ISO 834-7:2025

International
Standard
ISO 834-7
Second edition
Fire-resistance tests — Elements of
2025-07
building construction —
Part 7:
Specific requirements for columns
Essais de résistance au feu — Éléments de construction —
Partie 7: Exigences spécifiques relatives aux poteaux
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method A – Loaded columns . 2
4.1 Test equipment .2
4.2 Test conditions .2
4.2.1 Restraint and boundary conditions .2
4.3 Loading .3
4.4 Test specimen preparation .3
4.4.1 Specimen design .3
4.4.2 Specimen size .3
4.4.3 Number of test specimens . .3
4.4.4 Specimen conditioning .4
4.4.5 Specimen installation and restraint .4
4.5 Application of instrumentation .4
4.5.1 Furnace thermocouples (plate thermometer) .4
4.5.2 Specimen thermocouples .4
4.5.3 Deformation measurement .5
4.6 Test procedure .5
4.6.1 Load application . .5
4.6.2 Furnace control .5
4.6.3 Measurements and observations.5
4.7 Performance criteria .5
4.8 Validity of the test .6
4.9 Expression of results .6
4.10 Test report .6
5 Test method B – Protected steel columns tested without an applied axial load . 6
5.1 Test equipment .6
5.2 Test conditions .6
5.2.1 Restraint and boundary conditions .6
5.3 Test specimen preparation .6
5.3.1 Specimen design .6
5.3.2 Specimen size .7
5.3.3 Number of test specimens . . .7
5.3.4 Specimen conditioning .7
5.4 Application of instrumentation .7
5.4.1 Furnace thermocouples (plate thermometer) .7
5.4.2 Specimen thermocouples .7
5.5 Test procedure .8
5.5.1 Furnace control .8
5.5.2 Measurements and observations.8
5.6 Performance criteria .8
5.7 Validity of the test .9
Annex A (informative) General guidance on test methods A and B (as indicated) .10
Annex B (informative) Direct application of results – For test methods A and B .12
Bibliography .13

iii
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity, or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
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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
resistance.
This second edition cancels and replaces the first edition (ISO 834-7:2000), which has been technically
revised.
The main changes are as follows:
— an alternative method of test for the protection of steel columns without an applied axial load has been
added. The alternative method (non-loaded) is referred to as "Method B". The original method, which
requires columns to be tested with an applied axial load, is now referred to as "Method A".
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.

iv
Introduction
This document contains specific requirements for fire-resistance testing which are unique to the elements
of building construction described as columns. The requirements for these loadbearing elements are
intended to be applied as appropriate in conjunction with the detailed and general requirements contained
in ISO 834-1.
v
International Standard ISO 834-7:2025(en)
Fire-resistance tests — Elements of building construction —
Part 7:
Specific requirements for columns
1 Scope
This document specifies the procedures to be followed for determining the fire resistance of columns when
tested on their own. Two methods of testing are described:
— Method A, which is applicable to any type of column and in which the test is conducted with an applied
axial load to the column; and
— Method B, which is only applicable to protected steel columns with any type of protection system and
in which the test is conducted with no load applied to the column and the fire resistance is determined
based on steel temperature limits.
Method B is only applicable to protection systems that do not support any of the structural load. (See A.6).
The application of this test to other untested forms of construction is acceptable when the construction
conforms to the direct field of application as given in Annex B of this document, or when subjected to an
[1]
extended application analysis in accordance with ISO/TR 12470 (series) .
General guidance on test method A and test method B is given in Annex A.
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 834-1:2025, Fire-resistance tests — Elements of building construction — Part 1: General requirements
ISO 13943, Fire safety — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 834-1 and ISO 13943 and the
following 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
column
vertical non-separating element of building construction which is loadbearing
3.2
controlled eccentricity
defined distance from the vertical centre axis of the column to where the load is applied

3.3
loading platens
flat plates used between the loading equipment and each end of the column to ensure correct application of
the applied load
4 Test method A – Loaded columns
4.1 Test equipment
Equipment employed in the conduct of Test method A consists of a furnace, loading equipment, restraint and
support frames and instrumentation as specified in ISO 834-1. An example of the test equipment used for
loading is illustrated in Figure 1.
Key
1 hydraulic ram 4 column
2 loading frame 5 loading platens
3 furnace
Figure 1 — Example of the test arrangement for loaded columns
4.2 Test conditions
4.2.1 Restraint and boundary conditions
Restraint and boundary conditions shall conform to the requirements given in ISO 834-1 and the
requirements of this document.

4.3 Loading
4.3.1 All columns shall be tested when subjected to loads calculated in accordance with of ISO 834-1:2025,
6.3 a), b) or c), in consultation with the sponsor to produce the conditions the structure is designed to
accommodate. The material properties utilized in the calculation of the load shall be clearly indicated and
their source given.
4.3.2 When the height of the proposed test specimen is greater than can be accommodated in the test
furnace, the load shall be adjusted to be compatible with the slenderness ratio of the loadbearing elements
being tested, so that the load level of the full-size construction is provided.
4.3.3 The ends of the specimen shall be designed and detailed for the proper transmission of the test load
from the loading platens to the specimen with the required conditions of fixity and eccentricity. The load
bearing faces, at top and bottom, shall be nominally parallel and perpendicular to the axis of the column to
avoid introduction of bending moments.
4.3.4 For protection of the loading equipment against heat, provision shall be made for the attachment of
collars at each end of the specimen. These shall be designed to locate the column and to provide an adequate
seal with the furnace interior surfaces and shall be suitably attached and supported so that they remain
effective and in position throughout the heating period.
The method adopted to provide the seal shall allow the test specimen to move within the furnace without
affecting the load transmitted from the loading rig to the specimen or the fixity at the ends of the specimen.
4.3.5 The loading system shall be capable of compensating for the maximum allowable deformation of the
test specimen.
4.4 Test specimen preparation
4.4.1 Specimen design
The test specimen shall be full size such as to provide a test specimen that is truly representative of the
design, materials, and workmanship.
When in practice joints occur in fire resistance materials, the specimen shall include at least one
representative joint situated approximately at mid-height.
When hollow encasement is applied to columns, the encasement shall terminate so as to be representative
of the exposure and restraint conditions in practice. The gap at the top and between the encasement and the
column shall be sealed when such conditions are likely to exist in practice.
When testing columns with applied fire protection, provision should be made to ensure that no artificial
stresses are introduced in the fire protection as a result of applying the load.
The column shall be of an orientation (vertical or horizontal) representative of the application orientation
used in practice during application of the protection and vertical during the fire exposure.
4.4.2 Specimen size
The test specimen shall be full size. For elements that have a height in excess of 3 m, the minimum size of
specimen exposed to the heating shall not be less than 3 m. The overall height shall not exceed the heated
height by more than 300 mm at each end. This extra height shall be minimized to prevent conduction of heat
from the specimen under test and shall be used for locating the column into the loading equipment and also
for distancing the loading equipment from the furnace atmosphere.
4.4.3 Number of test specimens
The number of test specimens shall conform to the requirements given herein and in ISO 834-1:2025, 7.3.

4.4.4 Specimen conditioning
At the time of the test, the strength and moisture content of the test specimens shall approximate the
conditions expected in normal service. This includes any infills and jointing materials. Guidance on
conditioning is given in ISO 834-1. After equilibrium has been achieved, the moisture content or state of cure
shall be determined and recorded. Any supporting construction, including the lining to the test frame, is
exempt from this requirement.
4.4.5 Specimen installation and restraint
4.4.5.1 The column ends shall be either fully rotationally restrained or hinged to simulate conditions of
use in practice. However, the data cannot be transferred directly from one condition of restraint to the other.
When full information is required, multiple tests shall be carried out with different end fixity conditions.
When one or both ends are hinged, care is needed to ensure that there is no frictional restraint.
4.4.5.2 When a pin-joint is utilized, this shall be represented either by placing a spherical hinge, cylindrical
roller, or knif
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