Questions_and_Answers_07282021_0002.docx

1.1 WORK COVERED BY CONTRACT DOCUMENTS

B. "...20.62 KW PV system..."

Clarification: Verify this is the correct location.

· Govt Response - Yes, this (Lake Mead Pkwy entrance station) is the correct location.

Question: The spec of "20.62kW PV system" shall be clarified to mean a "minimum PV DC STC rating."

· Govt Response - Concur that the spec shall be "minimum 20.62kW PV DC STC rating."

1.3 SYSTEM REQUIREMENTS

A. "...20.62 kW minimum..."

Question: a) - What is the unit of measure for the 20.62kW requirement? Should be clarified to be the sum of PV module STC ratings. Spec in 1.1 B above and in this section shall match.

· Govt Response - Concur the unit of measure should be "minimum 20.62kW will be the sum of PV module DC STC ratings."

Question: b) - What are the specific test requirements? Itemized tests, test conditions, test durations, pass/fail criteria, etc.

· Govt Response - The following common types of testing will be conducted on the PV system:

· Continuity and resistance testing

· Polarity testing

· Voltage and current testing

· Insulation resistance testing

· Performance testing including measurements of array temperature and solar irradiance.

In all sections that require removal if materials such as roofing, electrical equipment, and related hardware, it shall be clarified that the bid includes the cost of material disposal.

· Govt Response - Specification Section 07 74 19 Waste Management & Disposal states "...remove waste materials from project site and legally dispose of them..." thus implying bid includes the cost of material disposal.

1.3 SYSTEM REQUIREMENTS

C. "and a data acquisition and monitoring system..."

Clarification: Statement of specific data acquisition requirements including specific data and collection interval.

· Govt Response - Alternative is an inverter with free lifetime monitoring so that the government can check the performance of the system. Inverter data manager will be connected to the internet via a LAN.

1.3 SYSTEM REQUIREMENTS

F. "...isolation fuse or breaker..."

Alternative: Should allow a micro-inverter technology, which does not require series PV strings, combiner boxes, or fuses.

· Govt Response - Micro-inverter technology is an acceptable alternative.

1.3 SYSTEM REQUIREMENTS

G. An isolation transformer...

Allowance: Certain PV inverter topologies are isolated and do not require an external isolation transformer per NEC. This saves cost and increases system conversion efficiency and energy harvest.

· Govt Response - Inverters that do not require an external isolation transformer per NEC is an acceptable allowance.

1.9 SUBMITTALS

9. DAS

Clarification: Please provide specifications and requirements of "existing facility data collection systems"

· Govt Response - "Existing facility data collection systems" is a LAN drop.

General: Please provide confirmation that the intended meaning of "PV modules" and "PV panels" is the same. Note that the definition of these two terms is quite different in the NEC and they are not interchangeable.

· Govt Response - Yes, the intended meaning of "PV modules" and "PV panels" is the same. The government uses the two (2) terms interchangeably as a single assembly.