171.24438.JBB_EscanabaRTUReplacement_Addendum2_Issued_250822.pdf
PDF 165 KB Posted
- Solicitation number
- RFQ 171 250000000582 3
- Issued by
- Clinton County, Edmore Village, Michigan
About this file
This is Addendum No. 2 to the contract documents for the Escanaba State Office Building Rooftop Unit Replacement project issued by Michigan Department of Technology, Management, and Budget (DTMB) on August 22, 2025. The project involves replacement of the rooftop RTU and associated mechanical and electrical systems. The bid date is Wednesday, August 27, 2025, and this addendum does not change the previously established bid deadline. Key project clarifications include: the building will transition from existing separate 480V three-phase and 240/120V single-phase electrical services to a new unified 480/277V four-wire three-phase service with no existing transformer to remain; hot mix asphalt patching is required to match existing conditions following underground electrical service installation rather than concrete alternatives; access to rooms below the RTU will be available both during the seven-day shutdown period and outside of it for preparatory work; a backup generator will not be required during the building power changeover; and no surge arrestors are required in the main distribution panel or sub-distribution panel at this time.
The project manual clarifies that no allowance is required for the state controls group. The mechanical schedules specify that a new roof curb is not required if the new unit supplier accepts the existing curb and provides warranty coverage; heating gas input shall be corrected to 525 mbh rather than the previously listed 800 mbh. The mechanical diagrams indicate the new RTU will feature packaged controls with BacNet MSTP interface to the existing Building Automation System, requiring RS-485 cable installation between the unit and existing BacNet panel. Low-voltage cable must be pulled for sensors including occupancy, smoke detector, building pressure, and duct static pressure devices, with building pressure and duct pressure sensors being newly installed components. All input/output points and BacNet-accessible readable and writable specifications are detailed in the provided IO sheet.
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Text version
ADDENDUM NO. 2
DATE: August 22, 2025
PROJECT: Escanaba State Office Building Rooftop Unit Replacement
DTMB File No.: 171/24438.JBB
OWNER: MI DTMB
BID DATE: Wednesday, August 27, 2025 ** THIS ADDENDUM DOES NOT CHANGE THE BID
DATE**
The following shall be incorporated into the Contract Documents dated 2025 AUG 01.
GENERAL
Question: Transformer T1 is shown on the new work plans, but not on the demo plans. Is this existing to remain or is the old one being demoed and replaced?
Answer: There is not an existing transformer. This building has two separate services. An existing 480V 3 phase service and an existing 240/120V single phase service. Both of these will be replaced with a new 480/277V 4 wire 3 phase service.
Question: It's been tough finding anyone to cooperate on the hot mix asphalt patch for after we run new underground for the electrical service. Is this a necessity or if we compact the soil would 4" thick fiber reinforced concrete suffice for patching the trench?
Answer: No, Hot patch to match existing is required
Question: Sheet M602 shows the analog inputs and outputs as well as digital inputs and outputs. (AI, AO, BI, BO) Are these all new devices and pulls? Or are some already existing? If new, do these all go back to the building's BACnet controller? And, what is the cable spec for these devices and cable pulls if in fact they are new runs?
Answer: See below M-602
Question: The room(s) below the RTU that will require work to be done overhead...will they be accessible for us at any time or will that access only be there for the 7 day shutdown?
Answer: Access will also be available outside the 7 day shutdown for prep work
Question: EDP101, General note 9 says "existing systems to remain are maintained throughout the duration of the project". This makes sense for pre-shutdown work, however what would need to remain on even during the shutdown week? Is there a need to provide a back-up generator for down time other than for the workers tools and equipment? (Thinking servers and/or racks with UPS systems, etc.?)
Answer: Generator will not be required during shutdown of the building power for changeover to new panels.
Question: The prints do not show a surge arrestor in either MDP or PDP. In today's world, it's becoming more common to see those. This is more of a comment than a question. If a surge arrestor is desired, let us know.
Answer: Not at this time.
PROJECT MANUAL
Clarification – No allowance is required for state controls group
DRAWINGS
M-601 – MECHANICAL SCHEDULES
Clarification – Rooftop schedule- New roofcurb is not required as long as new unit supplier is acceptable to existing curb and will warranty the unit with use of the existing curb.
Clarification – Rooftop schedule- Heating gas input (mbh) shall be corrected to list 525 mbh not 800 mbh as listed in the schedule.
M-602 – MECHANICAL DIAGRAMS
Clarification – The unit will be packaged controls with a BacNet MSTP interface to the existing BAS. A RS-485 cable will need to be pulled between the unit and the existing BacNet panel. Low voltage cable will need to be pulled for the sensors shown on this diagram as “(from Ex. BAS)” for example: Occupancy, smoke detector, building pressure and duct static pressure. The IO sheet shows all the points that the unit is expected to control via the packaged controls. The specification identifies which points need to be accessible as readable and writable via BacNet. Note that the building pressure and duct pressure sensors will need to be new devices.
End of Addendum No. 2
| ADDENDUM NO. 2 |
| GENERAL |
| PROJECT MANUAL |
| DRAWINGS |
File details come from the government source that posted it. Updated .