Which of the following methods is NOT used to test floor-to-wall systems?

The Clayton method is not recognized as a standard testing procedure for evaluating the firestop effectiveness of floor-to-wall systems. Instead, established testing methods such as ASTM E1966 and the Intermediate Scale Multi-story Apparatus are specifically designed to assess firestop systems in various construction configurations, including floor-to-wall interfaces.

Testing methods like ASTM E1966 focus on evaluating the fire resistance of joints and penetrations in building systems, which is crucial for ensuring that fire protection strategies function correctly in real-world conditions. The Intermediate Scale Multi-story Apparatus is also employed for large-scale testing of fire propagation and fire resistance, particularly in multi-story setups where the interactions between floor and wall systems can be critical.

While building code compliance tests may be used in practice, they refer more broadly to ensuring that construction meets various regulatory standards, rather than being specific methods for testing floor-to-wall firestop systems. Thus, the Clayton method stands out as the method not employed in this context, making it the correct choice for the question.