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Stone Initiatives - Stone Testing & Project Finishes Evaluation
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Stone analysis techniques | Mineralogical examination

Stone Initiatives can facilitate testing to analyse the composition of any dimension stone. Our specialist technicians can perform a wide range of mineralogical tests to analyse your dimension stone for the presence of naturally occurring asbestos minerals, crystalline silica, or other potentially deleterious mineral components.

Mineralogical examination and compositional analysis techniques include:
• Petrographic examination
• X-Ray diffraction (XRD)
• Polarised light microscopy

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Tests relevant to ceramic tiles include:

  • Water absorption, apparent porosity, apparent relative density and bulk density – AS ISO 10545.3:2020
  • Modulus of rupture and breaking strength – AS ISO 10545.4:2020
  • Impact resistance by measurement of coefficient of restitution – AS 4459.5-1999
  • Resistance to thermal shock – AS ISO 10545.9:2020
  • Frost resistance – AS ISO 10545.3:2020
  • Chemical & Stain Resistance (In-service) – SI-STAIN-18
  • Chemical resistance – AS 4459.13-1999
  • Resistance to stains – AS 4459.14-1999
  • Small colour difference – AS ISO 10545.16:2016
  • Slip Resistance – AS 4586:2013 & AS 4663:2013

For more tests see Summary of Our Capabilities.

Ceramic water absorption test explained

The water absorption of ceramic tiles is tested to AS ISO 10545.3:2020 “Ceramic Tiles – Method 3: Determination of water absorption, apparent porosity, apparent relative density and bulk density.” A standard number of specimens (which is determined by the size of the full tile) are dried to constant mass at 110 degrees C for a minimum of 24 hours. The specimens are weighed dry before being placed within a vacuum chamber, evacuating the air and slowly admitting water to fully immerse the specimens. The specimens remain submerged in the water under vacuum for 15 minutes before they are weighed soaked after patting excess water from the surface with a damp microfibre cloth. They are also weighed suspended in water. The water absorption, expressed as a percentage of the dry mass, is calculated using the dry weight and the soaked weight of the specimens. The suspended weight is used to determine the density.

The water absorption test is important for ceramic tiles because it is what determines which Group Classification the tile falls under (see section below for more on Group Classifications). We can then determine if the tile complies with the specifications of this Group Classification for dimensional and surface quality requirements, physical properties, and chemical properties. The Group Classification, along with the unique requirements of the job and the needs of the client, together influence which tests need to be performed.

Ceramic and porcelain tile classifications

Ceramic and porcelain tiles are classified by AS 13006:2020 (ISO 13006:2018) “Ceramic Tiles – Definitions, classification, characteristics and marking.” The ceramic tile is given a Group Classification, which depends on the method of manufacture of the tile and the water absorption properties.

Every ceramic tile, including those sourced internationally, is required to have its Group Classification specified on the packaging, or sometimes the Annex letter is written on the box as well as or instead of the Group Classification. Other information that should be included on the packaging are the manufacturer’s mark or trademark and the country where the tile was manufactured, the nature of the surface, i.e. glazed (GL) or unglazed (UGL), nominal and work sizes and “M” if modular, any surface treatment applied after firing and the total number of tiles in the package.

This information is important to know because it can help us determine which tests are relevant for the specific tile product. For tests such as stain and chemical resistance, it is important to know the nature of the tile surface – if it is glazed or unglazed, or if it has had any treatments applied to it after firing. In an instance where a client is having issues with a tile, we can complete a water absorption test in our lab to understand if the tile has been classified properly.

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mosaic-tiles-at-Sofitel-adelaide-tested-for-slip-resistance-1
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Above: Stain resistance testing of ceramic tiles; chemical resistance testing of ceramic tiles; potential to effloresce testing of ceramic tiles; mosaic tiles at Sofitel Adelaide underwent slip resistance testing.

ANNEXManufacture method / level of water absorption (Group title) Water absorption propertiesGroup classification
Annex A Extruded ceramic tiles with low water absorptionBetween 0.5% and 3% AIb
Annex B,
Annex C		Extruded ceramic tiles – Subgroup (Part) 1 Extruded ceramic tiles – Subgroup (Part) 2Between 3% and 6% AIIa
Annex D,
Annex E		Extruded ceramic tiles – Subgroup (Part) 1 Extruded ceramic tiles – Subgroup (Part) 2 Between 6% and 10% AIIb
Annex F Extruded ceramic tiles More than 10% AIII
Annex G Dry-pressed ceramic tiles with low water absorption Less than 0.5% BIa
Annex H Dry-pressed ceramic tiles with low water absorption Between 0.5% and 3% BIb
Annex J Dry-pressed ceramic tiles Between 3% and 6% BIIa
Annex K Dry-pressed ceramic tiles Between 6% and 10% BIIb
Annex L Dry-pressed ceramic tiles More than 10% BIII
Annex M Extruded ceramic tiles with low water absorption Less than 0.5% AIa

What is the difference between porcelain and ceramic?

Porcelain is a type of ceramic. Porcelain is fired at a different temperature and duration to traditional ceramics, and the composition of the source clay used to produce porcelain is also commonly different. Porcelain is typically identified as a Group BIa classified ceramic due to its very low water absorption properties.

Testing porcelain and other ceramic tiles on pedestals (sometimes called pods)

The use of pedestal systems for porcelain and other ceramic tiles can provide benefits such as reduced installation time, easier access to services, and benefits to drainage. However, there are also drawbacks and risks associated with pedestal systems, particularly when porcelain is involved. These include the risk of pedestrians falling through when a tile breaks and subsequent injuries, plus the cost of replacing broken tiles.

It is vital that appropriate tests are carried out on porcelain tiles intended for installation with a pedestal system. Testing can direct attention to these drawbacks and how they could affect the performance of a tile in service on the pedestal system.

The main tests recommended for porcelain tiles on pedestals:

  • Stone Initiatives method SI-CLCP – tests the concentrated static load capacity of the porcelain tiles while installed on a particular pedestal system.
  • British Standard method BS EN 14158:2004 (modified) – tests the impact rupture energy of the material.
  • Australian Standard AS ISO 10545.3:2020 – determines the water absorption capacity and density of the tile.
  • Australian Standard AS ISO 10545.4:2020 – determines the modulus of rupture and breaking strength of the tile.
  • Australian Standard AS 4586:2013 – determines and classifies the slip resistance of the surface of the tile.

Find sample requirements and other testing details on our FAQs page.

Get in touch to discuss your testing requirements.

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