Air sampling protocol document, 130 Cedar Street, Jan 2005

NYC 9/11 Public Portal Document

130 Cedar Street July 15, 2004 Selective Demolition and Façade Restoration Koenen Associates C. Hot-Water Wash: Use hot water applied by [low] [medium] [high]-pressure spray. D. Steam Cleaning: Apply steam at pressures not exceeding 80 psi (550 kPa). Is E. Detergent Cleaning:

1. Wet masonry with [cold] [hot] water applied by low-pressure spray. 2. Scrub masonry with detergent solution using medium-soft brushes until soil is thoroughly dislodged and can be removed by rinsing. Use small brushes to remove soil from mortar joints and crevices. Dip brush in solution often to ensure that adequate fresh detergent is used and that masonry surface remains wet. 3. Rinse with [cold] [hot] water applied by [low] (medium] [high]-pressure spray to remove detergent solution and soil. 4. Repeat cleaning procedure above where required to produce cleaning effect established by mockup. F. Mold, Mildew, and Algae Removal: 1. Wet masonry with [cold] [hot] water applied by low-pressure spray. 2. Apply mold, mildew, and algae remover by brush[ or low-pressure spray]. 3. Scrub masonry with medium-soft brushes until mold, mildew, and algae are thoroughly dislodged and can be removed by rinsing. Use small brushes for mortar joints and crevices. Dip brush in mold, mildew, and algae remover often to ensure that adequate fresh cleaner is used and that masonry surface remains wet. 4. Rinse with [cold] [hot] water applied by [low] [medium] [high]-pressure spray to remove mold, mildew, and algae remover and soil. 5. Repeat cleaning procedure above where required to produce cleaning effect established by mockup.

G. Nonacidic Gel Chemical Cleaning: 1. Wet masonry with [cold] [hot] water applied by low-pressure spray. 2. Apply nonacidic gel cleaner in 1/8-inch (3-mm) thickness by brush, working into joints and crevices. Apply quickly and do not brush out excessively so area will be uniformly covered with fresh cleaner and dwell time will be uniform throughout area being cleaned. 3. Let cleaner remain on surface for period indicated below:

a. As recommended by chemical cleaner manufacturer. b. As established by mockup. 4. Remove bulk of nonacidic gel cleaner by squeegeeing into containers for disposal. 5. Rinse with [cold] [hot] water applied by [low] [medium] [high]-pressure spray to remove chemicals and soil. 6. Repeat cleaning procedure above where required to produce cleaning effect established by mockup. Do not repeat more than once. If additional cleaning is required, use steam wash. H. Nonacidic Liquid Chemical Cleaning:

CLAY MASONRY RESTORATION AND CLEANING 04901 -13

NYC-WTC 000125180