Questions and Answers.doc

ARRA USGS in Menlo Park HVAC

1. M 1.1 Building Level Network Concept - Page 46 Scope of Work and Concept Design document states:

Project 6, paragraph 2, Campus Network: A. Plan trenching routes for fiber cable. B. Install fiber optic cable between Buildings 1,2,3,3A,and 15.

The attached drawing Building Level Network Concept shows an existing fiber cable tying buildings 1, 1C, 2, 3, 15, and 20 together.

Is there a need for redundant fiber between these buildings? No. Please see the revised scope of work as the references in the question statements above are from the original scope of work. There is existing fiber. Only new fiber between Building 1 and 2 is required, using an existing pathway/conduit/raceway.

2. Can we use the existing cable trays for plenum wiring? Yes.

3. Are there any existing CAV mechanical schedules for Building 15? Yes, they are posted.

4. Are there any valve schedules available? Yes, they are posted.

5. There are no HVAC drawings posted for building 15. We will need to know the branch line sizes in order to size new exhaust air valves and supply air devices. Yes, they are posted.

6. Project documents call for sash position sensing for Fume Hood Control - EPA has determined that Sidewall velocity sensing is a more accurate form of fume hood face velocity control. Almost all hood monitors and a substantial portion of hood controllers utilize sidewall face velocity sensing. Sidewall sensing is more economical to purchase and install, providing a benefit to the GSA. Can we substitute side wall velocity sensing for fume hood control? No.

7. Project documents call Venturi air valves on hood control - Damper style hood control elements provide equal control of face velocity when used in a closed loop control that measures actual face velocity.nDampers are substantially more economical to purchase and install, providing a benefit to the GSA Dampers use about 10% less fan energy than equivalent venturi valves, reducing energy consumption for the life of the building, providing further benefit to GSA. Can we substitute dampers for venturi air valves? No

8. Project documents call Venturi air valves on hood control - Project documents call for volumetric offset room pressure control but no room pressure measurement is shown.

Direct Pressure control based on measuring actual room pressure and modulating the supply and GEX in sequence to maintain ACH and room pressure is a proven method that gives GSA actual room pressure and is lower cost. Can we utilize Direct Pressure control? No.

9. Please provide drawings shown in figures 3.5, 3.6, 3.7, 3.16, 3.19 of the bridging document. These were not included in the "CA0915OO.zip" file. These figures will be provided as separate TIF files.

10. For project number 7, a request for information on quantity of roof top package units and size (tons).

There are approximately 11 rooftop units total. See also Project 15. Units are estimated to be 10 tons or less.