The exposure test wall was built at the National Bureau of Standards in connection with a long-time project to study the action of various weathering agents affecting stone masonry. The project is a cooperative investigation between the National Bureau of Standards and Committee C-18 on Natural Building Stones of the American Society for Testing Materials. This report sets forth problems on weathering, discoloration, and certain construction features. The four tables will serve as a permanent record of the individual samples in the wall. It is proposed to make detailed studies on the various materials as weathering becomes apparent and to issue additional reports when the data are available.
and Anderson, R.
Stone Exposure Test Wall, Building Materials and Structures Report 125, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914828
(Accessed May 29, 2023)