prescriptive building/fire regulations and it is unlikely that this conventional system will be

changed in the future for the majority of conventional types of buildings.

Since building designs by the P-B FSD method and by prescriptive building/fire regulations are very

different, the buildings designed by the P-B FSD method do not smoothly fit into the conventional

building control system. Various efforts are underway to devise a new system to control P-B FSD

designs but there is a long way to go. Also, it is not clear how widely and in what practical situations the

P-B FSD approach is used, and what fire safety engineering (FSE) tools are used in different countries.

It is the mission of ISO/TC 92/SC 4 to promote P-B FSD, and therefore SC 4 is concerned with how

it can effectively assist in the establishment of systems for P-B FSD and, more specifically, what

documents SC 4 can produce to benefit the development of P-B FSD. For this purpose, it is first necessary

to understand the current state and environment of P-B FSD, particularly the legal, administrative and

human environment.

This document is a summary of the results of a questionnaire survey conducted as the first step to

better understand the actual situation of P-B FSD in different countries.

Similar surveys have already been conducted: twice by CEN/TC 127, Fire safety in building, in 2001 and

[2]

2017 , for countries in Europe and several other countries; as well as other surveys with a similar

[3][4]
interest . Some results of these surveys are cited in this report as notes.
© ISO 2021 – All rights reserved
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 20413:2021(E)
Fire safety engineering — Survey of performance-based
fire safety design practices in different countries
1 Scope

This document is a summary of the results of a questionnaire survey, which was conducted to gather

information on the current state of performance-based fire safety design (P-B FSD) practices in various

countries.

The questions include what types of buildings and areas of fire safety systems are being applied, what

are the legislative environments in terms of acceptance of P-B FSD, and what documents are needed/

desired from ISO/TC 92/SC 4 if the countries/regions wish to adopt P-B FSD.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
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 Terms and definitions
3.1.1
authority having jurisdiction
AHJ

authority including national and local governments, committees, officials and other organizations/

persons that has jurisdiction
3.1.2
certifier

organization/person to certify buildings and their components that comply with performance-based

criteria
3.1.3
peer review

evaluation by third-party authority or engineer in the same field to comply with performance criteria

3.1.4
performance-based fire safety design
P-B FSD

design that is engineered to achieve specified fire safety design objectives based on performance

criteria
3.1.5
private certifier
accredited non-governmental certifier (3.1.2)
© ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/TR 20413:2021(E)
3.1.6
regulatory review

assessment conducted by the authority having jurisdiction (3.1.1) to determine if fire safety design

complies with performance criteria
3.2 Abbreviated terms
P-B FSD performance-based fire safety design
FSE fire safety engineering
CFD model computational fluid dynamics model
2001-MS member states of the EU at the year 2001
N-MS member states of the EU after the year 2001
2016-MS member states of the EU at the year 2016 (“2001-MS” + “N-MS”)
4 Method of survey

The questionnaires were distributed to all the members of ISO/TC 92/SC 4 through the Secretariat of

SC 4 during 7 to 10 October 2016. The selection of appropriate responders was left to the discretion of

the mirror committee of each country/region. The expected typical responders were architects, fire

safety engineers, building officials, etc.

The completed questionnaire was returned by 13 countries before 9 October 2016. Three responses

were subsequently added. Finally, the number of countries that responded was 16, of which 8 are

European countries.

The questionnaire is given in Annex A. There are 17 questions, which are classified into 4 sections:

― subjects of P-B FSD (see 5.3);
― societal and regulatory systems for P-B FSD (see 5.4);
― design fires and scenarios, criteria and calculation methods (see 5.5);
― the reasons why P-B FSD is not being adopted (see 5.6).

In general, the subjects of P-B FSD are buildings. Nevertheless, aircrafts, ships, trains and other types of

built environments such as tunnels are included in the questions.
5 Results of survey
5.1 General
The results of the survey are summarized in 5.2 to 5.6.

The completed questionnaire was returned by 16 countries, of which 11 countries responded with a

single answer while the other 5 countries (Canada, Germany, Spain, Sweden and the USA) responded

multiple times. The questionnaire answers are wrapped up by each country in the case that two or more

responses were received in a same country. The answers are not exactly the same even from the same

country. In addition, different countries use different terminology. This is thought to be partly because

some countries consist of local governments which retain high level of independence in autonomy and

jurisdiction and partly because the responders’ familiarity with the issues will not always cover all the

local rules and conditions. Remarks are included for the relevant answers.
© ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 20413:2021(E)

The countries/regions that responded to the questionnaire and the number of responses from each are

as follows:
― Austria (EU) 1
― Canada 2
― China 1
― France (EU) 1
― Germany (EU) 2
― Hungary (EU) 1
― Japan 1
― Republic of Korea 1
― Netherlands (EU) 1
― New Zealand 1
― Russian Federation 1
― Slovakia (EU) 1
― Spain (EU) 10
― Sweden (EU) 2
― Turkey 1
― United States of America (USA) 3
5.2 Usage of P-B FSD to actual buildings (answers to Q1)
Q1. Is P-B FSD already being used for actual buildings in your country/region?

Figure 1 shows that P-B FSD is being used in most of the 16 countries with two exceptions: Slovakia and

Turkey.
© ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/TR 20413:2021(E)
Key
No, 2: Slovakia and Turkey.

Yes, 14: Austria, Canada, China, France, Germany, Japan, the Republic of Korea, Hungary, New Zealand, the

Netherlands, the Russian Federation, Spain, Sweden and the USA.

Figure 1 — Q1. Is P-B FSD already being used for actual buildings in your country/region?

[2]

NOTE In CEN’s survey report , there is no direct question as Q1, but on the related question “4.5 Alternative

approval system or derogation” it is said that alternative and derogation are accepted in most of 2016-MS,

although “able to accept by regulatory system” and “being actually accepted” are not necessarily exactly the

same.
5.3 Subjects of P-B FSD (answers to Q2 to Q4)

Q2. What are typical types of facilities/uses to which the P-B FSD approach is applied?

Figure 2 shows that every kind of built environment can be a subject of P-B FSD in most countries.

However, P-B FSD tends to be applied mostly to high-rise buildings and various large-scale projects,

while applications to residential and educational buildings are relatively few. This can suggest that the

existing building and/or fire codes have not been able to catch up with the speed of change of height,

size, occupancy condition, etc., while several types of buildings (e.g. residential buildings) are relatively

simple so still tend to be constructed in a traditional way or omitted from the enforcement of rigorous

provisions.
© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/TR 20413:2021(E)

Figure 2 — Q2. What are typical types of facilities/uses to which the P-B FSD approach is

applied?

Looking into the answers in Table 1 for the difference by country, the application of P-B FSD to

transportation vehicles (e.g. aircrafts, trains, ships) is generally rare. It is suspected that the number of

products are relatively much lower than for buildings and expertise is highly specialized; therefore, the

safety designs are controlled by some other specialized systems and only a few fire safety engineers

can be involved in the design.
© ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
ISO/TR 20413:2021(E)
© ISO 2021 – All rights reserved
Table 1 — Main subjects of P-B FSD in each country (Q2)

Country Aus- Cana- China France Germa- Hun- Japan Re- New Nether- Russian Spain Swe- USA

tria da ny gary public Zealand lands Federa- den
of tion
Korea
High-rise building (50 m to x x x x x x x x x x x
200 m high)
Super high-rise building (over x x x x x x x x x
200 m high)
Mixed-use high-rise/ x x x x x x x x x
super high-rise
Office building x x x x x x x x
Shopping mall, mercantile or x x x x x x x x x x x x x
retail building
Exhibition hall x x x x x x x x x x x x x
Educational building, school x x x x x
Residential building x x x
Hotel x x x x x x x x
Parking garage x x x x x x x x x x
Multi-purpose covered stadium x x x x x x x x x x x x x x
Airport terminal building x x x x x x x x x x x x x x
Train station, subway station x x x x x x x x x x x
Tunnels x x x x x x x x x
Heritage building x x x x x x x x x
Nuclear power plant x x x x x x x
Industrial plants, manufactur- x x x x x x x x x x x
ing, etc.
Warehouse/storage x x x x x x x x x
Air crafts
Ships x x
Train, car, vehicle, etc. x x
Others x
NOTE No P-B FSD is used in Slovakia and Turkey.
---------------------- Page: 11 ----------------------
ISO/TR 20413:2021(E)
[3][4]

NOTE (According to the survey , responders: > 400 people from 40 countries.) With respect to the

application of FSE/PBD methods to fire safety, about 5 % to 10 % of designs are full PBD; depending on country,

about 5 % to 20 % are deviation from prescriptive (DTS) provisions using FSE; and the large majority, some 70 %

to 90 % designs, are strictly compliant with DTS solution/verification methods.
Q3. Which fire safety systems or features are included in P-B FSD analyses?

Figure 3 shows that any of the fire safety systems or means which are usually installed in buildings

have a need to apply the P-B FSD approach. This fact can imply that many building owners are not

always satisfied with the existing code provisions for these fire safety systems because of the cost,

restriction of design, efficiency or another reason.

Figure 3 — Q3. Which fire safety systems or features are included in P-B FSD analyses?

[2]

NOTE According to the CEN survey , according to the assessment for the five initiatives by BeneFeu as to

form the basis of regulatory compliance, the focused FSE areas are assessed by member countries as given in

Table 2.
Table 2
Assessment by CEN/TC 127/WG 8 Member countries
FSE area
Much work Little work Mature
SS1: Fire initiation and development 11 7 4
SS2: Smoke propagation 6 9 7
SS3: Compartmentation and stability 2 13 5
SS4: Detection, activation and suppression 5 11 3
SS5: Fire service intervention 11 5 3
Q4. What are the main reasons to apply the P-B FSD approach to buildings?

Figure 4 shows the major reasons that P-B FSD is used in building designs. The two major reasons are

“the type of building is out of scope of the existing prescriptive regulations” and “a desired aspect of

the building does not comply with the building or fire regulation”, followed by “economize building

cost” and “realize attractive/innovative building space”. These are, of course, considered to come from

the general feeling that the existing provisions are too restrictive, which can be reasonable or a poor

understanding of fire risk.
© ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
ISO/TR 20413:2021(E)

Figure 4 — Q4. What are the main reasons to apply the P-B FSD approach to buildings?

[3][4]

NOTE According to the survey , performance-based code has been introduced in Australia (1996), Japan

(2000), the Netherlands (1992), Spain (1999), Sweden (early 1990s) and Scotland (function-based system, 2005).

5.4 Societal and regulatory systems (answers to Q5 to Q9)
Q5. What regulatory systems make it possible to apply the P-B FSD to buildings?

The results of the answers in Figure 5 show that societal and regulatory systems vary among the

countries. The most common regulatory system that enables P-B FSD is the building/fire regulation,

either national or local, having some clause to allow buildings that do not comply with the specifications

of the regulations. Also, some countries have already established a system to accept P-B FSD. These

counties total 27, while another 8 countries accept P-B FSD by the discretion of building/fire officials

and 3 countries accept P-B FSD by designated approval organizations. It is possible this is because

administrative organizations in these countries are more discretionary or because these countries

have multiple ways to accept P-B FSD. Further clarification is desired.
© ISO 2021 – All rights reserved
---------------------- Page: 13 ----------------------
ISO/TR 20413:2021(E)

Figure 5 — Q5. What regulatory systems make it possible to apply the P-B FSD to buildings?

Q6. Which body/bodies perform a regulatory review of P-B FSD?

Most countries perform regulatory review both by an AHJ and designated approval organizations,

engineer/firms, authorized by the AHJ (see Figure 6 and Table 3).
Figure 6 — Q6. Which body/bodies perform a regulatory review of P-B FSD?

Only the AHJ shall/can perform regulatory review of the P-B FSD in Austria and China. On the other

hand, Sweden seems to be very unique in that AHJ is not, neither directly nor indirectly, involved in the

review. It will be interesting to check the system more in detail to see how it works.

© ISO 2021 – All rights reserved
---------------------- Page: 14 ----------------------
ISO/TR 20413:2021(E)
© ISO 2021 – All rights reserved
Table 3 — Body/bodies for regulatory review in different countries (Q6)

Country Austria Canada China France Germany Hungary Japan Repub- New Zealand Netherlands Russian Spain Sweden USA

lic of Federa-
Korea tion
AHJ for building/fire control x x x x x x x x x x x x x
Designated approval x x x x
organization
Special standing committee for x x
the peer review of P-B FSD
Ad hoc committee for the peer x
review of P-B FSD
Third-party engineer/firm x x x x x x x x x
selected by the AHJ
Engineer/firm selected by the x x x x x x x x
design team and approved by
the AHJ
Private certifier
Others x x
---------------------- Page: 15 ----------------------
ISO/TR 20413:2021(E)
[2]

NOTE According to the CEN survey , in 2001, most of the countries (16 of 17 MS) approved designs based

on calculations, only 14 accepted ad hoc tests and 15 expert judgement. Fifteen years later, the use of calculations

is accepted by Portugal, and Greece has introduced expert judgement as a tool for justifying an alternative or

derogation.
Q7. What professional qualification is required for the regulatory reviewers?

The requirements of professional qualification for the regulatory reviewers also vary. The professional

qualifications as a reviewer are issued or acknowledged typically by the government or a relevant

professional association. However, nearly half of the countries have no explicitly defined qualification

(see Figure 7). This can depend on how popular P-B FSD is in particular countries. If the number of P-B

FSDs is limited, it can be enough to assign relevant distinguished experts on a case-by-case basis as

reviewers.

Figure 7 — Q7. What professional qualification is required for the regulatory reviewers?

The answers of Canada, France and Spain are checked both at “required” and “not defined”, because

each state, city, etc. has its own building control system within the same country (see Table 4).

© ISO 2021 – All rights reserved
---------------------- Page: 16 ----------------------
ISO/TR 20413:2021(E)
© ISO 2021 – All rights reserved
Table 4 — Qualification of a reviewer of P-B FSD

Country Aus- Cana- China France Germa- Hunga- Japan Re- New Nether- Rus- Spain Sweden USA

tria da ny ry pub- Zealand lands sian
lic of Feder-
Korea ation
Holder of a government- x x x x x x
issued licence/certification
in a relevant category
Holder of a certification in x x
a relevant category issued
by a body designated by
the government
Holder of a certification by x x x x
a recognized professional
society/nominated body
Set of minimum education- x x x x
al/professional experience
acknowledged by
government
Qualification is not x x x x x x
explicitly defined
Others x x x
---------------------- Page: 17 ----------------------
ISO/TR 20413:2021(E)

Q8. Is there any peer review by a private certifier or similar, not only by regulatory review?

Although the meaning of each choice for this question is not always clear, there seems to be a legal

system to license private certifiers in some countries. However, regardless of whether such a system

exists, private certifiers are not often involved in the certification of P-B FSD.

There are peer reviews by a private certifier or similar in Sweden and in parts of Canada, France and the

USA. It can seem to be a contradiction that France, Canada and the USA have checked both the second

and third answers, but this is thought to be because the local governments in these countries have their

own jurisdictions and independent building control administrations, and therefore the introduction of

a private certifier is not uniform in the country (see Figure 8).

Figure 8 — Q8. Is there any peer review by private certifier or similar, not only by regulatory

review?
Q9. What qualification is required to engage in P-B FSD practices?

The qualifications for P-B FSD practitioners are required in half of the countries and not in the other

half. In Canada, China, Germany, Hungry and the Republic of Korea, some kind of licence or certification

is “required”. In Austria, Japan, New Zealand, the Russian Federation and Sweden, the qualification is

“not defined” (see Figure 9).
© ISO 2021 – All rights reserved
---------------------- Page: 18 ----------------------
ISO/TR 20413:2021(E)
Figure 9 — Q9. What qualification is required to engage in P-B FSD practices?

In France, Spain and the USA, both “required” and “not defined” exist (see Table 5).

[3][4]

NOTE 1 According to the survey , the way building control is performed in Spain differs from the other

European, or western, countries in that it relies solely on the qualification of professionals, normally architects

but sometimes civil engineers, who have ultimate responsibility for projects (much like registered architects in

Japan).
© ISO 2021 – All rights reserved
---------------------- Page: 19 ----------------------
ISO/TR 20413:2021(E)
© ISO 2021 – All rights reserved
Table 5 — Qualification of engineer for P-B FSD

Country Austria Canada China France Germa- Hunga- Japan Re- New Netherlands Rus- Spain Swe- USA

ny ry pub- Zealand sian den
lic of Feder-
Korea ation
Holder of a government- x x x x x x x
issued licence/certification
in a relevant category
Holder of a certification in x x x x
a relevant category issued
by a body designated by the
government
Holder of a certification by x x
a recognized professional
society/nominated body
Set of minimum educational/ x x x
professional experience
acknowledged by
government
Qualification is not x x x x x x x x x
explicitly defined
Others x
---------------------- Page: 20 ----------------------
ISO/TR 20413:2021(E)
Key
required
both
not defined

The requirements of professional qualification for the regulatory reviewers and for P-B FSD practices

are similar with the qualification of P-B FSD practitioners in each country (see Figure 10).

Key
for practitioners
for reviewers
Figure 10 — Comparison of Q7 and Q9
[2]

NOTE 2 According to the CEN survey , educational support for professionals is only 25 % of the N-MS.

However, about 50 % of the 2016-MS offer educational courses for professionals.
[3][4]

NOTE 3 According to this (questionnaire) survey , the percentages of qualified FSE are very low, around

1/4, across all countries surveyed, yet P-B FSD at each stage (e.g. design, peer review, approval, enforcement) is

being run not only by qualified FSE but largely by poorly qualified engineers.

5.5 Design fires and scenarios, criteria and calculation methods (answers to Q10 to

Q15)
Q10. How are the fire scenarios identified in a P-B FSD project?

According to the answers, the fire scenarios in a P-B FSD project are prescribed in the regulations in

more than a half of the countries. It is quite interesting, or rather surprising, that the fire scenario sets

have been already established for P-B FSD practices in the regulations of many countries. On the other

hand, the fire scenarios are decided by the discretion of building officials and approval organizations in

the other countries (see Figure 11).
© ISO 2021 – All rights reserved
---------------------- Page: 21 ----------------------
ISO/TR 20413:2021(E)
Figure 11 — Q10. How are the fire scenarios identified in a P-B FSD project?
Q11. How are the design fires determined in a P-B
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.