In multi-family buildings, how many consecutive units must pass before sampling can commence?

In the context of LEED certification for multi-family buildings, the guideline requires that sampling for specific assessments, such as Indoor Environmental Quality, begins only after a certain number of consecutive units have been verified to meet the criteria. The correct answer indicates that five consecutive units must pass before any sampling can commence.

This requirement ensures a statistically reliable and representative sample of the overall project. By establishing a baseline of five verified units, it helps confirm that the building systems are performing consistently across a number of units, reducing the likelihood that sample testing could be skewed by outliers or temporary conditions in the units that were tested. This approach aligns with principles of quality assurance and risk management fundamental to achieving sustainable building practices.

While lower numbers of consecutive units might seem practical for smaller projects, setting a higher threshold, as indicated by the correct answer, is intended to reflect a confidence in the building performance for a more extensive assessment, which ultimately supports the integrity of the LEED certification process.