Q_and__A__as_of_7-23-19.pdf

Quote: 129AC719Q0030

Questions and Answers as 7/23/2019

1. For the removal of the fuel tank, are there any further requirements beyond what is listed in 3.03 of the summary of work.

No other requirements for tank removal. Once removed, it will be contractor’s responsibility for meeting regulatory requirements for transport and disposal.

2. 1.01 In the description of items to be removed, it includes “Fuel Lines”. At the job walk it was said that the lines that travel under the ground from the tank to the building are to be capped and left. All accessible fuel lines to be removed. Can you please confirm this to be correct and that the underground fuel lines are not to be dug up and removed.

Fuel lines shall be drained and removed to 12” below grade and capped at ground locations, and cut back/capped to wall entry points within the building (including conduit sleeves carrying fuel lines, as applicable).

3. 1.01 only refers to duct removal as “non essential ducts”. And installation of new ductwork seems to refer only to what would be needed to connect the new air handlers to the existing duct system. 2.06 states “all branch runs to be galvanized 26 gauge or better with R-11 vinyl wrap. During the job walk, the existing duct system was noted to be in excellent condition and it was said that replacing the duct system was not known to be part of this job. Can you please confirm this and that only ductwork needed to connect the new equipment to the existing duct system is expected.

It is the intent to re-use existing ductwork throughout the building to distribute/transport supply and return air, except where new equipment must be retrofitted to tie-in with the existing duct system. The system must be complete and operational for both heating and cooling. It is the expectation that the existing ductwork be inspected for any signs of damage and any repairs be made as part of this contract.

There are no known damaged duct components, but it is possible that minor repairs to duct work could be encountered and we would expect those to made before putting new system into operation.

4. 3.08 says “install dampers to allow balancing of heating and cooling system”. If we are not replacing the duct system, are you requesting that dampers be installed at every supply register? Or is this possibly a boiler plate item and not applicable? If the duct system remains, the airflow distribution should change very little from what you have now. If you are requesting dampers to be installed, can you provide more specific detail as to type and locations.

Dampers beyond what may be part of the new air handling units is not a requirement.

5. In 1.01 and 2.01 there are references to quantities of equipment. “2-zone (4) heatpump system, (2) air handlers twinned”, and “back up heat strips (4)”. How many condensers and air handlers are you expecting to be bid? It sounds like it may be 4 air handlers (2 each twinned) with 2 heatpump condensers? Please see next question as well regarding this question.

See answer below.

6. This project entails removing 2 oil burning furnaces that have 150,000 BTU of heat output each. (total of 300,000 BTU) There are 2-5 ton Air conditioners, which are 60,000 BTU of cooling each.

(120,000 BTU) Replacing them with 2 5 ton heatpumps will only give you approximately 120,000 BTU of heating capacity (without the heat strips), resulting in a net loss of 180,000 BTU’s of heating capacity.

It was stated that the current air conditioners adequately cooled the building. However, without a load calculation being performed on the building, or specific sizing being given in the bid instructions, it is difficult to know how much of this heating capacity can be lost before the building cannot be adequately heated. It was noted the building is old construction and has substantial square footage of single pane glass. Considering the climate, it would go without saying that the heating load would be substantial in the coldest months. Is there a load calculation done by a mechanical engineer that is available? In absence of a load calculation or specific instruction in the bid, are we to match the BTUs of heating as close to 300,000 as possible? By way of example, the 2-5 ton ac’s can be replaced with 2-10 ton heatpumps. Each heatpump would have 2 air handlers each for a total of 4. This would give you 240,000 BTUs of heating capacity down to minus 15 degrees outside. With the addition of heat strips, you would have 300,000 BTUS of heating available. In addition, this type of unit would not be oversized in cooling as they are capable of running at any capacity needed all the way down to 1 ton.

That may be what you were asking in the equipment description when it said “2-zone (4) heatpump system, (2) air handlers twinned”, and “back up heat strips (4)”. Can you please provide clarification to this.

See answer below.

7 After looking at the existing furnaces and duct work in the basement, it appears that in order to install air handlers in a manor that would allow for the best air flow, installing them vertically just like the existing furnaces would be best. The current units sit on the floor of the basement. Is there a specific reason that the new air handlers were to be hung from the floor joist above? If there are 4 air handlers, this will potentially add up to 600 lbs of weight to the floor joists. Is there any concern with doing this? And finally, if standing up air handlers on the floor results in a better routing of airflow and a more practical installation, can this be done provided the equipment is protected from any moisture on the floor and mounted on isolators to reduce noise and vibration?

See answer below.

Response to Questions 5, 6, & 7: There are no load calculations to refer to. The intent of the new system is to install a replacement system for both heating and cooling in the form of new electric powered heat pumps and air handling units with a comparable system capacity and operational range (down to around -15 degrees exterior) with 15 kW heat strips. The example system described by Sierra Valley in Para. 3 of Question # 6 is consistent with the Government’s intent. The Gov’t is open to having the air handling units floor mounted but elevated above the floor such as with a pressure treated 2x6 wood framed platform, a minimum of 6” above existing concrete floor.

8 2.01 calls for 15kw heat strips, and 2.02 calls for 10kw heat strips. Can you clarify which is desired?

Heat strips to be 15kW.

9. Can an alternative unit be substituted?

Response: The intent would to provide the Mitsubishi system described in the solicitation, or an equivalent heat pump system, which provides a comparable capacity and range of operation of the existing system. Responses to the bidder questions below may help clarify also.

10. 3.15 Remove and dispose of all interior window ac units and base board heaters. Can you confirm that there are window ac’s and baseboard heaters that do need to be removed?

There are no AC window units nor baseboard heaters.