NYC-WTC_000233286

NYC 9/11 Public Portal Document

precleaning. Precleaning is intended for preparation work, not gross cleaning of visible asbestos debris such as disturbed ACM, PACM or asbestos material on floors or other work area surfaces. Precleaning shall be performed in the following order. (1) Locations in which critical barriers and isolation barriers are to be installed shall be cleaned first using a HEPA-filtered vacuum and wet cleaning methods before the barriers are installed. After the critical barriers and isolation barriers are installed, the negative air ventilation units shall be started. Once the negative air ventilation units are operational, the remainder of the precleaning shall take place and area plasticization shall begin. 56-7.11 Regulated Abatement Work Area Enclosure. (a) Criticai Barriers. Critical barriers shall be constructed to seal off all openings and penetrations to the regulated abatement work area including, but not limited to, operable windows and skylights, doorways and corridors (which shall not be used for passage), ducts, grills, diffusers. HVAC system seams, and any other penetrations to surfaces within the regulated abatement work area. Critical barriers shall be constructed using two (2) independent layers of at least six (6) mil fire-retardant plastic sheeting with each layer sealed separately with duct tape. Caulk and fire-retardant expandable foam may be used to seal small openings or penetrations. Doorways and corridors, which shall not be used for passage during the asbestos project, shall also be sealed. (b) Isolation Barriers. Temporary hardwall barriers to complete the containment enclosure and establish the asbestos project regulated abatement work area shall be constructed using the following, framing, sheathing, sealing and plasticizing criteria: (1) Framing. Isolation barrier partitions shall be constructed of wood or metal framing in all openings larger than 32 square feet, except that where any one dimension is one foot or less, framing is not required. Existing walls or framing may be used to support isolation barrier partition framing and sheathing. (2) Sheathing. A plywood or oriented strand board (OSB) sheathing material of at least 3/8-inch thickness shall be fastened to the regulated abatement work area side of the barrier partition. (3) Seaiing of isoiation Barriers. The edges of the isolation barrier partition shall be sealed at the floor, ceiling, walls and fixtures using caulk, fire- retardant expandable foam or duct tape to form an airtight seal. The seams of the partition sheathing shall also be sealed airtight using these techniques. (4) Piasticizing isoiation Barriers. The regulated abatement work area side of the isolation barrier partition shall be covered with two (2) layers of, at a minimum, six (6) mil fire-retardant plastic sheeting with staggered joints and sealed airtight.

12 NYCRR56 Subpart?, Page 66

CITY_21MC100_0 03235086

NYC-WTC_000233352