Twentieth Floor Clean Up Report, 100 Church Street, April 2003

NYC 9/11 Public Portal Document

New York City Law Department Twentieth Floor Clean-up Report

2.0 DESCRIPTION OF WORK

The cleaning performed by Branch Services was performed in four phases. The cleaning included a 11 a ir c onditioning s upply and r etum air d ucts, grills, a nd p erimeter i nduction u nits located on the 20th floor. Cleaning of all visible dust from the return air plenum including the top surface of the ceiling tiles. Cleaning of all dust bearing surfaces such as filing cabinets, computers, book shelves, storage boxes, papers, and any other vertical and horizontal surfaces including walls, floors, of all visible dust. All dust cleaning was performed top down using a HEPA vacuuming system and wet wiping with a mild detergent solution. The floor carpet was steam/wet vacuumed with a HEPA filtration system. Cleaning commenced at 6 pm on Friday and was finished for re-occupancy by 7 am following Monday, Affected personnel on the 20th floor were notified prior to commencement of cleaning activities.

The cleaning of cardboard boxes stored within the NYCLD space on the east side of the floor was completed first. The exterior of the boxes were cleaned of all visible dust. Samples for lead in dust were collected to confirm the effectiveness of the response actions. Phase I through fV was cleaned after the boxes were cleaned and moved off the floor. Each phase was isolated for air movement from the rest of the floor. Negative air machines were installed and operated to keep each phase under negative pressure prior to cleaning. TR.C collected samples for asbestos and lead concentration in air outside of the isolated work area under each phase.

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