Preserving Historic Houses: An Analysis Of Cleaning Methods for the Removal Of Fire Extinguisher Discharge On Historic Finished Plaster

Fire extinguishers are a necessity within any publicly accessible building, and their use is regulated by codes for public safety. When a fire extinguisher is used, the discharge residue can cause damage to the materials it comes into contact with. This potential damage presents an issue for many house museums, as the loss or removal of damaged material may affect the historic integrity of the site. With the ultimate goal of preserving the material integrity of historic sites, the ability to quickly and easily remove fire extinguisher discharge residue can allow materials, such as historic finished plaster, to remain in situ. As many smaller house museums do not have a professional conservator on staff, there is a need for research on various cleaning and removal methods to efficiently remove fire extinguisher discharge from historic finished plaster that can be completed by preservation staff. This thesis seeks to find an effective method for the removal of fire extinguisher discharge residue from historic finished plaster samples. The use of water, carbon dioxide, and chemical powder fire extinguishers, types likely to be found within historic house museums, allowed for testing the effectiveness of seven different cleaning methods. These cleaning methods were vacuuming and dry brushing, the use of a vulcanized soot eraser, VulpexTM Liquid Soap, a Latex-based peel, swabbing with deionized water, wet brushing, and drying. Each method was evaluated for changes in weight and moisture content as well as its ability to remove the discharge residue, prevent damage, and minimize paint color changes. Understanding the effectiveness of each method provides small historic house museums with fire extinguisher discharge residue on historic finished plaster the option to clean and preserve their material instead of replacing it.