Memo on WTC HVAC cleaning unit pricing, May 2003

NYC 9/11 Public Portal Document

Tex Krish Radhakrishnan P.E. Front David B. Ramberg Ph.D. Date: 2125/03 Roe Review of Draft WTC HVAC Cleaning unit Prices

Krish:

In order to avoid any confusion or misunderstanding of the type and items to be cleaned using the unit pricing schedule, the provided UNIT PRICING menu should refer to the VENTILATION SYSTEM EVALUATION FORM. For example, if the HVAC cleaning contractor has to dean an exhaust system he must refer to 2.2 Mechanical Exhaust System Visual Inspection Form. In this regard, the various subheadings probably should be assigned sub-group numbers such as 2.2.1 Exhaust air outlet and 2.2.2 Exhaust fan unit: Unit pricing provided this way will eliminate any confusion of how extensive the system cleaning will be. This method would also enable any re-inspection to focus on a particular item number If the cleaning contractor has to return to re-dean a specific component or area. If you choose to go this route, the description of the ITEMS in his list should conform to those In the VENTILATION SYSTEM EVALUATION FORM. According to how knowledgeable the cleaning contractor is will determine how well he can determine the cfm of a fan and ultimately the unit price to dean it. It is confusing me to determine the cost to clean Exhaust Branch Riser. Typically, there Is a portion of horizontal ductwork and vertical ductwork. Bathrooms usually have short horizontal runs ducted to vertical runs to the floor above. More details on the unit costs for these cleaning services should be detailed. The ITEM Single Inlet Centrifugal Blower is confusing. The basic type of fan used In a HVAC system Is the centrifugal fan or blower. If a Centrifugal Fan is used to exhaust corridor or hallway air, leaning the Interior housing, and impeller is difficult since there is limited access to the blower Interior.

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NYC-WTC 000135304