What type of material is classified as surfacing material in relation to asbestos?

The classification of surfacing material in relation to asbestos refers to materials that are typically applied on surfaces to provide a specific function, such as decorative or protective purposes. Decorative plaster coatings are specifically designed for aesthetic enhancement and can include mixtures that may contain asbestos. They are used to finish walls and ceilings, making them a prime candidate for inclusion in surfacing materials.

In contrast, while acoustic drop ceilings, flooring tiles, and HVAC duct insulation may contain asbestos, they do not primarily serve the decorative or surfacing role that defines surfacing materials. Acoustic drop ceilings are designed for sound absorption, flooring tiles are intended for durable surfaces underfoot, and HVAC duct insulation aims to control temperature and reduce noise. Therefore, those materials do not fit the definition of surfacing material as clearly as decorative plaster coatings do.