LITHOS Laboratory

“H.S.G.M.E.” – The Hellenic Survey of Geology and Mineral Exploration

In compliance with Article 25 of L.4602/2019 (issued: March 9th, 2019), the former Institute of Geology and Mineral Exploration (I.G.M.E.) of Greece was wound up, while a new Authority entitled Hellenic Survey of Geology and Mineral Exploration (H.S.G.M.E.) was established in its place. H.S.G.M.E. is a Legal Entity governed by public law and supervised by the Minister for the Environment and Energy. It is appointed to advise the State on Geoscience issues.

H.S.G.M.E.

In the above frame, the objective of H.S.G.M.E. is to investigate and scientifically monitor geological and mining issues on behalf of the State; to carry out studies and provide individuals or legal entities of public or private law with its opinion in the fields of geosciences, geohazards, geoenvironment, energy, mining and other related subjects; to perform geological, hydrogeological and mining research in the country, including exploitation studies of underground resources; and to exercise control and regulatory competent activities.

“LITHOS” – The Accredited Ornamental Stones Quality Control Laboratory of H.S.G.M.E.

QUALITY CONTROL LABORATORY OF H.S.G.M.E.

General information
LITHOS Laboratory has been established in 1999. They are active in offering services to the Ornamental Stones Sector, as well as in participating in various research projects and other relevant activities. In the Organization Chart of H.S.G.M.E., LITHOS stands under the Division of Economic Geology and Mineral Exploration.

LITHOS is accredited by the Hellenic Accreditation System (E.SY.D.) since 2002, following the provisions of standard ELOT EN ISO/IEC 17025.

At present, the Laboratory personnel consists of two Ph.D. Geologists, one Ph.D. Mining Engineer, and one Mining Technician, all of them highly experienced in the Ornamental Stones field. One of the Geologists and the Mining Engineer are current members of the “Technical Committee 77 – Natural Stones” (“TE 77”) of the Hellenic Organization for Standardization (EL.O.T.). TE 77 is the Hellenic equivalent of the EU Committees CEN/TC 246, 178, and 128.

LITHOS is well equipped with up-to-date certified testing machines and apparatuses, this being an important factor for carrying out high quality testwork according to the European (EN) and/or other international Standards. Nevertheless, its “Scope of Accreditation” includes only “Test Methods” according to EN Standards, being fully harmonized with the current practice in EU Member-States.

MARBLE-AREAS-OF-GREECE

For maintaining reliability in the process of determining the various physical mechanical properties of ornamental stones, LITHOS participate successfully in annually organized PT schemes together with other relevant European Laboratories.

Some EN Standards determine “Requirements” for various ornamental stone final products, aiming at assigning the “CE marking” on them, in relation to their potential applications. For those final products and applications, CE marking has become obligatory in Greece since 2008. Consequently, the lack of CE marking will render these products unable to face competition in the European and international markets.

To this effect, LITHOS, in their continuous effort towards upgrading the services offered, may refer to their existing capability to perform all the tests necessary for any producer or other interested person to assign the CE marking on the aforementioned products.

The objective of LITHOS Laboratory is to always maintain the traditionally high standards in the services offered, thus contributing, by strengthening the competitiveness of the relevant Sector’s private Companies, in the increase of the Hellenic Ornamental Stones share in the European and international markets.

The Physical Mechanical Properties of Ornamental Stones

The physical mechanical properties being determined for assigning the CE marking on various ornamental stone final products are:

• Denomination, EN 12440
Determination of the stone’s traditional, commercial or other relevant name.

• Petrographic examination, EN 12407
Together with the chemical assay, it classifies the stone and determines its aesthetic features.

LITHOS LABORATORY

• Apparent density, EN 1936
It is expressed in kg/m3. It is the ratio between the specimen’s mass and its apparent volume (i.e. the specimen’s volume, plus the volume of any voids).

• Open porosity, EN 1936
It is expressed in % vol. It is the volume of the specimen’s open voids, as a percentage of its apparent volume.

• Water absorption at atmospheric pressure, EN 13755
It is expressed in % wt. It is the mass of water held within a saturated specimen, as a percentage of its mass.

• Water absorption coefficient by capillarity, EN 1925
It is expressed in gr/(m2sec0,5). It is the ratio between the mass of water (in gr) being absorbed by the specimen through its cross section, i.e. plain to the direction of absorption (in m2) and the square root of the absorption time (in sec). It is an indication of the height that the “waterfront” reaches within the specimen, after a specific time lapse.

STONES-QUALITY-CONTROL

• Uniaxial compressive strength, EN 1926
It is expressed in MPa. It is the ratio between the load producing the breakage of the specimen and its cross-sectional area (perpendicular to the loading direction).

• Flexural strength under concentrated load (3-point), EN 12372 or
• Flexural strength under constant moment (4-point), EN 13161
It is expressed in MPa. It is the ratio between the bending moment producing the breakage of the specimen and the moment of resistance developed in it.

• Breaking load at dowel hole, EN 13364
It is expressed in Ν. It is the load being exerted on a steel dowel, resulting in the breaking of the specimen at the dowel hole, i.e. the hole where the dowel has been fixed.

• Abrasion resistance, EN 14157
It is expressed either as the width of the abraded groove on the specimen, in mm (Method A) or as the volume loss per abraded area of the specimen, in cm3/50 cm2 (Method B).

STONES QUALITY CONTROL LABORATORY

• Slip resistance, EN 14231
It is determined for dry and/or wet surfaces. It is expressed in arbitrary units and is a measure of the arc being traveled by the pointer on the circular scale of the pendulum friction tester, as the pendulum travels a specific distance on the “useable” surface of the specimen.

• Frost resistance (freeze – thaw cycles), EN 12371
It simulates the ageing of the stone, after its exposure in humidity and low temperatures. The specimen’s ageing is evaluated via visual inspection and by the potential change in its compressive or flexural strength (%).

• Resistance to ageing by thermal shock, EN 14066
It simulates the ageing of the stone, after its exposure in humidity and sharp temperature changes. The specimen’s ageing is evaluated via visual inspection and by the potential change in its open porosity (%) and its flexural strength (%).

Generally, the results of all the above test procedures are expressed by the mean value of the individual measurements (specimens). In certain cases, this mean value may be accompanied by the standard deviation, the variation coefficient, the maximum and/or minimum value, the maximum or minimum value expected, etc.

Requirements

The tests required for assigning the CE marking on various ornamental stone final products, depending on their application, are given in the following Table. The relevant EN standards are also included.

test-for-CE-marking
LEGEND
EN 1341: Slabs of natural stone for external paving – Requirements and test methods
EN 1342: Setts of natural stone for external paving – Requirements and test methods
EN 1343: Kerbs of natural stone for external paving – Requirements and test methods
ΕΝ 1469: Natural stone products – Slabs for cladding – Requirements
EN 12057: Natural stone products – Modular tiles – Requirements
EN 12058: Natural stone products – Slabs for floors and stairs – Requirements