Fire resistance tests -- Elements of building construction

The assessment detailed in ISO 834-11:2014 is designed to cover a range of thicknesses of the fire protection material, a range of steel sections characterized by their section factors, a range of design temperatures, and a range of valid fire resistance classification periods. ISO 834-11:2014 covers fire protection systems that include both passive (boards, mats, slabs, and spray materials) and reactive materials as defined in this document. The assessment procedure is used to establish: a) on the basis of the temperature data derived from testing loaded and unloaded specimens, a correction factor and practical constraints on the use of the fire protection system (the physical performance), and b) on the basis of the temperature data derived from testing unloaded short steel specimens, the thermal properties of the fire protection material (the thermal performance). The limits of applicability of the results of the assessment are defined together with permitted direct application of the results to different steel section sizes and strength grades (but not stainless steels) and to the fire protection system tested. The results of the tests obtained according to ISO 834‑10 and the assessment in this part of ISO 834 are directly applicable to steel sections of "I" and "H" cross-sectional shape and hollow sections. Results from analysis of I or H sections are directly applicable to angles, channels, and T-sections for the same section factor, whether used as individual elements or as part of a fabricated steel truss. The results of the assessment are applicable to fabricated sections. ISO 834-11:2014 does not apply to concrete-filled hollow sections, beams, or columns containing holes or openings of any type or solid bar.

Essais de résistance au feu -- Éléments de construction

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Published
Publication Date
09-Feb-2014
Current Stage
6060 - International Standard published
Start Date
08-Jan-2014
Completion Date
10-Feb-2014
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INTERNATIONAL ISO
STANDARD 834-11
First edition
2014-03-01
Fire resistance tests — Elements of
building construction —
Part 11:
Specific requirements for the
assessment of fire protection to
structural steel elements
Essais de résistance au feu — Éléments de construction —
Partie 11: Exigences spécifiques d’évaluation de la protection au feu
appliquées aux éléments des structures en acier
Reference number
ISO 834-11:2014(E)
ISO 2014
---------------------- Page: 1 ----------------------
ISO 834-11:2014(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

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Published in Switzerland
ii © ISO 2014 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 834-11:2014(E)
Contents Page

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

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

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

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

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

5 Assessment ................................................................................................................................................................................................................. 6

5.1 General ........................................................................................................................................................................................................... 6

5.2 Temperature data ................................................................................................................................................................................. 6

5.3 Correction for discrepancy in stickability and insulation performance over the thickness

range tested ............................................................................................................................................................................................... 7

5.4 Assessment procedures for thermal performance .................................................................................................. 7

5.5 Criteria for acceptability of the assessment method used and the resulting analysis .............. 7

6 Report of the assessment............................................................................................................................................................................. 8

7 Limits of the applicability of the results of the assessment..................................................................................... 9

7.1 General ........................................................................................................................................................................................................... 9

7.2 Permitted protection thickness for beams ..................................................................................................................10

7.3 Permitted protection thickness for columns .............................................................................................................10

7.4 Permitted section factor for beams ....................................................................................................................................10

7.5 Permitted section factor for columns ...............................................................................................................................10

7.6 Specific issues for passive protection ...............................................................................................................................11

Annex A (normative) The applicability of the results of the assessments for passive protection to

sections other than I or H sections .................................................................................................................................................12

Annex B (normative) Correction of data/nominal thickness ..................................................................................................14

Annex C (informative) Assessment methodology: Graphical approach ........................................................................19

Annex D (informative) Assessment methodology: Differential equation analysis (variable

λ approach) .............................................................................................................................................................................................................25

Annex E (informative) Assessment methodology: Differential equation analysis (constant

λ approach) .............................................................................................................................................................................................................31

Annex F (informative) Assessment methodology: Numerical regression analysis ...........................................34

Annex G (informative) Assessment methodology: 3D Interpolation method (reactive systems) .....36

Annex H (normative) Selection of test specimens — Reactive materials ....................................................................41

Annex I (normative) Selection of test specimens — Passive materials .........................................................................47

Bibliography .............................................................................................................................................................................................................................53

© ISO 2014 – All rights reserved iii
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ISO 834-11:2014(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 92, Fire safety, Subcommittee SC 2, Fire

containment.

ISO 834 consists of the following parts, under the general title Fire resistance tests — Elements of building

construction:
— Part 1: General requirements

— Part 2: Guidance on measuring uniformity of furnace exposure on test samples [Technical Report]

— Part 3: Commentary on test method and guide to the application of the outputs from the fire-resistance

test [Technical Report]
— Part 4: Specific requirements for loadbearing vertical separating elements
— Part 5: Specific requirements for loadbearing horizontal separating elements
— Part 6: Specific requirements for beams
— Part 7: Specific requirements for columns
— Part 8: Specific requirements for non-loadbearing vertical separating elements
— Part 9: Specific requirements for non-loadbearing ceiling elements

— Part 10: Specific requirements to determine the contribution of applied fire protection materials to

structural steel elements

— Part 11: Specific requirements for the assessment of fire protection to structural steel elements

— Part 12: Specific requirements for separating elements evaluated on less than full scale furnaces

iv © ISO 2014 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 834-11:2014(E)
Introduction

Technological advances in the fire protection of structural steelwork have resulted in a range of materials

being developed that are now in widespread use throughout the building construction industry. These

are broadly categorized as intumescent coatings, sprays, renders, and boards and are often referred to

as lightweight systems in comparison to the some of the more traditional materials such as brick, block,

and concrete.

Fire protection materials reduce the rate of temperature rise of steel members when exposed to fire by

a variety of methods. Apart from influencing heat transfer mechanism, such as conduction, convection,

and radiation, they often involve thermo-physical transformations, exothermic chemical reactions,

as well as shape changes that increase the thickness of the material and delay the rate at which the

underlying steel substrate heats up. Relatively simple changes such as the release of free moisture at

around 100 °C, or water of crystallization and sublimation, which all occur within specific temperature

ranges, often result in a plateau of rising temperature versus time of varying magnitude depending

upon the type of material and even the way in which it is applied to the steel substrate.

Understanding the behaviour of fire protection materials is complicated, not least when the physical/

chemical reactions and changes in thermal properties occur at different temperatures and at different

rates, depending on their chemical constitution and reaction temperature. This makes the development

of suitable standards for testing and quantifying their behaviour as insulation materials difficult.

In addition, with recent advances in structural fire engineering in which steel members are no longer

considered to fail at a unique temperature, information on fire protection thicknesses is a requirement

that can be specified over a range of limiting temperatures depending upon the type of loading system

(bending, shear, tension, and compression), the magnitude of the applied loads, and the degree of

exposure of the surface with respect to the fire/furnace.

Therefore, to rationalize the behaviour of fire protection products for protecting structural steelwork

into simple design tables that manufacturers can use to specify their products involves the permutation

of a large number of parameters.

In Europe, the development of testing and assessment protocols for fire protecting structural steel

commenced during the 1990s under a European mandate within CEN TC127 (Fire resistance tests) and

was the beginning of drafting European standards such as DD ENV YYY5. Since then, fire protection

manufacturers in collaboration with the test laboratories throughout Europe have developed a series

of test packages and assessment methods over the past 15 years which have been through a rigorous

appraisal process by the fire protection industry. This work has culminated in the drafting of EN 13381

Parts 4 and 8 which broadly cover passive and reactive products.

Some of the key issues in developing these standards have been identifying the number of specimens

required in a test package to characterize the performance of a fire protection product over the range of

fire resistance times, applicable section factors, type of structural element, and design temperature. In

addition, because of the vagaries in fire resistance testing, it has been necessary to establish a rationale

for applying correction factors to the test results for use in the assessment process partly to maximize

the validity of the data and keep the costs of testing to a minimum.

In Europe, four assessment methods have been developed, referred to as Graphical method, Differential

equation analysis (variable l), Differential equation analysis (constant l), and Numerical regression

analysis. Each method has been through a process of validation and are now included in the standards

EN 13381 Parts 4 and 8.

In this part of ISO 834, the four methods have been directly incorporated into the standard and technically

are identical to the European counterparts. However, it is recognized that other assessment methods

may be suitable and therefore this part of ISO 834 provides a set of criteria for their acceptability. One

such method which has undergone an evaluation process and meets the criteria for acceptability is the

3D method developed in the UK and currently used for reactive materials.
© ISO 2014 – All rights reserved v
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ISO 834-11:2014(E)

The 3D assessment was formerly presented as a published research paper at the SC2/WG2 meeting in

Kyoto, Japan in November 2006 (N414). Since 2006, it has been published and presented in various forms

in the technical journals and seminars and is now included in the Dutch Standard NEN 7878 (2011) and

the Dutch Fire Safety Handbook (2011).

This part of ISO 834 recognizes that some assessment method/s are more suited to particular types of

fire protection materials, and for this reason, they are presented as Informative Annexes, which enables

freedom of choice in their application. However, only a single method can be used for the assessment

process for a particular data set and cannot be mixed.

This part of ISO 834 specifies methods for assessing fire protection systems applied to structural steel

members, employed in buildings as beams, columns, or tension members. This part of ISO 834 is intended

for use in conjunction with the testing described in ISO 834-10.
vi © ISO 2014 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 834-11:2014(E)
Fire resistance tests — Elements of building
construction —
Part 11:
Specific requirements for the assessment of fire protection
to structural steel elements
1 Scope

The assessment detailed in this part of ISO 834 is designed to cover a range of thicknesses of the fire

protection material, a range of steel sections characterized by their section factors, a range of design

temperatures, and a range of valid fire resistance classification periods.

This part of ISO 834 covers fire protection systems that include both passive (boards, mats, slabs, and

spray materials) and reactive materials as defined in this document.
The assessment procedure is used to establish

a) on the basis of the temperature data derived from testing loaded and unloaded specimens, a

correction factor and practical constraints on the use of the fire protection system (the physical

performance) and

b) on the basis of the temperature data derived from testing unloaded short steel specimens, the

thermal properties of the fire protection material (the thermal performance).

The limits of applicability of the results of the assessment are defined together with permitted direct

application of the results to different steel section sizes and strength grades (but not stainless steels)

and to the fire protection system tested. The results of the tests obtained according to ISO 834-10 and

the assessment in this part of ISO 834 are directly applicable to steel sections of “I” and “H” cross-

sectional shape and hollow sections. Results from analysis of I or H sections are directly applicable to

angles, channels, and T-sections for the same section factor, whether used as individual elements or as

part of a fabricated steel truss.
The results of the assessment are applicable to fabricated sections.

This part of ISO 834 does not apply to concrete-filled hollow sections, beams, or columns containing

holes or openings of any type or solid bar.

Any assessment method is acceptable provided it meets the acceptability criteria given in 5.5. Examples

of assessment methods in common use are given in Annexes C to G.
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.

ISO 834-1, Fire-resistance tests — Elements of building construction — Part 1: General requirements

ISO 834-10, Fire resistance tests — Elements of building construction — Part 10: Specific requirements to

determine the contribution of applied fire protection materials to structural elements

ISO 8421-2, Fire protection — Vocabulary — Part 2: Structural fire protection
© ISO 2014 – All rights reserved 1
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ISO 834-11:2014(E)
ISO 13943, Fire safety — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 834-1, ISO 13943, ISO 8421-2,

and the following apply.
3.1
characteristic steel temperature

temperature of the structural steel member which is used for the determination of the correction factor

for stickability which is calculated according to 5.2.2
3.2
design temperature
temperature of the steel member for structural design purposes
3.3
fire protection

protection afforded to the steel member by the fire protection system such that the temperature of the

steel member is limited throughout the period of fire exposure
3.4
fire protection system

fire protection material together with any supporting system including mesh reinforcement as tested

Note 1 to entry: The reactive fire protection materials system includes the primer and top coat if applicable.

3.5
fire protection thickness

dry thickness of a single-layer fire protection system or the combined thickness of all layers of a fire

protection system

Note 1 to entry: The thickness of elements of the supporting system or joint cover strips is not included in the fire

protection thickness.

Note 2 to entry: For reactive fire protection systems, the thickness is the mean dry film thickness of the coating

excluding primer and top coat if applicable.
3.6
H section

steel member with wide flanges compared with the section depth whose main function is to carry axial

loads parallel to its longitudinal axis which can be combined with bending and shear

3.7
I section

steel joist or girder with short flanges shaped like a letter “I” whose main function is to carry loads

transverse to its longitudinal axis

Note 1 to entry: These loads usually cause bending of the beam member. The flanges may be parallel or tapered.

3.8
passive fire protection material

material, which do not change their physical form on heating, providing protection by virtue of their

physical or thermal properties

Note 1 to entry: Passive fire protection materials may include materials containing water or undergo endothermic

reactions which, on heating produce cooling effects. These may take the form of sprayed coatings, renderings, mat

products, boards, or slabs.
2 © ISO 2014 – All rights reserved
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ISO 834-11:2014(E)
3.9
reactive fire protection material

material which are specifically formulated to provide a chemical reaction upon heating such that their

physical form changes and in so doing provide fire protection by thermal insulative and cooling effects

3.10
reference section

steel section which is taken from the same length of steel as its equivalent loaded section

3.11
section factor (unprotected steel)

ratio of the fire exposed perimeter area of the structural steel member, per unit length, A to its cross-

sectional volume per unit length, V
3.12
section factor (profiled fire protection system):

ratio of the fire exposed outer perimeter area of the steel structural member excluding the protection

material, per unit length, A to its cross sectional volume per unit length, V
3.13
section factor (boxed fire protection system)

ratio of the internal surface area of the smallest possible rectangle or square box encasement which can

be measured around the steel structural member, A , to its volume per unit length, V

3.14
steel member

element of building construction, which is load bearing and fabricated from steel

Note 1 to entry: For the purpose of this part of ISO 834, the steel used in the testing must be of the same grade.

3.15
steel temperature

overall mean temperature to be used as input data for the analysis is calculated according to 5.2.1

3.16
stickability

ability of a fire protection system to remain sufficiently coherent and in position for a well-defined

range of deformations, furnace, and steel temperatures, such that the efficacy of the fire protection is

not significantly impaired
3.17
test package

set of steel sections which may include short or long specimens that is tested to evaluate the stickability

of the fire protection system and to provide thermal data over a range of protection thickness, steel

section factor, and steel temperatures
3.18
test specimen
steel section plus the fire protection system under test

Note 1 to entry: The steel test section, representative of a steel member for the purposes of this test, comprises

long and short steel columns or beams.
4 Symbols and abbreviated terms
Symbol Unit Description
A m area
A m exposed perimeter area of the structural steel member, per unit length
© ISO 2014 – All rights reserved 3
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ISO 834-11:2014(E)
Symbol Unit Description
for profile protection: exposed outer perimeter area of the structural
steel member excluding the protection material, per unit length
A m
for encased protection: the internal surface area of the smallest possi-
ble rectangle or square box encasement which can be measured around
the structural steel member
c J/(kgK) temperature-dependent specific heat capacity
temperature-independent specific heat capacity of the fire protection
c J/(kgK)
material
c - regression constants in constant λ method of assessment
n,n+1...
d mm thickness
d mm protection thickness of the short section
d - regression coefficients
n,n+1...
d mm maximum protection thickness of the loaded section
max
d mm minimum protection thickness of the loaded section
min
d mm thickness of fire protection material
d mm maximum thickness of fire protection material
p(max)
d mm minimum thickness of fire protection material
p(min)
thickness of fire protection material on an unloaded short column sec-
d mm
tion
d mm thickness of fire protection material of an unloaded beam section
D mm protection thickness for the loaded section or tall section
D mm protection thickness for the reference section
D min length of the moisture plateau
k - correction factor
k - stickability correction factor for the short section at thickness d
i i
k - stickability correction factor at maximum protection thickness
imax
k - stickability correction factor at minimum protection thickness
imin
K - constant applied to λ
δ (p)
K - range factor for thickness
K - range factor for section factor
n - number of specimens
P m perimeter of the steel section exposed to fire
S m section factor of the loaded or tall section
S m section factor of the reference section
s m section factor at factor K
p s
s m maximum section factor at K factor of 1
max s
s m minimum section factor at K factor of 0
min s
t mm thickness of the wall of the hollow steel section
t min time from the commencement of the test
t min time for the reference section to reach the design temperature
t min corrected time for thickness and section factor
4 © ISO 2014 – All rights reserved
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ISO 834-11:2014(E)
Symbol Unit Description
t min time required for a short section to reach the design temperature
time for an unloaded section to reach an equivalent temperature to the
t min
loaded beam at time t
t min time for the loaded section to reach the design temperature
t min time at recalculated steel temperature
recal
V m /m volume of the steel section per unit length
Δt min time interval
Δθ °C increase in steel temperature during the time interval Δt
θ °C design temperature
θ °C average steel temperature at time t
θ °C corrected mean temperature of an unloaded column section
c(SC)
θ °C corrected mean temperature of an unloaded beam section
c(uC)
θ °C characteristic steel temperature of a loaded beam
θ °C characteristic steel temperature of a loaded column
θ °C modified steel temperature of an unloaded section
m(SC)
θ °C average temperature of the furnace at time t
θ °C protective material temperature at time t
θ °C characteristic steel temperature of a loaded column
θ °C characteristic temperature of a short unloaded reference beam
λ W/(mK) mean value of λ calculated from all the short sections at a temperature
ave(p) p
λ W/(mK) characteristic value of the thermal conductivity of the fire protection
char(p)
material
λ W/(mK) effective thermal conductivity of the fire protection material

λ W/(mK) thermal conductivity of the fire protection material at time t and for a

p,t
thickness d of protection material
λ standard deviation of λ calculated from all the short sections at a tem-
δ(p) p
W/(mK)
perature θ
ρ Kg/m density
3 3
ρ Kg/m density of steel (normally 7 850 kg/m )
ρ Kg/m density of the fire protection on a loaded beam
ρ Kg/m density of the fire protection material
protection
ρ Kg/m density of the fire protection material on the unloaded beam
ρ Kg/m density of the fire protection material on the unloaded column section
LB - loaded beam
LC - loaded column
TC - tall column
LHB - loaded hollow beam
LHC - loaded hollow column
SIB - short I-section beam
SIC - short I-section column
© ISO 2014 – All rights reserved 5
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ISO 834-11:2014(E)
Symbol Unit Description
TCHS - tall circular hollow beam
TRHS - tall rectangular hollow beam
SHB - short hollow beam
SHC - short hollow column
RB - reference beam
5 Assessment
5.1 General

The assessment shall begin with the collection of the data from the fire testing obtained according to

ISO 834-10.

The temperature data obtained from the loaded and unloaded steel sections are used as a basis for

relating the time to reach a specified steel temperature, the thickness of fire protection material, and

section factor. Where the performance at minimum and maximum protection thickness of the loaded

section or tall column is less than that of the equivalent short reference section, the time to reach the

design temperature shall be corrected in accordance with Annex A.

The section factor and applied material thickness of the reference sections shall be within ±10 % of their

equivalent loaded or tall sections. The analysis of the data shall be made on the basis of an assessment of

the test data where the predicted performance satisfies the acceptance criteria given in 5.5 and is fully

described in the assessment report.

The results of the assessment may not be used to extrapolate fire protection thicknesses beyond the

maximum thicknesses evaluated.

Examples of the methods of analysis are given in Annexes C to G. It is incumbent upon the test laboratory

or other approved organization/company, in consultation with the manufacturer, to utilize the most

appropriate method to provide the best fit of the test data.

Only one method shall be utilized to provide the full scope of the assessment of the data from the testing

of the product, i.e. different methods cannot be used to evaliate different portions of the test data.

This part of ISO 834
...

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