MIA Perspective: Fabricators and stone testing
Obviously, this type of call is not simply a question, but rather a series of questions as below:
Why have I never been asked for this before?
The caller has never needed this information before because their sales have been limited to residential applications, or very light commercial applications without a specification for the stone supply. Once we bridge into supply of commercial construction applications, we will encounter some different practices and different mandates requiring compliance. One of these practices is a specification, which is often drafted with the aid of a â€œboiler plateâ€ specification that the architect obtains through one of several sample specification providers. This specification will indicate that the stone material is to comply with minimum performance standards, normally those established by ASTM. The responsibility of documenting the stone material's compliance with these standards lies on the supplier of the stone material.
Why doesn't MIA - or another stone industry association - just keep a library with all of these data which we could access?
Actually, there have been several publications over the years attempting to catalog this information. One of the most comprehensive was the Marble Institute's Dimension Stones of the World book, including photo facsimiles and physical property data on over 500 dimension stones. When volumes I and II were published in 1990 and 1993, respectively, these books represented a very large portion of the stones sold commercially at that time. With the explosion of stone imports over the last 10 to 15 years, and the development of stone quarries in countries not previously participating in the stone market, data on 500 stones in today's market is not even the tip of the iceberg. Further confusion is created due to the names of the stones being inconsistent. Importers, wholesalers and retailers of stone products are constantly applying their own names to their products in hopes of making them appear as a sole source provider of that material. If the data were held in a library by someone outside the supply chain, the likelihood of its obsolescence or misapplication is simply too great.
So where and how do I obtain this information?
The only way to ascertain that the data is in fact from the correct stone is to have the data supplied by the parties from within the supply chain. For major projects, the stone source is normally tested just prior to the start of supply to verify that the tested sampling is representative of the production stock. Sometimes, the testing program will extend through the duration of the supply as a quality control program. These elaborate and somewhat costly testing programs are usually not a requirement for light commercial applications. In most of these cases, test data not more than five years old, or in some cases up to 10 years old, is acceptable to document specification compliance. The data should be generated by a laboratory meeting the requirements of ASTM E 699, and in most cases, that means the testing will be completed within the U.S. The ideal situation is for the quarrier of the material to have the testing completed, and then supply the data to the importers, wholesalers and retailers along the supply chain. The quarrier is in the best position to evaluate changes in the quarry and make determinations regarding the frequency of retesting. The quarrier also has access to thicker stock dimensions, as some of the ASTM tests require a minimum of 2-inch (51 mm) slab thickness to prepare the test specimens. If the testing is completed in this fashion, the costs of sample prep and laboratory service need be paid only once every several years. These costs would be borne by the quarrier initially, and passed on to the rest of the supply chain through the purchase price of the product. If someone in the supply chain elects to market the stone under a different name, they will then be responsible for the cost of re-establishing the testing program under the new name.
But what if the suppliers do not have this information?
If the suppliers are already selling into other markets, they are most likely already providing this type of information in those markets. The European Union, for example, is well ahead of us in this regard. There are EN standards in place for the sale of pavement, curbing, setts, modular tiles, interior floors and stairs, and cladding materials which mandate that the seller provide basic information on the stone product. This information generally includes the location of the quarry, basic physical property values, and basic petrographic information identifying into which rock family the stone is classified. It is also a requirement that the stone is sold under its traditional trade name in the marketplace. There is currently no such EN standard in place for countertops, but there is a standard (EN 1468) in place which requires the same type of information to be available for slab sales. Compliance with this standard results in the same information being available to the countertop fabricator when the slabs are purchased.
Won't it be many years before we would develop a similar system in the U.S.?
Not likely, as we already have the ASTM standards system in place on which to build this system. Each stone group has an applicable ASTM standard to which it must comply:
â€¢ Marble: ASTM C 503
â€¢ Limestone: ASTM C 568
â€¢ Granite: ASTM C 615
â€¢ Quartz-based: ASTM C 616
â€¢ Slate: ASTM C 629
â€¢ Serpentine: ASTM C 1526
â€¢ Travertine: ASTM C 1527
Each of these specifications lists various physical property values based on standardized test procedures. The tests are completed, and the values obtained in the testing are then compared to these standards to verify compliance. Stones that do not meet the minimum values are not banned from the market. There are many applications where compliance with all of the properties is not necessary. If the specifier has the data, he/she can make the determination if the substandard property is significant in the intended application.
Why is this necessary? Aren't we just complicating the industry with more useless paperwork and adding unnecessary expense to the product?
The development of standards and the adherence to those standards is necessary. It provides a level playing field for the participants in the industry and provides a degree of protection to the consumer. Standards make it easier to specify stone products, and allow the specifier greater confidence in receiving appropriate materials for the intended application. In today's relatively un-controlled marketplace, we have stones that are grossly misidentified in regard to their petrographic family. As a result, the stones do not perform as expected, and the industry suffers as a whole due to decreased consumer confidence in stone products. The benefits will outweigh the burden.