International standards for marble, granite & Co: the Natural Stone Institute’s Chuck Muehlbauer was appointed chair of the Technical Committee TC 327

The logo of the International Organization for Standardization, which is also responsible for the many well-known ISO-standards.

The coming ISO-approved definitions will be about “requirements and test methods for blocks, slabs, semifinished and finished products intended for use in building and for monuments“

Natural Stone Institute technical director Chuck Muehlbauer has been appointed chair of the International Organization for Standardization’s (ISO) Technical Committee (TC) 327 on Natural stones. As chair, he is responsible for the overall management of the Committee, helping to manage standards projects effectively and leading the Committee in reaching consensus. He will serve in this capacity through 2025.

The scope of the standards is “definitions, requirements and test methods for natural stones relating to rough blocks, slabs, semifinished and finished products intended for use in building and for monuments“, as said on the ISO webpage.

They may describe the requirements for slabs for facade cladding, just to give an example.

About 12 years ago, the European Union had issued its CE standards for natural stone.

The Technical Committee currently has 13 global participating members (Belgium, Brazil, Columbia, Finland, France, Germany, India, Italy, Russian Federation, Spain, Sweden, United Kingdom, and United States), with another 10 national standards bodies observing. Participation in the Committee is expected to grow as its work advances. The Committee held its first virtual meeting on January 14, 2021, and it will continue to work virtually throughout 2021, with plans to bring global members to Las Vegas for an in-person event as part of TISE 2022.

On this way to international standards, the first step was very delicate as a proposal from Italy wanted to have natural stone and conglomerates/engineered stone in the same standard category.

That would have increased the consumers’ existing confusion created by the many fake-names given to copies of, e.g., real marble. The NSI had started strong efforts against that strategy and finally succeeded in preventing that mistake. Now two separate standards will be created.

The Committee for natural stone is TC 327 with the American National Standards Institute (ANSI) as secretariate and Chuck Muehlbauer as chair, the Committee for artificial stone is TC 328 with UNI as secretariate.

In the coming steps, existing standards from around the globe shall be assembled and used to create one unified standard. One such standard is the Natural Stone Institute’s Dimension Stone Design Manual (DSDM).

Additionally, a U.S. Technical Advisory Group (TAG) has been formed to develop and transmit, via ANSI, U.S.-consensus positions and comments on activities and ballots of the ISO TC. The U.S. TAG held its first virtual meeting on December 9, 2020, and is chaired by Scott Scallorn of Intertek’s York, PA location.

Natural Stone Institute’s CEO Jim Hieb comments on the steps taken: “Through our work with ISO TC 327, we will be able to develop uniform standards for natural stone with members in ISO in over 150 countries. We are moving our industry forward in new and exciting ways and ensuring a global connection for our association for years to come.”

In an interview with to be published in the coming days, NSI-president Michael Picco points out how much international standards will facilitate the architects’ decision to choose natural stone for a building.

Chuck Muehlbauer is the NSI-responsible for overseeing the development and revision of all association technical documents, technical bulletins, and the technical content of videos and other publications. He also serves as the primary contact for member technical questions and provides consultative assistance to industry design professionals using natural stone products.

ISO Technical Committee TC 327

Dimension Stone Design Manual (DSDM)

CE-standards for natural stone in the European Union

(07.03.2021, USA: 03.07.2021)