Law Department notice on WTC document preservation, Oct 2001

NYC 9/11 Public Portal Document

Study

Chiropractor’s Office 2“* Floor, Northwest comer. Liberty Street

Cleaning Methods: Test 4A - Area air filtration utilizing an air filtration device (AFD). Surface cleaning utilizing an industrial vacuum equipped with HEPA filtration. Nilfisk™ Vacuum (CFM 127), AFD. 4B - Surface cleaning of horizontal and vertical surfaces using a wet wipe with soap and water. 4C - Carpet cleaning using a commercial carpet wet vacuum with warm water Carpet Express™ (Model C-4) 4D - A/C Duct Cleaning. One air handling system located above the suspended ceiling supplies interior offices with air conditioning. The system has a central return grill located under the air handler. All flexible duct lines were removed and disposed of. Supply diffusers and return grills were removed for cleaning and reuse. A professional HVAC cleaning company was contracted to clean the HVAC system in accordance with the following work outline: ■ The work area immediately under the A/C system was protected using plastic sheeting. ■ Diffusers and return grills were cleaned with a degreasing agent. ■ Openings in the distribution duct were sealed with a protective barrier to prevent debris blow back. ■ Distribution ducts were cleaned using mechanical brushes under negative air and HEPA filtration, then washed with a degreasing agent. ■ The blower unit was washed with a degreaser, and the residues were removed using a vacuum. ■ All distribution ducts were fogged with a biocide, then encapsulated with an FDA approved sealer. 4E - Surface cleaning of horizontal and vertical surfaces consisting of wet wipe using water only (bathroom floor and desk top).

Equipment Used: Nilfisk® Vacuum (CFM 127); AFD; Carpet wet vacuum, (Model C-4) Filtration Status: HEPA Unit Size: 836 sq. ft.; 8,360 cu. ft. AFD Status: Required under method A and D AFD Specifications: 400/600 cfm Unit Air Exchange Rate: 20.9 min @ 400 cfm Minimum Air Exchange Required: Every 30 minutes

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NYC-WTC_000145191