Attach 6a - RFI Answers.pdf

DBEH 16-1577, Replace HVAC @ 85125 RFI's

Location Comment NEC Response

1 ED-105 Contractor to remove and retain camera for relocation. Is Gov or Contractor removing and reinstalling the camera?

Government is responsible for the removal of camera.

Removed ED-105 and replaced with Drawing ED-105 Dated 10 Sep 2021 (Attach 2a)

2 M-106 Note 1, states to install new chillers. Are we to install one at a time? Will a Temp chiller be required?

See answer in #5

3 - We cannot find a sequence or operation for the air cooled chillers. How are the (2) chillers to operate? Are they redundant lead lag? Are they designed to work together to satisfy the bldg load by discharge water temperature?

Assume they are redundant lead lag configuration.

Coordinate operation for new chillers with existing setup at start of construction.

4 - Please confirm all work can occur during normal work hours Monday thru Friday 0700-1530 hours?

Yes, work will be performed during normal business hours.

Personnel relocation will be coordinated with the construction inspector, facility manager and users.

5 - Will any temporary chillers be required or can the facility load be satisfied using (1) chiller while replacing the other chiller? If temporary chiller support is required, should it be the same size as the existing chiller(s)? Is additional power source available if a temporary chiller is required since the existing chiller power is being re-configured it will not be available for use on the temporary chiller?

Use the existing temporary chiller connections and provide temporary chiller during project. Temporary chiller size should be 180tons. Use the power source from one of the existing chillers to power the portable chiller. See revised Attach 1a - SOW (1.2.1.3.1)

6 - Please confirm that the valve trains on the existing air handlers are piped properly in that all 3-way valves being removed on these AHU’s are “Inside the isolation valves” for that particular AHU, and each AHU can be isolated to perform these modifications? If the government cannot confirm this, we request another site visit to confirm prior to bid

Contractor is welcome to verify via walkthrough.

7 - It was noted during the walkdown that significant insulation has been removed from the existing chilled water pumps. Should the contractors include re-insulation of this piping in their bids

Include reinsulation.

8 - Please define the extent of test and balance on this project? Is any pre test and balance required to establish a “Base Line” of CFM flow from the existing VAV’s? Since the VAV’s are being replaced, what will be the extent of the test and balance after replacement has been completed?

Verify the existing flows and test again to match previous performance.

Balance to attain original flows.

9 - Will the user relocate from the areas where VAV’s are being replaced? Some ceiling will need to be removed to support this effort so it would be most beneficial if the users furniture was not in the areas where this work was being performed. If the user will relocate, does the contractor have any responsibilities in helping them move?

The users will relocate as needed. The contractor is only responsible for coordinate with construction inspector to schedule when users would need to move.

- Please confirm the government will provide and install the requisite LAN drop to support the integration of the new LON BAS System into the base head end system?

The contractor is responsible for providing the cable from the new automation server to the existing switch located in the facility as shown on sheet M-601.

Coordinate with construction inspector if they want to make the final termination to switch.

- During a subsequent walkdown we looked into Room 210 and it appeared that the controllers on those VAV’s are not compatible with the new Ecostruxure DDC System. Please confirm those VAV’s will integrate into the new system without adding new controllers

VAV boxes in room 210 are being replaced in a separate project and will have compatible controllers already installed.

- The new Bray Control Valves tagged as ROV-1, 2, 3, & 4 are replacing what appeared to be 8” gear operated butterfly valves. Can the entire chilled water system be shutdown to make these replacements or will we need to freeze the piping to replace (1) system at a time.

Freeze piping to replace one system at a time

- Should the new Bray Control Valves include end/position switches to confirm each valve is

Yes open prior to that respective chiller from starting

- Do the new chilled water pumps require laser alignment after the installation has been completed

Install according to manufacturer requirements for alignment.

M-106/M-701 Can you confirm the isolation / control / ROV valve size on the chiller, 6" or 8". The schedule says 6" (M-701) but the drawing calls them out as 8" on the notes (M-106 Note 2).

Assume 8" for bid purposes. Verify in field prior to start of construction.

M-107 Can you please confirm who is responsible for the New "mushroom type" pushbutton emergency overrides? (M-107 Note 2) We only have this one note regarding the item, and it appears that ties into the new automation server. Is this considered life safety since it closes off the outside air in case of an emergency? Or is it the Electrical contractor?

(The information for the pushbutton is found under the electrical section of the specs.)

This is typically installed by the controls subcontractor.

- Per spec 23 30 00 para 2.7.3, outside air ductwork will be galvanized steel or aluminum sheets, will this need to also have a protective coating due to the salt air? Should this be stainless steel.

M-501 - All exterior ductwork to be stainless steel.

- Per spec 23 30 00 para 2.7.3, outside air ductwork will be galvanized steel or aluminum sheets, will this need to also have a protective coating due to the salt air? Should this be stainless steel.

M-501 - All exterior ductwork to be stainless steel.

Detail B, M-501 Are there any engineered drawings for the OSA duct tie-downs and wall supports, or wind load calculations available?

Wind load calculations are not available.

Contractor is responsible to provide properly sized wind rated supports.

MD-102 Specific note 1 talks about utilizing an existing chiller redundancy during demoliztion. Are the existing chillers redundant, are both necessary to cool the building? What is the total cooling load of the existing building? What is the cooling capacity of each of the existing chillers?

Is a temporary chiller required? If so what size can be assumed carried by on of the existing chillers?

Two chillers are not required to cool the facility. Provide temporary portable chiller rated to 180tons.

- Will the building be able to sustain for 8 hours without having existing cooling? Are we able to shut the building down to complete not only our chiller swaps but also the valve change-outs on the AHUs located in the mechanical rooms? We are trying to determine what type of temporary cooling is needed. If the spaces cooled by the air handlers' needs to have constant cooling we need clarification so that we can construct a temporary cooling plan. Are there specific rooms (i.e. comm room, computer room, electrical rooms) that require spot coolers during this required outages?

No the entire facility cannot be down for a whole day. Provide temporary chiller for building. Air handlers can be taken down individually to replace valves when scheduled with construction inspector, MD-105, Flag Note 1/ M-109, Flag Note 1

Please confirm that only one chilled water pump is required to supply chilled water to the entire building. Please confirm that only the existing pump is being replaced, not ancillary items such as expansion flexible connections, gauges, strainers, etc.

Only one chilled water pump is required. Only pump is being replaced.

MD-102 Have the two existing temporary chiller connection valves, that isolate the temp chiller connections, been exercised and is it known if they actually hold?

The valves are currently on a PM schedule and will be cycled prior to start of construction to confirm viability.

MD-102 When replacing valves in the chiller yard, there are only one set of valves, so it appears a shutdown of the entire yard will be required.

What kind of time frame will we have to bring it down and back up? Will we have to have a temporary chiller hooked up during that time?

What size? If one one of the existing chiller is not available there wouldn’t be any redundancy during that window. Is that acceptable?

Provide a temporary chiller sized to 180tons so the entire yard is not down during replacement.

MD-103, MD-104,

M-107, M-108

During the VAV replacement portion of the work, what are the expected hours of the day that we will be allowed access to these rooms?

We assume 2nd shift work. Is that correct? Are any temporary spot coolers required during this time? We assume these rooms will be unoccupied during the time we are working there. Is that correct?

Work will be performed during normal business hours. Personnel relocation will be coordinated with the construction inspector, facility manager and users.

M-501 Please confirm that the existing balance valve is to remain existing and not changed out to be a remote operated valve.

Existing balance valve to remain, but should remain closed after job is complete.

M-601 Please confirm that there is an existing pathway / network connection, etc. to connect the control items on this project to the EMCS server at Patrick and work station at bldg 1708 and EMCS server from the workstation in Hangar R&D at the Cape.

The SCADA cabinet in room 111 is anticipated point to connect new automation server to the CCSFS network.

Verify with construction manager.

M-701 and E-601 Please confirm that the voltage / amperage called out in the mechanical equipment schedules matches the existing conditions (available voltage / amperage available) and voltage / amperage shown on the partial single line diagram.

Information is correct to the best of our knowledge. Contractor is responsible to verify field conditions.