ISO/PRF 179-1

ISO /TC 61/SC 2
Secretariat: KATS
Date: 2026-xx-xx01-23
Plastics — Determination of Charpy impact properties —

Part 1:
Non-instrumented impact test
Plastiques — Détermination des caractéristiques au choc Charpy —

Partie 1: Essai de choc non instrumenté
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PROOF
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© ISO 2026 – All rights reserved
iii
ISO/DISPRF 179-1:2025(E2026(en)
Contents
Foreword . vi
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus . 3
6 Test specimens . 5
7 Procedure . 15
8 Calculation and expression of results . 15
9 Precision . 16
10 Test report . 16
Annex A (informative) Additional methods for investigating the influence of surface effects. 19
Annex B (informative) Precision data . 22
Annex C (informative) Determining the notch tip radius using a CCD microscope . 24
Bibliography . 29

Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
5.1 Test machine . 3
5.2 Micrometers and gauges . 3
6 Test specimens . 4
6.1 Preparation . 4
6.1.1 Moulding and extrusion compounds . 4
6.1.2 Sheets . 4
6.1.3 Long-fibre-reinforced materials . 4
6.1.4 Checking . 6
6.1.5 Notching . 7
6.2 Anisotropy . 7
6.3 Shape and dimensions . 7
6.3.1 Materials not exhibiting interlaminar shear fracture . 7
6.3.2 Materials exhibiting interlaminar shear fracture (e.g. long-fibre-reinforced materials) . 9
6.4 Number of test specimens . 9
6.5 Span between specimen supports, L .10
6.6 Conditioning .10
iv © ISO 20252026 – All rights reserved
iv
7 Procedure .10
8 Calculation and expression of results .11
8.1 Unnotched specimens.11
8.2 Notched specimens .12
8.3 Statistical parameters .12
8.4 Significant figures .12
9 Precision .12
10 Test report .12
Annex A (informative) Additional methods for investigating the influence of surface effects .15
Annex B (informative) Precision data .17
Annex C (informative) Determining the notch tip radius using a CCD microscope .19
Bibliography .22

© ISO 2026 – All rights reserved
v
ISO/DISPRF 179-1:2025(E2026(en)
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 document 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
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 61, Plastics, Subcommittee SC 2, Mechanical
behavior, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 179-1:2023), which has been technically
revised.
The main change is as follow:
— — replaced the correct dimensions of specimen type 3 in Table 10 (see 6.3.1.1).6.3.1.1).
A list of all parts in the ISO 179 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.
vi © ISO 20252026 – All rights reserved
vi
Introduction
The Charpy impact properties determination method described in the ISO 179 series has a greater range of
applicability than that given in ISO 180 and is more suitable for the testing of materials showing interlaminar
shear fracture or of materials exhibiting surface effects due to environmental factors.
The method is suitable for use with the following range of materials:
— — rigid thermoplastic moulding and extrusion materials (including filled and reinforced compounds in
addition to unfilled types) and rigid thermoplastics sheets;
— — rigid thermosetting moulding materials (including filled and reinforced compounds) and rigid
thermosetting sheets (including laminates);
— — fibre-reinforced thermosetting and thermoplastic composites incorporating unidirectional or multi-
directional reinforcements (such as mats, woven fabrics, woven rovings, chopped strands, combination
and hybrid reinforcements, rovings and milled fibres) or incorporating sheets made from pre-
impregnated materials (prepregs), including filled and reinforced compounds;
— — thermotropic liquid-crystal polymers.
Notched samples are not normally suitable for use with rigid cellular materials, long-fibre-reinforced
composites or thermotropic liquid-crystal polymers. In these cases, unnotched samples may be used.
The method is suited to the use of specimens moulded to the chosen dimensions, machined from the central
portion of a standard multipurpose test specimen (see ISO 20753) or machined from finished or
semifinishedsemi-finished products such as mouldings, laminates and extruded or cast sheet.
© ISO 2026 – All rights reserved
vii
International Standard ISO/DIS 179-1:2026(en)

Plastics — Determination of Charpy impact properties —

Part 1:
Non-instrumented impact test
1 Scope
This document specifies a method for determining the Charpy impact strength of plastics under defined
conditions. It defines a number of different types of specimen and test configurations. It also specifies different
test parameters according to the type of material, the type of test specimen and the type of notch.
The method described in this document can be used to investigate the behaviour of specified types of specimen
under the impact conditions defined and for estimating the brittleness or toughness of specimens within the
limitations inherent in the test conditions. It can also be used for the determination of comparative data from
similar types of material.
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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 293, Plastics — Compression moulding of test specimens of thermoplastic materials
ISO 294--1, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 1: General
principles, and moulding of multipurpose and bar test specimens
ISO 294--3, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small plates
ISO 295, Plastics — Compression moulding of test specimens of thermosetting materials
ISO 1268--11, Fibre-reinforced plastics — Methods of producing test plates — Part 11: Injection moulding of
BMC and other long-fibre moulding compounds — Small plates
ISO 2818, Plastics — Preparation of test specimens by machining
ISO 10724--1, Plastics — Injection moulding of test specimens of thermosetting powder moulding compounds
(PMCs) — Part 1: General principles and moulding of multipurpose test specimens
ISO 13802, Plastics — Verification of pendulum impact-testing machines — Charpy, Izod and tensile impact-
testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO/DISPRF 179-1:2025(E2026(en)
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 3.1
Charpy impact strength of unnotched specimen
a
cU
impact energy absorbed in breaking an unnotched specimen, referred to the original cross-sectional area of
the specimen
Note 1 to entry: It is expressed in kilojoules per square metre (kJ/m ).
3.2 3.2
Charpy impact strength of notched specimen
a
cN
impact energy absorbed in breaking a notched specimen, referred to the original cross-sectional area of the
specimen at the notch, where N = A, B or C, depending on the notch type
Note 1 to entry: See 6.3.1.1.2. See 6.3.1.1.2.
Note 2 to entry: It is expressed in kilojoules per square metre (kJ/m ).
3.3 3.3
edgewise impact
e
direction of blow parallel to the dimension b, with impact on the narrow longitudinal surface h × l of the
specimen
Note 1 to entry: See Figure 1 a) and Figures 2 and 4.
3.4Note 1 to entry: See 0 a) and 0 and 0.
3.4
flatwise impact
f
direction of blow parallel to the dimension h, with impact on the broad longitudinal surface b × l of the
specimen
Note 1 to entry: See Figure 1 b) and Figures 3 and 4.
3.5Note 1 to entry: See 0 b) and 0 and 0.
3.5
normal direction of blow
n
impact with the direction of blow normal to the plane of reinforcement
Note 1 to entry: See Figure 4. See 0.
3.6 3.6
parallel direction of blow
p
impact with the direction of blow parallel to the plane of reinforcement
2 © ISO 20252026 – All rights reserved
ISO/DISPRF 179-1:2026(en)
Note 1 to entry: See Figure 4. See 0.
4 Principle
The test specimen, supported near its ends as a horizontal beam, is impacted by a single blow of a striker, with
the line of impact midway between the supports, and bent at a high, nominally constant, velocity.
In the case of edgewise impact with notched specimens, the line of impact is directly opposite the single notch
[see Figure 1 a) and Figure 2].0 a) and 0].
The method specifies preferred dimensions for the test specimen. Tests which are carried out on specimens
of different dimensions or with different notches, or specimens which are prepared under different conditions,
can produce results which are not comparable. Other factors, such as the energy capacity of the apparatus, the
impact velocity and the conditioning of the specimens can also influence the results. Consequently, when
comparative data are required, these factors shall be carefully controlled and recorded.
The method is not intended to be used as a source of data for design calculations. Information on the typical
behaviour of a material can be obtained, however, by testing at different temperatures, by varying the notch
radius and/or the specimen thickness and by testing specimens prepared under different conditions.
5 Apparatus
5.1 Test machine
The principles, characteristics and verification of suitable test machines are detailed in ISO 13802.
ISO 13802 describes partial verification and full verification. In the case of full verification, some items are
difficult to verify when the apparatus is assembled. Such verifications are assumed to be incumbent on the
manufacturer.
5.2 Micrometers and gauges
Micrometers and gauges shall allow to determine the relevant dimensions of the test specimens with an
uncertainty not larger than 0,02 mm. For the determination of the dimension b of notched test specimens
N
measuring tips appropriate for the contour of the notch shall be used. For general information on the
determination of test specimen dimensions, see ISO 16012.
© ISO 2026 – All rights reserved
ISO/DISPRF 179-1:2025(E2026(en)

a) Edgewise impact b) Flatwise impact
Key
1 direction of blow
2 rod of pendulum
3 test specimen
4 notch
5 support
1 direction of blow
2 rod of pendulum
3 test specimen
4 notch
5 support
Figure 1 — Striking edge and support blocks for type 1 test specimen at moment of impact
4 © ISO 20252026 – All rights reserved
ISO/DISPRF 179-1:2026(en)
6 Test specimens
6.1 Preparation
6.1.1 Moulding and extrusion compounds
Specimens shall be prepared in accordance with the relevant material specification. The specimens shall be
either directly compression moulded in accordance with ISO 293 or ISO 295 or injection moulded from the
material in accordance with ISO 294-1, ISO 294-3 or ISO 10724-1, as appropriate, or machined in accordance
with ISO 2818 from sheet that has been compression or injection moulded from the compound. Type 1
specimens may be cut from multipurpose test specimens conforming with ISO 20753:2023, type A1.
6.1.2 Sheets
Specimens shall be machined from sheets in accordance with ISO 2818.
6.1.3 Long-fibre-reinforced materials
A panel shall be prepared in accordance with ISO 1268-11 or another specified or agreed upon preparation
procedure. Specimens shall be machined in accordance with ISO 2818.
© ISO 2026 – All rights reserved
ISO/DISPRF 179-1:2025(E2026(en)

Key
1 direction of blow
1 direction of blow
Figure 2 — Charpy edgewise impact (e) with single-notched specimen
6 © ISO 20252026 – All rights reserved
ISO/DISPRF 179-1:2026(en)
Key
1 direction of blow
1 direction of blow
Figure 3 — Charpy flatwise impact (f)
© ISO 2026 – All rights reserved
ISO/DISPRF 179-1:2025(E2026(en)

8 © ISO 20252026 – All rights reserved
ISO/DISPRF 179-1:2026(en)
Key
1 direction of blow
e edgewise
f flatwise
n normal
p parallel
1 direction of blow
e edgewise
f flatwise
n normal direction of blow
p parallel direction of blow
NOTE 1 Edgewise (e) and flatwise (f) indicate the direction of the blow with respect to the specimen thickness, h, and
specimen width, b. Normal (n) and parallel (p) indicate the direction of the blow with respect to the laminate plane.
NOTE 2 The Charpy “fn” and “ep” tests are used for laminates, while both the Charpy “en” and “ep” tests are used for
other materials. The Charpy “fn” and “fp” tests are used for testing materials exhibiting surface effects.
Figure 4 — Scheme of designations describing the direction of blow
© ISO 2026 – All rights reserved
ISO/DISPRF 179-1:2025(E2026(en)
6.1.4 Checking
The specimens shall be free of twist and shall have mutually perpendicular parallel surfaces. The surfaces and
edges shall be free from scratches, pits, sink marks and flash.
The specimens shall be checked for conformity with these requirements by visual observation against
straightedges, set squares and flat plates, and by measuring with micrometer callipers.
Specimens showing measurable or observable departure from one or more of these requirements shall be
rejected or machined to proper size and shape before testing.
6.1.5 Notching
6.1.5.1 6.1.5.1 Machined notches shall be prepared in accordance with ISO 2818. The profile
of the cutting tooth shall be such as to produce in the specimen a notch of the contour and depth as defined in
Table 2 and shown in Figure 5,0 and shown in 0, at right angles to its principal axes (see Note).
NOTE The radius of the notch tip can be measured by the method given in Annex C.Annex C.
6.1.5.2 6.1.5.2 Specimens with moulded-in notches may be used if specified for the material
being tested (see Note).
NOTE Specimens with moulded-in notches do not give results comparable to those obtained from specimens with
machined notches.
a) Type A b) Type B c) Type C
Radius of notch tip Radius of notch tip Radius of notch tip
rN = (0,25 ± 0,05) mm rN = (1,00 ± 0,05) mm rN = (0,10 ± 0,02) mm
Figure 5 — Notch types
6.2 Anisotropy
Certain types of sheet or panel material or specimen taken from injection-moulded plates can show different
impact properties, depending on the direction in the plane of the sheet or panel. In such cases, it is customary
to cut groups of test specimens with their major axes respectively parallel and perpendicular to the direction
of some feature of the sheet or panel which is either visible or inferred from knowledge of the method of
manufacture.
10 © ISO 20252026 – All rights reserved
ISO/DISPRF 179-1:2026(en)
6.3 Shape and dimensions
6.3.1 Materials not exhibiting interlaminar shear fracture
6.3.1.1 Moulding
...