Fire-resistance tests -- Elements of building construction

This document specifies a test and assessment method for determining the contribution made by fire protection systems to the fire resistance of structural steel beams, I and H sections, in the horizontal plane containing openings in the web which may affect the structural performance of the beam. It is applicable to beams subjected to three or four sided fire exposure. For any cellular beam with a single web opening or where the web openings are considered to be of small diameter in relation to the web depth the applicability of this document is intended to be determined by a structural engineer This document adopts the principle of establishing ratios of temperatures between and around openings in the web of a beam with the temperatures of a solid portion of that beam. This is with the intention that these data can be utilised within a structural model to derive the value and location of the associated limiting temperature of the beam at the fire limit state. The limiting temperature is then used in conjunction with data for the fire protection material determined from ISO 834-10 and ISO 834-11 to determine the necessary thickness of fire protection material for beams with web openings. This document applies to fire protection materials that have already been tested and assessed in accordance with ISO 834-10 and ISO 834-11 and is not intended to be used in isolation. It covers fire protection systems that include both passive and reactive materials which follow the section profile as defined in this document. This document includes the use of a multi-temperature analysis (MTA) derived from ISO 834-11 as the basis for determining the thickness of fire protection for beams with web openings. This document contains an assessment method, which prescribes how the analysis of the test data should be made and gives guidance on the procedures that could be undertaken. The assessment procedure can be used to establish: a) The thermal response of the fire protection system on cellular beams, (the thermal performance) on the basis of the temperature data derived from testing unloaded steel sections. b) The temperature ratio between the web post and the web reference temperature, which will vary depending on the web post width. c) The temperature ratio between points around the web openings and the web reference area. d) A structural model that can be used to derive limiting temperatures for cellular beams.

Essais de résistance au feu -- Éléments de construction

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Status
Published
Publication Date
20-May-2019
Current Stage
6060 - International Standard published
Start Date
25-Apr-2019
Completion Date
21-May-2019
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INTERNATIONAL ISO
STANDARD 834-13
First edition
2019-05
Fire-resistance tests — Elements of
building construction —
Part 13:
Requirements for the testing and
assessment of applied fire protection
to steel beams with web openings
Essais de résistance au feu — Éléments de construction —
Partie 13: Exigences pour les essais et l'évaluation de la protection
contre l'incendie appliquée aux poutres en acier avec ouvertures
dans l'âme
Reference number
ISO 834-13:2019(E)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 834-13:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
ii © ISO 2019 – All rights reserved
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ISO 834-13:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

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

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

5 Test equipment....................................................................................................................................................................................................... 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Furnace .......................................................................................................................................................................................................... 4

5.3 Test conditions ........................................................................................................................................................................................ 4

6 Test specimens........................................................................................................................................................................................................ 4

6.1 General ........................................................................................................................................................................................................... 4

6.2 Precautions against erroneous results ............................................................................................................................... 4

6.3 Construction of steel test specimens ................................................................................................................................... 4

6.3.1 Cellular beam test sections ..................................................................................................................................... 4

6.3.2 Application of the fire protection to the test sections ..................................................................... 8

6.4 Composition of test specimen component materials ............................................................................................ 8

6.4.1 Steel sections ....................................................................................................................................................................... 8

6.4.2 Fire protection materials .......................................................................................................................................... 9

6.4.3 Fire protection thickness requirements ...................................................................................................10

6.5 Selection of test specimens — Test packages ............................................................................................................11

7 Installation of test specimens ..............................................................................................................................................................12

7.1 Fixing ............................................................................................................................................................................................................12

7.2 Installation pattern ..........................................................................................................................................................................13

7.3 Furnace load ...........................................................................................................................................................................................14

7.4 Conditioning of the test specimens ....................................................................................................................................14

8 Application of instrumentation .........................................................................................................................................................15

8.1 General ........................................................................................................................................................................................................15

8.2 Instrumentation for measurement of furnace temperature .........................................................................15

8.2.1 General...................................................................................................................................................................................15

8.2.2 Furnace temperature in the region of test specimens ..................................................................15

8.3 Instrumentation for measurement and determination of steel temperatures .............................15

8.3.1 Location of thermocouples attached to the beams .........................................................................15

8.3.2 Location of web reference thermocouples .............................................................................................15

8.4 Instrumentation for measurement of pressure .......................................................................................................15

9 Test procedure .....................................................................................................................................................................................................15

9.1 General ........................................................................................................................................................................................................15

9.2 Furnace temperature and pressure ...................................................................................................................................15

9.3 Temperature of steelwork ..........................................................................................................................................................16

9.4 Observations ..........................................................................................................................................................................................16

9.5 Termination of test ...........................................................................................................................................................................16

10 Test results ...............................................................................................................................................................................................................16

10.1 Acceptability of test results .......................................................................................................................................................16

10.2 Test report and presentation of test results ...............................................................................................................16

11 Assessment ..............................................................................................................................................................................................................17

11.1 General ........................................................................................................................................................................................................17

11.2 Determination of web post and web reference temperatures ....................................................................17

11.2.1 Calculation of web post temperatures .......................................................................................................17

11.2.2 Calculation of web reference temperature .............................................................................................17

11.3 Determination of web-post lines ..........................................................................................................................................18

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ISO 834-13:2019(E)

11.4 Additional thermal modification factors .......................................................................................................................19

11.5 Location of limiting temperatures ......................................................................................................................................20

11.6 Determination of the elemental multi-temperature analysis (EMTA) .................................................20

12 Assessment report ...........................................................................................................................................................................................21

13 Limits of the applicability of the results of the assessment..................................................................................22

Annex A (informative) Determination of product thickness on beams with web openings ....................23

Annex B (informative) Logic for determining the web post average temperature ............................................27

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

iv © ISO 2019 – All rights reserved
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ISO 834-13:2019(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 2, Fire

containment.
A list of all parts in the ISO 834 series can be found on the ISO website.

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 2019 – All rights reserved v
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ISO 834-13:2019(E)
Introduction
Background

Recent developments in steel construction have seen the introduction of cellular beams consisting

of openings of various sizes and shapes cut in the web of the steel section. These offer a number of

advantages over conventional beams without openings such as lighter/less steel required to provide the

same structural performance and the ability to accommodate services within the depth of the section.

An opening in the web of a beam may be circular or rectangular but in reality can be any shape. Cellular

beams may have a mixture of opening shapes and in some cases there may only be a single isolated

opening.

Cellular beams can be fabricated from either hot rolled sections or welded steel plate. In the case of

structural sections this involves cutting around the centre line of the web along the beams length and

then welding the two halves together. Assymetric beams can be fabricated by welding together the two

halves of different size sections. In the case of plate girders, asymmetry can also be achieved by using

different plate thicknesses for the top and bottom flanges.

Beams with web openings behave differently to solid beams in that additional failure modes at the fire

limit state (FLS) are possible as a result of the proximity of openings and web slenderness. Solid beams

generally fail in bending but a beam with web openings can fail in one of several mechanisms which

include:
— buckling of the web-post,
— shear at an opening,
— Vierendeel bending around the opening.

These failure modes generally occur at lower temperatures than for a solid beam at similar utilisation

factors and therefore require greater thicknesses of fire protection.
Overview of structural geometry

A beam with circular web openings is illustrated in Figure 1. The figure also shows some of the

important dimensions that will affect beam’s performance in fire.
vi © ISO 2019 – All rights reserved
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ISO 834-13:2019(E)
Key
1 steel beam
2 circular opening
3 spacing of openings
4 web post
5 end post
6 span
7 composite floor slab
Figure 1 — Beam with circular openings

Data generated from the tests in this document can be used for beams with circular openings,

rectangular openings and elongated openings formed by joining two circular openings. The data can

also be used conservatively to assess openings of other shapes by forming around the opening a circular,

rectangular or elongated opening which just touches (circumscribes) the shape. Examples of this are

shown in Figure 2. For non uniform shapes the smallest circle is described touching the extreme tips

around the shape.
Key
1 height of rectangular opening
2 width of rectangular opening
3 position of opening
4 elongated opening with circular ends
5 hexagonal opening inside a circle
6 triangular opening inside a circle
Figure 2 — Beam with mixed openings
Interaction with ISO 834-10 and ISO 834-11

In most cases, failure of the web will be critical to the overall performance of the beam but failure of the

bottom flange may also occur.

Where the web is critical, its corresponding temperature can be used in conjunction with its relevant

web reference modification factor to find the limiting steel web temperature. This temperature together

© ISO 2019 – All rights reserved vii
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ISO 834-13:2019(E)

with its elemental web section factor and the product specific elemental re-analysis of ISO 834-10 test

data, can be used to determine a product thickness to achieve the required fire resistance rating.

Where the bottom flange is critical, a similar approach (without the need for modification factors) is

adopted using its limiting steel temperature, its corresponding elemental bottom flange section factor

and the product specific elemental re-analysis of ISO 834-10 test data to determine a product thickness

to achieve the required fire resistance rating.
Steel temperature distribution

A large number of fire resistance tests on fire protected beams have shown that if the temperatures of

various parts of the web of a beam in the vicinity of web openings are compared with the temperature

of the centre of the web away from any openings, the ratio of the temperatures is reasonably constant.

Where the web temperature is measured at least 250 mm from the edge of the hole it can be assumed

that the hole has no effect on this temperature measurement. This is referred to as the web reference

temperature.

In this document, a relationship is provided to assess the temperature ratios for both a range of web

post widths and a number of points around openings in relation to the web reference temperature.

The top flange steel temperature may be assumed to be 75 % of the temperature of an equal sized

bottom flange.
Process to determine the thickness of fire protection material

In order to determine a thickness of fire protection material to protect a beam with web openings it is

important to understand:
a) the structural failure mode at the fire limit state;
b) the web-post width at the point of failure (if failure is in the web);
c) the temperature of the web at failure;
d) the temperature of the bottom flange at failure.

The amount of fire protection required should be based on the thermal information derived from the

testing in this document and a suitable structural calculation model.

In order to derive limiting temperatures for cellular beams one should make use of a structural model.

Any structural calculation model should provide a realistic anlaysis of the beam exposed to fire. It should

be based upon fundamental physical behaviour in such a way as to lead to a reliable approximation of

the expected behaviour of the relevant structural component under fire conditions. It is not within the

scope of this document to define the detailed analysis methods of the structural model, however, the

following modes of failure as a minimum should be accounted for at the fire limit state:

— global vertical shear;
— global bending moment;
— vertical shear at openings;
— bending moment at openings;
— Vierendeel bending moment at openings;
— web-post buckling;
— web-post bending;
— web-post horizontal shear.
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ISO 834-13:2019(E)

In this document, three methods are described in the informative Annex A to determine the thickness

of fire protection for beams with web openings:
a) analysis for any fire protection material;

b) iterative thickness analysis incorporating product specific fire protection data;

c) iterative steel temperature analysis incorporating product specific fire protection data.

© ISO 2019 – All rights reserved ix
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INTERNATIONAL STANDARD ISO 834-13:2019(E)
Fire-resistance tests — Elements of building
construction —
Part 13:
Requirements for the testing and assessment of applied
fire protection to steel beams with web openings
1 Scope

This document specifies a test and assessment method for determining the contribution made by fire

protection systems to the fire resistance of structural steel beams, I and H sections, in the horizontal

plane containing openings in the web which may affect the structural performance of the beam. It is

applicable to beams subjected to three or four sided fire exposure.

For any cellular beam with a single web opening or where the web openings are considered to be of small

diameter in relation to the web depth the applicability of this document is intended to be determined by

a structural engineer

This document adopts the principle of establishing ratios of temperatures between and around

openings in the web of a beam with the temperatures of a solid portion of that beam. This is with the

intention that these data can be utilised within a structural model to derive the value and location of the

associated limiting temperature of the beam at the fire limit state. The limiting temperature is then used

in conjunction with data for the fire protection material determined from ISO 834-10 and ISO 834-11 to

determine the necessary thickness of fire protection material for beams with web openings.

This document applies to fire protection materials that have already been tested and assessed in

accordance with ISO 834-10 and ISO 834-11 and is not intended to be used in isolation. It covers fire

protection systems that include both passive and reactive materials which follow the section profile as

defined in this document.

This document includes the use of a multi-temperature analysis (MTA) derived from ISO 834-11 as the

basis for determining the thickness of fire protection for beams with web openings.

This document contains an assessment method, which prescribes how the analysis of the test data

should be made and gives guidance on the procedures that could be undertaken.
The assessment procedure can be used to establish:

a) The thermal response of the fire protection system on cellular beams, (the thermal performance)

on the basis of the temperature data derived from testing unloaded steel sections.

b) The temperature ratio between the web post and the web reference temperature, which will vary

depending on the web post width.

c) The temperature ratio between points around the web openings and the web reference area.

d) A structural model that can be used to derive limiting temperatures for cellular beams.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

© ISO 2019 – All rights reserved 1
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ISO 834-13:2019(E)

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

ISO 834-6, Fire-resistance tests — Elements of building construction — Part 6: Specific reqrements for beams

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 steel elements

ISO 834-11, Fire resistance tests — Elements of building construction — Part 11: Specific requirements for

the assessment of fire protection to structural steel elements
ISO 8421-2, Fire protection — Vocabulary — Part 2: Structural fire protection
ISO 13943, Fire safety — Vocabulary

ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding

procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys

3 Terms and definitions

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

and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
bottom flange temperature
average of the bottom flange temperatures
3.2
cellular beam
structural steel beams with openings in the web
3.3
elemental multi temperature analysis

outcome of an assessment carried out on data from ISO 834-11 based on a range of average temperatures

of the web and flanges separately
3.4
elemental section factor
section factor of the web or bottom flange in isolation
3.5
fire protection system

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

3.6
fire protection thickness
dry thickness of the fire protection system

Note 1 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.
3.7
limiting temperature

temperature at a point within the beam at which structural failure of the cellular beam will take place

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ISO 834-13:2019(E)
3.8
multi temperature analysis

outcome of an assessment carried out in accordance with ISO 834-11 based on a range of average

temperatures of the whole steel section
3.9
passive fire protection material

sprayed coatings or renderings formulated with ingredients enabling the retention of their physical

form upon heating while providing insulation to the substrate
3.10
plate girder dimensions
overall beam depth, by flange width, by flange thickness, by web thickness
Note 1 to entry: Plate girder dimensions are given in millimetres.
3.11
reactive fire protection material

reactive materials 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
3.12
stickability

ability of a fire protection material to remain in position for a defined range of deformations, furnace

and steel temperatures, such that its ability of the material to provide fire protection is not significantly

impaired
3.13
test specimen
steel test section plus the fire protection system
3.14
Vierendeel bending

mechanism by which shear is transferred across the web opening and causes bending in the top and

bottom, left and right, parts of the beam surrounding the opening
3.15
web post
portion of steel between the web openings
3.16
web post buckling

buckling that occurs when the web separating two openings is unable to transfer the required

horizontal shear force and the shear stress is greater than the shear strength of the web

3.17
web post temperature

proportioned average temperature of the web post derived from thermocouples fixed across the web at

mid-height
3.18
web reference temperature
mean temperature of a solid portion of the web without holes in close proximity
© ISO 2019 – All rights reserved 3
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ISO 834-13:2019(E)
4 Symbols and abbreviated terms
Symbol Unit Description
b m width of beam flanges
d m depth of beam
t m web thickness
t m flange thickness
a m heated perimeter
v m cross section area
5 Test equipment
5.1 General

The furnace and test equipment as appropiate, shall conform to that specified in ISO 834-1.

5.2 Furnace

The furnace shall be designed to permit the dimensions of the test specimens to be exposed to heating

as specified in 9.2 and their installation within the test furnace as specified in 7.2.

5.3 Test conditions

A number of short steel beams all containing web openings and protected by the fire protection system

shall be heated in a furnace according to the protocol given in ISO 834-1.

Where several test specimens are tested simultaneously, care shall be taken that each is adequately and

similarly exposed to the specified test conditions.

The procedures given in ISO 834-1 shall be followed in the performance of this test unless specific

contrary instructions are given.
6 Test specimens
6.1 General
The test sections should be chosen to suit the scope of the assessment.

There are specific test packages designed to suit a specified fire performance period as given in 6.5 and

Tables 1, 2, and 3.
6.2 Precaut
...

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