Questions and Answers as of 10.21.2024.pdf

Questions and Answers

6973GH-24-R-00220

CHA ATCT Roof Replacement, LPGBS System Optimization

1. Will the contract require the contractor or subcontractor be licensed to perform the roofing and electrical work?

Each trade must be licensed to perform the work they are contracted to support. Electrical work must be performed by licensed electricians (not necessarily in TN but licensed in some state to perform the subject scope of work). Roofing work must be performed by an installer that is recognized as an approved installer by at least one of the leading roof manufacturers and will be able to offer the manufacturers warranty on the finished product.

2. Will alternate methods for roof installation be approved? An alternate method we would suggest would be to install plywood over the parapet wall, run the membrane up and terminate below the existing coping cap, with a termination bar and new counterflashing metal installed underneath the coping.

Yes, alternate installation methods will be reviewed and considered for appropriateness and feasibility.

For instance, the SOW identified a mechanically fastened roof system, however if the bidders wish to present an alternate configuration / assembly, such as a liquid applied system, this will be an acceptable submission for review. Bidders should identify what they are proposing with their bid package so that the best value can be identified when performing the bid evaluation and review.

3. Currently there are two scuppers. Is it desired to add two?

Contractors are encouraged to submit the inclusion of two new roof scuppers as a BID OPTION.

4. The SOW document details four (4) equalization rings (top of tower@95ft, catwalk rail during site review there were discussed two (2) total equalization rings required (top of tower @ 95ft and @ 50ft).

Please advise which is correct?

The tower height of 95 feet requires an equalization loop at the roof top on the parapet, with horizontal air terminals installed and tied to the equalization loop. Bond to the vertical air terminal masts on roof parapet. Then provide another equalization loop at the cab level on the handrail, with horizontal air terminals. From here, an equalization loop at the base building roof height of 16 feet, bonded to the equalization loop on the base building roof. Assuming the cab height of 80-85 feet, there should be an additional equalization loop installed at approximately 48 feet. So, to meet 019G yes, four (4) equalization loops.

5. The catwalk has an existing arrestor with down conductor going into concrete structure beneath the catwalk, what should we do with existing?

If installing new down conductors, the recommendation would be to remove the existing where they go inside the building, and they run continuously inside. We never like to bring lightning conductors inside a building, so demolish existing conductors and install at least four (4) new on the building exterior. Tie to each exterior equalization loop and run them down to the EES (counterpoise), transitioning to 4/0 conductor at the 7’ height and then the 4/0 goes on down to be exothermically welded to the EES.

6. The Solicitation states that a bid guarantee is required. Will an electronic copy of the bid bond be accepted? If not, please advise where to send the original.

Yes, an electronic copy will be acceptable.