Which building component is NOT considered a substrate?

In the context of lead risk assessment and building materials, a "substrate" refers to the underlying material that supports a coating, such as paint or varnish, which may contain lead. Substrates are typically porous materials that can absorb and interact with lead-containing paints.

Glass is not considered a substrate because it is a non-porous, smooth surface that does not absorb paint in the same manner as wood, metal, or plaster. Glass surfaces are often used for windows and other architectural features where protective coatings or paints are not typically applied for structural or aesthetic purposes. In contrast, materials like wood and plaster are commonly painted or coated, thus serving as substrates that can hold lead-containing products.

The distinction is important in lead risk assessment as it helps determine where lead hazards may be located and what materials require monitoring or remediation efforts.