prEN 12504-5
(Main)Testing concrete in structures — Part 5: Determination of concrete cover using electromagnetic covermeters
Testing concrete in structures — Part 5: Determination of concrete cover using electromagnetic covermeters
This document gives recommendations on and describes the principles of operation of electromagnetic devices that may be used for estimating the position, depth and size of reinforcement buried in concrete. It also describes their methods of use and applications, the accuracy to be expected and the factors which may influence the results.
Electromagnetic covermeters can be used for:
a) quality control, to ensure correct location and cover to reinforcing bars after concrete placement;
b) investigation of concrete members for which records are not available or need to be checked;
c) location of reinforcement as a preliminary to some other form of testing in which reinforcement should be avoided or its nature considered, e.g. extraction of cores, ultrasonic pulse velocity measurement or “near-to-surface” methods;
d) location of buried ferromagnetic objects other than reinforcement, e.g. water pipes, steel joists, lighting conduits.
Prüfung von Beton in Bauwerken - Teil5: Bestimmung der Betondeckung mittels elektromagnetischer Betondeckungsmessgeräte
Dieses Dokument gibt Empfehlungen und beschreibt die Grundsätze des Betriebs von elektromagnetischen Geräten, die für die Abschätzung der Position, Tiefe und Größe von in Beton eingebetteter Bewehrung verwen
det werden dürfen. Es beschreibt des Weiteren auch die Verfahren zu deren Nutzung sowie Anwendungen, die zu erwartende Genauigkeit und die Faktoren, die die Ergebnisse beeinflussen können.
Elektromagnetische Betondeckungsmessgeräte können für Folgendes angewendet werden:
a)
Qualitätskontrolle, um die ordnungsgemäße Lage und Betondeckung über Bewehrungsstäben nach dem Einbringen des Betons sicherzustellen;
b)
Untersuchung von Betonbauteilen, über die keine Aufzeichnungen vorliegen oder die überprüft werden müssen;
c)
Lagebestimmung von Bewehrung als Vorbereitung auf Prüfungen anderer Art, bei denen eine Bewehrung vermieden werden sollte oder deren Art berücksichtigt werden sollte, z.B. Entnahme von Bohrkernen, Ultraschall-Impulsgeschwindigkeitsmessung oder „oberflächennahe“ Prüfverfahren;
d)
Lagebestimmung von anderen eingebetteten ferromagnetischen Objekten außer Bewehrung, z.B. Wasser
rohren, Stahlträgern, Lichtleitungen.
ANMERKUNG Einige Geräte können auch nicht ferromagnetische Metallgegenstände nachweisen. Eine derartige Ver
wendung liegt nicht im Anwendungsbereich dieser Norm und die Publikationen der Hersteller sollten in Bezug genommen werden.
Essais pour béton dans les structures - Partie 5 : Détermination de l’enrobage en béton à l’aide de pachomètres électromagnétiques
Le présent document fournit des recommandations sur les appareils électromagnétiques qui peuvent être utilisés pour estimer la position, la profondeur et les dimensions des armatures enfouies dans le béton, et en décrit les principes de fonctionnement. Il décrit également leurs méthodes d’utilisation et leurs applications, l’exactitude à laquelle on peut s’attendre et les facteurs qui peuvent influencer les résultats.
Les pachomètres électromagnétiques peuvent être utilisés aux fins suivantes :
a) le contrôle qualité, afin de s’assurer que l’emplacement et l’enrobage des barres d’armatures après la mise en place du béton sont corrects ;
b) l’étude des éléments en béton pour lesquels les données ne sont pas disponibles ou ont besoin d’être vérifiées ;
c) la localisation de l’armature en amont d’une autre forme d’essai pour laquelle il convient d’éviter l’armature ou de tenir compte de sa nature, par exemple l’extraction de carottes, le mesurage de la vitesse de propagation des ultrasons ou les méthodes « proches de la surface » ;
d) la localisation des objets ferromagnétiques enfouis autres que les armatures, par exemple les conduites d’eau, les poutrelles en acier, les gaines d’éclairage.
NOTE Certains appareils peuvent également détecter des objets métalliques non ferromagnétiques. Une telle utilisation n’entre pas dans le domaine d’application de la présente norme et il convient de se référer aux publications des fabricants.
Preskušanje betona v konstrukcijah - Part 5: Določanje zaščitnega sloja betona z elektromagnetnimi merilniki
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2023
Preskušanje betona v konstrukcijah - Part 5: Določanje zaščitnega sloja betona z
elektromagnetnimi merilniki
Testing concrete in structures — Part 5: Determination of concrete cover using
electromagnetic covermeters
Prüfung von Beton in Bauwerken - Teil5: Bestimmung der Betondeckung mittels
elektromagnetischer Betondeckungsmessgeräte
Essais pour béton dans les structures - Partie 5 : Détermination de l’enrobage en béton
à l’aide de pachomètres électromagnétiques
Ta slovenski standard je istoveten z: prEN 12504-5
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2023
ICS
English Version
Testing concrete in structures - Part 5: Determination of
concrete cover using electromagnetic covermeters
Prüfverfahren zur Messung der Betondeckung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 104.
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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12504-5:2023 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 . 5
5 Apparatus . 5
6 Procedures. 6
7 Test report . 10
Annex A (informative) Influence of test conditions . 11
A.1 General . 11
A.2 Steel . 11
A.3 Concrete . 12
A.4 Temperature . 12
A.5 Extraneous effects . 12
A.6 Corrosion of reinforcement . 12
A.7 Accuracy of measurement on site . 13
Annex B (informative) Method for determining bar size and cover when neither is known . 14
Bibliography . 15
European foreword
This document (prEN 12504-5:2023) has been prepared by Technical Committee CEN/TC 104
“Concrete and related products”, the secretariat of which is held by SN.
This document is currently submitted to the CEN Enquiry.
This standard is one of a series on testing concrete.
EN 12504, Testing concrete in structures, consists of the following parts:
— Part 1: Cored specimens — Taking, examining and testing in compression;
— Part 2: Non-destructive testing — Determination of rebound number;
— Part 3: Determination of pull-out force;
— Part 4: Determination of ultrasonic pulse velocity;
— Part 5: Determination of concrete cover using electromagnetic covermeters.
This document is based on British Standard BS 1881-204: 1988 Testing concrete - Part 204:
Recommendations on the use of electronic covermeters.
Electromagnetic covermeters have now been in use long enough for experience to have accumulated of
applications for a variety of types of structure and under different conditions. Development of other
forms of covermeter is in progress but no significant field experience is yet available.
A range of suitable devices is commercially available. Since the capabilities of these vary, the choice of
instrument may be governed by the particular test conditions and information required.
1 Scope
This document gives recommendations on and describes the principles of operation of electromagnetic
devices that may be used for estimating the position, depth and size of reinforcement buried in
concrete. It also describes their methods of use and applications, the accuracy to be expected and the
factors which may influence the results.
Electromagnetic covermeters can be used for:
a) quality control, to ensure correct location and cover to reinforcing bars after concrete placement;
b) investigation of concrete members for which records are not available or need to be checked;
c) location of reinforcement as a preliminary to some other form of testing in which reinforcement
should be avoided or its nature considered, e.g. extraction of cores, ultrasonic pulse velocity
measurement or “near-to-surface” methods;
d) location of buried ferromagnetic objects other than reinforcement, e.g. water pipes, steel joists,
lighting conduits.
NOTE Some devices may also detect non-ferromagnetic metal objects. Such use is outside the scope of this
Standard and reference should be made to manufacturers’ publications.
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.
EN 206, Concrete — Specification, performance, production and conformity
EN 12350-1, Testing fresh concrete — Part 1: Sampling and common apparatus
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 206 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
actual cover
least distance, c , between the face of the concrete and the surface of the reinforcement
Note 1 to entry: See Figure 1
3.2
Indicated cover
distance, c , between the face of the concrete and a notional surface of the reinforcing bar under
m
investigation as shown in Figure 1
Note 1 to entry: Where values of cover are required for compliance with specified cover to a bar of known cross
section, the indicated cover has to be converted to actual cover by a method such as that described in 6.2.2 a).
Key
1 Plain bar – indicated cover Cm = C1
2 Ribbed bar – indicated cover Cm = C2
3 Square twisted bar – indicated cover Cm = 0.5(C1 + C2)
Figure 1 — Typical examples of cover to reinforcement
4 Principle
An electromagnetic field is generated by the search head (see clause 5). When a reinforcing bar or other
metal object lies within this field, the lines of force become distorted. The disturbance caused by the
presence of the metal in turn produces a local change in field strength as detected by the search head
and indicated by the meter (see clause 5).
Both the orientation and the proximity of the metal to the search head affect the meter reading. It is
therefore possible to locate reinforcing bars and determine their orientation. Cover to a bar may also be
determined if a suitable calibration can be obtained for the particular size of bar and the materials
under investigation.
With some devices it is possible, under ideal conditions, to estimate both bar size and cover when
neither is known. (See appendix B.)
5 Apparatus
5.1 General
A number of suitable battery or mains operated covermeters exist. They comprise a search head, meter
and interconnecting cable. The concrete surface is scanned with the search head kept in contact with it
while the meter indicates by analogue or digital means the proximity of reinforcement.
The search head may consist of a single or multiple coil system. The physical principle involved can
either be one utilizing eddy current effects or magnetic induction effects or other suitable technologies.
NOTE 1 Covermeters based on the eddy current effects operate at frequencies above 1 kHz and are thus
sensitive to the presence of any conducting metal in the vicinity of the search head. Location of non-magnetic but
conducting material is outside the scope of this Standard. However, such instruments, being very dependent upon
the conductivity of the material, might be very susceptible to changes in steel type (see A.2.1) and special
calibration might be needed.
NOTE 2 With covermeters using magnetic induction, a multicoil search head is used with a lower operating
frequency than the eddy current type of device (typically below 90 Hz). The principle used is similar to that of a
transformer, in that one or two coils carry the driving current while one or two further coils pick up the voltage
transferred via the magnetic circuit formed by the search head and embedded reinforcing bar. Such instruments
are less sensitive to non-magnetic materials than those using the eddy current principle.
The meter should incorporate scales or digital display ranges (in this Part called scales), calibrated in
accordance with clause 6.1, so that the indicated cover to the reinforcement can be read directly. The
manufacturer’s instructions should state clearly the conditions under which such scales are applicable.
A reference scale, preferably linear, should also be provided for calibration by the user to suit particular
conditions of use (see clauses 1 and 7).
5.2 Performance requirements
The indicated cover to steel reinforcement, when the device is calibrated in the laboratory in the
manner described in clause 6.1, should be within ± 5 % or ± 2 mm of the true value, whichever is the
greater, over the working interval given by the manufacturer.
6 Procedures
6.1 Basic calibration of the covermeter
6.1.1 General
Regular calibrations on the covermeter should be carried out to check the measurement errors of the
calibrated scale readings. The frequency of such calibrations will depend on the manufacturer’s
instructions and the condition of use of the covermeter, but it is recommended that they be carried out
at least every6 months. The dates of calibration should be recorded and kept with the covermeter.
The calibration should show that all meter measurements taken lie within the true value interval stated
in clause 5.2. Instruments that do not comply should be returned to the manufacturer for adjustment.
Most covermeters in use are battery operated but, if mains operation is also available as an option,
calibration-should be performed under each type of power supply.
If different search heads are to be used with the same meter, calibration checks should be carried out
for each head.
The methods described in 6.1.2, and 6.1.3 may be used in the laboratory. Suitable methods for routine
site calibration checks are given in clause 6.2.
6.1.2 Method A
Typically, the calibration check is carried out on a test block provided by the manufacturer. It consists of
a steel rod, or reinforcement bar fi
...
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