C05_Attachment 8 RFI Questions and Answers 1232SA26Q0880.pdf

Tucson Solar Project

Attachment 8 RFI Questions and Answers

QUESTION: 1. Can the solar electrical equipment (such as the inverter and associated components) be installed inside the existing electrical room, or is it required to be installed adjacent to the utility switchgear with a new dedicated solar switchgear?

RESPONSE: The design intent is for the PV inverters to be installed in Electrical Room 130 as shown in the contract drawings. Associated solar distribution equipment and disconnecting means shall be installed at the locations indicated in the drawings. Bidders should base pricing on the issued design rather than assume a new dedicated solar switchgear adjacent to the utility switchgear.

QUESTION: 2. For the roof penetrations required for the solar attachments, what is the required warranty period that should be included in our proposal?

RESPONSE: The electrical design documents do not establish a separate roof-warranty duration. The Contractor shall coordinate all PV attachments and roof penetrations with the existing roofing manufacturer and warranty requirements and shall provide documentation confirming that the PV installation does not invalidate the existing roof warranty.

ARS LOCATION RESPONSE: Roof penetrations are already installed.

QUESTION: 3. The drawings specify certain inverter models and other equipment. Are we required to provide the exact equipment shown in the design documents, or are equivalent or newer models with similar or better specifications acceptable, provided they are readily available?

RESPONSE: Equipment identified by manufacturer and model number establishes the basis of design. Equivalent or newer equipment may be submitted for review, provided it meets or exceeds the specified electrical ratings, environmental ratings, certifications, warranty requirements, communications requirements, system performance, and compatibility with the complete PV system. This should be submitted in the Technical Approach solicitation document for evaluation to ensure it meets required specifications as identified above. Approval is not automatic and shall be obtained through the specified submittal or substitution process before procurement.

Utility Interconnection

QUESTION: Has the Tucson Electric Power (TEP) interconnection application already been submitted?

ARS LOCATION RESPONSE: No. This is the responsibility of the Contractor.

QUESTION: If so, what is its current status (approved, under review, etc.)?

RESPONSE: No approval or under-review status has been confirmed in the available project information.

QUESTION: Can the interconnection application, approval package, study results, or any utility correspondence be shared?

RESPONSE: No documents available.

QUESTION: Has TEP completed any preliminary screening, hosting capacity evaluation, or otherwise confirmed that the proposed system size is acceptable for interconnection?

RESPONSE: No screening, hosting-capacity evaluation, or TEP acceptance of the proposed system size has been designed or provided.

QUESTION: If interconnection approval has not yet been obtained, are bidders expected to assume the system can be interconnected as designed?

RESPONSE: Bidders shall assist with interconnection approval by providing all documentation necessary based on the contract document.

QUESTION: If TEP ultimately requires a reduction in system size, system redesign, utility upgrades, or other interconnection-related modifications as a condition of approval: Would those costs be handled through a change order? Who would be responsible for engineering revisions? Who would be responsible for utility-required infrastructure upgrades or interconnection improvements?

RESPONSE: Responsibility for costs, engineering revisions, utility upgrades, and any change-order entitlement resulting from future TEP requirements shall be determined by the Contracting Officer. These responsibilities are not established by the electrical drawings and should not be assumed by bidders without formal clarification.

Engineering Revisions / Permit Comments

QUESTION: If the City, AHJ, or TEP issues review comments requiring plan revisions, will the Engineer of Record be responsible for preparing and sealing those revisions, or is the Contractor expected to retain its own engineer? If contractor engineering is required, will it be compensated through a change order?

RESPONSE: Comments affecting the issued design will be evaluated by the Government and Engineer of Record.

The Contractor remains responsible for delegated design, product-specific engineering, shop drawings, and contractor-proposed substitutions or deviations required by the contract documents. Responsibility and compensation for other revisions will depend on the cause and shall be determined by the Contracting Officer.

Existing Design

QUESTION: Are the issued drawings considered 100% complete for construction, or should bidders anticipate additional design development after award?

RESPONSE: The issued drawings are the 100% construction documents for bidding. Bidders should not assume additional general design development after award. Normal submittal coordination, field verification, and responses to agency or utility comments will still be required.

Equipment Criteria

QUESTION: Is there a required or preferred DC/AC ratio for the PV system?

RESPONSE: The required system configuration, module quantities, and inverter capacities are shown in the drawings. There is no required or preferred DC/AC ratio.

QUESTION: Are bidders expected to provide the specified equipment, or will equivalent manufacturers and equipment be considered provided they meet the project's performance and specification requirements?

RESPONSE: Equipment identified by manufacturer and model number establishes the basis of design. Equivalent equipment may be submitted for review through the specified substitution process, provided it meets or exceeds all applicable performance, rating, listing, warranty, communications, and compatibility requirements. This shall be submitted in the Technical Approach as identified in the solicitation.

Permitting

QUESTION: Are all required permits and approvals already in place?

ARS LOCATION RESPONSE: No. Federal, State and Local permits required are the responsibility of the contractor.

Reference FAR Clause 52.236-7 Permits and Responsibilities.

Structural

QUESTION: Has the existing roof structure already been fully evaluated for the proposed PV loading?

RESPONSE: The existing building was designed with future rooftop solar anticipated; however, the Structural Engineer shall confirm whether the issued design constitutes a complete evaluation for the proposed PV loading and selected attachment system.

QUESTION: If unforeseen structural conditions are encountered, will the Engineer of Record issue the necessary revisions?

RESPONSE: Unforeseen structural conditions shall be reported before proceeding. The Government will determine the appropriate response, required engineering revisions, and contractual responsibility.

QUESTION: Question 1 - Existing Conduit Between Electrical Rooms: Please confirm whether there is an existing conduit pathway connecting Electrical Room 143, where MSB SWRC is located, to Electrical Room 130, where the PV inverters are scheduled to be installed. If such a conduit exists, please confirm whether it is available for use to route the AC feeder conductors supplying the inverters.

RESPONSE: There is no existing conduit between the electrical rooms. The contract documents show two 1.5-inch conduits routed from Electrical Room 143 to Electrical Room 130 for the inverter feeder conductors reference sheet EP601, where this routing is indicated on the one-line diagram. The Contractor shall include the raceway and conductor installation shown in the contract documents and field-verify the best means and methods for routing the conduits.

ARS LOCATION RESPONSE: There is no conduit that runs from Room 143 to Room 130. But there is a 4” conduit that Runs from the IT room to IT Storage rooms which are adjacent Rooms 143 and 130. It could be utilized if conduit is extended and routed into rooms 143 and 130.

QUESTION: Question 2 - Alternate Roof Mounting System: Would the Owner/Engineer approve an alternate mounting system that attaches directly to the existing standing seam metal roof, provided it is engineered for the application, maintains the roof warranty, and meets all structural, wind, and code requirements?

RESPONSE: An alternate standing-seam attachment system may be submitted for review. It must be specifically engineered for the existing roof assembly and project loads, comply with applicable codes, maintain the existing roof warranty, and provide required support, bonding, grounding, and corrosion resistance. Acceptance is subject to review of the complete product and engineering submittal.

ARS LOCATION RESPONSE: USDA understanding of this roofing system that it was designed for the PV array would be mounted/attached to the standing seam.

QUESTION: Question 3 - Alternate PV Array Layout: Would an alternate PV array layout be acceptable, provided it maintains required system capacity, code compliance, and fire access pathways and setbacks?

RESPONSE: An alternate array layout may be submitted for review, provided it maintains required system capacity and performance, fire access pathways, setbacks, structural limitations, roof warranty, lightning-protection coordination, equipment clearances, and electrical stringing requirements. Revised calculations, module/string schedules, and coordinated drawings shall be submitted. The alternate shall not be implemented before approval.

Reference: Spec Section 26 31 00, Art. 2.1(c)

Section 26 31 00 requires the contractor to “coordinate with roofing to provide certificate of roof warranty not invalidated by solar PV installation.”

QUESTION: RFI 01 a) - Existing Roof Warranty: Identify the roofing manufacturer and installer holding the current warranty; b) Confirm whether the original roofing contractor must perform or approve attachment/flashing work to preserve the warranty; c) and provide a copy of the existing roof warranty terms.

RESPONSE: The Contractor is responsible for coordinating the PV installation with the existing roofing system and providing documentation that the installation does not invalidate the existing roof warranty. The roofing manufacturer, original installer, warranty term, approval requirements, and current warranty shall be provided or confirmed by the Government/Architect.

QUESTION: RFI 02 - Referenced Spec Section 07 60 00 Not Included: Please provide Section 07 60 00 FLASHING AND SHEET METAL or confirm it does not apply.

RESPONSE: Section 26 31 00, paragraph 2.1.c shall be revised to eliminate the following “For rigid solar cell PV systems on metal roofing panels, integrate with the roofing system, Section 07 60 00 FLASHING AND SHEET METAL.” Section 07 60 00 is not required for this project.

QUESTION: RFI 03 - Commissioning - Conflicting Requirements: Please clarify whether commissioning is required and define the scope for pricing.

RESPONSE: Yes, see section 26 31 00 paragraph 3.8 Commissioning. Remove all references to section 01 91 00.15.

QUESTION: RFI 04 - Referenced Spec Sections 01 91 00.15 and 26 08 00 Not Included: Please provide these sections or confirm they do not apply.

RESPONSE: Yes, see section 26 31 00 paragraph 3.8 Commissioning

QUESTION: RFI 05 - Warranty Term Conflict - 1-Year SOW vs. 5-Year Spec: Confirm the applicable warranty and clarify the cybersecurity warranty.

RESPONSE: 1-year full warranty on all materials and labor. 5-year for all equipment.

QUESTION: RFI 06 - Inverter Warranty Measured from Date of Manufacture: Confirm whether a standard warranty plus purchased extension to 20 years is acceptable and whether the term may begin at substantial completion/acceptance.

RESPONSE: A manufacturer standard warranty supplemented by a Contractor purchased extension may be submitted to satisfy the specified 20-year minimum, provided the complete coverage and commencement date comply with the final clarified contract requirement. The Government shall clarify whether the warranty period is measured from manufacture, shipment, installation, substantial completion, or acceptance.

QUESTION: RFI 07 - Buy American Compliance of Basis-of-Design Equipment: Confirm which clause governs, whether basis-of-design equipment complies or is excepted, and whether domestic or-equal substitutions are permitted.

RESPONSE: The PV modules are not identified by a specific manufacturer or model in the electrical documents;

the specifications establish performance requirements for the PV system. The Contractor shall provide equipment that complies with the applicable solicitation Buy American / domestic preference requirements where compliant products are reasonably available and meet the project performance requirements. If compliant PV modules or other equipment are not reasonably available, do not meet the required performance criteria, or require an exception, the Contractor shall submit the required documentation to the Contracting Officer for determination.

Any exception to the Buy American requirements, or modification to the governing clause, shall be determined by the Contracting Officer and not the Engineer of Record.

QUESTION: RFI 08 - Utility Interconnection Application and Net Meter:

Reference: Drawings (supply-side tap via bus tap lugs in indoor main switchboard, 600A main CB, new utility net meter)

The drawings show a supply-side tap at the existing 600A main switchboard and a new utility net meter. Please confirm:

(a) whether an interconnection application has been filed with or pre-approved by the serving utility;

(b) who is responsible for the interconnection application, utility fees, and net-meter provisioning; and

(c) the existing switchboard bus bracing and available fault current ratings.

RESPONSE: The Contractor shall provide all documentation for application and net metering. No formal TEP interconnection application has been submitted or approved. Existing switchboard ratings shall be field-verified from equipment nameplates and manufacturer documentation before modification. Available fault-current information shall be coordinated with TEP and existing facility electrical documentation.

QUESTION: RFI 09 - Utility Shutdown Notice Period -Conflicting Durations

Reference: SOW §4.h (10 working days); SOW §5.7.b (7 working days); Spec Div 01, Art. 1.2.5

Confirm whether 10 or 7 working days governs and identify permitted number, duration, and scheduling of shutdowns.

RESPONSE: Contractor will need to work with the location Facility Operations Specialist/ Location Monitor for this, prefer 10 days but 7 days at minimum. Please provide how many utility shutdowns are anticipated and length of time.

QUESTION: RFI 11 - Option CLIN 2 - Exercise Window and Performance Period: Confirm the option exercise period and whether the 200-calendar-day performance period will be extended.

RESPONSE: Option will remain available to exercise until 09/30/2026. However, it will be available to exercise throughout the project as long as the contractor honors the CLIN pricing.

QUESTION: RFI 12 - NABCEP Certification - Scope: Confirm whether one NABCEP-certified professional supervising the installation satisfies the requirement.

RESPONSE: Yes, this should satisfy this requirement.

QUESTION: RFI 13 - Qualified Testing Organization - Independence: Confirm third-party independence and whether installer checks may be witnessed/verified by the independent organization.

RESPONSE: A third party is required but the installer check must be verified. It is the third party that will need to confirm if the work is to be witnessed.

QUESTION: RFI 13 - System Size vs. Basis-of-Design Equipment: Confirm whether the 250 kW DC / 200 kW AC minimum applies to combined Base + Option and state the Base-only DC capacity and production requirement.

RESPONSE: The 200-kW AC shown in the contract documents is the minimum system required. Provide additional equipment necessary to achieve full system capacity shown in the contract documents.

QUESTION: RFI 14 - Inverter Communications: Confirm whether hard-wired Ethernet is required or cellular is acceptable and whether cellular coverage has been verified.

RESPONSE: Provide hardwired communications connections.

QUESTION: RFI 15 - PV Disconnect PV-D Location: Confirm support for a TEP variance, responsibility for submitting it, and cost treatment if denied.

RESPONSE: Base-bid pricing shall include the PV disconnect at the location shown in the contract documents.

The Contractor may submit a variance request to TEP for an alternate accessible and lockable location, including required placarding. No alternate may be used without written TEP approval and acceptance by the Government and Engineer of Record. Responsibility for submitting the variance and treatment of additional costs if denied shall be clarified by the Contracting Officer.

QUESTION: RFI 16 - Interconnection Classification: Confirm whether the connection is true supply-side at the SES or load-side at MSB-SWRC; verify NEC 705.12 compliance; address the proposed 450A breaker reduction; define revised SES scope if applicable; and confirm TEP review and redesign responsibility.

RESPONSE: The contract documents indicate that the PV system connection is made at the MSB-SWRC bus tap lugs, as shown on the one-line diagram. The design does not include reducing an existing 600A breaker to 450A for the PV interconnection. Bidders shall base their pricing on the bus-tap-lug interconnection shown in the contract documents. Upon further review, the feeders from MSB-SWRC to PV-D shall be rated for 600 amps. Refer to the revised one-line diagram for this modification. As an alternate, bidders may provide a 250-amp breaker with conductors rated for 250 amps. If this alternate is proposed, submit an RFI for review. Any alternate interconnection method, breaker modification, or utility-required revision shall be submitted for review and shall not be assumed unless approved through the addendum process.

QUESTION: RFI 17 - Drone Footage: Is any Government or A/E drone footage available for review?

RESPONSE: The design team does not have confirmed drone footage available for distribution.

ARS LOCATION RESPONSE: No drone footage available from the Government.