The LEED for Homes v4 rating system, under IEQ Credit: Contaminant Control, mandates specific measures to prevent the contamination of building systems during construction. After the HVAC rough-in, it is a prerequisite to seal all ductwork openings, including boots, vents, and registers, with plastic or other durable materials. This action prevents construction dust, debris, and other airborne particulates from entering and accumulating within the duct system. Failure to do so would result in the HVAC system becoming a source of indoor air pollution once it is commissioned, distributing contaminants throughout the home and compromising occupant health.

A. A building flush-out is a post-construction procedure performed immediately before occupancy to remove volatile organic compounds (VOCs), not a mid-construction step.

B. Opening windows provides general ventilation but does not specifically protect the interior of the HVAC ductwork from construction dust and debris.

D. Installing temporary fans helps with air circulation but is not the required method for preventing contaminants from entering the newly installed ductwork.

---

1. U.S. Green Building Council. (2018). LEED v4 for Homes Design and Construction. Washington, DC: U.S. Green Building Council.

Reference: IEQ Credit: Contaminant Control, Section "During Construction," Requirement 2. The guide explicitly states, "Cover and protect HVAC registers, grilles, and ductwork openings from dust and debris."

2. Kyllo, J. M., & O'Brien, P. (2016). Sustainable Construction and Design. Pearson.

Reference: Chapter 10, "Indoor Environmental Quality," section on Construction IAQ Management Plan. This university-level textbook outlines best practices aligned with LEED, specifying that "all ductwork openings must be sealed during construction to prevent contamination."

3. University of Florida, Program for Resource Efficient Communities. (2015). Construction Best Practices for Florida-Friendly Building.

Reference: Section 4.2, "Indoor Air Quality," page 4-4. This document, used in university extension programs, details construction phase IAQ management: "Seal all supply and return air ducts after rough-in to prevent dust and debris from entering the system."