QandA Sheet.pdf

Q&A Sheet

6973GH-23-R-00199: ILM ATCT Air Chiller

Q1. Drawing TSC-23-160-006, Controls Schematic: the following points are shown and need clarification:

a. Water Flow – the larger project where we are replacing the control system is provided with a flow meter on the bldg. return piping, is the “Water Flow” point shown for each chiller required? If so, how would you like this accomplished? IE Calculated from DP across the chiller barrel, Flow meter at the chiller

i. It is in our experience that flow across the chillers is redundant information to the return water flow that is already being installed. We feel this is not necessary and not common practice for other FAA projects. Please advise

A. We understand that the ILM HVAC Upgrade project requires Analog Inputs for Chiller Flow Rate, Pump-1 flow Rate and Pump-2 Flow Rate. Our expectation is those requirements should be consistent with the BacNet integration.

b. Run Capacity – This is shown as an AI point, in the schedule it calls for a BacNet integration. Typically run capacity or Demand is a BacNet point.

i. Do we need this to be an analog point (AI) or can you confirm this is not part of the BacNet

A. We understand that the ILM HVAC Upgrade project required Analog Inputs for Run capacity. Our expectation is those requirements should be consistent with the BacNet integration.

c. Aux Contacts: There are 2 shown per chiller. What exactly are these for?

A. Future expansion and monitoring.

d. For Clarification, we typically have the following points for a basic chiller on previous FAA projects: Isolation Valve Command, Isolation Valve Status, Enable, Amps, Alarm, For bidding purpose, are these acceptable in totality?

A. Yes

Q2. Drawing TSC-23-160-004: Chiller Controls note indicates that both chillers are included in the ILM HVAC Modernization project – this is not the case, as the FAA drawing set only mentions the single existing chiller to be put on the new DDC control system.

A. The Chiller Controls note on dwg 004 informs the vendor that additional conduit and control wiring will be required for a second chiller. It does not indicate that both chillers are replaced in the ILM HVAC project – the existing chiller was accounted for in the ILM HVAC Upgrade project as existing, not new. It is expected that in the ILM HVAC project the existing conduit for the existing chiller would have been re-used for new points to an existing chiller. Since one of the replacement chillers is located where the existing chiller is located, the expectation is that existing conduit can be re-used and an additional conduit installed for the second chiller. If unforeseen site conduits prove otherwise, the Contracting Officer should be notified at that time.

1. Please understand that pricing for this offering will include new controls for this added chiller

A. This is understood

2. Also, the new controller scheduled for the HVAC project will not handle the additional points, therefore an upgraded controller will be priced for this offering

A. This is understood

Q3. Scheduling for pricing: As it is unclear how the schedule for this project will coincide with the HVAC modernization project –

1. Are we to price this project with wiring for both chillers as the HVAC modernization project I assume will be nearly completed prior to this project starting.

A. Yes

Q4. Is the air control in this system being replaced as well? If not, what precautions are being ensured to all of us from a chiller and pump perspective?

A. Air control components are relatively new. Replacement is not part of scope.

Q5. Should we price flushing the system and refilling after several wash-throughs?

A. Flushing is required in specification 23 21 13, section 3.9.