This is a pre-solicitation notice for a construction project at NIST in Gaithersburg, MD, involving HEPA filter replacement, repair, rebalance, and recertification in the Building 215 Cleanroom. The contractor must limit outages by working 24/7 from Friday evenings through weekends, with a maximum one-week outage per cleanroom bay. The estimated budget for the project is between $1 million and $5 million. All work will be performed at the NIST campus located at 100 Bureau Drive, Gaithersburg, MD 20899. The government anticipates awarding a single firm-fixed price contract to a total small business set-aside.