What material should the holes drilled in cured SFRM accommodate?

The correct answer is focused on the requirement for accurately assessing the thickness of the Sprayed Fire-Resistive Material (SFRM) after it has cured. Holes drilled in cured SFRM are specifically designed to accommodate a thickness gauge pin. This tool is essential in measuring the depth of the SFRM to ensure that it meets the specified fire-resistance performance criteria required for safety regulations and building codes.

Using a thickness gauge pin allows for precise measurements without causing damage to the SFRM, hence ensuring that the fire protection remains intact and effective. This measurement is critical in maintaining the integrity of fire safety systems in construction.

Other tools mentioned, such as calibration rods, measurement tapes, or screwdrivers, do not serve this specific purpose effectively. Calibration rods may be useful for other types of measurements but are not designed for assessing thickness in materials like SFRM. Measurement tapes are generally used for longer distances rather than precise thickness checks, and screwdrivers do not provide any measurement capabilities relevant to the thickness of the SFRM. Thus, the use of a thickness gauge pin is the most suitable and effective choice for this application.