HVAC cleaning containment and decontamination procedures

NYC 9/11 Public Portal Document

Draft 2 Comments by Covino Environmental Associates, Inc, r January 5, 2003

or AFDs may be connected in series so that a second unit filters the exhaust air from the first. Another method of verifying that air contaminants do not leak through an air cleaning device is through in-place leak-testing of the filtration component using POP testing.

6. Install one layer of 6 mil poly over all bathroom and kitchen exhaust grilles and secure in place with painters tape.

i^Insert and inflate isolation/zone pillows, as necessary to isolate system, so that floors beyond the cleaning scope area outside the work zoner, and to maintain sufficient negative pressure in the section of the ventilation system being cleaned.

6r8.Remove the mushroom or other fan type housing or weather cap assembly from the roof j mounting.

^^Disassemble and clean the mushroom assembly using HEPA vacuums with brush | attachments and wet methods, as necessary to remove dust (any electrical equipment will not be cleaned with wet methods).

10. Clean the main riser from the roof or top most floor of the cleaning zone, using a combination of techniques including whips, brushes, and compressed air (note; compressed air may be used only if the system is sufSciently isolated and vacuum collection equipment is used to maintain a duct velocity of approximately 3000 feet per minute to capture and transport dislodged material). The riser should be cleaned prior to cleaning the branch ducts.

11. Reinstall the mushroom, other type housing or weather cap once the riser or top zone is cleaned.

12. For accessible branch ducts (typically 6 or less in length from access point): One by one, place an approximately 6’ x 6’ drop cloth of polyethylene sheeting on the surfaces below each bathroom and kitchen exhaust vent. Remove and clean each bathroom and kitchen exhaust grille inside the affected apartment. Clean all branch ducts from inside the apartment bathrooms and kitchens, using HEPA vacuums with brush attachments and wet methods. After cleaning, reinstall the bathroom or kitchen exhaust grille and cover again with polyethylene sheeting secured with painter’s tape to help maintain negative pressure within the exhaust ventilation system before moving on to the next grille. Roll up the polyethylene sheeting protecting the surfaces below the exhaust vent and place in a 6 mil polyethylene bag for disposal.

8.RemGve and clean all bathroom-aad kitchen exhaust grills inside affected apartments.

Q.Clean- all branch ducts from inside the apartment bathrooms and kitchens, using HEPA vacumns with brush attachments and wet methods. P 13. For inaccessible branch ducts (typically 6’ or greater in length from access point): prior » to inserting mechanical cleaning devices into the access point, construct a “cube” or “cocoon” to contain the access point. Remove and clean the grille. Clean the branch duct using a combination of whips, brushes, and compressed air (note: compressed air

NYC-WTC_000140028