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Plaster Study Classifies Wall and Ceiling Plasters in 200 Buildings Built Between 1880 and 1980

case_env_campusplasterAn old and prestigious university had plaster in many buildings that contained asbestos at concentrations below regulatory limits, but which represented an exposure hazard to workers. The university had over 200 academic buildings, some of which were more than 100 years old. Plaster had been used in walls and ceilings in most of these buildings. Identification of plasters with an asbestos content was critical to support ongoing renovation projects as well as worker protection programs.

Previous attempts at analysis of the plasters proved to be futile resulting in a chaotic situation. Normal analysis of plaster was too imprecise to accurately characterize the asbestos content, resulting in a failure to identify plasters that required asbestos abatement prior to renovation, and those that required asbestos work practices and worker protection when disturbed. Unfortunately, only one laboratory in the world was able to analyze plaster with the needed precision, and this lab could only handle a small number of samples at a time.

We conducted a campus-wide Plaster Study. This started with development of a method for collecting complete plaster core samples, which left all plaster layers intact so that plasters could be categorized by function and layer.  Approximately 5,000 core samples were collected from approximately 200 buildings. Morse developed a plaster classification system in which cores were examined under stereoscopic microscope, with each layer identified and further classified by cement type and color, aggregate type and color, and reinforcing fiber.

Our plaster classification system unified the plasters found in buildings throughout the campus and as such, was able to minimize the number of samples requiring analysis. A sampling program was developed that used this classification system to meet both EPA and OSHA sampling requirements and permit timely analysis. This allowed planned renovations to proceed on schedule and enabled an earlier roll out of worker protection procedures.