Preliminary scope of work document for cleaning 114 Liberty Street,

NYC 9/11 Public Portal Document

December 17, 2002 114 LIBERTY STREET REMOVAL OF DUST, DEBRIS, AND CONTAMINATED MATERIALS

unit's capacity. The area receiving the exhaust shall have sufficient, non-recycling exhaust capacity to the outside of the structure. Vent second unit to a controlled area in the building, as approved by Ambient Group, Inc.

2. Ensure that controlled area is isolated from balance of building by isolation barriers at all times that units are in operation.

3. Routine smoke testing, air monitoring and daily inspections shall be performed by the Supervisor to ensure that the ducting does not release fibers, dust, or debris into uncontaminated building areas.

4. Mount units to exhaust directly or through disposable ductwork.

H. Use ductwork and fittings of the same diameter or larger than discharge connection on fan unit.

Use new inflatable, disposable plastic ductwork in lengths not greater than 100 feet.

J. Use new spiral wire-reinforced flex duct in lengths not greater than 50 bet.

K. The negative pressure system must produce a minimum pressure differential of negative 0.02 inches of water (during removal) as measured between the Work Area and the adjacent spaces. The contractor is required to maintain the negative pressure system as stated. In the event that the pressure differential falls below the stated pressure levels, all work shall stop until adequate pressure levels are re-established.

L. Ambient Group, Inc. shall measure the pressure differential and confirm negative pressure through manometer measurement, recording devices, and smoke testing PRIOR to any demolition work and removal.

M. Ambient Group, Inc. resenes the right to test air plume capacity of AFD units to verify actual CFM exhausted from the work zone.

END OF SECTION 08

37 © AMBIENT GROUP, INC. - 2002 PRESSURE DIFFERENTIAL & AIR FILTRATION SYSTEM

NYC-WTC 000155565