A3_RFI_9_-_30_and_Responses.pdf

RFP AMENDMENT 3

RFI 9 – 30 AND RESPONSES

Question 9. Who is the current DDC / Controls Contractor for the site? Can you provide a contact?

Response 9: There is no explicit controls contractor for Site DDC. Campus automation is managed and maintained by OFPM DDC group. Controls contractors are awarded projects for renovations and new construction.

Question 10. Will temporary environmental conditioning be required? If so to what extent? Is the temporary conditioning, if required, for more than the curing of construction materials?

Response 10: No temporary environmental conditioning will be required.

Question 11. Will airflow pre-readings be required for the project? If so to what extent? (i.e. at the unit, to the air terminals, etc.)

Response 11: Airflow pre-readings will be required at the air handling unit level, i.e. supply, return, and outside air flows.

Question 12. To what extent will the final air flow readings be required? (i.e. at the unit, to the air terminals, etc.)

Response 12: Final air flow measurements shall be as above for the preliminary readings, as well as airflows per branch (reheat zone, cold deck, hot deck).

Question 13. Will water balancing be a requirement of the project?

Response 13: Yes, water balancing for chilled water coils and hot water coils will be required.

Question 14. Will a laydown area be provided for material equipment storage? Will access to a storage area inside the building be made available? If yes, Will the areas be close to the area of work? If no, will we be allowed to supply a storage unit near the area of work?

Response 14: Laydown areas will be provided for materials and equipment storage. Areas inside of the building will have to be determined on a case by case basis to ensure we do not interfere with normal operations of NIST staff. A storage unit near the area of work may be supplied by the contractor.

Question 15. Are the Building 202 RM 303 phasing general notes below from drawing # 202-077 correct?

Note 1. ANY AIR CONDITIONING UNIT ACU 6 THRU 10 SHALL NOT BE SHUT DOWN FOR MORE THAN 5 CONTINUOUS AND TOTAL BUSINESS DAYS AT ANY TIME DURING CONSTRUCTION. AN ADDITIONAL 5

BUSINESS DAYS CAN BE UTILIZED TO MAKE PIPING CONNECTIONS FOR COMPLETE OPERATION.

Note 2. ANY PARTIAL SHUTDOWN NECESSARY ACROSS PHASES SHALL BE COORDINATED AND

SCHEDULED DURING OFF HOURS OR ON THE WEEKEND.

Note 3. THE FIRST WEEK SHALL BE USED TO DEMOLISH EXISTING ACU'S 7 THRU 10, INSTALL NEW ACU'S 7 THRU 10 AND THE ASSOCIATED DUCTWORK TO START AIR MOVEMENT BY THE END OF 5 BUSINESS

DAYS. WEEKENDS ON EITHER END MAY BE USED IF REQUIRED.

Note 4. THE SECOND WEEK SHALL BE USED TO DEMOLISH ACU-6, MAKE PIPE CONNECTIONS FOR UNITS 7 THRU 10 AND PROVIDE NEW DUCTWORK FOR ACU-6 TO START AIR MOVEMENT BY THE END OF 5 BUSINESS DAYS. BY END OF THIS WEEK, ACU'S 7 THRU 10 SHALL BE FULLY FUNCTIONAL. WEEKENDS

ON EITHER END MAY BE USED IF REQUIRED.

Note 5. THE THIRD WEEK SHALL BE USED TO MAKE THE PIPE CONNECTIONS FOR ACU-6 AND PROVIDE

FULL FUNCTIONALITY. WEEKENDS ON EITHER END MAY BE USED IF REQUIRED.

Response 15: The phasing notes are correct.

Question 16. Spec. Section 230713 for Building 301 states in paragraph 1.2 A.4 to insulate return duct in un-conditioned areas but paragraph 3.10.a does not list return ducts to be insulated. Which paragraph should be followed?

Response 16: Follow paragraph 1.2 A 4.

Question 17. There are Two specifications associated with this project, one for Building 202 and the other for Building 301. Specification section 230700.3.13 for Building 202 allows the use of fiberglass insulation for chilled water and steam systems. Specification section 230719.3.11 for building 301 allows only cellular glass insulation for chilled water and steam systems. We would like to request using one of the above insulation specked materials for both building’s chilled water and steam systems.

Please advise on which Spec. shall be used.

Response 17: Use specification section 230700 (Building 202) for both buildings 202 and 301.

Question 18. Reference DWG.301-374 – Point List for AC-1 and AC-2 requires BAS to monitor unit supply and exhaust fan VFDs fault and operational status through low voltage wiring from VFD factory provided alarm and operational status dry contact outputs. However, VFD run status is based on signal from an independent VFD compatible current sensing relay as shown on BAS control diagrams for Building 202 (as an example reference DWG.202-092). AE recommends hardwiring VFD remote enable/disable, remote speed reference and speed % feedback signals to these VFDs rather than performing these functions through BACnet communications interface between BAS and VFDs. All other VFD data can obtained by BAS through BACnet communication interface.

To summarize AE recommends the following for each VFD for each Building:

1 – Start/Stop Signal (Binary Output) – Hardwired control point from BAS to VFD 2 – Remote Speed Reference Signal (Analog Output) – Hardwired control point from BAS to VFD 3 – Speed Feedback Signal – (Analog Input) – (Hardwired control point from VFD to BAS) Note:

Current sensing relay (shown for VFD status for Building 202 ACUs) could be “valued engineered” out of project by replacing it with another hardwired point from VFD to BAS for speed feedback signal (Analog Input from VFD to BAS to determine run/fault status).

4 – BACnet communications between VFD and BAS

In effort to standardize BAS points, please confirm this is acceptable to follow for all VFDs regardless of the building or equipment served. Additionally, please advise if it is desired to eliminate current sensing relay and instead substitute with VFD speed feedback analog input signal to BAS.

Response 18: In Buildings 202 and 301, do not use current sensing relays to prove fan status on fans driven through VFD’s. Provide following BAS-VFD interface:

1 – Start/Stop Signal (Binary Output) – Hardwired control point from BAS to VFD

2 – Remote Speed Reference Signal (Analog Output) – Hardwired control point from BAS to

VFD

3 – Speed Feedback Signal – (Analog Input) – (Hardwired control point from VFD to BAS) 4 – BACnet communication between BAS and VFD is not required.

Question 19. Reference DWG.202-092 – AE recommends adding a duct mounted supply air temperature sensor (this sensor would provide cooling coil discharge air temperature measurement and monitoring through BAS and aid in check-out/commissioning of unit). This would apply to ACU-6 through ACU-10 for Building 202 and please note these supply air temperature sensors are shown on contract drawings to be utilized throughout Building 310 for ACU units. Please advise.

Response 19: Each system should have outside air temperature and humidity sensor, return air temperature and humidity sensor, mixed air temperature sensor, preheat discharge temperature sensor (averaging RTD stranded at downstream face of preheat coil) and supply air duct mounted (center of airstream) temperature and humidity sensors.

Question 20. Reference DWG.202-092 – AE recommends adding a steam preheat coil leaving air temperature sensor. This sensor would provide preheat discharge air temperature measurement, monitoring and control through BAS and aid in check-out/commissioning of the unit. Additionally, this sensor would be programmed to monitor preheat chamber temperature and control preheat valve to prevent freeze condition from occurring. This would act as added protection along with hardwired freezestat and it will also keep the freezestat from tripping prematurely on initial fan start-up by not introducing outdoor prior to warming pre-heat coil chamber. This would apply to Building 202, ACU-6 through ACU-10. Building 301 already has preheat coil discharge air temperature sensors shown on BAS control diagrams. Please advise.

Response 20: Agree that preheat discharge temperature sensors are required for preheat valve control.

Please refer to response to Question 19.

Question 21. Reference DWG.202-091, ACU-12, Sequence of Operation Item E.2. Please provide exact intentions/requirements for panel override switches: (2-position shut-down emergency override type switch and/or purge initiation switch?). Is this switch to act as the manual 100% purge mode switch (Reference DWG.202-092 Sequence Item E.1) or should they match as defined in Building 301 (Reference DWG.301-374, Drawing Note: 2 “Provide (graphical) button on OWS screen with adjustable run time and purge reset. Provide a physical push button (2-position momentary switch) on the control cabinet to run purge for 60 minutes (adj)”. Please advise.

Response 21: Pushbutton to manually override/shut down ACU’s is not required. Remove note E-2 on DWG 202-091 and both notes D-2 on DWG 202-092. For all ACU’s in Buildings 202 and 301 (except for 100% outdoor air units) provide (graphical) button on OWS screen with adjustable run time and purge reset. Provide a physical push button (2-position momentary switch) on the control cabinet to run purge for 60 minutes (adj)”

Question 22. Reference DWG.202-091, ACU-12, Specific Note No.1: “Component shall operate under factory packaged controls”. A remote BAS control panel location for this unit is shown on DWG.202-06, New Work Plan Note: 17. AE recommends controllers and control devices to be field mounted. Please advise if all references to packaged controllers and/or control devices may be omitted for ACU-12 (Note: Also typical for Building 202 AC Units, ACU-6 through ACU-10).

Response 22: Remove Specific Note 1 from control diagrams for Building 202 ACU’s 6 through 10 and ACU-12. Note does not apply.

Question 23. Reference DWG.202-092, ACU-6, Specific Note No. 3: “Differential pressure sensor shall be installed to measure pressure differential between the plenum and outside”.

Does this note apply? If yes, please define “plenum”. Is a differential pressure transmitter required to measure outdoor air pressure versus lab space pressure for each lab served by ACU-6 or one (1) differential pressure transmitter measuring outdoor air pressure versus one common “plenum” for ACU- 6? (Note: Also typical for ACU-7 through ACU-10). Please advise.

Response 23: Remove Specific Note 3 from control diagrams for Building 202 ACU’s 6 through 10 and ACU-12. Note does not apply.

Question 24. Reference DWG.202-089, Custom Air Handling Units, Note 13: Provide new DDC temperature and humidity sensors in the respective lab to replace old pneumatic devices. How many labs served by each AC Unit, AC-6 through AC-10? Or more simply for estimating purposes, how many total sets of temp/humidity sensors need to be replaced within all associated labs?

Response 24: Each air handling unit serves a single room, as follows:

ACU-6 CONSTANT TEMP, ROOM 231 (1,000,000 Weight Room) ACU-7 CONSTANT TEMP, ROOM 230 (300,000 Weight Room) ACU-8 CONSTANT TEMP, ROOM 229 (100,000 Weight Room) ACU-9 CONSTANT TEMP, ROOM 228 (100,000 Weight Room) ACU-10 CONSTANT TEMP, ROOM 227 (10,000 Weight Room)

One set of sensors is required for each room. Note that ACU-9 and ACU-10 have two reheat coils each, but each set of reheat coils serves the same room.

Question 25. New custom air handling unit, ACU-6, is specified to utilize two (2) fans, VFDs, and individual motorized isolation control dampers. AE will hardwire each supply fan isolation control damper end switch contacts directly to respective supply fan VFD factory provided safety shutdown contacts but additionally, should low static pressure safety switch be provided downstream of isolation damper and upstream of fan?

Please consider individual supply fan backdraft dampers be provided in lieu of motorized isolation control dampers to effectively prevent reverse fan rotation. This would eliminate need for control dampers, motorized actuators and hardwired end switches (and possibly low static safety switch;

however AE recommends installing low static safety pressure switch regardless since malfunction in unit outdoor and return air control dampers/linkage could create supply fan inlet isolation condition when running).

Response 25: Low static pressure safety switches will not be required between isolation dampers and fans. Backdraft dampers will not be allowed, provide individual motorized damper actuators with end switches wired to VFD safety shutdown contacts.

Question 26. Reference DWG.301-374, ACU-1 and ACU-2: Pre-filter and final filter show one (1) differential pressure transmitter and one (1) pressure gauge across both pre-filter and final filter assembly. Reference DWG.202-092 ACU-6 through ACU-10: One (1) differential pressure transmitter shown across filter assembly without presence of pressure gauge. Are pressure gauges required for all ACU units for Building 202 as shown for Building 301 ACUs and RTUs? Is it desired to have individual differential pressure transmitters/gauges across each individual filter bank for pre-filter and post filter individual pressure drop readings? Are filter gauges to be mounted at filter assembly location or on associated BAS control panel door face?

Response 26: Provide one (1) differential pressure transmitter and one (1) pressure gauge across both pre-filter and final filter assembly as shown on DWG 301-374 for all ACU’s in Buildings 202 and 301.

Air filter differential pressure gauges shall be mounted at filter assemblies.

Question 27. Many of the ACU unit and RTU BAS control flow diagram drawings for Buildings 202 and 301 show duct mounted outdoor air temperature and humidity transmitters. Can these transmitters be valued engineered out of project requirements? In their absence, BAS would utilize outdoor temperature and humidity readings from one common set of global outdoor air temperature and humidity transmitters installed at each Building 202 and 301 locations.

Response 27: Each ACU or RTU shall have its own OA temperature and humidity sensor – no mapping of values will be used.

Question 28. Duct smoke detectors (General):

Please provide responsible contracting divisions for the following:

• Furnish duct smoke detectors

• Mechanical installation of duct smoke detectors

• Furnishing and installing power wiring to duct smoke detectors

• Furnishing and installing low voltage signal wiring from duct smoke detector to building FAS

• Furnishing and installing low voltage signal wiring from duct smoke detector to associated unit supply fan and control dampers for shut-down

• Furnishing and installing low voltage signal wiring from duct smoke detector to associated Alerton BAS controller input terminals

Response 28: NIST does not differentiate which subcontractor performs any requirements for this contract. NIST requires the contractor to provide what is required on the contract drawings. Contractors who are not self-performing 100% of the contract work shall determine what parties perform what work.

Duct smoke detectors and fire alarm wiring requirements are within specification 283111. Remove specification section 283111 for Building 202 from the document set for this contract – Building 301 Section 283111 shall be used for all fire alarm work. Smoke detector installation is also referenced in the Building 301 Direct Digital Control Systems Specification Section 230923 2.6 “FIRE PROTECTION DEVICES.” Any other specifications for wiring, conduit, supports etc. may be found in Division 26 sections of the specification.

Question 29. Reference: DWG.217-146, Sequence Item 2.A.”Power steam generator off through BAS”. This is the only reference of BAS for humidifier work in drawing set and specifications. Please elaborate. Is this remote “Off” signal wiring from the BAS be wired from new BAS provided under this contract or to the existing BAS controller serving the associated ACU? Please advise.

Response 29: This note only applies to construction procedure – disable humidifier function during the removal and installation of humidifier bars.

Question 30. Refer to DWG 202-087A. Detail number 1 shows integral face and bypass pre-heat steam coil, however no units seem to utilize this type of control.

Response 30: This type of control is not used for any air conditioning units involved in this project.

Delete Detail 1.