Questions and Answers for SIR 6973GH-20-R-00046.docx

Questions and Answers for SIR 6973GH-20-R-00046 There are very limited drawings associated with our VOR facilities. No as-built drawings exist. I’ve included several drawings to assist in the contract SIR. I’ve also included a picture of a typical VOR facility. This picture is not any of the specific facilities in the SIR, but is a typical representation.”

1) Please clarify the building size out to out dimensions at Dalhart DHT VOR and Texico TXO VOR as there are no drawings that state this.

There is no site drawings specific to these details. However, the attached drawing for Dalhart shows a 52’ diameter counterpoise so we can assume that the building is a standard 36’ x 36’ building. The Texico drawing identifies it as a 36’ x 36’ building.

2) Are there any existing drawings or as-builts for DHT VOR, TXO VOR, and DMN VOR?

There are no existing as-built drawings for the roofs for these specific facilities.

3) The coordinates published for the buildings is not recognized by Google Earth. Is there better coordinates, or is there a physical address recognized by the US Postal Service?

I’ve included drawings indicating the locations of the facilities.

4) Schematic drawing of the antennal shelter is requested, so we can see where the anchor plates are located and how lifting will be accomplished.

The antenna shelter will be either lifted using the tacan lifting eyes or using straps in a choke configuration. We will have the correct lifting sling available.

5) Drawing showing where lightning protection downleads are located.

The earth grounding drawing is attached. There will be four down conductors (one at each corner of the building) which must be cad welded to the earth counterpoise system.

6) How long is it anticipated for refurbishment of the fiberglass antenna shelters, performed offsite by others.

A refurbished antenna will be available once the roof work is completed. A spare shelter will be used and the removed shelter will become the new spare.

7) Are the structures occupied, or is it equipment only? Will the equipment need to be covered during demolition to prevent dust contamination?

The facilities house equipment only. Normally, it will not have to be covered unless contractor does not weatherproof building prior to installation of new roof.

8) Grounding: Dalhart VOR and Texico VOR Building EES: Contractor shall install 4 ground rods (10’ x ¾” Copper clad steel) installed 2-6 feet outside the foundation or exterior footing of the VOR building and interconnected by a 4/0 AWG stranded copper conductor, minimum of 2 feet below grade with ends exothermically welded. These ground rods shall be spaced to comply with NEC 250.53 (B) requirement which is 6 feet minimum. (Does this mean that only 4 ground rods are required?) Top of the Ground rods shall not be less than 1 foot below grade level. All connections to the ground rods shall be exothermically welded. Contractor shall exothermically weld a bond between the new and old building EES. The size of the bond conductor shall be field determined to be compatible with both systems. The roofing down conductors shall be welded to the new 4/0 AWG ground conductor.

The earth counterpoise will have a ground rod located at each corner of the building. An additional ground rod will be installed midway between corners if distance exceeds 30 feet.

9) Am I correct in that VOR at Deming does not receive any lightning protection system maintenance or repair?

The Deming VOR facility does not require a new earth electrode system. However, the down conductors from the building must be cad welded to the earth electrode system and continuity verified.

10) What is Owner address?

See attached “dmn-d-vor-c001” drawing.

11) In the SOW Specs – Pg. 15, #5.104, C. 1. (Rigid of insulation system) to have ‘Minimum average R-value 30.0.’ Drawings provided by the FAA show there is fiberglass blanket insulation in the ceiling, which provides the R-30 insulation for the roof deck assembly, which complies with IBC for insulation values for commercial building roof deck assemblies. Do we still schedule and bid a new rigid roof insulation system that will be approximately 5in-thick?

Insulation: Since this is not a manned facility, we only require 1.5 inches of Dens-Deck insulation to be installed. ¾ inch AC plywood will be installed on the roof deck, followed by the metal mesh, then the Dens-Deck, and then the PVC membrane on top.

DensDeck panel is 1.5 inches thick. (Paragraph 5.105 Cover Board states the use of Dens-Deck Prime ½ inch thick shall be utilized. Paragraph 5.104 Insulation is not applicable.)

12) In the SOW Specs – Section 6 – Sheet Metal Flashing and Trim Throughout this section, downspouts, gutters, scuppers, drain sumps and copings are referred to. But Drawings provided show no parapet walls (which would require copings and scuppers). Do any of the three buildings have parapet walls? Are gutters and downspouts required? Is there an internal roof drain that will require drain sump flashings, or does water shed over the roof edge?

Section 6: There are no parapets on these facilities. The rain sheds directly over the roof edge.