Addendum #2: Ventilation system components and WTC dust contamination areas,

NYC 9/11 Public Portal Document

ADDENDUM #2 World Trade Center Dust Cleaning Program Monitoring Contract Scope of Work

Note that exhaust systems such as bathroom and kitchen exhaust fans that directly remove room air to the outdoors are not included in this evaluation procedure. Components of direct exhaust systems typically include exhaust grilles, exhaust duct, exhaust fan, and rooftop or wall exhaust outlet devices. If information suggests that contamination of direct exhaust systems may be present, an evaluation may be performed using the same principles outlined for items 1, 2, and 3 above. Similarly, any ventilation equipment encountered that does not fall into any of these categories can be inspected using principles outlined in this section.

The locations within the ventilation system equipment expected to have the greatest impact from WTC-related dust include air intakes and intake ducts, intake air dampers, intake air filters and various system components located downstream of the intake air filters, depending on the system’s filtration efficiency. Dust may collect at potential impingement points such as duct terminations, transitions and elbows, and interior system components such as control devices, dampere, thermal coils, turning vanes, fans, etc.

One factor that may be considered in performing the evaluation is whether or not the ventilation equipment operated during the WTC collapse and in the weeks immediately following the collapse. Equipment that was not operating due to power loss, or due to concerns about entrained dust may not have been impacted as heavily as equipment that operated throughout the collapse and immediate clean-up response.

Item 6.3 includes a listed of recommended equipment for performing the evaluation.

Item 6.4 includes a list of system components for each equipment category.

Item 6.5 includes the evaluation procedures that may be applied to each system component.

6.2 Documentation of Existing Mechanical Conditions

Prior to the start of the evaluation, the HVAC/Electrical Professional shall ensure that the ventilation system is cycled and that there are no obvious existing deficiencies affecting proper mechanical operation of the system for which the evaluation team may later be held responsible.

6.3 Recommended Supplies and Equipment

Personal protective equipment (see 5.0) Sampling supplies (see 6.5.2.3) Disposal bags (see 6.5.2.3) Spray bottle containing soapy water Cleaning cloths Ladders (as needed) Lifts or scaffolding (as needed) Extension cords Hand tools (screw driver, pliers, etc.)

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