QUESTIONS_0003.docx

QUESTIONS

140P5326R0020 – BLRI WASTE WATER SYSTEM

1. Design Requirements: Are you looking for us to provide the design for Bid Items 2 and 3? There does not appear to be specific electrical design information or drawings for the control panels.

1. Bid Item 2 – There is no exact design for the Bid Item No. 2 New Shade Structure. Shade structures that meet the performance requirements are valid.

2. Bid Option 3 – is no longer required, please disregard.

2. Electrical Specifications: Are there specifications available for the electrical equipment, control panels, drives, etc.? The specifications we received appear to only address the coating/painting work.

1. See Question 4 about Drives and Soft Starters, in that response are the electrical SPECS for the original blowers.

3. SCADA System: Is there an existing SCADA system that the new controls will need to connect to? If so, what communication protocol is currently being used—fiber, Modbus, Ethernet, or another system?

1. There is no SCADA system. Bid Option/Item 3 has been removed. For The Blowers (Bid Option/Item 4) the Soft Starter/ (or VFD) will integrate with the blower motorer and its existing timer.

4. Drives vs. Soft Starts: Would NPS prefer variable frequency drives (VFDs) or soft starters? VFDs are more expensive but provide additional control capabilities.

1. Either are acceptable. Soft Starters are acceptable. Below are the SPECs for the currently installed blower system with a timer:

I. Low Pressure Air Supply System:

1. Air supply blower units shall be furnished and installed at the location shown on the drawings. All units shall be completely factory assembled and tested before shipping to the project site.

2. Blower shall be a rotary positive displacement type with V-belt drive, horizontal configuration. Motor shall be mounted on an adjustable motor mounting base to accommodate adjustment of the “V” belt drive connection. Blower shall be manufactured by Sutorbilt, Roots/Dresser or approved equal.

3. Each blower shall be mounted on a self contained base. The base structure shall be adequately reinforced to support the blower and motor unit.

4. The blower discharge shall be fitted with a check valve, isolation valve and a flexible rubber discharge coupling.

5. To help reduce blower vibration and noise, the blower base shall be mounted on vibration dampeners. For purposes of determining the blower performance, and/or diffuser condition, a pressure relief valve and pressure gauge shall be mounted in the air discharge manifold.

6. An inlet filter/silencer shall be installed on the inlet end of the blower, and a discharge silencer shall be installed on the discharge end of the blower. Silencer shall be manufactured by Universal Silencer.

7. Each blower and motor shall be enclosed within a fiberglass weatherproof enclosure. The fiberglass hood shall be designed for easy access to service the blower. The hood shall be equipped with a latching handle.

8. Blower schedule:

Unit Identification Service Air Volume No.1 Aerated Equalization Basin (Duty) Minimum CFM 30 No. 2 Aerated Equalization Basin (Standby) Minimum CFM 30 No. 3 Aeration Zone Supply (Duty) Train 1 Minimum CFM 75 No. 4 Aeration Zone Supply (Duty) Train 2 Minimum CFM 75 No. 5 Aeration Zone Supply (Standby Unit) Minimum CFM 75 No. 6 Aerated Solids Holding (Duty) Tank 1 Minimum CFM 30 No. 7 Aerated Solids Holding (Duty) Tank 2 Minimum CFM 30 No. 8 Aerated Solids Holding (Standby Unit) Minimum CFM 30

9. The blower air supply volume capacities and pressure shall be based on the following parameters:

a. Air supply volume capacities shall be based on service conditions stated in Section 2.2. The manufacturer shall include the air requirements to operate the air lift pumps he elects to furnish.

b. Site service conditions are as follows:

1) Density of air: .0635 lbs/Cu.Ft. (4,600 ft @ 68 DegF).

2) Transfer efficiency of coarse bubble diffuser: 10%.

3) Inlet temperatures:

a) Night time – 10 DegF – 45 DegF from March 1 to November 1.

b) Day Time Summer – 85 DegF – 90 DegF from July to August

c. Pressure requirements will be based on the following parameters:

1) Inlet side:

a) Atmospheric pressure: 12.45 psia (elevation 4,600).

b) Adjust inlet pressure to reflect drop for filter/silencer furnished.

c) System Pressure Supply Side:

(1) Diffuse Depth: As determined by manufacturer.

(2) Air Distribution loss size piping to minimize loss to .1 psig.

(3) Add pressure loss through discharge silencer based on unit furnished.

2.4 ELECTRICAL AND INSTRUMENTATION/CONTROL

A. Air Supply Control Center:

1. To provide the necessary electrical controls for the air supply equipment provide an electrical control center. The control center shall be mounted within a NEMA 4X enclosure.

2. The control center shall be a complete factory built and tested, UL 508A listed electrical control panel furnished with all the necessary controls for each blower/motor unit and associated plant equipment listed below.

3. The control center shall be provided with a main disconnect per NFPA 70 430.102.

4. The control center shall be mounted adjacent to the blower units. There shall be sufficient panel height to allow bottom entrance of all electrical connections.

5. The controls shall be mounted on a removable sub-panel within the enclosure. The electrical controls shall consist of the necessary circuit breaker protection, magnetic starters, overload protection, time clock, hand-off-auto switch, wiring, and terminal block for each blower motor. All operator/control devices shall be mounted to a swinging subpanel located behind a solid door.

6. The control panel shall be equipped for future SCADA signals (dry contacts) for the following: Blower motor failure, individual motor run status. The signals shall be wired to terminal blocks located within the control panel.

7. The programmed time clock for each blower unit shall be a 24-hour, 7-day time clock capable of being programmed to control the blower run cycle, and to adjust both the start set point and the blower run time. The timer switch can be programmed to have 1 to 48 operations per day in 15-minute multiples. The clock shall also include a skip-a-day feature, which will allow a separate program for weekends (when required). The clock shall be a Paragon Model number 1015.

8. Provide a time delay relay to provide sequential motor starting in case of power failure. The time delay shall be set approximately at 15 second minimum to a maximum delay of one minute intervals.

9. The control center shall be mounted as shown on the drawings. All wire and conduit required between the control panel and the equipment to which it supplies electrical power shall be installed by the Contractor. All wire and conduit necessary to make connection between the control center and the electrical power service shall be provided by the Contractor.

10. The power supply for this control center shall be 240V, 1 Phase, 60 cycle, 3 wire.

5. Installation Scope: Should our pricing include complete installation of the new drives/control panels and associated electrical work, or are you only requesting pricing for furnishing the new equipment?

1. No longer require Bit Item #3

2. Bid Item #4, pricing should include the installation and associated electrical work to install the sort starters (or VFDs) for the blower motors.