Draft comments on encapsulant coating application standards, Jan 2003

NYC 9/11 Public Portal Document

. • Draft2 Comments by Covino Environmental Associates. Inc, January 6.2003

7. Cover all open supply air grilles, supply diffusers, and return air grilles located in the affected ductwork using fire-retardant polyethylene sheeting or bags and duct tape.

3-Vertical risers will be-treated similarly to the procedures identified-for exhaust ducts.

4;Look out-end tag out-the fan unit. I ^rS.Prepare-the unit to be cleaned. Outdoor fan units or units in non occupied areas require minimal prep. Fan ^HHts located in occupied areas or-common areas used by tenants will require-more extensive prep including isolating the work area, using negative pressure-or local exhaust ventilation m appropriate, plasticize the horizontal surfaces below the-unit if it is above greund. (Place the air handling units and their components under )< containment prior to beginning work.^jA temporary Zip-wall containment of 6-mil. fire retardant polyethylene sheeting extending from the floor to the ceiling deck, and maintained under negative pressure using a HEPA-filtered air filtration device is sufficient. The footprint of the containment should be large enough to accommodate a ladder or scaffolding if needed^

9. If there is an outside air intake, clean the intake louvers by damp wiping. If there is an outside air duct and it is accessible, clean the interior surfaces using HEPA vacuums with brush attachments and wet methods. If access to the outside air duct is limited, clean it using a combination of whips (whips only used in ducts without interior insulationl brushes (use soft brushes if ducts have interior insulation), and compressed air (note: compressed air may be used only if the system is sufficiently isolated and vacuum collection equipment is used to maintain a duct velocity of approximately 3^ feet per minute). Note that vertical risers may be treated similarly to the procedures identified for exhaust ducts.

10. Clean the air intake louvers and filter racks at the return air sides of the AC/ventilation units by damp wiping.

11. Clean all accessible-parts of the a/eA/C or ventilation fan unit exposed to the air stream including thermal coils, the blower assembly and housing, and all other components using HEPA vacuum brush attachments and minimal wet methods.- Electric coils and components shall be cleaned using dry methods. When wet cleaning thermal coils, apply manufacturer-approved cleaning solution to the coils using low pressure methods (i.e.. airless sprayer, hand operated pump), until all suspect WTC dust is removed.

12. Clean all supply mains and branch ducts in the direction of air flow, starting from the furthest point from the AFP or vacuum collection device. If the ducts are accessible (typically 6’ or less in length from access point) they may be cleaned using HEPA vacuums with brush attachments and wet methods. If access to the ducts is limited, clean them using a combination of whips (whips only used in ducts without interior insulation). brushes (use soft brushes if ducts have interior insulation), and compressed air (note: compressed air may be used only if the system is sufficiently isolated and vacuum collection equipment is used to maintain a duct velocity of approximately 3000 feet per minute).

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