6973GH-20-R-00085 Question and Answers as of 2-8-2021.docx

All Questions & Answers received on SIR 6973GH-20-R-00085:

HVAC System Upgrade at the AGS ASR Facility located in Augusta, GA as of 2/8/2021

Q. Are you specifying any mechanical controls manufacturer or is that up to the contractor as long as it meets requirements laid out in the Mechanical Control Systems drawing AGS-1504022-M003?

A. The contractor has the option to propose any controls manufacturer. The final approval is the decision of the FAA. There have been issues with past project where the controls contractor has not recognized the DDC system is required to have an open front end (JACE), similar to Tridium Niagara.

Q. Equipment schedule - the basis of design is a Trane 12.5 ton rooftop unit, however for specified cooling loads it shows 120,000 which would be 10-tons. Please confirm A. Please provide the 12.5-Ton unit as scheduled on the drawings.

Q. Does the existing equipment pad(s) need to be removed and replaced, repaired, or enlarged?

A. The existing equipment pad is to be reused in its existing condition. There is no work associated with the pad.

Q. Will the ceiling(s) need to be removed or modified?

A. The ductwork routes below the ceiling. There is no anticipated ceiling work. As an FYI, the existing ceiling is gypsum board

Q. Is hot gas reheat dehumidification system required for the package units?

A. Hot gas reheat is not required.

Q. Specs talking about DDC Controls with programmable software and also Bacnet interface with thermostats and wiring required for the project? Which one is applicable? Please confirm.

A. A DDC system is required as outlined in the Controls Drawing M003.

Q. Can the contractor use onsite restrooms or should they get their own?

A. There are no restroom facilities on site. The contractor will need to provide their own facilities.

Q. Will the FAA provide a storage room for the units?

A. A secured on site staging area will be provided for the contractor. The staging location will be provided at the construction kickoff meeting.

Q. Will the FAA provide an office room for the Contractor?

A. The facility does not have offices. There may be a desk that the local FAA technician can periodically make available for the contractor for limited computer work.

Q. The prints show new 4X SS disconnects outside and also factory mounted disconnects on the units-this seems redundant. Are both needed?

A. No, please provide outside disconnects. The units shall not be provided with factory mounted disconnects Q. The prints show TVSS on each new exterior disconnect and an SPD on each unit. If the FAA wants both the 4X disconnects and the factory mounted disconnects do they also want the TVSS and the SPD as they also seem redundant?

A. Please provide an SPD on only the exterior disconnect switches. Both the factory mounted disconnects and associated SPD are not required.

Q. The drawings show 40 am breakers for the MOCP protection of the HVAC units. The Carrier units we would be supplying would only require a manufacturer recommended MOCP of 30 amps. The 30 amp would be a different circuit breaker size and also downsize the wire by one gauge. Is this the correct statement?

A. That is correct. In addition to revising the breaker and conductor sizes, the disconnect shall be reduced to 60 Amps, and the fuses to 30 Amps.

Q. The new unit is 1" longer than the pad, will this be a problem? The ductwork can be made to work.

A. = The intent is for the new system to sit on the existing concrete pad.

Q. Is there any LEAD/Asbestos removal is included in the Scope?

A. = There is no Lead/Asbestos removal included in the SOW.

Q. Are we allowed to use EQUAL TO manufacturer equipment for the project?

A = Alternate brands of manufacturers can be submitted as long as they have the salient features listed in the basis of design.

Q. Is working 4 days 10 hours is possible for the project instead of 5 days 8 hours?

A = The work schedule will be worked out with the Resident Engineer during the pre-construction meeting.

Q. Does the existing equipment pads need to be removed and replaced, repaired, or enlarged?

A = The intent of the design is to reuse the existing concrete pad. If the new units proposed by the contractor are larger than the existing pad, it will be the responsibility of the contractor to extend the dimensions of the concrete pad.

Q. Will the ceiling(s) need to be removed or modified?

A = The ceiling should not be impacted during this installation.

Q. Is coil coating protection required for the Packaged RTU Units?

A = Yes. An environmental protective coating similar to E-Coating should be applied to the AHU coils.

Q. Does the equipment require an ECONOMIZER?

A = No. The basis of design does not include an economizer.

Q. Are there any site access requirements that we need to consider in our proposal?

A. No. The contractors will be escorted everyday by the RE. No special badging will be required. The ASR facility is an unmanned stand-alone building.

Q. Is it the intent of the temp unit to maintain 2 units cooling the building during construction? If not, we can demo/reinstall one unit at a time and a temp unit will not be required.

A. Except for when cleaning the ductwork (see below), a minimum of two (2) air conditioning units shall be operational at all times. These units shall be arranged in a primary/standby configuration by staging the thermostat settings. Before any unit can serve as the primary unit it shall satisfy a 72 hour run-in period. During the run-in period the air conditioner may serve as the standby unit. This will require a phased approach to replacing the central units. At the option of the contractor, two (2) temporary units can be provided allowing for both central units to be replaced simultaneously.

Q. The duct cleaning will require a shutdown of the existing systems to ensure the cleaning is done properly, but it seems the intent is to always maintain service in this duct. Please advise on how this is to be handled.

A. For the duration of the cleaning process the temporary unit shall be used to cool the space while both central units are de-energized. Prior to de-energizing the central units a cleaning plan shall be presented and approved by the Resident Engineer that accomplishes the cleaning in the most expedited manner. At least one central unit shall be maintained in a state of ready in the event the temporary unit fails.

Q. Please provide the model/serials or a picture of the data plate for the existing equipment.

A. See attached for photos for data plate and overall units. (SIR Amendment 2)

Q. Specification 26 08 00.13, Part 3, 3.3 B refers to Low Voltage Circuit Breaker testing. Is this going to be required for the 40 Amp and 20 Amp breakers we will be furnishing?

A. This is a general requirement covering all breakers serving equipment and their support systems. In some scenarios, older breakers are re-used and need to be tested per the specification requirements. For this project all new breakers are being installed (Three (3) 40 Amp breakers & one (1) 20 amp breaker). We will not require initial testing of these breakers.

Q. Please provide pictures of the existing electrical and control panels.

A. See attached for photos. (SIR Amendment 2)

Q. Are smoke detectors to be tied into a fire alarm panel or are they only required for unit shutdown? If they are to be tied in, who is the contractor for the fire alarm system?

A. It is believed that the duct detectors will be utilized for unit shutdown only. This can be confirmed along with service contractor information during the project’s pre-bid meeting.

Q. Drawing E004, Cable and Count Schedule, P2, P3, P4 indicate (2) runs of 4#8’s to each ECU disconnect, ECU equipment and ECU Surge Protective Device. Is this correct?

A. Yes, based on the 40 Amp disconnect size and NEC tables the conductor sizes are correct. At the option of the contractor, the ground wire can be reduced to a #10. If the contractor feels these sizes are incorrect please submit recommended sizes along with an explanation and we will review.

Q. Drawing E004, Equipment Schedule Item D-NEMA 4x, 100 Amp Disconnect Fused at 40 Amps. This will require fuse adapters to convert the frame size of the fuses to work in the disconnect. This would typically be a 60 Amp disconnect, rather than a 100 Amp disconnect. Please advise.

A. A 60 Amp disconnect should be utilized for this installation. The drawings will be updated to reflect this.

Q. Refrigerant high/low pressure monitoring is on the points list for controls. This will require tapping into the refrigerant lines and installing pressure sensors. We can control the system the same way with Fan status, DP sensors, and compressor status/fault. Is this required to be monitored or is it acceptable to monitor the other points listed above?

A. We do not want to tap the refrigerant lines. The basis of design unit shall utilize the ReliaTel control system to monitor high pressure and low pressure lockout. Through the use of a factory provided BacNet card this can be monitored by the DDC system.

Q. Is there an existing DDC system that the new equipment will interfere with via Bacnet protocol?

A. The existing control system will be completely removed during this project. There will be nothing to interfere with.

Q. Could you provide the length and breadth of the concrete pad?

A. A very rough estimate taken from an overhead photo measures about 12’ x 14’ for each unit. The actual dimensions will need to be field verified.

Q. What is the distance from electrical panel DP? To the existing 2 units and also to the temporary unit?

A. Panel DP1 is on the opposite wall of the facility. This is roughly 50 linear feet away from each unit. The temporary unit will likely sit at least 55 – 60 feet away from the panel DP1.

Q. Drawing E003 note 1 says to feed the temporary a/c from each of the ECU feeds as you replace them. E004 single line diagram says to feed the temporary a/c from panel DP-1 and when complete label the 40a breaker spare. Which drawing supersedes?

A. Both drawings are correct. The attempt is to phase out one unit at a time, while keeping a pad-mounted RTU and the temporary available at all times. In the first phase unit 2 and the temporary will run while unit 1 is removed. The second phase will involve the new unit 1 running along with the temporary serving as backup while unit 2 is removed. Once both primary units are replaced, the temporary unit will be removed. Then the 40A breaker used for connection to the temporary will be labeled as “spare”.

Q. Does the equipment has to be Trane?

A. No. The unit presented in the drawings is considered a “basis of design”. Whatever unit the contractor submits will need to have the same “salient features” present on the unit used as the basis of design.

Q. Are you able to provide the existing building controls contractor, or are the controls maintained internally by the FAA?

A. All of the maintenance on the existing HVAC units and controls are performed by the local FAA technician.