Comments on 114 Liberty cleaning and monitoring documentation, February 2003

NYC 9/11 Public Portal Document

(3) A third party air monitoring firm shall perform air sampling and provide project oversight. [CLEARANCE SAMPLING?]

(4) The asbestos contractor shall provide sufficient equipment and experienced personnel to complete work area preparation and cleaning activities of the building interiors within three (3) weeks. At least one asbestos supervisor shall be present per work area during the duration of the clean-up activities. Work shall be performed 24 hours per day, seven (7) days per week.

(5) Water/electrical supply shall be provided by residents/owner.

(6) Personal protective equipment including disposable clothing, gloves, and respirators shall be worn during this clean-up activity.

(7) Warning signs shall be posted at the approach to each work area.

(8) A separate worker and waste decontamination enclosure system in compliance with Title 15, Chapter 1 of the RCNY shall be installed at the entrance to each work area. More than one work area may be established. Work shall proceed from the 12th floor down to the first floor. The use of a remote decontamination enclosure system is acceptable. Prior approval must be received from the NYCDEP for decontamination enclosure system placement and phasing of clean-up activities, if required.

(9) An entry/exit log in compliance with the requirements set forth in Title 15, Chapter 1 of the RCNY shall be maintained in the clean room. The site supervisor shall maintain an activity log.

(10) Initially, the interior of the elevator shaft, including the top of the elevator car and the elevator pit, shall be HEPA vacuumed and wet wiped to allow for the use of the elevator during the clean up. Once the clean up throughout the building is complete, the elevator shaft, including the top of the elevator car and the elevator pit, shall be re-cleaned prior to clearance air monitoring.

(11) Isolation barrier locations (i.e.: wall or ceiling penetrations, windows, vents, doors, etc.) shall be HEPA vacuumed and wet wiped prior to installing two-layers of 6-mil polyethylene sheeting and sealed with tape. Window wells, ledges, guards, etc., that are accessible from the interior shall be cleaned.

(12) Negative pressure ventilation equipment (air filtration devices —AFDs) shall be installed and operated continuously 24 hours per day during all clean-up activities. Equipment shall run continuously until clearance air monitoring. A minimum of one air change every 15 minutes shall be provided. When ducting to the outside is not possible, a second negative air unit compatible with the primary unit may be connected in series. [SHOULD ALSO STIPULATE MINIMUM NEGATIVE PRESSURE OF 0.2" WATER COLUMN]

(13) Dropped ceilings at functional air plenums shall be removed. Interior and perimeter walls shall be removed, AS WELL AS ANY INSULATION BERING THOSE WALLS, to access the interstitial spaces for cleaning. Only one side of each wall shall be removed, FROM FLOOR TO CEILING, to access the space. The back SIDE OF THE walls scheduled to remain (i.e. tiled bathroom walls) shall be wet wiped and HEPA-vacuumed. For specific information regarding walls to be removed, please refer to the plans. Dust suppression techniques shall be used to minimize the generation of visible dust emissions.

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NYC-WTC 000138899