NYC 9/11 Public Portal Document
Guidance for Ventilation System Evaluation Form
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Accessible in-line fire dampers, accessible turning vanes, exhaust air grilles - roughly
estimate the number of each type of component present. If the component is completely
inaccessible, the estimated quantity should be listed as “unknown”. If the component is clearly
not present, the estimated quantity is zero. Indicate the number of locations where the listed
component was accessed for inspection in the space provided.
Other components - use this space to describe any other component not already included on the
form that is part of the mechanical exhaust system.
Other information - use this space if needed to indicate any other information relevant for
documenting the condition of the mechanical exhaust system.
General impression - this space is for the HVAC Evaluator’s general impression of whether or
not cleaning is indicated based on the presence of WTC dust. The HVAC Evaluator should note
any other comments that are deemed relevant to the determination of WTC dust or comments on
conditions that would likely impact the scope or feasibility of cleaning.
2.3 Mechanical Make-up Air System
Perform the most vigorous visual inspection possible. Minimum inspection equipment should
include screwdrivers, a utility knife (for opening panels, diffusers, grilles, etc. that are painted or
caulked in place), cordless drill, hole plugs, telescoping mirror, flashlight, and portable
borescope. In addition, the HVAC Evaluator should attempt to penetrate visible dust to
determine if a WTC layer is present.
When a ventilation system component is accessed for inspection, indicate whether or not surface
dust/debris is present, and whether or not suspect WTC dust is present in the second and third
columns, respectively.
Associated Mechanical Room - indicate if there is a mechanical room associated with the
mechanical make-up air system, e.g., the make-up air handling unit is located in the mechanical
room, the mechanical room is an air mixing chamber for the air handling unit, etc.
Outside air intake, make-up air handling unit - please check for all components that apply. If
a listed component is not part of the system, then indicate “not present” (NP) in the right-hand
column. If the component is likely to be present, but it cannot be located, indicate “not found”
(NF) in the right-hand column. If the listed component is present and is located, but is not
accessible for inspection, indicate “inaccessible” (I) in the right-hand column.
Make-up air distribution - Roughly estimate the total linear footage of supply air ducts
associated with the mechanical make-up air system, and indicate the number of locations where
the interior of the duct was accessed for inspection in the spaces provided. Also circle the type
of material from which the duct is constructed (e.g., metal, fibrous glass lined metal, masonry,
fibrous glass board, flex duct, wood). If more than one type of duct material is present, circle all
that apply.
NYC-WTC_000160410
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