prEN 14579

• Abstract:

  This document specifies a method for the determination of the velocity of propagation of pulses of ultrasonic longitudinal waves in natural stone, both in laboratory and in situ.

• Status: Not Published
• Publication Date: 29-Sep-2026
• ICS: 73.020 - Mining and quarrying
• ICS: 91.100.15 - Mineral materials and products
• Technical Committee: CEN/TC 246 - Natural stones
• Drafting Committee: CEN/TC 246/WG 2 - Test methods
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 15-Oct-2026
• Due Date: 10-Sep-2025
• Completion Date: 15-Oct-2026
• Ref Project: oSIST prEN 14579:2026 - Natural stone test methods - Determination of sound speed propagation

• Revises: EN 14579:2004 - Natural stone test methods - Determination of sound speed propagation
• Effective Date: 31-Jul-2024

prEN 14579 is a CEN draft European Standard for testing natural stone. It specifies a method for determining the velocity of propagation of ultrasonic longitudinal pulses in natural stone, for use in both laboratory testing and in situ measurements.

The draft is prepared by CEN/TC 246 and will supersede EN 14579:2004 if adopted. In practice, it gives laboratories and site testers a common way to measure sound speed in stone blocks, units, and other natural stone elements.

What does prEN 14579 specify?

prEN 14579 specifies a test method for measuring the velocity of ultrasonic longitudinal waves in natural stone. Clause 1 covers the scope, Clauses 4 to 10 cover the principle, apparatus, specimen preparation, procedure, results and reporting, and Annexes A and B cover indirect transmission and influencing factors.

Annex	What it covers
Annex A, normative	Determination of pulse velocity in indirect, or surface, transmission
Annex B, informative	Factors influencing measurement of the velocity of sound

The method is intended for laboratory specimens and for in situ work. The document is organized as a practical test method: it tells the user what equipment to use, how to prepare specimens, how to run the measurement, how to calculate the result, and what to record in the report.

What are the key requirements of prEN 14579?

prEN 14579 is built around measuring the travel time of an ultrasonic pulse through stone and converting that time into pulse velocity. The important practical point is that the test is sensitive to setup, specimen condition, and the transmission geometry, so the method specifies how to control those factors.

Measurement principle and apparatus

Clause 4 states that an electro-acoustical transducer sends a pulse into the stone and a transponder receives it after it has crossed a known path length. Clause 6 requires equipment for pulse generation, reception, amplification and timing, and it allows oscilloscope, interval timer, or fixed-distance indirect/surface apparatus.

For the reader, this means the test is not just a timing exercise - the equipment must be able to detect the first front of the received pulse and measure transit time accurately enough for comparison between stones and test sites.

Performance and transducer conditions

Clause 6 requires the timing system to measure calibration-bar transit times within ±0.1 µs, with a sharp pulse onset and a low enough repetition frequency to avoid interference from reverberations. The transducer natural frequency is specified in the range 20 kHz to 150 kHz.

In practice, the frequency choice matters because higher frequencies give a cleaner onset but attenuate more quickly in stone, while lower frequencies are better for longer path lengths.

Specimen preparation

Clause 7 requires at least 6 specimens from a homogeneous batch, with sawn or honed faces and prism-shaped specimens of at least 180 mm length. If the stone has planes of anisotropy, the long axis of the specimen is prepared parallel or perpendicular to those planes.

Clause 7 also requires drying at (70 ± 5) °C to constant mass. That matters because moisture changes the measured velocity and can make results from different stones or different sites difficult to compare.

Transmission arrangements and path length

Clause 8 allows direct, semi-direct, and indirect or surface transmission. Direct transmission uses opposite faces, semi-direct uses adjacent faces, and indirect transmission uses the same face.

For direct transmission, the path length is measured with ±1 % accuracy. Indirect measurements can be improved by taking readings at several separations and using Annex A, and the draft also allows a fixed-distance apparatus for indirect or surface measurements.

Coupling, calculation and reporting

Clause 8 requires good acoustical coupling, typically with a coupling medium and firm pressure, and rough surfaces may need grinding or epoxy resin. Clause 9 requires velocity to be expressed to the nearest 0.01 km/s, with indirect transmission calculated according to Annex A.

Clause 10 sets out the test report contents, including specimen details, apparatus used, transmission method, path lengths, transit times, calculated velocities, deviations, and measurement uncertainty where appropriate.

What terms does prEN 14579 define?

prEN 14579 uses these symbols and transmission terms in its method:

• V - pulse velocity, expressed in km/s.
• L - path length, the distance travelled by the pulse through the stone, in mm.
• T - time taken by the pulse to traverse the path length, in µs.
• Transducer - the transmitting electro-acoustical unit that generates the ultrasonic pulse.
• Transponder - the receiving unit that converts the incoming pulse into an electrical signal.
• Direct transmission - transducer and transponder are placed on opposite faces of the stone.
• Semi-direct transmission - transducer and transponder are placed on adjacent faces.
• Indirect or surface transmission - transducer and transponder are placed on the same face.

Who uses prEN 14579?

prEN 14579 is used by testing laboratories, natural stone producers, quarry operators, inspection bodies, and engineers working with stone in buildings or civil works. It is useful when a buyer, quality manager, or engineer needs a reproducible measure of sound speed to compare stone materials, check consistency within a batch, or investigate the effect of anisotropy, fissures, voids, or moisture.

It is also used for in situ measurements when only one face of the stone is accessible. That makes it relevant to assessment of installed stone elements as well as laboratory testing of stone products.

What changed in prEN 14579 from the previous edition?

prEN 14579 will supersede EN 14579:2004. The stated significant technical change is the inclusion of the possibility to measure sound speed propagation with an apparatus using a fixed distance between the transducer and transponder.

Which standards are used with prEN 14579?

The foreword places prEN 14579 within the CEN series of natural stone test methods, alongside EN 12370, EN 12372, EN 12407, EN 13161, EN 13364, EN 13373, EN 13755, EN 14066, EN 14231, EN 14157, EN 14158, EN 14580 and EN 14581. These are related test methods for other properties of natural stone.

The bibliography also cites EN 12504-4 for correlating ultrasonic test results with compressive strength, EN 12670 for natural stone terminology, and ASTM D2845:2008 as an external reference.

What does the prEN 14579 document contain?

prEN 14579 includes the measurement principle, apparatus requirements, specimen preparation, test procedure, result expression, and reporting rules. It also includes a figure showing direct, semi-direct and indirect transmission arrangements.

Annex A gives the graphical procedure for indirect transmission, where a line is fitted through transit-time measurements at different separations. Annex B discusses factors that influence measured velocity, including water content, path length, specimen size and shape, and fissures or voids.

The document also provides a table of specimen-dimension guidance in relation to transducer frequency and sound speed. For a user, these contents are the practical instructions needed to set up the test, run it consistently, and record a report that others can interpret.

SLOVENSKI STANDARD
01-oktober-2026
Preskušanje naravnega kamna - Ugotavljanje hitrosti širjenja zvoka
Natural stone test methods - Determination of sound speed propagation
Prüfverfahren für Naturstein - Bestimmung der Geschwindigkeit der Schallausbreitung
Méthodes d'essai pour pierres naturelles - Détermination de la vitesse et propagation du
son
Ta slovenski standard je istoveten z: prEN 14579
ICS:
73.020 Rudarstvo in kamnolomsko Mining and quarrying
izkopavanje
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2026
ICS 73.020; 91.100.15 Will supersede EN 14579:2004
English Version
Natural stone test methods - Determination of sound
speed propagation
Méthodes d'essai pour pierres naturelles - Prüfverfahren für Naturstein - Bestimmung der
Détermination de la vitesse et propagation du son Geschwindigkeit der Schallausbreitung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 246.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14579:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Symbols and abbreviations . 4
6 Apparatus . 4
6.1 General. 4
6.2 Performance requirements . 5
6.3 Transducer . 5
6.4 Apparatus for the determination of the arrival time of the pulse. 5
6.5 Other apparatus . 5
7 Preparation of the specimens . 5
7.1 Sampling . 5
7.2 Test specimens . 5
7.2.1 General. 5
7.2.2 Dimensions. 5
7.2.3 Drying the specimens . 6
8 Test procedure . 6
8.1 General. 6
8.2 Determination of pulse velocity . 6
8.2.1 Factors influencing pulse velocity measurements . 6
8.2.2 Transducer-transponder . 6
8.2.3 Arrangement . 6
8.2.4 Path length measurement. 7
8.2.5 Coupling the transducer and transponder onto the stone. 7
8.2.6 Measurement of the transit time . 7
9 Expression of the results . 7
10 Test report . 8
Annex A (normative) Determination of pulse velocity in the case of indirect transmission . 10
Annex B (informative) Factors influencing the measurement of the velocity of sound . 11
B.1 General points . 11
B.2 Water content . 11
B.3 Path length . 11
B.4 Shape and sizes of the test specimens . 11
B.5 Fissures and voids . 12
Bibliography . 13

European foreword
This document (prEN 14579:2026) has been prepared by Technical Committee CEN/TC 246 “Natural
stones”, the secretariat of which is held by UNI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 14579:2004.
EN 14579:2026 includes the following significant technical changes with respect to EN 14579:2004:
— inclusion of the possibility to measure the sound speed propagation with an apparatus using a fixed
distance between the transducer and transponder.
This standard is one of the series for tests on natural stone.
Test methods for natural stone consist of the following parts:
— EN 12370, Natural stone test methods — Determination of resistance to salt crystallization
— EN 12372, Natural stone test methods — Determination of flexural strength under concentrated load
— EN 12407, Natural stone test methods — Petrographic examination
— EN 13161, Natural stone test methods — Determination of flexural strength under constant moment
— EN 13364, Natural stone test methods — Determination of the breaking load at dowel hole
— EN 13373, Natural stone test methods — Determination of geometric characteristics on units
— EN 13755, Natural stone test methods — Determination of water absorption at atmospheric pressure
— EN 14066, Natural stone test methods — Determination of resistance to ageing by thermal shock
— EN 14231, Natural stone test methods — Determination of the slip resistance by means of the
pendulum tester
— EN 14157, Natural stone test methods — Determination of abrasion resistance
— EN 14158, Natural stone test methods — Determination of rupture energy
— EN 14580, Natural stone test methods — Determination of the static elastic modulus
— EN 14581, Natural stone test methods — Determination of linear thermal expansion coefficient

1 Scope
This document specifies a method for the determination of the velocity of propagation of pulses of
ultrasonic longitudinal waves in natural stone, both in laboratory and in situ.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
4 Principle
A pulse of longitudinal vibrations is produced by an electro-acoustical transducer held in contact with
one surface of the stone under test. After traversing a known path length in the stone, the pulse is received
converted into an electrical signal by a transponder and electronic timing circuits enable the transit time
of the pulse to be measured.
5 Symbols and abbreviations
V pulse velocity, in km/s
L path length, in mm
T time taken by the pulse to transverse the length, in µs
6 Apparatus
6.1 General
The apparatus consists essentially of an electrical pulse generator, a transducer (transmitting a pulse at
a defined frequency), a compatible transponder (receiving the pulse), an amplifier and an electronic
timing device for measuring the time interval elapsing between the onset of a pulse generated at the
transmitting transducer and the onset of its arrival at the receiving transponder.
Three forms of electronic timing apparatus are available:
a) an oscilloscope on which the first front of the pulse is displayed in relation to a suitable time scale;
b) an interval timer with a direct reading digital display;
c) an apparatus for indirect or surface transmission with a direct reading digital display, having fixed
distance between transmitting and transponder thus providing a reading computed from frequency,
time and path length.
NOTE 1 An oscilloscope provides the facility for examining the wave form, which can be advantageous in
complex situations.
NOTE 2 A graphic representation of the various forms of transducer-transponder arrangement is reported in
Figure 1.
6.2 Performance requirements
The apparatus shall comply with the following performance requirements:
— to measure transit times in the calibration bar to an accuracy of ±0,1 µs;
— to ensure a sharp pulse onset, that is the electronic excitation pulse applied to the transducer shall
have a rise time of not greater than one-quarter of its natural period;
— the pulse repetition frequency shall be low enough to ensure that the onset of the received signal is
free from interference by reverberations.
6.3 Transducer
The natural frequency of the transducer shall be within the range 20 kHz to 150 kHz.
NOTE Frequencies as low as 10 kHz and as high as 200 kHz is sometimes used. High frequency pulses have a
well-defined onset, but, as they pass through the natural stone, they become attenuated more rapidly than pulses
of lower frequency. It is therefore preferable to use high frequency transducers (82 kHz to 200 kHz) for short path
lengths (down to 50 mm) and low frequency transducers (10 kHz to 40 kHz) for long path lengths (up to a maximum
of 15 m). Transducers with a frequency of 40 kHz to 82 kHz are found to be useful for most applications.
6.4 Apparatus for the determination of the arrival time of the pulse
The apparatus receives the signal from the transponder and shall be capable of determining the time of
arrival of the first front of the pulse, even though this may be of small amplitude compared with that of
the first half wave of the pulse.
6.5 Other apparatus
A weighing instrument with an accuracy of 0,01 % of the mass to be weighed.
A ventilated oven capable of maintaining a temperature of (70 ± 5) °C.
7 Preparation of the specimens
7.1 Sampling
Sampling is not the responsibility of the test laboratory except where specially requested.
At least 6 specimens shall be selected from a homogeneous batch (see also 7.2.2).
7.2 Test specimens
7.2.1 General
As a standard reference the surface finish of the faces o
...